Title of the invention: A method for identifying the position of the thrust reaction force action point and a method for rolling a rolled material.
Technical field
[0001]
　The present invention relates to a method for identifying the position of a thrust reaction force acting point in a rolling mill and a method for rolling a rolled material.
Background technology
[0002]
　One of the important issues in the rolling operation of metal plate material is to make the elongation rate of the rolled material equal on the working side and the driving side. If the elongation of the rolled material is uneven between the working side and the driving side, there may be a problem of passing the rolled material due to meandering, a shape defect due to camber, and the like. In order to equalize the elongation ratio between the working side and the driving side of the rolled material, the difference between the rolling position on the working side and the rolling position on the driving side of the rolling mill, that is, the leveling is corrected.
[0003]
　For example, Patent Document 1 discloses a technique for correcting leveling based on the ratio of the measured load of the rolling load cell in the rolling direction to the sum of the differences between the working side and the driving side. However, the difference between the working side and the driving side of the load cell measurement load in the rolling direction of the rolling mill includes a thrust force acting in the roll axial direction between the rolls arranged in contact with each other as a disturbance. For example, in the case of a four-stage rolling mill, a thrust force acts in the roll axial direction between the working roll and the reinforcing roll. Further, in the case of a 6-stage rolling mill, a thrust force acts in the roll axial direction between the working roll and the intermediate roll and between the intermediate roll and the reinforcing roll.
[0004]
　Therefore, for example, in Patent Document 2, the thrust force, which is a disturbance of the difference between the working side and the driving side of the load cell measurement load in the rolling direction of the rolling mill, is separated, and the rolling mill is set in the rolling position and the rolling position is controlled. The technology to be performed is disclosed. In the plate rolling method described in Patent Document 2, the vertical reinforcing roll and the vertical working roll are tightened in a contact state, and at least the roll axial thrust reaction force acting on all the rolls other than the reinforcing roll is measured, and the vertical reinforcing roll is measured. The reaction force of the reinforcing roll acting in the rolling direction at each rolling fulcrum position is measured. Then, based on the measured values ​​of the thrust reaction force and the reinforcing roll reaction force, at least one of the zero point of the rolling device and the deformation characteristic of the plate rolling mill is calculated, and based on the calculation result, the rolling position at the time of rolling execution is calculated. Perform setting or rolling position control.
Prior art literature
Patent documents
[0005]
Patent Document 1: Japanese Patent Application Laid-Open No. 55-156610
Patent Document 2: International Publication No. 1999/043452
Patent Document 3: Japanese Patent Application Laid-Open No. 2014-4599
Outline of the invention
Problems to be solved by the invention
[0006]
　In the technique described in Patent Document 2, the thrust reaction force acting on the rolls other than the reinforcing rolls during tightening or rolling of the kiss rolls in which the rolls are tightened in contact with each other and the positions of the rolling down fulcrums of the upper and lower reinforcing rolls. Measure the acting reinforcing roll reaction force. Here, the thrust reaction force is to hold the roll in a fixed position in each roll against the resultant force of the thrust force generated on the contact surface of the roll body mainly due to the presence of a minute cloth between the rolls. It is the reaction force of. The thrust reaction force is indirectly obtained by, for example, a device that directly detects the load acting on the thrust bearing in the roll chock, or a force that acts on a structure that fixes the roll chock in the roll axial direction such as a keeper plate. It is possible to measure with a device that detects. However, the reinforcing roll receives a large load from the reduction device and the roll balance device in addition to the keeper plate, and the frictional force caused by these vertical loads can also be a part of the thrust reaction force. Therefore, the position of the thrust reaction force on the reinforcing roll with respect to the resultant force of the thrust force generated on the contact surface of the roll body due to the presence of a minute cloth between the rolls (hereinafter referred to as "thrust reaction force action point position"). ) Is generally unknown.
[0007]
　Therefore, in the technique described in Patent Document 2, a roll other than the reinforcing roll is extracted, and a known thrust force is applied to the reinforcing roll in a state where a vertical load is applied to the body of the reinforcing roll to apply a known thrust force to the reinforcing roll to reduce the load cell. Measure the laterality of the measured load. Then, the position of the thrust reaction force acting point of the reinforcing roll is identified from the equilibrium equation regarding the force and the moment based on the left-right difference of the measured load in the reduction direction load cell.
[0008]
　However, in the technique described in Patent Document 2, it is necessary to pull out a roll other than the reinforcing roll and apply a known thrust force to the reinforcing roll by using a calibration device. Can not.
[0009]
　Therefore, the present invention has been made in view of the above problems, and an object of the present invention is a novel invention that can be easily carried out even when the work roll is not rearranged, for example, during idle time of a rolling mill. Further, it is an object of the present invention to provide an improved method for identifying a thrust reaction force action point position of a reinforcing roll and a method for rolling a rolled material.
Means to solve problems
[0010]
　A method of identifying the position of a thrust reaction force acting point in a rolling mill, wherein the rolling mill comprises a plurality of rolls including at least a pair of working rolls and a pair of reinforcing rolls supporting the working rolls. It is a rolling mill with four or more stages, and by changing at least one of the friction coefficient between rolls or the cross angle between rolls under the same tightening load, multiple levels of thrust force are applied between rolls, and thrust is applied. At each of the multiple levels of force, in the kiss-roll state in which the rolls are tightened and brought into contact with each other by a reduction device, the thrust in the roll axial direction acting on each roll constituting at least one of the roll pairs other than the reinforcing rolls. The first step of measuring the reaction force and measuring the reaction force of the reinforcing roll acting on each reinforcing roll in the rolling direction at the position of the reduction fulcrum, and the thrust reaction force and the reinforcing roll acting on each of the measured rolls. Based on the reaction force, the thrust reaction of the thrust reaction force acting on the reinforcing roll is used by using the first equilibrium condition formula for the force acting on each roll and the second equilibrium condition formula for the moment generated on each roll. A method for identifying a thrust reaction point position is provided, which comprises a second step of identifying the force action point position.
[0011]
　In the first step, for all roll pairs other than the reinforcing rolls, the thrust reaction force in the roll axial direction acting on each roll constituting the roll pair is measured, and at the reduction fulcrum position, with respect to each reinforcing roll. The reaction force of the reinforcing roll acting in the rolling direction may be measured.
[0012]
　The rolling mill can cross at least the roll axial direction of the upper roll assembly including the upper working roll and the upper reinforcing roll and at least the roll axial direction of the lower roll assembly including the lower working roll and the lower reinforcing roll 4 It may be a step rolling mill. At this time, in the first step, a plurality of levels of thrust force is applied between the rolls by changing the cross angle between the rolls of the upper work roll and the lower work roll.
[0013]
　Alternatively, the rolling mill may be a rolling mill provided with an external force applying device that applies different rolling direction external forces to the working side roll chock and the driving side roll chock for at least one roll. At this time, in the first step, by applying different rolling direction external forces to the working side roll chock and the driving side roll chock of the roll provided with the external force applying device, the cross angle between the rolls with respect to all the roll systems of the roll is changed. Multiple levels of thrust force act between rolls.
[0014]
　Further, in the second step, at each of the plurality of levels of the tightening load, the tightening in each kiss roll state is performed based on the result of identifying the thrust reaction force action point position of the reinforcing roll at the plurality of levels regarding the thrust force. The relationship between the load and the position of the thrust reaction force action point may be acquired.
[0015]
　Further, in order to solve the above-mentioned problems, according to another viewpoint of the present invention, a step of identifying the thrust reaction force action point position of the reinforcing roll and a rolling mill by the above-mentioned method of identifying the thrust reaction force action point position In the kiss roll state in which the rolls are tightened and brought into contact with each other, the thrust reaction force in the roll axial direction acting on each roll constituting the roll pair is measured for all roll pairs other than the reinforcing rolls, and each roll pair is at the rolling fulcrum position. The process of measuring the reinforcing roll reaction force acting in the rolling direction on the reinforcing roll, the measured value of the thrust reaction force, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll. The step of calculating at least one of the zero point position of the rolling mill or the deformation characteristics of the rolling mill based on the above, and the rolling of the rolled material, which sets the rolling position by the rolling mill at the time of rolling execution based on the calculation result. The method is provided.
[0016]
　Further, in order to solve the above-mentioned problems, according to another viewpoint of the present invention, a step of preliminarily identifying the thrust reaction force action point position of the reinforcing roll by the above-mentioned method of identifying the thrust reaction force action point position and the rolled material In the rolling of, at least one of the upper roll assembly including the upper working roll and the upper reinforcing roll or the lower roll assembly including the lower working roll and the lower reinforcing roll, in the roll axial direction acting on the roll other than the reinforcing roll. For the reinforcing roll of the roll assembly that measures the thrust reaction force and at least measures the thrust reaction force, the step of measuring the reinforcing roll reaction force acting on the reinforcing roll in the reducing direction at the position of the reduction fulcrum, and the thrust reaction force. Based on the measured value of, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll, the process of calculating the target value of the reduction position operation amount corresponding to the rolling load, and the reduction A method for rolling a rolled material is provided, which includes a step of controlling a reduction position by a reduction device based on a target value of a position manipulation amount.
[0017]
　Further, in order to solve the above-mentioned problems, according to another viewpoint of the present invention, a step of preliminarily identifying the thrust reaction force action point position of the reinforcing roll and rolling by the above-mentioned method of identifying the thrust reaction force action point position. Roll axial direction acting on rolls other than the reinforcing rolls during rolling of the material, at least in either the upper roll assembly including the upper working roll and the upper reinforcing roll or the lower roll assembly including the lower working roll and the lower reinforcing roll. For the reinforcing roll of the roll assembly that measures the thrust reaction force of the roll assembly and at least measures the thrust reaction force, the step of measuring the reinforcing roll reaction force acting on the reinforcing roll in the reducing direction at the position of the reduction fulcrum and the thrust reaction. Thrust force acting at least between the reinforcing roll and the roll in contact with the reinforcing roll based on the measured value of the force, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll. The asymmetry of the roll axial distribution of the rolling load acting between the rolled material and the working roll is calculated in consideration of, and the target value of the reduction position operation amount corresponding to the rolling load is calculated based on the calculation result. A method for rolling a rolled material is provided, which includes a step of performing a reduction position and a step of controlling a reduction position by a reduction device based on a target value of a pressure reduction position operation amount.
[0018]
　The rolling mill is a six-stage rolling mill having three roll pairs of a pair of working rolls, a pair of intermediate rolls supporting the working rolls, and a pair of reinforcing rolls. In the first step, the roll pairs of the intermediate rolls are provided. Alternatively, for any of the roll pairs of the working roll, the thrust reaction force in the roll axial direction acting on each roll constituting the roll pair is measured, and at the rolling fulcrum position, it acts on each reinforcing roll in the rolling direction. The reaction force of the reinforcing roll may be measured.
[0019]
　The rolling mill is provided with an external force applying device for applying different rolling direction external forces to the working side roll chock and the driving side roll chock for at least one of the rolls, and in the first step, the work of the roll provided with the external force applying device is provided. By applying different rolling direction external forces to the side roll chock and the driving side roll chock, the cross angle between the rolls for all the roll systems of the roll may be changed, and a plurality of levels of thrust force may be applied between the rolls.
[0020]
　Further, in the second step, at each of the plurality of levels of the tightening load, the tightening in each kiss roll state is performed based on the result of identifying the thrust reaction force action point position of the reinforcing roll at the plurality of levels regarding the thrust force. The relationship between the load and the position of the thrust reaction force action point may be acquired.
[0021]
　Further, in order to solve the above problem, according to another viewpoint of the present invention, the thrust reaction force action point position of the reinforcing roll is identified by the above-mentioned method for identifying the thrust reaction force action point position in the 6-stage rolling mill. Roll axial thrust acting on each roll constituting the roll pair for either the roll pair of the intermediate roll or the roll pair of the working roll in the kiss roll state in which the rolls are tightened and brought into contact with each other by the rolling mill. Identification of the step of measuring the reaction force and the step of measuring the reinforcing roll reaction force acting in the rolling direction on each reinforcing roll at the rolling fulcrum position, the measured value of the thrust reaction force, and the measured value of the reinforcing roll reaction force. Based on the position of the thrust reaction force acting point of the reinforcing roll, at least one of the zero position of the rolling device or the deformation characteristic of the rolling mill is calculated, and based on the calculation result, the rolling is reduced at the time of rolling. A method of rolling a rolled material is provided for setting a rolling position by an apparatus.
[0022]
　Further, in order to solve the above-mentioned problems, according to another viewpoint of the present invention, the thrust reaction force action point position of the reinforcing roll is previously determined by the method for identifying the thrust reaction force action point position in the 6-stage rolling mill described above. Either the upper roll assembly containing the upper working roll, the upper intermediate roll and the upper reinforcing roll or the lower roll assembly including the lower working roll, the lower intermediate roll and the lower reinforcing roll during the step of identifying and rolling the rolled material. In, the reinforcing roll of the roll assembly that measures the thrust reaction force in the roll axial direction acting on the intermediate roll or the working roll and at least measures the thrust reaction force acts on the reinforcing roll in the rolling direction at the rolling fulcrum position. Corresponds to the rolling load based on the step of measuring the reinforcing roll reaction force to be performed, the measured value of the thrust reaction force, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll. A method for rolling a rolled material is provided, which includes a step of calculating a target value of a reduction position operation amount and a step of controlling a reduction position by a reduction device based on a target value of a reduction position operation amount.
[0023]
　Further, in order to solve the above problem, according to another viewpoint of the present invention, the thrust reaction force action point position of the reinforcing roll is previously determined by the method for identifying the thrust reaction force action point position in the 6-stage rolling mill described above. Either the upper roll assembly containing the upper working roll, the upper intermediate roll and the upper reinforcing roll or the lower roll assembly including the lower working roll, the lower intermediate roll and the lower reinforcing roll during the step of identifying and rolling the rolled material. In, the reinforcing roll of the roll assembly for measuring the thrust reaction force in the roll axial direction acting on the intermediate roll or the working roll and at least measuring the thrust reaction force acts on the reinforcing roll in the rolling direction at the rolling fulcrum position. Based on the step of measuring the reinforcing roll reaction force to be performed, the measured value of the thrust reaction force, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll, at least the reinforcing roll and the corresponding Considering the thrust force acting between the rolls in contact with the reinforcing rolls, the asymmetry of the roll axial distribution of the rolling load acting between the rolled material and the working rolls is calculated, and rolling is performed based on the calculation results. A method for rolling a rolled material is provided, which includes a step of calculating a target value of a reduction position operation amount corresponding to a load and a step of controlling a reduction position by a reduction device based on a target value of a reduction position operation amount. Roll.
Effect of the invention
[0024]
　As described above, according to the present invention, it is possible to identify the thrust reaction force action point position of the reinforcing roll that can be easily carried out even when the working roll is not rearranged, for example, during the idle time of the rolling mill.
A brief description of the drawing
[0025]
FIG. 1A is an explanatory view showing a configuration example of a four-stage rolling mill.
FIG. 1B is an explanatory diagram showing a configuration example of a 6-stage rolling mill.
FIG. 2A is a schematic diagram showing a thrust force in the roll axial direction acting on each roll in a kiss roll tightened state and an asymmetric component between the working side and the driving side in the vertical direction in a four-stage rolling mill. ..
FIG. 2B is a schematic diagram showing a thrust force in the roll axial direction acting on each roll in a kiss roll tightened state and an asymmetric component between the working side and the driving side in the vertical direction in a 6-stage rolling mill. ..
FIG. 3 is a flowchart showing a method of identifying a thrust reaction force action point position of a reinforcing roll according to an embodiment of the present invention.
FIG. 4A is a flowchart showing an example of a method for identifying a thrust reaction force action point position of a reinforcing roll according to an embodiment of the present invention, showing a case where the friction coefficient between rolls is changed.
FIG. 4B is a flowchart showing another example of the method for identifying the thrust reaction force action point position of the reinforcing roll according to the embodiment of the present invention, showing a case where the friction coefficient between the rolls is changed.
FIG. 5 is a flowchart showing an example of a method for identifying a thrust reaction force action point position of a reinforcing roll according to the same embodiment, and shows a case where the cross angle between rolls is changed by using a pair cloth rolling mill.
[Fig. 6A] Fig. 6A is a flowchart showing an example of a method for identifying a thrust reaction force action point position of a reinforcing roll according to the same embodiment, showing a case where the cross angle between rolls is changed by using a normal rolling mill. ..
[Fig. 6B] Fig. 6B is a flowchart showing another example of the method for identifying the thrust reaction force action point position of the reinforcing roll according to the same embodiment, in which the cross angle between the rolls is changed by using a normal rolling mill. Is shown.
FIG. 7 is an explanatory diagram showing an example of the relationship between the kiss roll tightening load and the position of the thrust reaction force acting point.
FIG. 8A is a flowchart showing an example of processing for setting a reduction position by adjusting a zero point by the reduction device according to the present embodiment.
FIG. 8B is a flowchart showing another example of the process of setting the reduction position by adjusting the zero point by the reduction device according to the present embodiment.
FIG. 9A is a flowchart showing an example of processing for setting a reduction position based on a deformation characteristic of a housing-reduction system according to the present embodiment.
[Fig. 9B] Fig. 9B is a flowchart showing another example of the processing of setting the reduction position by the deformation characteristic of the housing-reduction system according to the present embodiment.
FIG. 10A is a schematic view showing a thrust force in the roll axis direction acting on each roll during rolling and an asymmetric component between a working side and a driving side in the vertical direction in a four-stage rolling mill.
FIG. 10B is a schematic view showing a thrust force in the roll axis direction acting on each roll during rolling and an asymmetric component between a working side and a driving side in the vertical direction in a 6-stage rolling mill.
FIG. 11A is a flowchart showing an example of rolling position control during rolling according to the present embodiment.
FIG. 11B is a flowchart showing another example of rolling position control during rolling according to the present embodiment.
Mode for carrying out the invention
[0026]
　Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.
[0027]
　[1. Method for identifying the position of the thrust reaction force action point of the reinforcing roll]
　[1-1. Configuration of Rolling Machine]
　First, with reference to FIGS. 1A and 1B, a schematic configuration of a rolling mill to which the method for identifying the thrust reaction force action point position of the reinforcing roll according to the embodiment of the present invention will be described. FIG. 1A is an explanatory view showing a configuration example of a four-stage rolling mill. FIG. 1B is an explanatory view showing a configuration example of a 6-stage rolling mill. The present invention can be applied to a four or more-stage rolling mill having a plurality of rolls and having a plurality of roll pairs including at least a pair of working rolls and a pair of reinforcing rolls supporting the working rolls. Further, in FIGS. 1A and 1B, the working side is represented as WS (Work Side) and the driving side is represented as DS (Drive Side) in the roll axis direction.
[0028]
(Structure of 4-stage rolling mill) The
　rolling mill 100 shown in FIG. 1A is a 4-stage rolling mill having a pair of working rolls 1 and 2 and a pair of reinforcing rolls 3 and 4 supporting the working rolls 1 and 2. The upper work roll 1 is supported by the upper work roll chock 5a and 5b, and the lower work roll 2 is supported by the lower work roll chock 6a and 6b. Further, the upper reinforcing roll 3 is supported by the upper reinforcing roll chock 7a, 7b, and the lower reinforcing roll 4 is supported by the lower reinforcing roll chock 8a, 8b. The upper working roll 1 and the upper reinforcing roll 3 form an upper roll assembly, and the lower working roll 2 and the lower reinforcing roll 4 form a lower roll assembly. The upper working roll chock 5a, 5b, the lower working roll chock 6a, 6b, the upper reinforcing roll chock 7a, 7b, and the lower reinforcing roll chock 8a, 8b are held by the housing 11. In FIG. 1A, the housing 11 shows only a portion located below the lower reinforcing roll 4.
[0029]
　The rolling mill 100 includes upper load detecting devices 9a and 9b for detecting the rolling load in the lower roll assembly, and lower load detecting devices 10a and 10b for detecting the rolling load in the lower roll assembly. The upper load detecting device 9a and the lower load detecting device 10a detect the rolling downward load on the working side, and the upper load detecting device 9b and the lower load detecting device 10b detect the rolling downward load on the driving side.
[0030]
　Above the upper load detecting devices 9a and 9b, a reducing device for applying a vertically downward load to the upper reinforcing roll chocks 7a and 7b is provided. The reduction device includes pressing blocks 12a and 12b, screws 13a and 13b, and a reduction device drive mechanism 14. The pressing blocks 12a and 12b press the upper reinforcing roll chock 7a and 7b from above the upper load detecting devices 9a and 9b provided on the upper side of the upper reinforcing roll chock 7a and 7b. The screws 13a and 13b are mechanisms for adjusting the reduction position, and are an example of the reduction device. The pushing amount of the pressing blocks 12a and 12b is adjusted by the screws 13a and 13b. The screws 13a and 13b are driven by the reduction device drive mechanism 14. The reduction device drive mechanism 14 is, for example, a motor or the like.
[0031]
　The upper work roll 1 and the lower work roll 2 according to the present embodiment include work roll shift devices 15a and 15b that move the roll position in the roll axis direction. The working roll shift devices 15a and 15b may be configured by, for example, a hydraulic cylinder. Further, the upper work roll 1 and the lower work roll 2 are provided with thrust reaction force measuring devices 16a and 16b for measuring the thrust reaction force applied to the rolls, respectively. The thrust reaction force measuring devices 16a and 16b may be configured by, for example, a load cell.
[0032]
　Here, the thrust reaction force is to hold the roll in a fixed position on the contact surface of each roll body against the resultant force of the thrust force generated by the presence of a minute cross angle between the rolls. It is a reaction force to do. Normally, the thrust reaction force is applied to the keeper plate via the roll chock, but in the case of the rolling mill 100 having the working roll shift devices 15a and 15b, the thrust reaction force is applied to the working roll shift devices 15a and 15b. Further, the reaction force of the reinforcing rolls acting on the respective reduction fulcrum positions of the upper and lower reinforcing rolls 3 and 4 is usually measured by the load cell. However, when a reduction device using a hydraulic cylinder or the like is provided, it is also possible to calculate the reinforcing roll reaction force from the measured value of the pressure in the hydraulic cylinder.
[0033]
　The rolling mill 100 according to the present embodiment includes an arithmetic unit 21 and a reduction device drive mechanism control device 23 as devices that perform information processing for setting the reduction position and controlling the reduction position by the reduction device. The arithmetic unit 21 is for identifying the thrust reaction force action point position of the reinforcing roll based on the measurement results of the upper load detecting devices 9a and 9b, the lower load detecting devices 10a and 10b, and the thrust reaction force measuring devices 16a and 16b. Perform arithmetic processing. Further, the arithmetic unit 21 performs an calculation for setting the rolling position of the rolling mill 100 based on the position of the thrust reaction force acting point of the identified reinforcing roll, and calculates the rolling position operation amount during rolling. The reduction device drive mechanism control device 23 calculates a control value for driving the reduction device drive mechanism 14 based on the calculation result of the calculation device 21, and drives the reduction device drive mechanism 14 based on the calculated control value.
[0034]
(Structure of 6-stage rolling mill) In the
　rolling mill 200 shown in FIG. 1B, three roll pairs of a pair of working rolls 1 and 2, a pair of intermediate rolls 31 and 32 supporting the working rolls 1 and 2, and a pair of reinforcing rolls 3 and 4. It is a 6-stage rolling mill equipped with. The upper work roll 1 is supported by the upper work roll chock 5a and 5b, and the lower work roll 2 is supported by the lower work roll chock 6a and 6b. The upper intermediate roll 31 is supported by the upper intermediate roll chock 41a, 41b, and the lower intermediate roll 32 is supported by the lower intermediate roll chock 42a, 42b. The upper reinforcing roll 3 is supported by the upper reinforcing roll chock 7a, 7b, and the lower reinforcing roll 4 is supported by the lower reinforcing roll chock 8a, 8b.
[0035]
　The upper working roll 1, the upper intermediate roll 31 and the upper reinforcing roll 3 form an upper roll assembly, and the lower working roll 2, the lower intermediate roll 32 and the lower reinforcing roll 4 form a lower roll assembly. The upper work roll chock 5a, 5b, the lower work roll chock 6a, 6b, the upper middle roll chock 41a, 41b, the lower middle roll chock 42a, 42b, the upper reinforcing roll chock 7a, 7b, and the lower reinforcing roll chock 8a, 8b are held by the housing 11. There is. In FIG. 1B, the housing 11 shows only a portion located below the lower reinforcing roll 4.
[0036]
　The rolling mill 200 includes upper load detecting devices 9a and 9b for detecting the rolling load in the lower roll assembly, and lower load detecting devices 10a and 10b for detecting the rolling load in the lower roll assembly. Above the upper load detecting devices 9a and 9b, a reducing device for applying a vertically downward load to the upper reinforcing roll chocks 7a and 7b is provided. The reduction device includes pressing blocks 12a and 12b, screws 13a and 13b, and a reduction device drive mechanism 14. These function in the same manner as the four-stage rolling mill 100 shown in FIG. 1A.
[0037]
　The upper work roll 1 and the lower work roll 2 include work roll shift devices 15a and 15b that move the roll position in the roll axis direction. Further, the upper intermediate roll 31 and the lower intermediate roll 32 include intermediate roll shift devices 15c and 15d that move the roll position in the roll axis direction. The working roll shift devices 15a and 15b and the intermediate roll shift devices 15c and 15d may be configured by, for example, a hydraulic cylinder.
[0038]
　The upper work roll 1 and the lower work roll 2 are provided with thrust reaction force measuring devices 16a and 16b for measuring the thrust reaction force applied to the rolls, respectively. Further, the upper intermediate roll 31 and the lower intermediate roll 32 are provided with thrust reaction force measuring devices 16c and 16d, respectively, for measuring the thrust reaction force applied to the roll. The thrust reaction force measuring devices 16a, 16b, 16c, 16d may be configured by, for example, a load cell. The reaction force of the reinforcing rolls acting on the respective reduction fulcrum positions of the upper and lower reinforcing rolls 3 and 4 is usually measured by a load cell. However, when a reduction device using a hydraulic cylinder or the like is provided, it is also possible to calculate the reinforcing roll reaction force from the measured value of the pressure in the hydraulic cylinder.
[0039]
　The rolling mill 200 according to the present embodiment includes an arithmetic unit 21 and a reduction device drive mechanism control device 23 as devices that perform information processing for setting the reduction position and controlling the reduction position by the reduction device. The arithmetic unit 21 determines the thrust reaction force action point position of the reinforcing roll based on the measurement results of the upper load detecting devices 9a and 9b, the lower load detecting devices 10a and 10b, and the thrust reaction force measuring devices 16a, 16b, 16c and 16d. Perform arithmetic processing for identification. Further, the arithmetic unit 21 performs an calculation for setting the rolling position of the rolling mill 200 based on the position of the thrust reaction force acting point of the identified reinforcing roll, and calculates the rolling position operation amount during rolling. The reduction device drive mechanism control device 23 calculates a control value for driving the reduction device drive mechanism 14 based on the calculation result of the calculation device 21, and drives the reduction device drive mechanism 14 based on the calculated control value.
[0040]
　The schematic configuration of the 4-stage rolling mill 100 and the 6-stage rolling mill 200 has been described above. The configurations of the rolling mills 100 and 200 shown in FIGS. 1A and 1B are examples. For example, a rolling mill that pushes the pressing blocks 12a and 12b by flood control instead of the screws 13a and 13b that push the pressing blocks 12a and 12b. May be used.
[0041]
　[1-2. Identification process]
(1) Outline In the
　method for identifying the thrust reaction force action point position of the reinforcing roll according to the present embodiment, the upper and lower parts can be easily carried out even when the work roll is not rearranged, for example, during the idle time of the rolling mill. It makes it possible to identify the thrust reaction point position of the reinforcing roll.
[0042]
　The inter-roll thrust force generated by the inter-roll microcross is one of the factors that make the load distribution between the rolls asymmetric, and causes a difference in the downward load between the working side and the driving side. Such an inter-roll thrust force causes meandering of the rolled material. Therefore, it is necessary to correctly obtain the thrust force and the load distribution between the rolls from the balance between the force acting on the roll in the roll axis direction and the moment, and to set and control the leveling accordingly. In calculating the thrust force and the load distribution between the rolls from the balance between the force acting on the roll in the roll axis direction and the moment, it is necessary to identify the thrust reaction force action point positions of the upper and lower reinforcing rolls.
[0043]
(In the case of a 4-stage rolling mill)
　Here, FIG. 2A shows the thrust force in the roll axial direction acting on each roll when the kiss roll is tightened in the 4-stage rolling mill, and the working side and the driving side in the vertical direction. A schematic diagram showing an asymmetric component between and is shown. Among the force components shown in FIG. 2A, the following four components can be obtained as measured values.
[0044]
　T W T : top work roll chock 5a, thrust reaction force acting on 5b
　T W B : thrust counterforces acting on the lower work roll chock 6a, 6b
　P df T : the rolls reaction force at the pressure support position of the upper backup roll 3 Difference between work side and drive side
　P df B : Difference between work side and drive side of reinforcement roll reaction force at the position of the reduction fulcrum of the lower reinforcement roll 4.
[0045]
　Further, by measuring the thrust reaction force and the reinforcing roll reaction force, in the case of a four-stage rolling mill, the following 10 unknowns are involved in the equilibrium condition of the force and the moment acting on each roll.
[0046]
　T B T : upper roll chock 7a, thrust reaction force acting on 7b
　T WB T : thrust force acting between the upper work roll 1 and the upper backup roll 3
　T WW : the upper work roll 1 and the lower work roll 2 thrust force acting between the
　T WB B : thrust forces acting between the lower work roll 2 and a lower backup roll 4
　T B B : thrust counterforces acting on the lower reinforcing roll chocks 8a, 8b
　p df WB T : top Difference between work side and drive side of linear load distribution between work roll 1 and upper reinforcement roll 3
　p df WB B : Work side and drive side of linear load distribution between lower work roll 2 and lower reinforcement roll 4 difference
　p df WW : the difference in the linear load distribution working side and the driving side of between the upper work roll 1 and the lower work roll 2
　h B T : upper roll chock 7a, the point of action of the thrust reaction force acting on 7b position
　h B B : lower reinforcing roll chocks 8a, the action point of the thrust reaction force acting on 8b
[0047]
　Here, the linear load distribution is the roll axial distribution of the tightening load acting on each roll body, and the load per unit body length is referred to as the linear load. Needless to say, if the thrust reaction force acting on the roll chocks 7a, 7b, 8a, 8b of the reinforcing rolls 3 and 4 can be measured, it is preferable because the calculation can be performed with higher accuracy. 7b, 8a, and 8b are simultaneously receiving a reinforcing roll reaction force much larger than the thrust reaction force. Therefore, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are generally different from the roll axis positions. Since it is not easy to measure the thrust reaction force, it is assumed here that the measured values ​​of the thrust reaction force of the reinforcing rolls 3 and 4 cannot be used. If the thrust reaction forces of the reinforcing rolls 3 and 4 can be measured, the number of unknowns including the position of the point of action is reduced by four. Therefore, the number of equations is larger than the number of unknowns described below, and the unknowns can be obtained as the minimum square solution of all equations, and the calculation accuracy is further improved.
[0048]
　The equations that can be applied to obtain the above 10 unknowns are the equilibrium conditional equations (first equilibrium conditional equations) relating to the force in the roll axis direction of each roll shown in the following equations (1-1) to (1-4). There are a total of eight, four and four equilibrium conditional equations (second equilibrium conditional equations) for the moments of each roll shown in the following equations (1-5) to (1-8).
[0049]
[Number 1]

[0050]
　Here, D B T is the diameter of the upper reinforcing roll 3, D W T is the diameter of the upper working roll 1, D W B is the diameter of the lower working roll 2, and D B B is the diameter of the lower reinforcing roll 4. Further, a B T is the distance between fulcrums of the upper backup roll 3, a B B is the distance between fulcrums of the lower rolls 4, l WB T upper backup roll 3 and the upper work roll 1 and the contact region length, l WW Is the length of the contact area between the upper work roll 1 and the lower work roll 2, and l WB B is the length of the contact area between the lower reinforcing roll 4 and the lower work roll 2. Here, it is assumed that the equilibrium condition formula for the vertical force of each roll has already been considered, and the unknowns that are involved in the equilibrium condition formula for the vertical force are excluded.
[0051]
　Since there are 10 unknowns for the 8 equations (1-1) to (1-8) above, it is necessary to measure or identify the two unknowns in order to obtain all the unknowns. It becomes. Here, since the thrust force and the linear load distribution are the forces acting between the rolls, it is difficult to measure them directly. Thus, the upper roll chock 7a, 7b and lower reinforcing roll chocks 8a, thrust reaction force acting point acting 8b position h B T , h B B be previously identified a realistic solution. These thrust reaction force acting point position h B T , h B B When you are identified, for the remaining eight unknowns, equilibrium relates moment equilibrium condition and each roll about the roll axis direction of the force of each roll By solving the conditional expression, it is possible to find all the unknowns.
[0052]
(In the case of a 6-stage rolling mill)
　Next, as shown in FIG. 2B, the thrust force in the roll axial direction acting on each roll when the kiss roll is tightened in the 6-stage rolling mill, and the working side and the driving side in the vertical direction. A schematic diagram showing an asymmetric component between and is shown. Among the force components shown in FIG. 2B, the following six components can be obtained as measured values.
[0053]
　T W T : top work roll chock 5a, thrust reaction force acting on 5b
　T W B : lower work roll chock 6a, a thrust reaction force acting on 6b
　T I T : upper intermediate roll chocks 41a, thrust reaction force acting on the 41b
　T I B : Thrust reaction force acting on the lower intermediate roll chocks 42a and 42b
　P df T : Difference between the working side and the driving side of the reinforcing roll reaction force at the reduction fulcrum position of the upper reinforcement roll 3
　P df B : Reduction of the lower reinforcement roll 4 Difference between the working side and the driving side of the reinforcing roll reaction force at the fulcrum position
[0054]
　Further, by measuring the thrust reaction force and the reinforcing roll reaction force, in the case of the 6-stage rolling mill, the following 14 unknowns are involved in the equilibrium condition of the force and the moment acting on each roll.
[0055]
　T B T : upper roll chock 7a, thrust reaction force acting on 7b
　T IB T : thrust force acting between the upper intermediate roll 31 and the upper backup roll 3
　T WI T : upper work roll 1 and the upper intermediate roll 31 thrust force acting between the
　T WW : thrust force acting between the upper work roll 1 and the lower work roll 2
　T WI B : thrust forces acting between the lower work roll 2 and the lower intermediate roll 32
　T IB B : thrust forces acting between the lower intermediate roll 32 and the lower backup roll 4
　T B B : lower reinforcing roll chocks 8a, thrust reaction force acting on 8b
　p df IB T : upper intermediate roll 31 and the upper backup roll 3 the difference of the work side and drive side of the line load distribution between the
　p df WI T : difference between the working side and the driving side of the line load distribution between the upper work roll 1 and the upper intermediate roll 31
　p df WI B : the working side of the line load distribution between the lower work roll 2 and the lower intermediate roll 32 Difference between the upper work roll and the drive side
　p df IB B : Difference between the work side and the drive side of the linear load distribution between the lower intermediate roll 32 and the lower reinforcement roll 4
　p df WW : Between the upper work roll 1 and the lower work roll 2. the difference in the working side of the line load distribution of the drive side
　h B T : upper roll chock 7a, the point of action of the thrust reaction force acting on 7b position
　h B B : lower reinforcing roll chocks 8a, the action of the thrust reaction force acting on 8b Point position
[0056]
　In this case as well, if the thrust reaction forces of the reinforcing rolls 3 and 4 can be measured, the number of unknowns including the position of the point of action is reduced by four. Therefore, the number of equations is larger than the number of unknowns described below, and the unknowns can be obtained as the minimum square solution of all equations, and the calculation accuracy is further improved.
[0057]
　The equations that can be applied to obtain the above 14 unknowns are the equilibrium conditional equations (first equilibrium conditional equations) relating to the force in the roll axis direction of each roll shown in the following equations (2-1) to (2-6). There are a total of 12 pieces, 6 pieces and 6 pieces of equilibrium conditional equations (second equilibrium condition formulas) for the moments of each roll shown in the following formulas (2-7) to (2-12).
[0058]
[Number 2]

[0059]
　Here, D I T is the diameter of the upper intermediate roll 31, D I B is the diameter of the lower intermediate roll 32. Further, l IB T is the length of the contact area between the upper reinforcing roll 3 and the upper intermediate roll 31, l WI T is the length of the contact area between the upper intermediate roll 31 and the upper working roll 1, and l WI B is the lower intermediate roll 32. The length of the contact area between the lower working roll 2 and l IB B is the length of the contact area between the lower reinforcing roll 4 and the lower intermediate roll 32. Here, it is assumed that the equilibrium condition formula for the vertical force of each roll has already been considered, and the unknowns that are involved in the equilibrium condition formula for the vertical force are excluded.
[0060]
　Since there are 14 unknowns for the 12 equations in the above equations (2-1) to (2-12), it is necessary to measure or identify the two unknowns in order to obtain all the unknowns. It becomes. Here, since the thrust force and the linear load distribution are the forces acting between the rolls, it is difficult to measure them directly. Thus, the upper roll chock 7a, 7b and lower reinforcing roll chocks 8a, thrust reaction force acting point acting 8b position h B T , h B B be previously identified a realistic solution. These thrust reaction force acting point position h B T , h B B When you are identified, for the remaining 12 unknowns, equilibrium relates moment equilibrium condition and each roll about the roll axis direction of the force of each roll By solving the conditional expression, it is possible to find all the unknowns.
[0061]
　Further, in the 6-stage rolling mill, the thrust reaction force may be measured by only one of the working roll and the intermediate roll. For example, the thrust of the work roll reaction force T W T , T W B If only be measured, the thrust of the intermediate roll reaction force T I T , T I B becomes unknown. In this case, the unknowns in the above equations (2-1) to (2-12) increase from 14 to 16. In such a case, the upper roll chock 7a as described above, 7b and lower reinforcing roll chocks 8a, thrust reaction force acting point acting 8b position h B T , h B B previously identified, for example, reinforcing the intermediate rolls By assuming that the thrust forces TIB T and TIB B acting between the rolls are zero, the number of unknowns can be twelve. Even if such a condition is not satisfied, it is possible to obtain all the remaining unknowns by making at least two of the above unknowns known.
[0062]
　Regarding the identification of the thrust reaction force action point positions of the conventional upper and lower reinforcing rolls, for example, in the technique described in Patent Document 2, first, the rolls other than the reinforcing rolls are extracted, and a vertical load is applied to the body of the reinforcing rolls. In this state, a known thrust force is applied to the reinforcing roll to measure the laterality of the load cell measurement load in the reduction direction. Then, the position of the thrust reaction force acting point of the reinforcing roll is identified from the equilibrium equation regarding the force and the moment based on the left-right difference of the measured load in the reduction direction load cell. However, since the thrust force depends on the friction coefficient of the roll and the cross angle, it is difficult to constantly generate a known thrust force. Further, since it is necessary to remove the rolls other than the reinforcing rolls, it can be carried out only when the work rolls are rearranged.
[0063]
　The inventor of the present application has studied a method that can be easily implemented and accurately separates the thrust force included as a disturbance from the difference between the working side and the driving side of the load cell measurement load in the rolling direction of the rolling mill. As a result, it was found that the position of the thrust reaction force acting point of the reinforcing roll fluctuates depending on the magnitude of the rolling load. In the conventional identification of the thrust reaction force action point positions of the upper and lower reinforcing rolls described in Patent Document 2, since the fluctuation of the thrust reaction force action point position of the reinforcing roll due to the change of the rolling load is not taken into consideration, it is considered as a disturbance. It is probable that the thrust reaction force could not be sufficiently separated and the thrust reaction force action point positions of the upper and lower reinforcing rolls could not be identified with high accuracy.
[0064]
　Therefore, in the method for identifying the thrust reaction force action point position according to the present embodiment, the process shown in FIG. 3 is carried out in order to consider the change in the thrust reaction force action point position of the reinforcing roll due to the change in the rolling load. That is, first, under the same tightening load, the thrust force of the level number (required level number) required for identifying the thrust reaction force action point position is applied between the rolls at the time of identification, and at each level N, other than the reinforcing rolls. The thrust reaction force in the roll axial direction acting on each roll constituting at least one of the roll pairs and the reinforcing roll reaction force acting in the downward direction with respect to the reinforcing rolls are measured (S1: First step). Then, based on the measured thrust reaction force and the reinforcing roll reaction force, the thrust reaction force acting on the reinforcing roll is obtained from the first equilibrium condition formula regarding the force acting on each roll and the second equilibrium condition formula regarding the moment. The position of the thrust reaction force action point of the above is identified (S2: second step).
[0065]
　More specifically, the inter-roll thrust force T changes according to the inter-roll load P. The relationship between the inter-roll thrust force T and the inter-roll load P can be expressed by the following equation (3) , where the thrust coefficient is μ T.
[0066]
[Number 3]

[0067]
　Here, the thrust coefficient mu T , according to Patent Document 3, an inter-roll cross angle phi, the friction coefficient mu, Poisson's ratio gamma, modulus G, inter-roll line load p, WR radius R W , BUR radius R Using B , it can be expressed by the following equation (4).
[0068]
[Number 4]

[0069]
　Here, Poisson's ratio gamma, modulus G, WR radius R W and BUR radius R B is known, the roll between line load p is assumed to be constant, the thrust force T between the rolls, as a result, the following As shown in equation (5), it can be expressed by a function that changes only by the cross angle φ between rolls and the friction coefficient μ.
[0070]
[Number 5]

[0071]
　Therefore, different thrust forces can be generated by changing at least one of the cross angle between rolls and the coefficient of friction between rolls while keeping the tightening load the same. Utilizing this, for multiple levels of thrust force, with the thrust force acting between the rolls, the reinforcing roll reaction force due to the kiss roll tightening state and the axial thrust reaction force acting on all rolls other than the reinforcing rolls. Measure. By carrying out the measurement a plurality of times in this way, the above equations (1-1) to (1-8) in the case of a 4-stage rolling mill and the above equation (2-1) in the case of a 6-stage rolling mill. The number of equilibrium conditional expressions shown in (2-12) exceeds the number of unknowns, and all unknowns can be obtained.
[0072]
(2) Specific method
(a. When changing the friction coefficient)
(i. When the thrust reaction force of all rolls other than the reinforcing rolls can be measured)
　First, the friction coefficient between the rolls is calculated based on FIG. 4A. The case of changing will be described. FIG. 4A is a flowchart showing an example of a method for identifying the thrust reaction force action point position of the reinforcing roll according to the present embodiment, and shows a case where the friction coefficient between the rolls is changed. The process shown in FIG. 4A can be carried out in a rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing rolls, and can be applied to a rolling mill having four or more stages.
[0073]
　The coefficient of friction between rolls can be changed by changing the roll lubrication conditions.
[0074]
(4-stage case of the rolling mill)
　in the case of example 4-high rolling mill, the thrust forces T acting between the upper work roll 1 and the upper backup roll 3 WB T between the upper WW acting on the lower working roll 2 and the thrust force T WB B acting between the lower working roll 2 and the lower reinforcing roll 4 can be expressed by the following equations (6-1) to (6-3).
[0075]
[Number 6]

[0076]
　Here, φ WB T is the cross angle between the rolls of the upper work roll 1 and the upper reinforcing roll 3, φ WW is the cross angle between the rolls of the upper work roll 1 and the lower work roll 2, and φ WB B is the lower work roll 2. This is the cross angle between the rolls and the lower reinforcing roll 4. Further, μ WB T is the coefficient of friction between the upper work roll 1 and the upper reinforcing roll 3, μ WW is the coefficient of friction between the upper work roll 1 and the lower work roll 2, and μ WB B is the lower work roll 2. This is the coefficient of friction between the lower reinforcing roll 4 and the lower reinforcing roll 4.
[0077]
　From this, when the unknowns involved in the equilibrium conditional expression regarding the force acting on each roll and the equilibrium conditional expression regarding the moment are decomposed, the following 13 unknowns are obtained.
[0078]
　　φ WB T : Cross angle between rolls of upper work roll 1 and upper reinforcement roll 3
　　φ WW : Cross angle between rolls of upper work roll 1 and lower work roll 2
　　φ WB B : Lower work roll 2 and lower reinforcement roll 4 Cross angle between rolls
　　μ WB T : Friction coefficient between upper work roll 1 and upper reinforcement roll 3
　　μ WW : Friction coefficient between upper work roll 1 and lower work roll 2
　　μ WB B : Lower work roll friction coefficient between the 2 and the lower backup roll 4
　　T W T : top work roll chock 5a, thrust reaction force acting on 5b
　　T W B : lower work roll chock 6a, a thrust reaction force acting on 6b
　　p df WB T: The difference of the work side and drive side of the line load distribution between the upper work roll 1 and the upper backup roll 3
　　p df WB B : the working side of the line load distribution between the lower work roll 2 and a lower backup roll 4 the difference of the driving-side
　　p df WW : difference upper work roll 1 and the work side and drive side of the line load distribution between the lower work roll 2
　　h B T : upper roll chock 7a, the action of the thrust reaction force acting on 7b point location
　　h B B : lower reinforcing roll chocks 8a, the action point of the thrust reaction force acting on 8b
[0079]
　The equations that can be applied to obtain these unknowns are the four equilibrium conditional equations for the force in the roll axis direction of each roll shown in the above equations (1-1) to (1-4) and the above equation (1- 5) The four equilibrium conditional equations for the moments of each roll shown in (1-8) and the two hypothetical equations with the same friction coefficient between each roll (that is, μ = μ WB T = μ WW = μ). WB B ), a total of 10 pieces.
[0080]
　In this way, the number of unknowns exceeds the number of equations by three, and it is not possible to obtain all unknowns in one measurement. Therefore, the level of the friction coefficient is changed and the measurement is performed a plurality of times. Increasing the level of the coefficient of friction by one increases the number of equations by 10. On the other hand, regarding the unknown number, when the cross angle between the rolls is constant and the kiss roll tightening load is the same, the position of the thrust reaction force acting point acting on the upper and lower reinforcing roll chocks 7a, 7b, 8a, 8b does not change. Therefore, unknown to vary by changing the coefficient of friction, mu WB T , mu WW , mu WB B , T W T , T W B , p df WB T , p df WB B , p df WW eight is there.
[0081]
　In other words, by performing the measurement under the friction coefficient condition of a total of 3 levels with the same tightening load, the total number of unknowns is 29 and the total number of equations is 30, and the number of equations exceeds the number of unknowns. , It is possible to find all unknowns.
[0082]
(In the case of a
　6-stage rolling mill ) In the case of a 6-stage rolling mill, the thrust force TIB T acting between the upper intermediate roll 31 and the upper reinforcing roll 3, and between the upper working roll 1 and the upper intermediate roll 31. Thrust force T WI T acting on, thrust force T WW acting between the upper work roll 1 and the lower work roll 2, thrust force T WI B acting between the lower work roll 2 and the lower intermediate roll 32 , The thrust force TIB B acting between the lower intermediate roll 32 and the lower reinforcing roll 4 can be expressed by the following equations (7-1) to (7-5).
[0083]
[Number 7]

[0084]
　Here, φ IB T is the cross angle between the rolls of the upper intermediate roll 31 and the upper reinforcing roll 3, φ WI T is the cross angle between the rolls of the upper working roll 1 and the upper intermediate roll 31, and φ WW is the upper working roll 1. The cross angle between the rolls of the lower work roll 2 and the lower work roll 2, φ WI B is the cross angle between the rolls of the lower work roll 2 and the lower intermediate roll 32, and φ IB B is the cross between the rolls of the lower work roll 2 and the lower intermediate roll 32. It is a horn. Further, μ IB T is the coefficient of friction between the upper intermediate roll 31 and the upper reinforcing roll 3, μ WI T is the coefficient of friction between the upper working roll 1 and the upper intermediate roll 31, and μ WW is the upper working roll 1. The coefficient of friction between the lower working roll 2 and μ WI B is the coefficient of friction between the lower working roll 2 and the lower intermediate roll 32, and μ IB B is the coefficient of friction between the lower intermediate roll 32 and the lower reinforcing roll 4. Is.
[0085]
　From this, when the unknowns involved in the equilibrium conditional expression regarding the force acting on each roll and the equilibrium conditional expression regarding the moment are decomposed, the following 19 unknowns are obtained.
[0086]
　　φ IB T : Cross angle between rolls of upper intermediate roll 31 and upper reinforcing roll 3
　　φ WI T : Cross angle between rolls of upper working roll 1 and upper intermediate roll 31
　　φ WW : Upper working roll 1 and lower working roll 2 Cross angle between rolls
　　φ WI B : Cross angle between rolls between lower working roll 2 and lower intermediate roll 32
　　φ IB B : Cross angle between rolls between lower intermediate roll 32 and lower reinforcing roll 4
　　μ IB T : Upper middle Coefficient of friction between roll 31 and upper reinforcing roll 3
　　μ WI T : Coefficient of friction between upper working roll 1 and upper intermediate roll 31
　　μ WW : Coefficient of friction between upper working roll 1 and lower working roll 2
　　μ WI B : Coefficient of friction between the lower working roll 2 and the lower intermediate roll 32
　　mu IB B : coefficient of friction between the lower intermediate roll 32 and the lower backup roll 4
　　T W T : top work roll chock 5a, thrust reaction force acting on 5b
　　T W B : lower work roll chock 6a, thrust reaction acting on 6b power
　　p df IB T : upper difference working side and the driving side of the line load distribution between the intermediate roll 31 and the upper backup roll 3
　　p df WI T : linear load between the upper work roll 1 and the upper intermediate roll 31 Difference between work side and drive side of distribution
　　p df WW : Difference between work side and drive side of line load distribution between upper work roll 1 and lower work roll 2
　　p df WI B : Lower work roll 2 and lower intermediate roll the difference of the work side and drive side of the line load distribution between the 32
　　p df IB B: Difference between the linear working side and the driving side of the load distribution between the lower intermediate roll 32 and the lower backup roll 4
　　h B T : upper roll chock 7a, the point of action of the thrust reaction force acting on 7b position
　　h B B : lower Position of the thrust reaction force acting on the reinforcing roll chocks 8a and 8b
[0087]
　The equations that can be applied to obtain these unknowns are the six equilibrium conditional equations relating to the force in the roll axis direction of each roll shown in the above equations (2-1) to (2-6) and the above equation (2-). 7) 6 equilibrium conditional equations for the moments of each roll shown in (2-12) and 4 hypothetical equations with the same friction coefficient between each roll (that is, μ = μ IB T = μ WI T = μ WW = μ WI B = μ IB B ), for a total of 16 pieces.
[0088]
　In this way, the number of unknowns exceeds the number of equations by three, and it is not possible to obtain all unknowns in one measurement. Therefore, the level of the friction coefficient is changed and the measurement is performed a plurality of times. By increasing the level of the coefficient of friction by one, the number of equations increases by 16. On the other hand, regarding the unknown number, when the cross angle between the rolls is constant and the kiss roll tightening load is the same, the position of the thrust reaction force acting point acting on the upper and lower reinforcing roll chocks 7a, 7b, 8a, 8b does not change. Therefore, unknown to vary by changing the coefficient of friction, mu IB T , mu WI T , mu WW , mu WI B , mu IB B , T B T , T B B , p df IB T , p df WI T , P df WW , p df WI B , p df There are 12 IB Bs .
[0089]
　In other words, by performing the measurement under the friction coefficient condition of a total of 2 levels with the same tightening load, the total number of unknowns is 31 and the total number of equations is 32, and the number of equations exceeds the number of unknowns. , It is possible to find all unknowns.
[0090]
　Each level of these friction coefficients can be easily realized by setting, for example, no lubrication, water lubrication, oil lubrication, or the like. Further, by carrying out the measurement at a higher level of friction coefficient, it becomes possible to use the minimum squared solution of the equation, and the calculation accuracy can be further improved.
[0091]
　Specifically, the method for identifying the thrust reaction force action point position of the reinforcing roll, which is performed by changing the friction coefficient between the rolls, can be performed as follows. Such an identification method is carried out by, for example, the arithmetic unit 21 shown in FIG. 1A.
[0092]
　As shown in FIG. 4A, first, the number of levels of the friction coefficient is set to N, and the number of levels N is set to 1 (S100a). Next, after setting the friction coefficient of the level N (S110a), a reduction load is applied by the reduction device until a predetermined kiss roll tightening load is reached to bring the kiss roll tightening state (S120a). Here, the predetermined kiss roll tightening load may be set to an arbitrary value equal to or less than the maximum load that can be applied by the rolling mill. For example, in the case of a hot rolling mill, it may be set to about 1000 tonf.
[0093]
　Then, in the kiss roll tightened state, the reaction force of the reinforcing roll acting on the reinforcing rolls 3 and 4 in the rolling direction is measured at the rolling fulcrum position (S130a). Further, the thrust reaction force in the roll axial direction acting on the rolls other than the reinforcing rolls 3 and 4 is measured (S140a). For example, in the case of a four-stage rolling mill, the thrust reaction force of the upper working roll 1 and the lower working roll 2 is measured. In the case of a 6-stage rolling mill, the thrust reaction force between the upper working roll 1 and the lower working roll 2 and the upper intermediate roll 31 and the lower intermediate roll 32 is measured.
[0094]
　When the reinforcing roll reaction force and the thrust reaction force at one level are measured, the level number N is increased by 1 (S150a), and the level number N is the minimum level number m at which the number of equilibrium equations can exceed the unknown number. Is determined (S160a). The minimum level number m at which the number of equilibrium equations can exceed the number of unknowns is obtained in advance. For example, in the case of a 4-stage rolling mill, it is 3 levels (m = 3), and in the case of a 6-stage rolling mill, it is 2 levels (m = 2). In step S160a, when N is equal to or less than the minimum level number m in which the number of equilibrium equations can exceed the number of unknowns, the processes of steps S110a to S150a are repeated.
[0095]
　On the other hand, in step S160a, when N exceeds the minimum level number m in which the number of equilibrium equations can exceed the number of unknowns, the equilibrium condition equation regarding the force in the roll axis direction of each roll and the equilibrium condition equation of each roll By solving the equilibrium condition equation of the moment, the position of the thrust reaction force acting point of the reinforcing roll can be obtained (S170a). For example, in the case of a four-stage rolling mill, the equilibrium condition equations relating to the forces in the roll axial direction shown in the above equations (1-1) to (1-4) for the working rolls 1 and 2 and the reinforcing rolls 3 and 4 By solving the four equations and the four equations for the equilibrium condition of the moments shown in the above equations (1-5) to (1-8), the thrust reaction force action point position of the reinforcing roll can be obtained. Further, in the case of a 6-stage rolling mill, the roll axial directions shown in the above formulas (2-1) to (2-6) for the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 By solving the six equilibrium condition equations related to the force of and the six equilibrium condition equations of the moments shown in the above equations (2-7) to (2-12), the thrust reaction force action point position of the reinforcing roll can be obtained. ..
[0096]
　In this way, by keeping the cross angle between rolls constant, setting a plurality of roll lubrication states, and measuring the reduction load in the kiss roll tightening state in each roll lubrication state, the thrust reaction force action point of the reinforcing roll The location can be identified.
[0097]
(When only the thrust reaction force of either the working roll or the intermediate roll can be measured in the ii. 6-stage rolling mill)
　Next, another example of changing the friction coefficient between the rolls will be described based on FIG. 4B. To do. FIG. 4B is a flowchart showing an example of a method for identifying the thrust reaction force action point position of the reinforcing roll according to the present embodiment, and shows another example in the case where the friction coefficient between the rolls is changed. The process shown in FIG. 4B is a process in a 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll.
[0098]
　In 6-high mill, for example, the thrust of the work roll reaction force T W T , T W B only thrust counterforces T of the intermediate roll when it is not possible to measure I T , T I B becomes unknown, the thrust reaction forces of the intermediate rolls T I T , T I B only thrust reaction force T of the case can not be measured is the work roll W T , T W B is an unknown. Therefore, the number of unknowns increases by 2 to 21 as compared with the case of the 6-stage rolling mill capable of measuring the thrust reaction force of the working roll and the intermediate roll. On the other hand, as described above, the equations that can be applied to obtain these unknowns are the six equilibrium conditional equations relating to the force in the roll axis direction of each roll shown in the above equations (2-1) to (2-6). And 6 equations for equilibrium condition of the moment of each roll shown in the above equations (2-7) to (2-12) and 4 equations for assuming that the friction coefficient between each roll is the same, for a total of 16 equations. is there.
[0099]
　In this way, the number of unknowns exceeds the number of equations by 5, and it is not possible to find all unknowns in one measurement. Therefore, the level of the friction coefficient is changed and the measurement is performed a plurality of times. By increasing the level of the coefficient of friction by one, the number of equations increases by 16. On the other hand, regarding the unknown number, when the cross angle between the rolls is constant and the kiss roll tightening load is the same, the position of the thrust reaction force acting point acting on the upper and lower reinforcing roll chocks 7a, 7b, 8a, 8b does not change. Therefore, unknown to vary by changing the coefficient of friction, mu IB T , mu WI T , mu WW , mu WI B , mu IB B , T I T , T I B , T B T , T B B , p df IB T , p df WI T , p df WW, The p- Df WI B , the p- Df IB B is fourteen.
[0100]
　In other words, by performing the measurement under the friction coefficient condition of a total of 4 levels with the same tightening load, the total number of unknowns is 63 and the total number of equations is 64, and the number of equations exceeds the number of unknowns. , It is possible to find all unknowns. As described above, the four levels of friction coefficient can be realized by setting, for example, no lubrication, water lubrication, oil lubrication, or the like, or by using a plurality of lubricants. Further, by carrying out the measurement at a higher level of friction coefficient, it becomes possible to use the minimum squared solution of the equation, and the calculation accuracy can be further improved.
[0101]
　Specifically, the method for identifying the thrust reaction force action point position of the reinforcing roll, which is performed by changing the friction coefficient between the rolls, can be performed as follows. Such an identification method is carried out by, for example, the arithmetic unit 21 shown in FIG. 1B.
[0102]
　As shown in FIG. 4B, first, the number of levels of the friction coefficient is set to N, and the number of levels N is set to 1 (S100b). Next, after setting the friction coefficient of the level N (S110b), a reduction load is applied by the reduction device until a predetermined kiss roll tightening load is reached to bring the kiss roll tightening state (S120b). Here, the predetermined kiss roll tightening load may be set to an arbitrary value equal to or less than the maximum load that can be applied by the rolling mill. For example, in the case of a hot rolling mill, it may be set to about 1000 tonf. Then, in the state where the kiss roll is tightened, the reaction force of the reinforcing roll acting on the reinforcing rolls 3 and 4 in the rolling direction is measured at the position of the rolling fulcrum (S130b). Further, the thrust reaction force in the roll axial direction acting on the upper work roll 1 and the lower work roll 2, or the upper intermediate roll 31 and the lower intermediate roll 32 is measured (S140b).
[0103]
　When the reinforcing roll reaction force and the thrust reaction force at one level are measured, the number of levels N is increased by 1 (S150b), and the number of levels N is the minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns. Whether or not it has been exceeded is determined (S160b). The minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns has been determined in advance, and in this example, there are four levels. In step S160b, when N is equal to or less than the minimum level number at which the number of equilibrium equations can exceed the number of unknowns, the processes of steps S110b to S150b are repeated. Further, in step S160b, when N exceeds the minimum level number at which the number of equilibrium equations can exceed the number of unknowns, each roll shown in the above equations (2-1) to (2-6). The thrust reaction of the reinforcing roll is solved by solving the six equilibrium condition equations for the force in the roll axis direction and the six equilibrium condition equations for the moments of each roll shown in the above equations (2-7) to (2-12). The position of the force acting point is obtained (S170b).
[0104]
　In this way, by keeping the cross angle between rolls constant, setting a plurality of roll lubrication states, and measuring the reduction load in the kiss roll tightening state in each roll lubrication state, the thrust reaction force action point of the reinforcing roll The location can be identified.
[0105]
　In this method, it is not easy to apply the lubricant only between specific rolls, so the assumption is given that the friction coefficients between the rolls are all the same. However, for example, when the surface roughness of the rolls is dominant, the friction coefficient between the rolls may be different even if the lubricant is the same, and the calculation accuracy may deteriorate. In such a case, as will be described later, it is desirable to apply a method of measuring at a plurality of levels by changing the cross angle between rolls.
[0106]
(B. When changing the cross angle between rolls)
　Next, a case where the cross angle between rolls is changed will be described with reference to FIGS. 5 to 6B. When changing the cross angle between rolls, it is necessary to consider separately for a normal rolling mill and a rolling mill capable of crossing upper and lower roll assemblies such as a pair cross rolling mill in the horizontal direction.
[0107]
　FIG. 5 is a flowchart showing an example of a method for identifying the thrust reaction force action point position of the reinforcing roll according to the present embodiment, and shows a case where the cross angle between rolls is changed by using a pair cloth rolling mill. 6A and 6B are flowcharts showing an example of the method for identifying the thrust reaction force action point position of the reinforcing roll according to the present embodiment, and the cross angle between the rolls is changed by using a normal rolling mill. Show the case. The process shown in FIG. 6A can be performed in a rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing rolls, and can be applied to a rolling mill having four or more stages. The process shown in FIG. 6B is applicable to a 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll.
[0108]
(B-1. When a pair cloth rolling mill is used)
　First, based on FIG. 5, a reinforcing roll 3 when a rolling mill capable of horizontally crossing upper and lower roll assemblies such as a pair cloth rolling mill is used. The method of identifying the position of the thrust reaction force action point of No. 4 will be described. That is, the rolling mill has at least the roll axial direction of the upper roll assembly including the upper working roll 1 and the upper reinforcing roll 3 and the roll axial direction of the lower roll assembly including at least the lower working roll 2 and the lower reinforcing roll 4. It is a rolling mill that can be crossed. With such a rolling mill, the cross angle φ WW between the upper and lower working rolls 1 and 2 is changed, and the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified.
[0109]
　In this case, the number of unknowns involved in the equilibrium condition regarding the force and the moment is 13, and the number of equations is 10, as in the case of changing the coefficient of friction between the rolls described above. The number of unknowns exceeds the number of equations by three, and it is not possible to find all unknowns in one measurement. Therefore, the tightening load is the same, the level of the cross angle φ WW between the upper and lower work rolls 1 and 2 is changed, and the measurement is performed a plurality of times. By increasing the level of the cross angle φ WW between rolls by one, the number of equations increases by eight. On the other hand, regarding the unknown number, when the friction coefficient is constant and the kiss roll tightening load is the same, the position of the thrust reaction force acting point acting on the upper and lower reinforcing roll chocks 7a, 7b, 8a, 8b does not change. Therefore, the cross angle phi between the rolls WW unknowns which changes by changing the can, phi WW , T W T , T W B , p df WB T , p df WB B , p df WW is six.
[0110]
　That is, by performing the measurement under the cross angle condition between the upper and lower work rolls 1 and 2 of a total of 3 levels, the total number of unknowns is 25, the total number of equations is 26, and the number of equations is unknown. Since it exceeds the number, it is possible to find all the unknowns. In the case of a pair cross rolling mill, the actuator used for shape control can be used as it is, so that the cross angle between the upper and lower work rolls 1 and 2 can be easily changed. Further, by performing the measurement at the level of the cross angle between the upper and lower working rolls 1 and 2, it becomes possible to use the minimum squared solution of the equation, and the calculation accuracy can be further improved.
[0111]
　Further, in this identification method, it is assumed that the friction coefficients between the rolls are all the same, as in the case of changing the friction coefficient. However, for example, when the roll surface roughness is dominant, the friction coefficient between the rolls is different, and the calculation accuracy may deteriorate. If this assumption is excluded, the number of equations will be eight, but by performing the measurement under the cross-angle condition between the upper and lower working rolls 1 and 2 of a total of 4 levels, the total number of unknowns will be 31. The total number of equations is 32. Since the number of equations can exceed the number of unknowns in this way, it is possible to find all unknowns.
[0112]
　Specifically, the method for identifying the thrust reaction force action point position of the reinforcing roll, which is performed by changing the cross angle condition between the upper and lower working rolls 1 and 2, can be performed as follows. Such an identification method is carried out by, for example, the arithmetic unit 21 shown in FIG. 1A.
[0113]
　As shown in FIG. 5, first, the number of levels of the cross angle φ WW between the upper and lower working rolls 1 and 2 is set to N, and the number of levels N is set to 1 (S200). Next, after setting the level N inter-roll cross angle φ WW (S210), a reduction load is applied by the reduction device until a predetermined kiss roll tightening load is reached to bring the kiss roll tightening state (S220). Here, the predetermined kiss roll tightening load may be set to an arbitrary value equal to or less than the maximum load that can be applied by the rolling mill. For example, in the case of a hot rolling mill, it may be set to about 1000 tonf. Then, in the kiss roll tightened state, the reaction force of the reinforcing roll acting in the reducing direction with respect to the reinforcing rolls 3 and 4 at the position of the reduction fulcrum is measured (S230). Further, in the case of a roll other than the reinforcing rolls 3 and 4, and in the case of a 4-stage rolling mill, the thrust reaction force in the roll axial direction acting on the upper working roll 1 and the lower working roll 2 is measured (S240).
[0114]
　When the reinforcing roll reaction force and the thrust reaction force at one level are measured, the number of levels N is increased by 1 (S250), and the number of levels N is the minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns. Whether or not it has been exceeded is determined (S260). The minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns has been determined in advance, and in this example, there are three levels. In step S260, when N is equal to or less than the minimum level number at which the number of equilibrium equations can exceed the number of unknowns, the processes of steps S210 to S250 are repeated. Further, in step S260, when N exceeds the minimum level number at which the number of equilibrium equations can exceed the number of unknowns, the roll axis direction of each roll shown in the above equations (1) to (4). The four equilibrium condition equations for the force of the above and the four equilibrium condition equations for the moments of each roll shown in the above equations (5) to (8) are solved to obtain the thrust reaction force action point position of the reinforcing roll (S270). ).
[0115]
　In this way, in the pair cross rolling mill, the cross angle φ WW between the rolls of the plurality of upper and lower working rolls 1 and 2 is set, and the rolling load in the kiss roll tightened state at each roll cross angle φ WW is measured. Therefore, the position of the thrust reaction force action point of the reinforcing roll can be identified.
[0116]
(B-2. When a normal rolling mill is used)
　Next, based on FIGS. 6A and 6B, the thrust reaction force action of the reinforcing rolls 3 and 4 when a normal rolling mill other than the pair cross rolling mill is used. A method for identifying the point position will be described. At this time, the rolling mill is provided with an external force applying device that applies different rolling direction external forces to the working side roll chock and the driving side roll chock for at least one of the rolls. The external force applying device is, for example, a hydraulic cylinder. The external force applying device makes it possible to apply different rolling direction external forces to the working side roll chock and the driving side roll chock of the roll provided with the external force, and to change the cross angle between the rolls for all the roll systems of the roll. Then, the reinforcing roll reaction force and the thrust reaction force are measured at a plurality of levels of cross angles between the rolls, and the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified.
[0117]
( 　I. When the thrust reaction force of all rolls other than the reinforcing rolls can be measured)
(For 4-stage rolling mill) In the case of
4-stage rolling mill, equilibrium regarding force and moment is the same as when using a pair cross rolling mill. The number of unknowns involved in the condition is 13, and the number of equations is 10. The number of unknowns exceeds the number of equations by three, and it is not possible to find all unknowns in one measurement. Therefore, for example, for at least one roll, the tightening load is the same, the cross angle relative to all roll systems (hereinafter, also referred to as “relative cross angle”) is changed, and a plurality of measurements are performed. In the following, when the cross angle between rolls of the lower working roll 2 for all roll systems is changed to measure the reinforcing roll reaction force and the thrust reaction force, and the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified. think of.
[0118]
　At this time, the cross angle φ WW between the rolls of the upper and lower work rolls 1 and 2 and the cross angle φ WB B between the rolls of the lower work roll 2 and the lower reinforcing roll 4 change. However, the relative angle between the upper working roll 1 and the lower reinforcing roll 4 does not change. Therefore, by using the constant C, the following equation (8) holds between these roll-to-roll cross angles. Considering the equation (8), the number of unknowns is 14 including C, and the number of equations is 11 including the equation (8).
[0119]
[Number 8]

[0120]
　By increasing the level by one, the number of equations including the above equation (8) increases by nine. On the other hand, regarding the unknown number, when the friction coefficient is constant and the kiss roll tightening load is the same, the position of the thrust reaction force acting point acting on the upper and lower reinforcing roll chocks 7a, 7b, 8a, 8b does not change. Therefore, unknowns, phi vary by varying the relative cross angle of the lower work roll WW , phi WB B , T W T , T W B , p df WB T , p df WB B , p df WW 7 amino Is.
[0121]
　In other words, by performing the measurement under the relative cross angle condition of the lower working roll with a total of 3 levels, the total number of unknowns is 28, the total number of equations is 29, and the number of equations exceeds the number of unknowns. It is possible to find all unknowns.
[0122]
(In the case of a
　6-stage rolling mill ) In the case of a 6-stage rolling mill, the number of unknowns involved in the equilibrium condition regarding force and moment is 19, and the number of equations is 16. The number of unknowns exceeds the number of equations by three, and it is not possible to find all unknowns in one measurement. Therefore, for example, for at least one roll, the relative cross angle is changed with the same tightening load, and a plurality of measurements are performed. In the following, when the cross angle between rolls of the lower working roll 2 for all roll systems is changed to measure the reinforcing roll reaction force and the thrust reaction force, and the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified. think of.
[0123]
　At this time, the cross angle φ WW between the rolls of the upper and lower work rolls 1 and 2 and the cross angle φ WI B between the rolls of the lower work roll 2 and the lower intermediate roll 32 change. However, the relative angle between the upper working roll 1 and the lower intermediate roll 32 does not change. Therefore, by using the constant C', the following equation (9) holds between these roll-to-roll cross angles. Considering the equation (9), the number of unknowns is 20 including C', and the number of equations is 17 including the equation (9).
[0124]
[Number 9]

[0125]
　By increasing the level by one, the number of equations including the above equation (9) increases by 13. On the other hand, for unknowns, if the coefficient of friction is constant (that is, μ = μ IB T = μ WI T = μ WW = μ WI B = μ IB B ) and the kiss roll tightening load is the same, the upper and lower sides The position of the thrust reaction force acting point acting on the reinforcing roll chocks 7a, 7b, 8a, 8b does not change. Therefore, the unknowns that change by changing the relative cross angle of the lower work roll are φ WW , φ WI B , T B T , T B B , p df IB T , p df WI B , p df WW , p df. WI B, The p- Df IB B is a nine.
[0126]
　In other words, by performing the measurement under the relative cross angle condition of the lower working roll with a total of 2 levels, the total number of unknowns is 29, the total number of equations is 30, and the number of equations exceeds the number of unknowns. It is possible to find all unknowns.
[0127]
　The relative cross angle of the lower working roll can be easily changed by changing the difference between the working side and the driving side of the rolling direction load, for example, in a rolling mill in which a hydraulic cylinder is mounted in the gap between the roll chock and the housing. it can. Further, by performing the measurement at the level of the relative cross angle of more lower working rolls, it becomes possible to use the minimum squared solution of the equation, and the calculation accuracy can be further improved.
[0128]
　Further, in this identification method, it is assumed that the friction coefficients between the upper and lower working rolls 1 and 2 are all the same, as in the case of changing the cross angle between the rolls. However, for example, when the roll surface roughness is dominant, the friction coefficient between the rolls is different, and the calculation accuracy may deteriorate. Excluding this assumption, in the case of a four-stage rolling mill, the number of equations is nine. However, if the measurement is carried out under the cross angle condition between the upper and lower working rolls 1 and 2 of a total of 4 levels, the total number of unknowns can be 35 and the total number of equations can be 36. Further, in the case of a 6-stage rolling mill, the number of equations is 13 when the assumption regarding the coefficient of friction is excluded. However, if the measurement is carried out under the cross angle condition between the upper and lower working rolls 1 and 2 of a total of 3 levels, the number of unknowns can be 38 in total and the number of equations can be 39 in total. Since the number of equations can exceed the number of unknowns in this way, it is possible to find all unknowns.
[0129]
　Specifically, the method for identifying the thrust reaction force action point position of the reinforcing roll, which is performed by changing the relative cross angle condition of the lower working roll, can be performed as follows. Such an identification method is carried out by, for example, the arithmetic unit 21 shown in FIG. 1A.
[0130]
　As shown in FIG. 6A, first, the number of levels of the relative cross angle of a certain roll is set to N, and the number of levels N is set to 1 (S300a). Next, after setting the relative cross angle of at least one roll of level N (S310a), a reduction load is applied by the reduction device until a predetermined kiss roll tightening load is reached to bring the kiss roll tightening state (S320a). Here, the predetermined kiss roll tightening load may be set to an arbitrary value equal to or less than the maximum load that can be applied by the rolling mill. For example, in the case of a hot rolling mill, it may be set to about 1000 tonf.
[0131]
　Then, in the kiss roll tightened state, the reaction force of the reinforcing roll acting on the reinforcing rolls 3 and 4 in the rolling direction at the rolling fulcrum position is measured (S330a). Further, the thrust reaction force in the roll axial direction acting on the rolls other than the reinforcing rolls 3 and 4 is measured (S340a). For example, in the case of a four-stage rolling mill, the thrust reaction force of the upper working roll 1 and the lower working roll 2 is measured. In the case of a 6-stage rolling mill, the thrust reaction force between the upper working roll 1 and the lower working roll 2 and the upper intermediate roll 31 and the lower intermediate roll 32 is measured.
[0132]
　When the reinforcing roll reaction force and the thrust reaction force at one level are measured, the level number N is increased by 1 (S350a), and the level number N is the minimum level number m at which the number of equilibrium equations can exceed the unknown number. Is determined (S360a). The minimum level number m at which the number of equilibrium equations can exceed the number of unknowns is obtained in advance. For example, in the case of a 4-stage rolling mill, it is 3 levels (m = 3), and in the case of a 6-stage rolling mill, it is 2 levels (m = 2). In step S360a, when N is equal to or less than the minimum level number m in which the number of equilibrium equations can exceed the number of unknowns, the processes of steps S310a to S350a are repeated.
[0133]
　On the other hand, in step S360a, when N exceeds the minimum level number m in which the number of equilibrium equations can exceed the number of unknowns, the equilibrium condition equation regarding the force in the roll axis direction of each roll and the equilibrium condition equation of each roll By solving the equilibrium condition equation of the moment, the position of the thrust reaction force acting point of the reinforcing roll can be obtained (S370a). For example, in the case of a four-stage rolling mill, the equilibrium condition equations relating to the forces in the roll axial direction shown in the above equations (1-1) to (1-4) for the working rolls 1 and 2 and the reinforcing rolls 3 and 4 By solving the four equations and the four equations for the equilibrium condition of the moments shown in the above equations (1-5) to (1-8), the thrust reaction force action point position of the reinforcing roll can be obtained. Further, in the case of a 6-stage rolling mill, the roll axial directions shown in the above formulas (2-1) to (2-6) for the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 By solving the six equilibrium condition equations related to the force of and the six equilibrium condition equations of the moments shown in the above equations (2-7) to (2-12), the thrust reaction force action point position of the reinforcing roll can be obtained. ..
[0134]
　In this way, even in a rolling mill that is not a pair cross rolling mill, the relative cross angles for all roll systems are set for at least one roll, and the rolling load in the kiss roll tightened state at a plurality of relative cross angles is measured. Therefore, the position of the thrust reaction force action point of the reinforcing roll can be identified.
[0135]
(When only the thrust reaction force of either the working roll or the intermediate roll can be measured in the ii
　. 6- stage rolling mill) Next, based on FIG. 6B, only the thrust reaction force of either the working roll or the intermediate roll is measured. A method for identifying the thrust reaction force action point position of the reinforcing roll, which is performed by changing the relative cross angle condition of the lower working roll in a 6-stage rolling mill that cannot be performed, will be described.
[0136]
　In 6-high mill, for example, the thrust of the work roll reaction force T W T , T W B only thrust counterforces T of the intermediate roll when it is not possible to measure I T , T I B becomes unknown, the thrust reaction forces of the intermediate rolls T I T , T I B only thrust reaction force T of the case can not be measured is the work roll W T , T W B is an unknown. Therefore, the number of unknowns increases by 2 to 22 as compared with the case of the 6-stage rolling mill capable of measuring the thrust reaction force of the working roll and the intermediate roll. On the other hand, as described above, the equations that can be applied to obtain these unknowns are the six equilibrium conditional equations relating to the force in the roll axis direction of each roll shown in the above equations (2-1) to (2-6). And 6 equilibrium conditional equations of the moment of each roll shown in the above equations (2-7) to (2-12), 4 hypothetical equations having the same coefficient of friction between each roll, and a cross angle between rolls. There are a total of 17 of the above equations (9).
[0137]
　By increasing the level by one, the number of equations increases by 13 and the number of unknowns increases by 11. Therefore, by performing the measurement under the relative cross angle condition of the lower working roll with a total of 4 levels, the total number of unknowns is 55, the total number of equations is 56, and the number of equations exceeds the number of unknowns. It is possible to find all unknowns.
[0138]
　Also, excluding the assumption that the friction coefficients between the rolls are all the same, the number of equations is 13. In this case, if the measurement is performed under the cross angle condition between the upper and lower working rolls 1 and 2 of a total of 6 levels, the total number of unknowns can be 77 and the total number of equations can be 78. Since the number of equations can exceed the number of unknowns in this way, it is possible to find all unknowns.
[0139]
　In a 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll, the method of identifying the thrust reaction force action point position of the reinforcing roll performed by changing the relative cross angle condition of the lower working roll is as follows. Specifically, it can be performed as follows. Such an identification method is carried out by, for example, the arithmetic unit 21 shown in FIG. 1B.
[0140]
　As shown in FIG. 6B, first, the number of levels of the relative cross angle of a certain roll is set to N, and the number of levels N is set to 1 (S300b). Next, after setting the relative cross angle of at least one roll of level N (S310b), a reduction load is applied by the reduction device until a predetermined kiss roll tightening load is reached to bring the kiss roll tightening state (S320b). Here, the predetermined kiss roll tightening load may be set to an arbitrary value equal to or less than the maximum load that can be applied by the rolling mill. For example, in the case of a hot rolling mill, it may be set to about 1000 tonf. Then, in the kiss roll tightened state, the reaction force of the reinforcing roll acting on the reinforcing rolls 3 and 4 in the reducing direction is measured at the position of the reducing fulcrum (S330b). Further, the thrust reaction force in the roll axial direction acting on the upper work roll 1 and the lower work roll 2, or the upper intermediate roll 31 and the lower work roll 32 is measured (S340b).
[0141]
　When the reinforcing roll reaction force and the thrust reaction force at one level are measured, the number of levels N is increased by 1 (S350b), and the number of levels N is the minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns. Whether or not it has been exceeded is determined (S360b). The minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns has been determined in advance, and in this example, there are four levels. In step S360b, when N is equal to or less than the minimum level number at which the number of equilibrium equations can exceed the number of unknowns, the processes of steps S310b to S350b are repeated. On the other hand, in step S360b, when N exceeds the minimum level number at which the number of equilibrium equations can exceed the number of unknowns, each roll shown in the above equations (2-1) to (2-6). The thrust reaction of the reinforcing roll is solved by solving the six equilibrium condition equations for the force in the roll axis direction and the six equilibrium condition equations for the moments of each roll shown in the above equations (2-7) to (2-12). The position of the force acting point is obtained (S370b).
[0142]
　In this way, even in a rolling mill that is not a pair cross rolling mill, the relative cross angles for all roll systems are set for at least one roll, and the rolling load in the kiss roll tightened state at a plurality of relative cross angles is measured. Therefore, the position of the thrust reaction force action point of the reinforcing roll can be identified.
[0143]
　The specific example of the method for identifying the thrust reaction force action point position of the reinforcing roll according to the present embodiment has been described above. In the above specific example, a case where different thrust forces are generated by changing either the cross angle between rolls or the friction coefficient between rolls has been described, but the present invention is not limited to such an example. For example, if it is not possible to set the minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns simply by increasing the number of levels by changing the cross angle between rolls, the number of levels can be increased by changing the coefficient of friction. It may be increased. Conversely, if it is not possible to set the minimum number of levels at which the number of equilibrium equations can exceed the number of unknowns simply by increasing the number of levels by changing the coefficient of friction, the number of levels can be changed by changing the cross angle between rolls. May be increased. In either case, by performing the measurement a plurality of times, the number of equilibrium conditional expressions exceeds the number of unknowns, and it becomes possible to obtain all the unknowns.
[0144]
(3) Relationship between
　Kiss Roll Tightening Load and Action Point Position According to the above-mentioned method for identifying the thrust reaction force action point position of the reinforcing roll, the kiss roll tightening load and the thrust reaction force action point position of the reinforcement rolls 3 and 4 are The relationship shown in FIG. 7 is acquired. As shown in FIG. 7, the thrust reaction force action point position does not change much for both the upper reinforcing roll 3 and the lower reinforcing roll 4 until the kiss roll tightening load becomes a kiss roll tightening load from 0, but the position thereof does not change much. When the kiss roll tightening load is exceeded, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 become smaller and approach the roll axis. In particular, in the upper reinforcing roll 3, when a certain kiss roll tightening load is exceeded, the thrust reaction force action point position sharply decreases. In this way, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 change according to the kiss roll tightening load.
[0145]
　By acquiring the relationship between such rolling load and the position of the thrust reaction force acting point of the reinforcing rolls 3 and 4, it is applied according to at least one of the set value and the actual value of the rolling load at the time of rolling. It is possible to determine the thrust reaction force action point positions of the reinforcing rolls 3 and 4. The relationship between the rolling load and the thrust reaction force action point positions of the reinforcing rolls 3 and 4 can be determined in the system by using a model or table showing the correspondence between the rolling load and the thrust reaction force action point positions of the reinforcing rolls 3 and 4, for example. It is possible to introduce it.
[0146]
　Since the reinforcing roll chocks 7a, 7b, 8a, and 8b simultaneously receive a reinforcing roll reaction force much larger than the thrust reaction force, the position of the thrust reaction force action point generally fluctuates according to the magnitude of the reinforcing roll reaction force. Is the target. The reinforcing roll reaction force during rolling is, that is, the rolling reaction force, and the rolling reaction force changes according to the operating conditions such as the material of the rolled material or the rolling reduction ratio. Therefore, the magnitude of the reaction force of the reinforcing rolls also changes, and the positions of the thrust reaction force action points of the reinforcing rolls 3 and 4 change. Therefore, by modeling or tabulating the relationship between the rolling load and the thrust reaction force action point position in advance, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 according to the rolling load at the time of rolling are appropriately set. It becomes possible. As a result, it becomes possible to calculate the optimum leveling operation amount more accurately.
[0147]
　[2. Rolling method of rolled material]
　Next, when rolling the rolled material using the thrust reaction force action point positions of the reinforcing rolls 3 and 4 identified by the above-mentioned method for identifying the thrust reaction force action point position of the reinforcing roll. The rolling position setting and the rolling position control will be described.
[0148]
　[2-1. Setting
　the rolling position by adjusting the zero point] First, based on FIGS. 8A and 8B, setting the rolling position by adjusting the zero point by the rolling mill 100 will be described as the setting of the rolling position of the rolling mill 100. 8A and 8B are flowcharts showing a reduction position setting process by adjusting the zero point by the reduction device. The process shown in FIG. 8A can be executed in a rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing rolls, and can be applied to a rolling mill having four or more stages. The process shown in FIG. 8B is applicable to a 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll.
[0149]
　The zero point of the rolling mill is the difference between the working side and the driving side of the roll flattening caused by the difference between the working side and the driving side of the linear load distribution acting between each roll of the rolling mill 100, and the thrust force between the rolls is increased. When it does not occur, the true working side and the driving side are evenly deviated from the rolling position. Therefore, it is necessary to always correct this error amount at the time of setting the reduction, or more practically, to correct the zero point itself in consideration of the error amount. In any case, the reaction force of the reinforcing roll at each reduction fulcrum position of the reinforcing rolls 3 and 4 and the thrust reaction force acting on the rolls other than the reinforcing rolls 3 and 4 are measured, and the work of linear load distribution between the rolls is performed. It is necessary to estimate the difference between the side and the drive side. Even if any of the measured values ​​is missing, for example, in the case of a 4-stage rolling mill, the number of unknowns is 8 or more, and the difference between the working side and the driving side of the linear load distribution between the rolls cannot be estimated.
[0150]
　By the way, in the case where the rolling mill 100 is not a 4-stage rolling mill but a 6-stage rolling mill in which intermediate rolls are further increased, the contact region between rolls is increased by one place for each additional intermediate roll. In this case as well, if the thrust reaction force of the intermediate roll is measured, the two unknowns that increase are the thrust force acting on the added inter-roll contact region and the difference between the working side and the driving side of the linear load distribution. Is. On the other hand, the number of available equations will be increased by two, the equilibrium condition equation for the force in the roll axis direction of the intermediate roll and the equilibrium condition equation for the moment. It is possible to find a solution.
[0151]
　In this way, even in the case of a rolling mill having four or more stages, by measuring the thrust reaction force acting on at least all the rolls except the reinforcing rolls, the work of the linear load distribution acting between all the rolls in the kiss roll state It is possible to accurately obtain the difference between the side and the drive side. This makes it possible to accurately adjust the zero point of the reduction device, especially including the asymmetry between the working side and the driving side.
[0152]
(I. When the thrust reaction force of all rolls other than the reinforcing roll can be measured)
　First, processing with a four-stage or more rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing roll will be described. As shown in FIG. 8A, first, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified (S10a). The identification process of step S10a may be performed by using, for example, any of the methods for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4 shown in FIGS. 4A, 5 or 6A described above.
[0153]
　Next, a reduction load is applied by the reduction device until a predetermined reduction zero adjustment load is reached to bring the kiss roll into a tightened state (S11a), and the reduction position is reset (S12a). The reduction zero adjustment load is set to about 1000 tonf in the case of a hot rolling mill, for example. In step S12a, for example, the reduction position may be reset to zero. Then, in the kiss roll tightened state, the reaction force of the reinforcing roll acting on the reinforcing rolls 3 and 4 in the reducing direction is measured at the position of the reducing fulcrum (S13a). Further, the thrust reaction force in the roll axial direction acting on the rolls other than the reinforcing rolls 3 and 4 is measured (S14a). In the case of a 4-stage rolling mill, the thrust reaction forces of the upper working roll 1 and the lower working roll 2 are measured, and in the case of a 6-stage rolling mill, the upper working roll 1 and the lower working roll 2, the upper intermediate roll 31 and the lower The thrust reaction force with the intermediate roll 32 is measured.
[0154]
　Then, based on the thrust reaction force action point positions of the reinforcing rolls 3 and 4 previously identified in step S10a, the thrust reaction force of the reinforcing rolls 3 and 4 and the thrust force and the line acting between each roll of all the rolls. The laterality of the load distribution is calculated (S15a). The left-right difference in thrust force and linear load distribution is obtained for each roll of work rolls 1 and 2 and reinforcing rolls 3 and 4 in the case of a 4-stage rolling mill, and in the case of a 6-stage rolling mill, work roll 1 and 2. Obtained between each of the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4.
[0155]
　The thrust reaction force action point positions of the reinforcing rolls 3 and 4 are set to the thrust reaction force action point positions corresponding to the reduction zero adjustment load. The left-right difference between the thrust reaction force, the thrust force, and the linear load distribution can be obtained by calculating the above-mentioned equilibrium condition equation for the force in the roll axis direction and the equilibrium condition equation for the moment. Specifically, in the case of a four-stage rolling mill, an equilibrium condition equation relating to the force in the roll axial direction of the working rolls 1 and 2 and the reinforcing rolls 3 and 4 shown in equations (1-1) to (1-4). And, it can be obtained based on the equilibrium condition equation of the moments of the working rolls 1 and 2 and the reinforcing rolls 3 and 4 shown in the above equations (1-5) to (1-8). In the case of a 6-stage rolling mill, equilibrium conditions regarding the forces of the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 shown in the formulas (2-1) to (2-6) in the roll axial direction. It can be obtained based on the equation and the equilibrium condition equation of the moments of the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 shown in the above equations (2-7) to (2-12).
[0156]
　Then, based on the calculation result of step S15a, the total of the left-right difference of the roll deformation amount in the reduction zero adjustment state is calculated, and the left-right difference of the roll deformation amount is converted into the reduction fulcrum position (S16a). As a result, the correction amount of the reduction zero position is calculated.
[0157]
　Next, the reduction position when there is no difference between the left and right roll deformation amounts is set to the reduction zero position (S17a). That is, the reduction zero position is corrected by the amount of correction calculated in step S16a. Then, the reduction position is set based on the corrected reduction zero position (S18a).
[0158]
(Ii. When only the thrust reaction force of either
　the working roll or the intermediate roll can be measured in the 6-stage rolling mill ) Next, in the 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll. The processing of is explained. As shown in FIG. 8B, first, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified (S10b). The identification process of step S10b may be performed by using, for example, any of the methods for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4 shown in FIGS. 4B, 5 or 6B described above.
[0159]
　Next, a reduction load is applied by the reduction device until a predetermined reduction zero adjustment load is reached to bring the kiss roll into a tightened state (S11b), and the reduction position is reset (S12b). The reduction zero adjustment load is set to about 1000 tonf in the case of a hot rolling mill, for example. In step S12b, for example, the reduction position may be reset to zero. Then, in the kiss roll tightened state, the reaction force of the reinforcing roll acting on the reinforcing rolls 3 and 4 in the reducing direction is measured at the position of the reducing fulcrum (S13b). Further, the thrust reaction force in the roll axial direction acting on the working rolls 1 and 2 or the intermediate rolls 31 and 32 is measured (S14b).
[0160]
　Then, based on the thrust reaction force action point positions of the reinforcing rolls 3 and 4 previously identified in step S10b, the thrust reaction force of the reinforcing rolls 3 and 4 and the working rolls 1 and 2 or the intermediate rolls 31 and 32 are measured. Left-right difference in thrust reaction force and linear load distribution acting between each roll of all rolls (that is, working rolls 1, 2, intermediate rolls 31, 32 and reinforcing rolls 3, 4) Is calculated (S15b).
[0161]
　The thrust reaction force action point positions of the reinforcing rolls 3 and 4 are set to the thrust reaction force action point positions corresponding to the reduction zero adjustment load. The difference between the left and right thrust reaction force, thrust force and linear load distribution is the rolls of the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 shown in the above formulas (2-1) to (2-6). The equilibrium condition equation for the axial force and the equilibrium condition equation for the moments of the working rolls 1, 2 and the intermediate rolls 31, 32 and the reinforcing rolls 3 and 4 shown in the above equations (2-7) to (2-12). Can be calculated based on.
[0162]
　Then, based on the calculation result of step S15b, the total of the left-right difference of the roll deformation amount in the reduction zero adjustment state is calculated, and the left-right difference of the roll deformation amount is converted into the reduction fulcrum position (S16b). As a result, the correction amount of the reduction zero position is calculated.
[0163]
　Next, the reduction position when there is no difference between the left and right roll deformation amounts is set to the reduction zero position (S17b). That is, the reduction zero position is corrected by the amount of correction calculated in step S16b. Then, the reduction position is set based on the corrected reduction zero position (S18b).
[0164]
　The process of adjusting the zero point by the reduction device has been described above. In the zero point adjustment process by the reduction device, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified by using the above-mentioned method for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4, which is higher. It is possible to adjust the zero point with accuracy. As a result, the rolling position of the rolling mill can be adjusted accurately.
[0165]
　When a plurality of reduction zero adjustment loads are used, a plurality of levels of thrust force may be measured at each of the plurality of levels of the reduction zero adjustment load, or the rolling load and the thrust reaction of the reinforcing rolls 3 and 4 may be measured. A model or table representing the correspondence with the position of the force acting point may be used.
[0166]
　[2-2. Housing-Reduction position setting based on the deformation characteristics of the reduction system]
　Next, based on FIGS. 9A and 9B, the reduction position setting based on the deformation characteristics of the housing-reduction system will be described as the reduction position setting of the rolling mill 100. 9A and 9B are flowcharts showing a process of setting the reduction position according to the deformation characteristic of the housing-reduction system. The reduction position setting based on the deformation characteristics of the housing-reduction system can be performed in parallel with the reduction position setting by the zero point adjustment described above. The process shown in FIG. 9A can be executed in a rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing rolls, and can be applied to a rolling mill having four or more stages. The process shown in FIG. 9B is applicable to a 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll.
[0167]
(I. When the thrust reaction force of all rolls other than the reinforcing roll can be measured)
　First, processing with a four-stage or more rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing roll will be described. As shown in FIG. 9A, first, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified (S20a). The identification process of step S20a may be performed by using, for example, any of the methods for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4 shown in FIGS. 4A, 5 or 6A described above. When the process shown in FIG. 9A is executed in parallel with the reduction position setting by the zero point adjustment of FIG. 8A, either step S20a or step S10a of FIG. 8A may be executed.
[0168]
　Next, the reinforcement roll reaction force acting in the reduction direction with respect to the reinforcement rolls 3 and 4 at the reduction fulcrum position is measured with respect to each reduction position condition for a predetermined kiss roll tightening load by the reduction device, and the reinforcement rolls 3 and 3. The thrust reaction force in the roll axis direction acting on the rolls other than 4 is measured (S21a). The thrust reaction force is measured for the upper work roll 1 and the lower work roll 2 in the case of a 4-stage rolling mill, and the upper work roll 1 and the lower work roll 2 and the upper intermediate roll 31 and the upper intermediate roll 31 in the case of a 6-stage rolling mill. Measured with respect to the lower intermediate roll 32. Here, the predetermined kiss roll tightening load may be set to an arbitrary value equal to or less than the maximum load that can be applied by the rolling mill. For example, in the case of a hot rolling mill, it may be set to about 1000 tonf.
[0169]
　After that, based on the thrust reaction force action point positions of the reinforcing rolls 3 and 4 previously identified in step S20a, the thrust reaction force of the reinforcing rolls 3 and 4 and the thrust force and the line acting between each roll of all the rolls. The laterality of the load distribution is calculated (S22a). The left-right difference in thrust force and linear load distribution is obtained for each roll of work rolls 1 and 2 and reinforcing rolls 3 and 4 in the case of a 4-stage rolling mill, and in the case of a 6-stage rolling mill, work roll 1 and 2. Obtained between each of the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4.
[0170]
　The thrust reaction force action point positions of the reinforcing rolls 3 and 4 are set to the thrust reaction force action point positions corresponding to each kiss roll tightening load. The left-right difference between the thrust reaction force, the thrust force, and the linear load distribution can be obtained by calculating the above-mentioned equilibrium condition equation for the force in the roll axis direction and the equilibrium condition equation for the moment. Specifically, in the case of a four-stage rolling mill, an equilibrium condition equation relating to the force in the roll axial direction of the working rolls 1 and 2 and the reinforcing rolls 3 and 4 shown in equations (1-1) to (1-4). And, it can be obtained based on the equilibrium condition equation of the moments of the working rolls 1 and 2 and the reinforcing rolls 3 and 4 shown in the above equations (1-5) to (1-8). In the case of a 6-stage rolling mill, equilibrium conditions regarding the forces of the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 shown in the formulas (2-1) to (2-6) in the roll axial direction. It can be obtained based on the equation and the equilibrium condition equation of the moments of the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 shown in the above equations (2-7) to (2-12).
[0171]
　Then, based on the calculation result of step S22a, the deformation amounts of all the rolls under each reduction position condition are calculated including the left-right difference, and the displacement generated at the reduction fulcrum positions of the reinforcing rolls 3 and 4 is calculated by the calculated deformation amount. (S23a). The amount of deformation of the roll is, for example, roll bending and roll equality. The amount of deformation of the roll is calculated for the working rolls 1 and 2 and the reinforcing rolls 3 and 4 in the case of the 4-stage rolling mill, and the working rolls 1 and 2 and the intermediate rolls 31 and 32 and the reinforcing in the case of the 6-stage rolling mill. Calculated for rolls 3 and 4. In step S23a, the amount of deformation of the roll system for each reduction position condition is calculated.
[0172]
　After that, the deformation characteristic of the housing-rolling system of the rolling mill is calculated by subtracting the deformation amount of the roll system calculated in step S23a from the deformation amount of the entire rolling mill at the rolling fulcrum position evaluated by the change of the rolling position. (S24a). The deformation characteristics of the housing-compression system are calculated independently on the left and right sides on the working side and the driving side. Then, the reduction position is set based on the deformation characteristics of the housing-reduction system calculated in step S24a (S25a).
[0173]
(Ii. When only the thrust reaction force of either
　the working roll or the intermediate roll can be measured in the 6-stage rolling mill ) Next, in the 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll. The processing of is explained. First, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified (S20b). The identification process of step S20b may be performed by using, for example, any of the methods for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4 shown in FIGS. 4B or 6B described above. When the process shown in FIG. 9B is executed in parallel with the reduction position setting by the zero point adjustment in FIG. 8B, either step S20b or step S10b in FIG. 8B may be executed.
[0174]
　Next, the reduction device measures the reaction force of the reinforcement rolls acting on the reinforcement rolls 3 and 4 at the reduction fulcrum position in the reduction direction for each reduction position condition for the predetermined kiss roll tightening load, and the work rolls 1 and 1. The thrust reaction force in the roll axis direction acting on 2 or the intermediate rolls 31 and 32 is measured (S21b). Here, the predetermined kiss roll tightening load may be set to an arbitrary value equal to or less than the maximum load that can be applied by the rolling mill. For example, in the case of a hot rolling mill, it may be set to about 1000 tonf.
[0175]
　Then, based on the thrust reaction force action point positions of the reinforcing rolls 3 and 4 previously identified in step S20b, the thrust reaction force of the reinforcing rolls 3 and 4 and the working rolls 1 and 2 or the intermediate rolls 31 and 32 are measured. The thrust reaction force of the non-existing one, and the thrust force acting on all rolls (that is, working rolls 1, 2, intermediate rolls 31, 32, and reinforcing rolls 3, 4) and the laterality of the linear load distribution are calculated. (S22b).
[0176]
　The thrust reaction force action point positions of the reinforcing rolls 3 and 4 are set to the thrust reaction force action point positions corresponding to each kiss roll tightening load. The left-right difference between the thrust reaction force, the thrust force, and the linear load distribution can be obtained by calculating the above-mentioned equilibrium condition equation for the force in the roll axis direction and the equilibrium condition equation for the moment. That is, the equilibrium condition equation regarding the force in the roll axial direction of the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 shown in the equations (2-1) to (2-6), and the above equation (2). It can be obtained based on the equilibrium condition equation of the moments of the working rolls 1 and 2, the intermediate rolls 31 and 32 and the reinforcing rolls 3 and 4 shown in -7) to (2-12).
[0177]
　Then, based on the calculation result of step S22b, the deformation amounts of all the rolls under each reduction position condition are calculated including the left-right difference, and the displacement generated at the reduction fulcrum positions of the reinforcing rolls 3 and 4 is calculated by the calculated deformation amount. (S23b). The amount of deformation of the roll is, for example, roll bending and roll equality, and is calculated for the working rolls 1 and 2, the intermediate rolls 31 and 32, and the reinforcing rolls 3 and 4. In step S23b, the amount of deformation of the roll system for each reduction position condition is calculated.
[0178]
　After that, the deformation characteristic of the housing-rolling system of the rolling mill is calculated by subtracting the deformation amount of the roll system calculated in step S23b from the deformation amount of the entire rolling mill at the rolling fulcrum position evaluated by the change of the rolling position. (S24b). The deformation characteristics of the housing-compression system are calculated independently on the left and right sides on the working side and the driving side. Then, the reduction position is set based on the deformation characteristics of the housing-reduction system calculated in step S24b (S25b).
[0179]
　The reduction position setting process based on the deformation characteristics of the housing-reduction system has been described above. In the reduction position setting process based on the deformation characteristics of the housing-reduction system, the thrust reaction force action point positions of the reinforcement rolls 3 and 4 are identified by using the above-mentioned method for identifying the thrust reaction force action point positions of the reinforcement rolls 3 and 4. This makes it possible to obtain the deformation characteristics of the housing-compression system with higher accuracy. As a result, the rolling position of the rolling mill can be adjusted accurately.
[0180]
　When a plurality of reduction zero adjustment loads are used, a plurality of levels of thrust force may be measured at each of the plurality of levels of the reduction zero adjustment load, or the rolling load and the thrust reaction of the reinforcing rolls 3 and 4 may be measured. A model or table representing the correspondence with the position of the force acting point may be used.
[0181]
　[2-3. Control of rolling position during rolling]
(1) When only the asymmetry of linear load is considered as the asymmetry of linear load distribution
　Next, the control of rolling position during rolling will be described with reference to FIGS. 10A to 11B. FIG. 10A is a schematic view showing a thrust force in the roll axis direction acting on each roll of the four-stage rolling mill 100 during rolling and an asymmetric component between the working side and the driving side in the vertical direction. FIG. 10B is a schematic view showing a thrust force in the roll axis direction acting on each roll of the 6-stage rolling mill 200 during rolling and an asymmetric component between the working side and the driving side in the vertical direction. 11A and 11B are flowcharts showing rolling position control during rolling. The process shown in FIG. 11A can be executed in a rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing rolls, and can be applied to a rolling mill having four or more stages. The process shown in FIG. 11B is applicable to a 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll.
[0182]
(In the case of a 4-stage rolling mill) In the
　normal 4-stage rolling mill shown in FIG. 10A, at the thrust reaction force in the roll axial direction acting on the upper and lower working rolls 1 and 2, and at each rolling fulcrum position of the upper reinforcing roll 3. The reinforcing roll reaction force acting in the rolling direction is measured. In this case, among the forces involved in the roll axis direction of the force and equilibrium condition concerning moment acting on the upper work roll 1 and the upper backup roll 3, unknowns, T B T , T WB T , p df WB T , p Df , H B T a five.
[0183]
　The above unknowns do not include the thrust force TMW acting between the rolled material S and the working rolls 1 and 2, for the following reasons. The thrust force between the rolls is due to the contact between the elastic bodies. Since the magnitudes of the roll peripheral speeds on the contact surfaces are almost the same, the frictional force vector rolls when the roll axial components of the peripheral speed vectors of the rolls that are in contact with each other are inconsistent due to the generation of a minute cross angle between rolls. The direction is along the axial direction. For example, when a minute cross angle between rolls of about 0.2 ° is generated, the ratio of the thrust force in the roll axis direction to the rolling load is about 30%, which is almost equal to the friction coefficient.
[0184]
　On the other hand, in the case of the thrust force acting between the rolled material S and the working rolls 1 and 2, the speed of the rolled material S and the peripheral speeds of the working rolls 1 and 2 are obtained at a place other than the neutral point in the roll bite. The sizes themselves do not match. Therefore, the direction of the frictional force vector does not match the roll axis direction even when an inter-roll cross angle of about 1 ° is given as in a roll cross mill. Therefore, the thrust force obtained by integrating the roll axial component of the frictional force vector in the roll bite is significantly smaller than the friction coefficient and is about 5%. Therefore, in the case of a normal rolling mill that does not positively cross the working rolls 1 and 2, the cross-roll angle that can be caused by the gap between the roll chock and the housing is usually 0.1 ° or less. Therefore, the thrust force TMW acting between the rolled material S and the working rolls 1 and 2 can be ignored.
[0185]
　The equations that can be used to obtain the above five unknowns are the two equilibrium conditional equations for the forces of the upper working roll 1 and the upper reinforcing roll 3 in the roll axial direction, and the equilibrium of the moments for the upper working roll 1 and the upper reinforcing roll 3. There are a total of four conditional equations. Since there are five unknowns for these four equations, it is necessary to measure or identify one unknown in order to obtain all the unknowns. In this case as well, it is realistic to identify in advance the position of the thrust reaction force acting on the upper reinforcing roll chocks 7a and 7b, as in the process of identifying the position of the thrust reaction force acting point of the reinforcing rolls 3 and 4. It becomes a solution. In this case, all the unknowns can be obtained by simultaneously solving the equilibrium conditional equations relating to the forces and moments of each roll for the remaining four unknowns. If the above unknowns are obtained, it is possible to accurately calculate the deformation of the upper roll assembly, including the asymmetric deformation between the working side and the driving side.
[0186]
　For the lower roll assembly, the difference between the working side and the driving side of the linear load distribution between the rolled material S and the working roll 2 has already been obtained. This is equal to the equilibrium condition of the force acting on the rolled material S. Therefore, it is possible to calculate the linear load distribution between the lower working roll 2 and the lower reinforcing roll 4 including the asymmetric deformation between the working side and the driving side. The equations that can be applied when solving this problem are a total of four equilibrium conditional equations relating to the force and moment in the roll axis direction of the lower working roll 2 and the lower reinforcing roll 4. For example, the unknowns relating to the equation of if you can not even measure the thrust reaction force rolls reaction force of the lower roll assembly, T B B , T WB B , T W B , p df WB B , P df B , h B B of There will be 6 pieces.
[0187]
　Of these, if the positions of the thrust reaction force acting points acting on the lower reinforcing roll chocks 8a and 8b can be identified in advance, the number of unknowns is five. Further, in a well-controlled rolling mill, the thrust force TWB B acting between the lower working roll 2 and the lower reinforcing roll 4 may be negligibly small. In this case, by setting the thrust force T WB B to zero, it is possible to obtain all the remaining unknowns. Even if such a condition is not satisfied, it is possible to obtain all the remaining unknowns by making at least one of the above unknowns known or actually measuring it. More preferably, if the difference between the thrust reaction force of the working roll 2 and the working side and the driving side of the reinforcing roll reaction force can be measured for the lower roll assembly, the number of unknowns is less than the number of equations. In this case, by finding the minimum squared solution, more accurate calculation becomes possible.
[0188]
(In the case
　of a 6-stage rolling mill) In the 6-stage rolling mill shown in FIG. 10B, the thrust reaction force in the roll axial direction acting on the upper and lower working rolls 1 and 2 and the intermediate rolls 31 and 32, and each of the upper reinforcing rolls 3 The reinforcing roll reaction force acting in the rolling direction at the rolling fulcrum position is measured. In this case, among the forces involved in the upper work roll 1, the upper intermediate roll 31 and the roll axis direction of the force and equilibrium condition concerning moment acting on the upper backup roll 3, is unknown, T B T , T IB T , T WI T , the p- Df IB T , the p- Df WI T , the p- Df , H B T a seven. In these unknowns, as described in the case of the four-stage rolling mill described above, the thrust force TMW acting between the rolled material S and the working rolls 1 and 2 has a magnitude that can be ignored. Therefore, it is not included.
[0189]
　The equations that can be used to obtain the above seven unknowns are three equilibrium conditional equations regarding the force in the roll axis direction of the upper working roll 1, the upper intermediate roll 31, and the upper reinforcing roll 3, and the upper working roll 1 and the upper intermediate roll. There are a total of 6 moment equilibrium conditional equations for 31 and the upper reinforcing roll 3. Since there are seven unknowns for these six equations, it is necessary to measure or identify one unknown in order to obtain all the unknowns. In this case as well, it is realistic to identify in advance the position of the thrust reaction force acting on the upper reinforcing roll chocks 7a and 7b, as in the process of identifying the position of the thrust reaction force acting point of the reinforcing rolls 3 and 4. It becomes a solution. In this case, all the unknowns can be obtained by simultaneously solving the equilibrium conditional equations relating to the forces and moments of each roll for the remaining 6 unknowns. If the above unknowns are obtained, it is possible to accurately calculate the deformation of the upper roll assembly, including the asymmetric deformation between the working side and the driving side.
[0190]
　For the lower roll assembly, the difference between the working side and the driving side of the linear load distribution between the rolled material S and the working roll 2 has already been obtained. This is equal to the equilibrium condition of the force acting on the rolled material S. Therefore, it is possible to calculate including the asymmetric deformation between the lower working roll 2 and the lower intermediate roll 32, and the linear load distribution between the lower intermediate roll 32 and the lower reinforcing roll 4 on the working side and the driving side. Become. The equations that can be applied when solving this problem are a total of six equilibrium conditional equations relating to the forces and moments of the lower working roll 2, the lower intermediate roll 32, and the lower reinforcing roll 4 in the roll axial direction. For example, the unknowns relating to the equation of if you can not also measured thrust counterforces also rolls reaction force of the lower roll assembly, T W B , T I B , T B B , T WI B , T IB B , p df WI B , the p- Df IB B , P Df B , H B B becomes nine.
[0191]
　Of these, if the positions of the thrust reaction force acting points acting on the lower reinforcing roll chocks 8a and 8b can be identified in advance, the number of unknowns is eight. Furthermore, the well managed mill lower work rolls 2 and the lower intermediate roll 32, and the thrust force T acting between the lower intermediate roll 32 and the lower backup roll 4 WI B , T IB B is negligible May be as small as. In this case, by setting the thrust forces T WI B and T IB B to zero, it is possible to obtain all the remaining unknowns. Even if such a condition is not satisfied, it is possible to obtain all the remaining unknowns by making at least two of the above unknowns known or actually measuring them. More preferably, even for the lower roll assembly, if the difference between the thrust reaction force of the working roll 2 and the intermediate roll 32 and the reinforcing roll reaction force between the working side and the driving side can be measured, the number of unknowns is less than the number of equations. In this case, by finding the minimum squared solution, more accurate calculation becomes possible.
[0192]
　If the above unknowns are obtained, it is possible to accurately calculate the deformation of the lower roll assembly, including the asymmetric deformation between the working side and the driving side. As a result, the roll deformation of the upper and lower roll assemblies is totaled, and the deformation characteristics of the housing-reduction system calculated as a function of the reinforcing roll reaction force are superimposed on this, and the upper and lower reduction positions are taken into consideration. With respect to the gap between the work rolls 1 and 2, it is possible to accurately calculate the asymmetry between the work side and the drive side. This makes it possible to calculate the plate thickness wedge resulting from the rolling mill deformation.
[0193]
　After making the above preparations, it is possible to calculate the target value of the reduction position operation amount, particularly the leveling operation amount, for achieving the target value of the plate thickness wedge required from the viewpoint of meandering control or camber control. By performing the reduction position control based on this target value, it is possible to suppress the occurrence of meandering or camber with higher accuracy. It should be noted that even when the upper and lower roll assemblies are exchanged in the above description, it can be carried out in exactly the same manner.
[0194]
　Specifically, the rolling position control during rolling can be performed as follows. Such processing is carried out by, for example, the arithmetic unit 21 shown in FIG. 1A or FIG. 1B.
[0195]
(I. When the thrust reaction force of all rolls other than the reinforcing roll can be measured)
　First, processing with a four-stage or more rolling mill capable of measuring the thrust reaction force of all rolls other than the reinforcing roll will be described. As shown in FIG. 11A, first, the reinforcing roll reaction force acting on the rolling fulcrum positions of the upper and lower reinforcing rolls 3 and 4 during rolling and the thrust reaction force acting on all the rolls other than the upper and lower reinforcing rolls 3 and 4 Is measured (S31a). The thrust reaction force is measured for the upper work roll 1 and the lower work roll 2 in the case of a 4-stage rolling mill, and in the case of a 6-stage rolling mill, the upper work roll 1 and the lower work roll 2 and the upper intermediate roll 31 and Measured with respect to the lower intermediate roll 32.
[0196]
　Then, based on the equilibrium condition equation for the force in the roll axial direction acting on all the rolls and the equilibrium condition equation for the moment, the thrust reaction force of the reinforcing rolls 3 and 4, the thrust reaction force acting between all the rolls, and the linear load. The laterality of the distribution and the laterality of the thrust force and linear load distribution acting between the work rolls 1 and 2 and the rolled material S are calculated (S32a). Here, between all the rolls is between the working roll and the reinforcing roll in the case of a 4-stage rolling mill, between the working roll and the intermediate roll in the case of a 6-stage rolling mill, and between the intermediate rolls. Between the and the reinforcing roll. At this time, the rolling load and the thrust reaction force action point position obtained by using any of the methods for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4 shown in FIGS. 4A, 5 or 6A. The thrust reaction force action point position corresponding to the rolling load is specified from the model or table representing the correspondence relationship, and the above value is calculated based on the thrust reaction force action point position. As a result, these values ​​can be obtained with high accuracy.
[0197]
　If a model or table has not been obtained, the thrust reaction force action point positions identified in advance by the method shown in FIGS. 4A, 5 or 6A can be used for the rolling load assumed during rolling. Good. As the assumed rolling load, for example, the rolling load obtained by the setting calculation may be used, or the rolling load estimated from the actual value corresponding to the steel type and the plate size may be used.
[0198]
　Further, based on the calculation result of step S32a, the deformation amounts of all the rolls are calculated including the left-right difference, and the deformation characteristics of the housing-rolling system of the rolling mill 100 are calculated as a function of the reinforcing roll reaction force. Then, the plate thickness distribution of the rolled material S at the present time is calculated (S33a). The amount of deformation of the roll is, for example, roll bending and roll equality, and is calculated for the working rolls 1 and 2, the intermediate rolls 31 and 32, and the reinforcing rolls 3 and 4. In step S33a, the actual value of the plate thickness distribution of the rolled material S at the present time is estimated.
[0199]
　After that, the target value of the rolling position operation amount is calculated based on the target plate thickness distribution in the rolling mill and the actual value of the plate thickness distribution at the present time estimated in step S33a (S34a). Then, the reduction position is controlled based on the target value of the reduction position operation amount calculated in step S34a (S35a).
[0200]
(Ii. When only the thrust reaction force of either
　the working roll or the intermediate roll can be measured in the 6-stage rolling mill ) Next, in the 6-stage rolling mill that can measure only the thrust reaction force of either the working roll or the intermediate roll. The processing of is explained. As shown in FIG. 11B, first, the reinforcing roll reaction force acting on the rolling fulcrum positions of the upper and lower reinforcing rolls 3 and 4 during rolling and the upper and lower working rolls 1 and 2 or the upper and lower intermediate rolls 31 and 32 act on them. The thrust reaction force is measured (S31b).
[0201]
　Next, among the thrust reaction forces of the reinforcing rolls 3 and 4, the working rolls 1, 2 or the intermediate rolls 31 and 32, based on the equilibrium condition equation regarding the force in the roll axial direction acting on all the rolls and the equilibrium condition equation regarding the moment. The left-right difference between the unmeasured thrust reaction force and the thrust force acting on all rolls (that is, working rolls 1, 2, intermediate rolls 31, 32 and reinforcing rolls 3, 4) and the linear load distribution is calculated. (S32b). At this time, the correspondence between the rolling load obtained by using either of the methods for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4 shown in FIGS. 4B or 6B and the thrust reaction force action point positions is shown. The thrust reaction force action point position according to the rolling load is specified from the represented model or table, and the above value is calculated based on the thrust reaction force action point position. As a result, these values ​​can be obtained with high accuracy.
[0202]
　If a model or table has not been obtained, the thrust reaction force action point position identified in advance by the method shown in FIG. 4B or FIG. 6B may be used for the rolling load assumed during rolling. As the assumed rolling load, for example, the rolling load obtained by the setting calculation may be used, or the rolling load estimated from the actual value corresponding to the steel type and the plate size may be used.
[0203]
　Further, based on the calculation result of step S32b, the deformation amounts of all the rolls are calculated including the left-right difference, and the deformation characteristics of the housing-rolling system of the rolling mill 200 are calculated as a function of the reinforcing roll reaction force. Then, the plate thickness distribution of the rolled material S at the present time is calculated (S33b). The amount of deformation of the roll is, for example, roll bending and roll equality, and is calculated for the working rolls 1 and 2, the intermediate rolls 31 and 32, and the reinforcing rolls 3 and 4. In step S33b, the actual value of the plate thickness distribution of the rolled material S at the present time is estimated.
[0204]
　After that, the target value of the rolling position operation amount is calculated based on the target plate thickness distribution in the rolling mill and the actual value of the plate thickness distribution at the present time estimated in step S33b (S34b). Then, the reduction position is controlled based on the target value of the reduction position operation amount calculated in step S34b (S35b).
[0205]
　The reduction position control during rolling has been described above. In the reduction position control during rolling, the thrust reaction force action point positions of the reinforcing rolls 3 and 4 are identified by using the above-mentioned method for identifying the thrust reaction force action point positions of the reinforcing rolls 3 and 4, with higher accuracy. It is possible to obtain the target value of the rolling position operation amount. As a result, it becomes possible to accurately control the rolling position of the rolling mill.
[0206]
(2) When the asymmetry of the linear load and the off-center amount are considered as the asymmetry of the linear load distribution In the
　above description, the asymmetry of the linear load distribution between the rolled material S and the working rolls 1 and 2 is used. , Only the difference between the working side and the driving side of the line load was considered. However, as the asymmetry of the distribution of the linear load in the roll axis direction, not only the asymmetry of the linear load but also the case where the center of the rolled material S is passed at a position different from the mill center can be considered.
[0207]
　The distance between the center of the rolled material S and the mill center is referred to as the off-center amount below. The off-center amount is basically suppressed within a predetermined allowable amount by the side guide provided on the entry side of the rolling mill 100. If the amount of off-center that can still occur cannot be ignored, it is preferable to estimate from, for example, the measured value by the meandering sensor provided on the entry side or the exit side of the rolling mill 100. Further, when the meandering sensor cannot be installed and an off-center amount that cannot be ignored can occur, the off-center amount can be obtained by, for example, adopting the following method.
[0208]
　From the equilibrium condition equation for the moments of the working rolls 1 and 2, two unknowns, the off-center amount and the difference between the working side and the driving side of the linear load distribution between the rolled material S and the working rolls 1 and 2, are separated. It is impossible to extract. Therefore, there are cases where the above-mentioned off-center amount is set to zero and only the difference between the working side and the driving side of the line load is unknown, and where the difference between the working side and the driving side of the line load is zero and the off-center amount is unknown. For these two, the target value of the reduction position operation amount is calculated. For example, the target value of the actual reduction position operation amount is determined from the weight average of the calculation results of both. This weighting method will be adjusted as appropriate while observing the rolling conditions. As a general theory, a large weight is given to the side with a small reduction position operation amount to make it a control output, or the value with the smaller operation amount is adopted, and the tuning factor (usually 1.0 or less) is set for the operation amount. A method of multiplying to obtain a control output is realistic.
[0209]
　Further, in the case where the rolling mill 100 is not a 4-step rolling mill but a 6-step rolling mill in which the number of intermediate rolls is further increased, the contact region between rolls is increased by one place for each additional intermediate roll. In this case as well, if the thrust reaction force of the intermediate roll is measured, the two unknowns that increase are the thrust force acting on the added inter-roll contact region and the difference between the working side and the driving side of the linear load distribution. Is. On the other hand, the number of available equations will be increased by two, the equilibrium condition equation for the force in the roll axis direction of the intermediate roll and the equilibrium condition equation for the moment. It is possible to find a solution.
[0210]
　In this way, even in the case of a rolling mill with four or more stages, by measuring the thrust reaction force acting on at least all the rolls except the reinforcing rolls, the working side of the linear load distribution acting between the rolls during rolling can be measured. It is possible to obtain all unknowns including the difference from the drive side. As a result, it is possible to calculate the optimum rolling position operation amount as in the case of the 4-stage rolling mill.
[0211]
　[3. Summary] As described
　above, the reduction position setting and reduction performed based on the method for identifying the thrust reaction force action point position of the reinforcing roll according to the present embodiment and the relationship between the rolling load and the thrust reaction force action point position identified by this method. Position control has been described. According to the present embodiment, in a kiss roll state in which the rolls are tightened and brought into contact with each other by a reduction device at a plurality of levels, a roll acting on each roll constituting at least one of the roll pairs other than the reinforcing rolls. In addition to measuring the thrust reaction force in the axial direction, the first step of measuring the reinforcing roll reaction force acting on each reinforcing roll in the rolling direction at the reduction fulcrum position, and the thrust reaction acting on each measured roll. Based on the force, the thrust reaction force of the thrust reaction force acting on the reinforcing roll is used by using the first equilibrium condition formula for the force acting on each roll and the second equilibrium condition formula for the moment generated on each roll. A second step of identifying the position of the point of action is carried out. This makes it possible to easily identify the position of the thrust reaction force acting point of the reinforcing roll even when the working roll is not rearranged, for example, during the idle time of the rolling mill.
[0212]
　Further, by acquiring the relationship between the tightening load in the kiss roll state and the thrust reaction force action point position by the above identification method, the thrust reaction force action that changes according to the rolling load in the reduction position setting and the reduction position control. The point position can be set accurately. As a result, it becomes possible to set and control the reduction position with high accuracy.
Example
[0213]
　The cross angle between the rolls was changed for the stand of the hot finish rolling mill having the configurations shown in FIGS. 1A and 1B, and the position of the thrust reaction force action point was identified. In each of the comparative examples, the method shown in Patent Document 2 was used. That is, after the rolls other than the reinforcing rolls were pulled out from the stand, the positions of the thrust reaction force action points were identified, and then the rolls were incorporated into the stand. On the other hand, in the example, the position of the thrust reaction force action point was identified without removing the roll.
[0214]
　Table 1 shows the results of Comparative Examples and Examples performed by the 4-stage rolling mill shown in FIG. 1A, and Table 2 shows the results of Comparative Examples and Examples performed by the 6-stage rolling mill shown in FIG. 1B. The measurement time was the same in the comparative example and the example in both the 4-stage rolling mill and the 6-stage rolling mill. On the other hand, the roll rearrangement time was 70 to 80 minutes in the comparative example, but was 0 minutes in the example because it was not necessary to remove the roll. Therefore, in the embodiment, the total time of the roll rearrangement time and the measurement time can be significantly shortened, and the decrease in productivity can be minimized.
[0215]
[table 1]

[0216]
[Table 2]

[0217]
　Further, in the comparative example, in order to identify the position of the thrust reaction force action point, it is necessary to remove the roll other than the reinforcing roll from the stand. Therefore, in the comparative example, the change with time due to wear of various sliding portions of the rolling mill, etc., which occurred before the roll rearrangement is not taken into consideration, the identification accuracy is lowered. On the other hand, in the embodiment, since it is not necessary to remove the roll, the position of the thrust reaction force action point can be identified in consideration of the change with time due to wear of various sliding portions of the rolling mill.
[0218]
　Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical ideas described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.
Code description
[0219]
　1 Upper work roll
　2 Lower work roll
　3 Upper reinforcement roll
　4 Lower reinforcement roll
　5a Upper work roll chock (work side)
　5b Upper work roll chock (drive side)
　6a Lower work roll chock (work side)
　6b Lower work roll chock (drive side)
　7a Upper Reinforcing roll chock (working side)
　7b Upper reinforcing roll chock (driving side)
　8a Lower reinforcing roll chock (working side)
　8b Lower reinforcing roll chock (driving side)
　9a Upper load detecting device (working side)
　9b Upper load detecting device (driving side)
　10a Lower Load detection device (work side)
　10b Lower load detection device (drive side)
　11 Housing
　12a Press block (work side)
　12b Press block (drive side)
　13a Screw (work side)
　13b Screw (drive side)
　14 Reduction device drive mechanism
　15a Work roll shift device (upper work roll)
　15b Work roll shift device (lower work roll)
　15c Intermediate roll shift device (upper middle roll)
　15d Intermediate roll shift device (lower middle roll) )
　16a thrust reaction force measuring device (upper work
　roll) 16b thrust reaction force measuring device (lower work
　rolls) 16c thrust reaction force measuring device (upper intermediate
　roll) 16d thrust reaction force measuring device (lower intermediate roll)
　21 arithmetic unit
　23 pressure Device drive mechanism Control device
　31 Upper intermediate roll
　32 Lower intermediate roll
　41a Upper intermediate roll chock (working side)
　41b Upper intermediate roll chock (driving side)
　42a Lower intermediate roll chock (working side)
　42b Lower intermediate roll chock (driving side)
　100, 200 Roller
The scope of the claims
[Claim 1]
　A method of identifying the position of a thrust reaction force acting point in a
　rolling mill , wherein the rolling mill comprises a plurality of roll pairs including at least a pair of working rolls and a pair of reinforcing rolls supporting the working rolls. It is a four-stage or more rolling mill having rolls, and a
　plurality of levels of thrust force is applied between the rolls by changing at least one of the friction coefficient between the rolls or the cross angle between the rolls under the same tightening load. In 　the kiss roll state in which the rolls are tightened and brought into contact with
　each other by the
reduction device at each of the plurality of levels relating to the thrust force , the rolls other than the reinforcing rolls are subjected to at least one roll pair.
　The first step of measuring the thrust reaction force in the rolling axis direction acting and measuring the reinforcing roll reaction force acting in the rolling direction with respect to each of the reinforcing rolls at the reduction fulcrum position, and the
　measured rolls. Based on the thrust reaction force and the reinforcing roll reaction force acting on the rolls, the first equilibrium condition equation for the force acting on each roll and the second equilibrium condition equation for the moment generated on each roll are used. A
method for identifying a thrust reaction force point position , which comprises a second step of identifying the thrust reaction force action point position of the thrust reaction force acting on the reinforcing roll .
[Claim 2]
　In the first step, for all roll pairs other than the reinforcing rolls, the thrust reaction force in the roll axial direction acting on each roll constituting the roll pair is measured, and at the
　reduction fulcrum position, each of the reinforcing rolls is measured. The method for identifying the position of a thrust reaction force acting point according to claim 1, wherein the reinforcing roll reaction force acting in the downward direction with respect to the force is measured.
[Claim 3]
　The rolling mill can cross at least the roll axial direction of the upper roll assembly including the upper working roll and the upper reinforcing roll and at least the roll axial direction of the lower roll assembly including the lower working roll and the lower reinforcing roll. It is a four-stage rolling mill, and in
　the first step, the thrust force of the plurality of levels is applied between the rolls by changing the cross angle between the rolls of the upper working roll and the lower working roll. The method for identifying a thrust reaction point position according to claim 2.
[Claim 4]
　The rolling mill is provided with an external force applying device that applies different rolling direction external forces to the working side roll chock and the driving side roll chock with respect to at least one of the rolls, and in
　the first step, the external force applying device is provided. By applying different rolling direction external forces to the working side roll chock and the driving side roll chock of the roll, the cross angle between the rolls with respect to all the roll systems of the roll is changed, and the thrust force of the plurality of levels is applied between the rolls. , The method for identifying the position of the thrust reaction force action point according to claim 2.
[Claim 5]
　In each of the kiss roll states, based on the result of identifying the thrust reaction force action point position of the reinforcing roll at the plurality of levels with respect to the thrust force at each of the plurality of levels of the tightening load in the second step. The method for identifying the thrust reaction force action point position according to any one of claims 1 to 4, wherein the relationship between the tightening load and the thrust reaction force action point position is acquired.
[Claim 6]
　The step of identifying the thrust reaction force action point position of the reinforcing roll by the method of identifying the thrust reaction force action point position of any one of claims 2 to 5 and the
　roll being tightened and brought into contact with the rolling mill. In the kiss roll state, for all roll pairs other than the reinforcing roll, the thrust reaction force in the roll axial direction acting on each roll constituting the roll pair is measured, and rolling is performed on each of the reinforcing rolls at the rolling fulcrum position. Based on the step of measuring the reinforcing roll reaction force acting in the direction,
　the measured value of the thrust reaction force, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll. Then
　, based on the step of calculating at least one of the zero point position of the rolling mill or the deformation characteristic of the rolling mill and the calculation result, the rolling material that sets the rolling position by the rolling mill at the time of rolling execution. Rolling method.
[Claim 7]
　The step of identifying the thrust reaction force action point position of the reinforcing roll in advance by the method of identifying the thrust reaction force action point position of any one of claims 2 to 5
　, and
　at least during the rolling of the rolled material, the upper working roll. The thrust reaction force in the roll axial direction acting on the rolls other than the reinforcing rolls in either the upper roll assembly including the upper reinforcing roll or the lower working roll and the lower roll assembly including the lower reinforcing roll is measured, and the thrust reaction force is measured. At least for the reinforcing roll of the roll assembly for measuring the thrust reaction force, a step of measuring the reinforcing roll reaction force acting on the reinforcing roll in the rolling direction at the reduction fulcrum position,
　a measured value of the thrust reaction force, and the measurement value of the thrust reaction force. A step of calculating a target value of a reduction position operation amount corresponding to a rolling load based on a measured value of the reinforcement roll reaction force and the thrust reaction force action point position of the identified reinforcement roll, and a
　reduction position. A
method for rolling a rolled material , which comprises a step of controlling a reduction position by the reduction device based on a target value of an operation amount .
[Claim 8]
　The step of identifying the thrust reaction force action point position of the reinforcing roll in advance by the method of identifying the thrust reaction force action point position of any one of claims 2 to 5
　, and
　at least during the rolling of the rolled material, the upper working roll. The thrust reaction force in the roll axial direction acting on the rolls other than the reinforcing rolls in either the upper roll assembly including the upper reinforcing roll or the lower working roll and the lower roll assembly including the lower reinforcing roll is measured, and the thrust reaction force is measured. At least for the reinforcing roll of the roll assembly for measuring the thrust reaction force, a step of measuring the reinforcing roll reaction force acting on the reinforcing roll in the rolling direction at the reduction fulcrum position,
　a measured value of the thrust reaction force, Based on the measured value of the reinforcing roll reaction force and the position of the thrust reaction force acting point of the identified reinforcing roll, at least the thrust force acting between the reinforcing roll and the roll in contact with the reinforcing roll is considered. Then, the asymmetry of the roll axial distribution of the rolling load acting between the rolled material and the working roll is calculated, and
　the target value of the reduction position operation amount corresponding to the rolling load is calculated based on the calculation result. A method for rolling a rolled material
　,
which comprises a step of controlling the rolling position by the reduction device based on a target value of the reduction position operation amount .
[Claim 9]
　The rolling mill comprises a pair of work rolls, said pair of supporting the work rolls of the intermediate rolls and the pair of rolls, a rolling mill of the six stages with three pairs of rollers,
　in the first step, the For either the roll pair of the intermediate roll or the roll pair of the working roll, the thrust reaction force in the roll axial direction acting on each roll constituting the roll pair is measured
　, and at the rolling fulcrum position, each of the reinforcing rolls is subjected to the measurement. The method for identifying the position of a thrust reaction force acting point according to claim 1, wherein the reinforcing roll reaction force acting in the rolling direction is measured.
[Claim 10]
　The rolling mill is provided with an external force applying device that applies different rolling direction external forces to the working side roll chock and the driving side roll chock with respect to at least one of the rolls, and in
　the first step, the external force applying device is provided. By applying different rolling direction external forces to the working side roll chock and the driving side roll chock of the roll, the cross angle between the rolls with respect to all the roll systems of the roll is changed, and the thrust force of the plurality of levels is applied between the rolls. , The method for identifying the position of the thrust reaction force action point according to claim 9.
[Claim 11]
　In each of the kiss roll states, based on the result of identifying the thrust reaction force action point position of the reinforcing roll at the plurality of levels with respect to the thrust force at each of the plurality of levels of the tightening load in the second step. The method for identifying the thrust reaction force action point position according to claim 9 or 10, wherein the relationship between the tightening load and the thrust reaction force action point position is acquired.
[Claim 12]
　The step of identifying the thrust reaction force action point position of the reinforcing roll by the method of identifying the thrust reaction force action point position of any one of claims 9 to 11 and the
　roll being tightened and brought into contact with the rolling mill. In the kiss-roll state, for either the roll pair of the intermediate roll or the roll pair of the working roll, the thrust reaction force in the roll axis direction acting on each roll constituting the roll pair is measured, and each at the rolling fulcrum position. The step of measuring the reinforcing roll reaction force acting in the rolling direction on the reinforcing roll
　, the measured value of the thrust reaction force, the measured value of the reinforcing roll reaction force, and the thrust reaction of the identified reinforcing roll. The step of calculating at least one of the zero point position of the rolling mill or the deformation characteristic of the rolling mill based on the force acting point position, and the rolling position
　by the rolling mill at the time of rolling execution based on the calculation result. How to roll the rolled material.
[Claim 13]
　The step of identifying the thrust reaction force action point position of the reinforcing roll in advance by the method of identifying the thrust reaction force action point position of any one of claims 9 to 11
　, and the
　upper work roll during rolling of the rolled material , In any one of the upper roll assembly including the upper intermediate roll and the upper reinforcing roll or the lower working roll, and the lower roll assembly including the lower intermediate roll and the lower reinforcing roll, in the roll axial direction acting on the intermediate roll or the working roll. A step of measuring the thrust reaction force and at least measuring the reinforcing roll reaction force acting on the reinforcing roll in the reducing direction at the reduction fulcrum position for the reinforcing roll of the roll assembly for measuring the thrust reaction force, and the
　above. Based on the measured value of the thrust reaction force, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll, the target value of the reduction position operation amount corresponding to the rolling load is set. A method for rolling a rolled material
　,
which comprises a step of calculating and a step of controlling a reduction position by the reduction device based on a target value of the reduction position operation amount .
[Claim 14]
　The step of identifying the thrust reaction force action point position of the reinforcing roll in advance by the method of identifying the thrust reaction force action point position according to any one of claims 9 to 11
　, and the
　upper work roll during rolling of the rolled material . In any one of the upper roll assembly including the upper intermediate roll and the upper reinforcing roll or the lower working roll, and the lower roll assembly including the lower intermediate roll and the lower reinforcing roll, in the roll axial direction acting on the intermediate roll or the working roll. A step of measuring the thrust reaction force and at least measuring the reinforcement roll reaction force acting on the reinforcement roll in the reduction direction at the reduction fulcrum position for the reinforcement roll of the roll assembly for measuring the thrust reaction force, and the
　above. Based on the measured value of the thrust reaction force, the measured value of the reinforcing roll reaction force, and the position of the thrust reaction force acting point of the identified reinforcing roll, at least the reinforcing roll and the roll in contact with the reinforcing roll The asymmetry of the roll axial distribution of the rolling load acting between the rolled material and the working roll is calculated in consideration of the thrust force acting between them, and the
　reduction corresponding to the rolling load is calculated based on the calculation result. A method for rolling a rolled material ,
　comprising a step of calculating a target value of a position manipulated amount and a step of controlling a
rolling position by the rolling device based on the target value of the rolling position manipulation amount .