0001]The present invention relates to a front axle beam and a manufacturing method thereof.
BACKGROUND
[0002]Front axle beam (hereinafter may be referred to as "front axle") is primarily a vehicle (e.g. a truck or bus, etc. (however, two-wheeled vehicles are excluded)) front wheel mounted to support the vehicle body They are used to. The front axle, as a component for transmitting the load of the vehicle body to the left and right front wheels, and, as a structural safety components, is important. The front axle, by securing a front wheel of the steering performance while securing the wheel in position, responsible for the running stability. Further, during braking, the front axle is a transmission path for transmitting the braking forces of the wheels. In this way, the front axle, running property, a steering resistance, and strongly affect parts in braking performance. Since required high rigidity for the front axle, the front axle weight is greater. On the other hand, from the viewpoint of fuel efficiency, weight reduction of the front axle is required.
[0003]
　In general, for the running stability of the vehicle, heavy object is disposed in a low position of the vehicle height direction of the vehicle. That is, the position of the engine mounted on the front axle is preferably mounted on a lower vehicle height direction position. Kingpin mounting portion is provided at both ends of the front axle. It is attached underbody parts to the front wheels of the vehicle. Kingpin is inserted into a front wheel of the undercarriage parts through the kingpin mounting portion from the vehicle height direction improves side connecting the front axle and the front wheels. The front wheel is pivoted a king pin in the axial turn off the steering of the vehicle by the configuration. Because of this configuration, as shown in FIG. 2, front axle, for example, vehicle-widthwise center is low in vehicle height direction, the vehicle width direction end portion is higher in the vehicle height direction, a bow shape. The front axle cross-section is in the H-type, but is not produced by the universal rolling machine as H-section steel. Because the arcuate shape is can not be molded by a universal rolling mill.
[0004]
　Normally, the front axle is produced by die forging. For forging, for example, as shown in FIG. 14, the angle Q for demolding, the draft of Q 'is required. Therefore, the shape of the front axle is limited. As a result, improvement of the rigidity of the front axle is limited.
[0005]
　JP 2003-285771 (Patent Document 1) proposes a front axle which can reduce the aerodynamic resistance during vehicle travel. The invention described in Patent Document 1 is aimed at improving fuel economy by reducing the aerodynamic drag.
[0006]
　Also, it has been proposed also a method for manufacturing the front axle. JP 2009-106955 (Patent Document 2) discloses a manufacturing method of the axle beam with a pair of left and right spring seat. In this manufacturing method, press molding one of the spring seat in the first round of the pressing process, press-molding the other spring seat at the second pressing step.
[0007]
　One strategy lighter front axle, and to increase the rigidity of the front axle. If it is possible to increase the rigidity of the front axle, the same rigidity as the conventional, more or lighter front axle can be realized in a more compact front axle. Further, if it is possible to increase the rigidity of the front axle, with the same cross-sectional size and the same weight as the conventional products, the front axle is possible to improve the various properties concerned. Therefore, new technology that can increase the rigidity of the front axle is required.
[0008]
　On the other hand, around the front axle, the moving parts of the engine and steering are arranged densely. Therefore, the front axle, is also required to fit into tight spaces so as not to interfere with these peripheral parts. Therefore, its rigidity can be enhanced techniques without increasing the cross-sectional size of the front axle, in particular sought.
CITATION
Patent Document
[0009]
Patent Document 1: JP 2003-285771 Patent Publication
Patent Document 2: JP 2009-106955 JP
Summary of the Invention
Problems that the Invention is to Solve
[0010]
　In such circumstances, one object of the present invention, the front axle beam capable of increasing its rigidity, and to provide its manufacturing method.
Means for Solving the Problems
[0011]
　Manufacturing method according to an embodiment of the present invention includes a web portion, a manufacturing method of the front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion. Manufacturing method, in the cross section, forging material in a die paired with the central axis of the web portion at the boundary. Further, in the cross-section, bent towards the flange portion facing the flange portion.
[0012]
　Front axle beam according to an embodiment of the present invention includes a web portion, a front axle beam with a beam portion of the H-shaped cross-section of which comprises a joint the flanges at both ends of the web portion. In the cross section, towards the tip of the spacing of the flange portion opposite from the length of the web portion is narrow.
The invention's effect
[0013]
　According to the present invention, the front axle beam is obtained with high rigidity. According to the production method of the present invention can be easily produced the front axle beam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
[1] Figure 1 is a perspective view schematically showing an example of a front axle of the first embodiment.
FIG. 2 is a diagram showing the front of the front axle as shown in FIG. 1 schematically.
FIG. 3 is a diagram showing the upper surface of the front axle as shown in FIG. 1 schematically.
[4] FIG. 4 is a diagram showing a cross section of the front axle as shown in FIG. 1 schematically.
[Figure 5A] Figure 5A is a perspective view schematically showing a portion of an exemplary forging produced in die forging step of the manufacturing method of the second embodiment.
[Figure 5B] Figure 5B is a diagram illustrating the forging of the cross section shown in FIG. 5A schematically.
[Figure 6A] Figure 6A is a cross-sectional view schematically showing a state before the start of deformation of an example of a bending process.
[Figure 6B] Figure 6B is a cross-sectional view showing a state during deformation completion schematically an example shown in FIG. 6A.
[Figure 7A] Figure 7A is a cross-sectional view of the bending another example state before deformation starting the process shown schematically.
[Figure 7B] Figure 7B is a cross-sectional view showing a state during deformation completion schematically an example shown in FIG. 7A.
[FIG. 8A] Figure 8A is a cross-sectional view of the bending another example state before deformation starting the process shown schematically.
[Figure 8B] Figure 8B is a cross-sectional view showing a state during deformation completion schematically an example shown in FIG. 8A.
FIG 9A] FIG 9A is a cross-sectional view of the bending another example state before deformation starting the process shown schematically.
[FIG. 9B] FIG 9B is a sectional view showing a state during deformation completion schematically an example shown in Figure 9A.
[10] FIG 10 is a diagram showing bending the change in cross-sectional profile of the forging before and after the process.
[11] FIG 11 is a cross-sectional view of the bending another example state before deformation starting the process shown schematically.
[12] FIG 12 is a diagram showing a sectional shape of the sample which is assumed in the examples.
[13] FIG 13 is a diagram showing a method of testing assumed in the examples.
FIG. 14 is a cross-sectional view of a conventional front axle is a diagram schematically illustrating.
DESCRIPTION OF THE INVENTION
[0015]
　As a result of intensive studies, the present inventors have found that to improve the rigidity of the front axle by devising the sectional shape of the front axle. In addition, it was found also method of manufacturing a highly rigid front axle. The present invention is based on this new finding.
[0016]
　Manufacturing method according to an embodiment of the present invention includes a web portion, a manufacturing method of the front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion. Manufacturing method, in the cross section, forging material in a die paired with the central axis of the web portion at the boundary. Further, in the cross-section, bent towards the flange portion facing the flange portion.
[0017]
　In the above manufacturing method, a flange portion bent may be curved.
[0018]
　Front axle beam according to an embodiment of the present invention includes a web portion, a front axle beam with a beam portion of the H-shaped cross-section of which comprises a joint the flanges at both ends of the web portion. In the cross section, towards the tip of the spacing of the flange portion opposite from the length of the web portion is narrow.
[0019]
　If the front axle, in the cross section, the flange portion may be curved.
[0020]
　Said front axle, when comprising at least two spring mounting seat, said transverse surface may be a cross-section between the spring mounting seat.
[0021]
　Further, in another aspect, the manufacturing method according to an embodiment of the present invention is the beam part and the method for producing a front axle beam and two kingpin mounting portions provided respectively on both longitudinal ends of the beam portions . Beam portion includes a web portion extending in the longitudinal direction, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion.
　Manufacturing method,
　a rough web portion comprising a web portion, forging a comprising four coarse flanges top and from the respective lower ends of the shaped plate projecting towards the front and rear of the crude web portion, using a mold Te and die forging forming by forging a steel,
　by pressing at least one first mold at least one specific rough flange portion of the four crude flange portion, the inside of the vertical forging headed and a step bending to form the particular crude flange portion a bent portion that is bent.
[0022]
　In the above manufacturing method, at least one specific rough flange portion may include a first and second specific rough flange are aligned in the longitudinal direction or the vertical direction. The first mold includes a first inclined surface, the angle formed between the first inclined surface may include a second inclined surface is less than 180 °. In this case, the bending process, the first specific crude flange portion press the first inclined surface, and may be done by pressing the second specific crude flange portion by the second inclined surface.
[0023]
　In the above manufacturing method, when a rough flange bend is not formed and a particular rough flange portion are arranged in the longitudinal direction, bending at step not bend is formed rough flange particular crude flange in a fixed state it may be formed bent portion.
[0024]
　In the above manufacturing method, at least one specific crude flange portion, and the first and second specific crude flange portion, may consist third and fourth particular rough flange. In this case, the bending process and, at the same time the first and second specific crude flange pressed by one of the first slope and the second slope of the first die, the third first gold other specific crude flange portion of press the first inclined surface of the mold, and may be carried out by pressing by the second inclined surface of the fourth first mold certain crude flange portion of the other.
[0025]
　In the above manufacturing method, the first specific rough flange portion and a second specific rough flange portion, when in a row in the vertical direction of the forged product, the bending step, the longitudinal direction of the forged product of the first mold it may be performed by causing moved. In this production method, the bending step includes a boundary portion of the two coarse flange portion protruding from the upper end of the rough web portion, and a boundary portion of the two coarse flange portion protruding from the lower end of the rough web portion, from the vertical direction 2 One of the may be performed in a state sandwiched by the second mold.
[0026]
　In the above manufacturing method, the first specific rough flange portion and a second specific rough flange portion, when in a row in the longitudinal direction of the forged product, the bending step, the first mold in the vertical direction of the forged product it may be performed by causing moved. In this production method, the bending step may be performed in a state sandwiched by the second mold from the front and rear direction of the crude web portion of the two coarse web portion.
[0027]
　Further, in another aspect, the front axle beam, according to an embodiment of the present invention is a front axle beam comprising a beam portion, and two kingpin mounting portions provided respectively on both longitudinal ends of the beam portions. Beam portion includes a web portion extending in the longitudinal direction, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion. At least one of the four flange portions is a specific flange portion including the bend portion. Bend it is closer to the end of the bent portion is bent to be closer to the flange portion facing the bent portion.
[0028]
　For the front axle, four flange portions includes two specific flange are aligned in the longitudinal direction or the vertical direction, it is preferable.
[0029]
　Hereinafter, embodiments of the present invention will be described by way of example. The present invention is not limited to the examples described below.
[0030]
　In this specification, when referring to the direction of the members constituting the front axle and which, unless otherwise stated, it refers to a direction in a state of arranging the front axle in the direction of use. For example, the term vertical direction of the front axle, unless otherwise stated, refers to a vertical direction in a state of arranging the front axle in the direction of use. That is, the up and down direction, which is the vehicle height direction of the front axle. Similarly, the horizontal and longitudinal directions, means a direction in a state of arranging the front axle in the direction of use. That is, the horizontal direction is a vehicle width direction of the front axle. The front-rear direction, which is the vehicle length direction of the front axle. Here, the front axle is provided with a beam portion having a H-shaped cross section of the beam portion comprises a plate-shaped web portion, and four plate-like flange portion protruding from both ends of the web portion. When placing the front axle in the direction of use, the beam portion is disposed in a horizontal direction. Furthermore, in cross-section of the front axle, the web portion extends in the vertical direction, the four flange portions projecting in the front-rear direction. Therefore, in the transverse plane of the front axle, the vertical direction is the same direction as the extending direction of the web portion, the front-rear direction is the same direction as the direction orthogonal to the extending direction of the web portion. Incidentally, the front and rear of the front axle, respectively, a front axle means in the same direction as the front and rear of the vehicle to be located. However, if the front axle is in the form of a symmetrical before and after the one direction and the front to the other direction as the rear. Further, when the direction of the member refers constituting intermediate product (such as forging) and it in the production of the front axle, unless otherwise stated, means the same direction as the front axle is a finished product.
[0031]
　(Manufacturing method of the front axle beam)
　the production method of the present embodiment is manufactured and the beam portion, the front axle (front axle beam) comprising two kingpin mounting portions provided respectively on both longitudinal ends of the beam portions it is a method. The beam portion includes a web portion extending in the longitudinal direction, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion. That is, the manufacturing method of this embodiment includes a web portion, in the manufacturing method of the front axle (front axle beam) with a beam portion of H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion, the is there. This manufacturing method includes a die forging process and the bending process described below. In the present disclosure, means that simply integrated in the bonding, does not necessarily mean that joining by means of welding or fastening.
[0032]
　Die forging step is a step of forming a forging (e.g., FIG. 5A and FIG. 5B) by forging a steel material with a mold. The forging includes a coarse web portion comprising a web portion, and four rough flange plate of the respective upper and lower ends protruding toward the front and rear of the coarse web portion. Four of the crude flange portion is a portion to be a four flange portions of the front axle.
[0033]
　That is, in the manufacturing method of this embodiment, die-forging a material (steel) using a pair of molds (forging die). Forging die are paired with the center line of the web portion (coarse web portion) to the boundary.
[0034]
　Usually, the forged article obtained by the die forging process burrs are formed. Therefore, it may be carried out burr punching step between step bending mold forging step. There is no limitation on the burr punching process may be applied to known methods. When performing burr punching process, forgings burr has been removed, is subjected to a bending process.
[0035]
　Bending process, four of the at least one particular crude flange portion by pressing at least one first mold and forgings vertical identify coarse a bent portion that is bent toward the inside of the rough flange a step of forming the flange portion.
[0036]
　That is, in the manufacturing method of this embodiment, bend toward the flange portion (specific rough flange portion) other flange portions facing the (specific crude flanges or not a particular rough flange crude flange portion). Bent flange portion may be curved.
[0037]
　In this specification, when referred to the inner and outer the flanges (or coarse flange portion), unless contrary to the context, refers to inner and outer in the vertical direction VD of the front axle or forging. If the flange portion projecting from the upper end of the web portion (or coarse web portion) (or coarse flange portion), the inner direction means downward, the outer direction means upward. If the flange portion projecting from the lower end of the web portion (or coarse web portion) (or coarse flange portion), the inner direction means upwards, the outward direction refers to lower.
[0038]
　At least one of the four crude flange portion (one, two, three, or four) is a specific rough flange portion including the bend portion (e.g. 132 in FIG. 4). From the viewpoint of production process, it is preferable to bend the two coarse flange are arranged at the same time. Therefore, in a preferred example, a two or four of the particular crude flange portion of the four crude flange portion.
[0039]
　Bend portion may be formed over the entire longitudinal direction of the beam portion may be formed only on part of the length of the beam portion. Normally, the front axle has two spring mounting seat. Bend may be formed on all or part of the region between the two spring mounting seat thereof.
[0040]
　It said at least one specific rough flange portion may include a first and second specific rough flange are aligned in the longitudinal direction or the vertical direction. The first mold includes a first inclined surface, (310a, for example FIG. 6A, 310b) a second slope angle between the first inclined surface is less than 180 ° and may contain. Then, the bending process, the first specific crude flange portion press the first inclined surface, and may be done by pressing the second specific crude flange portion by the second inclined surface.
[0041]
　Angle P formed between the first inclined surface and the second slope may be set to an angle bending process can be carried out is not particularly limited. In one example, the angle P may be in the range of 30 ° ~ 170 °. The angle P may be in the range of 90 ° ~ 160 °. An example of the first mold is a mold recess is formed with a first inclined surface and a second inclined surface. Examples of such recess (see Fig. 6A) cross section a V-shaped recess, and cross section includes a U-shaped recess (see FIG. 8A). The first mold by the other of the mold may be configured with one mold and the second inclined surface having a first slope.
[0042]
　Consider the case where a rough flange bend is not formed and a particular rough flange portion are arranged in the front-rear direction. In this case, bending at step may be formed bends on the particular crude flange portion in a state of fixing the crude flange bend is not formed. According to this configuration, the force applied when forming a specific flange portion can be suppressed that the rough flange arranged in the longitudinal direction of the particular crude flange displaced.
[0043]
　At least one specific rough flange portion includes first and second specific rough flange portion described above may consist third and fourth particular rough flange. That is, all four coarse flange portion may be a specific rough flange. In this case, the bending process and, at the same time the first and second specific crude flange pressed by one of the first slope and the second slope of the first die, the third first gold other specific crude flange portion of press the first inclined surface of the mold, and a fourth particular crude flange portion may be pressed by the second inclined surface of the first mold other.
[0044]
　Said a first specific rough flange portion and the second specific crude flange portion, may be lined in the vertical direction of the forged product, it may be arranged in the longitudinal direction of the forged product. An example of a bending process in the case of the former (the first example), and will be described an example of a bending process in the latter case the (second example) as follows. Note that the former and latter example, all four coarse flange portion includes form a specific rough flange. In this case, as described above, it may be Squeeze the forgings by two first mold.
[0045]
　Bending process of the first example, the first specific rough flange portion and a second specific rough flange portion is performed when the are arranged in the vertical direction of the forged product. Bending process of the first embodiment is carried out by moving the first mold in the longitudinal direction of the forged product. Press first specific crude flange portion at the first slope of the first mold, by pressing the second specific crude flange portion at the second inclined surface can be formed simultaneously bend to both (e.g., Figure 6B).
[0046]
　Bending process of the first example, the boundary portion of the two coarse flange portion protruding from the upper end of the rough web portion, and a boundary portion of the two coarse flange portion protruding from the lower end of the rough web portion, from the vertical direction 2 One of the may be performed in a state sandwiched by the second mold. Of these four crude flange portion, at least two rough flange portion arranged in the vertical direction is first and second specific rough flange. By sandwiching the boundary portion by the two second mold, the bending process to stabilize the posture of the forging can be performed stably.
[0047]
　Bending process of the second example, the a first specific rough flange portion and a second specific rough flange portion is performed when the are arranged in the longitudinal direction of the forged product. Bending process of the second embodiment is carried out by moving the first mold in the vertical direction of the forged product. First presses a particular crude flange portion at the first slope of the first mold, by pressing the second specific crude flange portion at the second inclined surface can be formed simultaneously bend to both.
[0048]
　Bending process of the second example, the crude web portion from the longitudinal direction of the rough web portion may be performed in a state sandwiched by the two second mold. Since a large force in a specific rough flange joining the bending step, it is preferable to carry out the crude web portion fixed by the two second mold. According to this configuration, the bending process to stabilize the posture of the forging can be performed stably, rough web portion can be prevented from being deformed (e.g., Fig. 7B).
[0049]
　(Front axle beam)
　front axle of the embodiment (front axle beam) can be produced by the production method of this embodiment. Matter manufacturing method described in this embodiment, it is possible to apply to the front axle of the present embodiment, there may be omitted the duplicate description. Also, matters described front axle of this embodiment is applicable to the production method of this embodiment. Incidentally, the front axle of this embodiment may be manufactured by a method other than the manufacturing method of this embodiment.
[0050]
　Front axle of this embodiment includes a web portion, and four flange portions joined to opposite ends of the web portion, the beam portion of the H-shaped cross-section of which comprises a. Spacing of the tip portions of the two flanges facing each other is narrower than the length of the web portion. This is at least one of the two flange portions, because a specific flange portion having a curved portion. In the present disclosure, means that simply integrated in the bonding, does not necessarily mean that joining by means of welding or fastening.
[0051]
　Front axle of this embodiment includes a beam portion, and two kingpin mounting portions provided respectively on both longitudinal ends of the beam portions. Beam portion includes a web portion extending in the longitudinal direction of the beam portion, and four flange portions projecting forwardly and rearwardly from the respective upper and lower ends of the web portion. At least one of the four flange portions is a specific flange portion including the bend portion. Bend it is closer to the end of the bent portion is bent to be closer to the flange portion facing the bent portion. Here, the flange portion facing the bend, a flange portion arranged in the vertical direction with a specific flange portion. Also the flange may be a specific flange portion. Bend may be formed by the above-mentioned bending process.
[0052]
　Specific flange portion includes the bent portion. That is, the tip end portion of the particular flange portion, and the distal end portion of another flange portion opposed to the particular flange section (specific flange or flange portion not specific flange portion), the distance, than the length of the web portion narrow. In this case, the cross section of the front axle, to a limited extent, the center of gravity of a particular flange to a position relatively far from the center of gravity of the beam portion is disposed. Therefore, as compared with the flange portion of a conventional front axle extending in a plate shape, it is possible to increase the second moment of the particular flange portion without increasing the cross-sectional size of the front axle. As a result, according to the front axle of the present embodiment, it is possible to increase the rigidity (flexural rigidity in the longitudinal direction HD) without increasing the cross-sectional size. Furthermore, in comparison with the conventional flange portion, by having a bend portion particular flange, a number of members at a position far from the center of gravity of the entire cross-section is arranged continuous to the twisting direction (circumferential direction). Therefore, it is possible to increase the polar second moment. As a result, according to the front axle of the present embodiment, it is possible to increase the torsional rigidity without increasing the cross-sectional size.
[0053]
　In another aspect, the bend portion of one particular flange, when the specific flange portion viewed horizontally from the side which projects, with a portion to be a blind spot in the vertical direction of the inner surface. Such bend, since the inverse gradient in the mold forging step, it is difficult to form such a bend only at the die forging process. Therefore, when forming a specific flange by a manufacturing method comprising the die forging process requires bending steps described above. Conversely, the shape of the bent portion can be easily formed by a manufacturing method comprising the die forging step and the bending step described above. Therefore, the front axle of this embodiment is also advantageous in terms of manufacturing.
[0054]
　Here, we define the length of the web portion at the junction of the flange portion and web portion, as follows. In cross-section of the beam portion, the base of the contour of the web portion has an arc rather than a right angle. In other words, there is a corner R. Of the flange portion, the center point of the thickness of a portion not in contact with the web portion of the web in the vicinity, determined on either side of the flange portion sandwiched between the web portion. A direction connecting the center points between the extending direction of the flange portion. The extending direction of the flange portion, the tangent of the corner R, the angle between the tangent of the contact is increased closer to the web portion center. A flange portion extending direction, the tangent of the corner R, the angle of the tangent contact point of the corner R of when it becomes 10 °, determined on either side of the flange portion sandwiched between the web portion. The straight line connecting the contact points regarded as the boundary of the flange portion and web portion. Based on this boundary to assess the length of the web portion.
[0055]
　Here, the cross section of a conventional front axle 500 (cross section perpendicular to the longitudinal direction LD), shown in Figure 14. By die forging, when manufacturing front axle, line by moving in the direction in which the flange portions 530a ~ 530d protrudes (longitudinal direction HD (direction orthogonal to the extending direction of the web portion 520)) mold (forging die) divide. Therefore, the flange portion 530a ~ 530d, are provided gradients for demolding. Figure 14 shows the angle Q, Q 'of the draft for stamping direction (front-rear direction HD). For this slope, in the conventional front axle 500, the distance between the two flanges facing each other (e.g., the flange portion 530a and the flange portion 530b), extends closer to their tip. In contrast, in the present embodiment, the interval between the tip portions of the two flanges facing each other is narrower than the length of the web portion. That is, the spacing of the two flanges facing each other are narrower closer to their tip.
[0056]
　Bend it may be inclination increases relative to the more horizontal distance increases from the boundary between the specific flange portion and web portion. That is, a flange portion having a curved portion may be curved.
[0057]
　Of the four flange portions, at least one (one, two, three, or four) is the specific flange portion. The four flange portions may include two specific flange are aligned in the longitudinal direction or the vertical direction. Moreover, all four flange portion may be a specific flange portion.
[0058]
　As described above, the bent portion, at least a portion of the region between the two spring mounting seat may be formed in (some or all). For example, bend 50% of the region between the two spring mounting seat (based on the length in the longitudinal direction LD) may be formed above. In other words, cross-section containing a specific flange portion is a cross-section between two spring mounting seat.
[0059]
　(Manufacturing apparatus)
　In another aspect, the present invention relates to apparatus for manufacturing front axle. This manufacturing apparatus includes bending the mold described above to be used in the process, and a mechanism for moving the mold as described above. The said mechanism can be applied to mechanisms that have been used in such known pressing apparatus.
[0060]
　The following description with reference to the drawings exemplary embodiments of the present invention. The embodiments described below are exemplary, at least a portion of the configuration in the following embodiment, can be replaced with the above-described configuration. In the following description, it may be omitted from redundant explanation are denoted by the same reference numerals to like parts. Moreover, are all figures schematically shown below, may be omitted and unnecessary portions in the description.
[0061]
　(First Embodiment)
　In the first embodiment, an example of a front axle of the embodiment. A perspective view of the front axle 100 of the first embodiment, shown in FIG. A front view of the from the front of the front axle 100 viewed horizontally front axle 100, shown in FIG. A top view of the front axle 100 shown in FIG. Furthermore, the cross-sectional view taken along the line IV-IV in FIG. 3, shown in FIG. 4. The drawing described in these figures and the following, the front axle 100 (or forgings 200) may indicate the forward direction FWD, vertical VD, and the front-rear direction HD. Similarly, the figures may indicate a longitudinal direction LD of the beam portion 110 (or coarse beam portion 210).
[0062]
　Referring to FIG. 1, the front axle (front axle beam) 100 includes a beam portion 110, and two kingpin mounting portion 150 provided on both ends in the longitudinal direction LD of the beam portion 110. The kingpin mounting portion 150, through hole kingpin is attached is formed. Normally, the front axle 100 has a generally symmetrical shape about a center in the vehicle width direction, and have a generally arcuate shape as a whole. As shown in FIG. 2, the kingpin mounting portion 150, the tire 1 is connected via a kingpin.
[0063]
　Beam portion 110 includes a web portion 120 and the four flange portions 130. Four flanges 130 is projected forward and backward from the respective upper and lower ends of the web portion 120. That is, four one of the flange portion 130 protrudes forwardly from the upper end of the web portion 120, one protrudes rearward from the upper end of the web portion 120, one protrudes forward from the lower end of the web portion 120, 1 One protrudes rearward from the lower end of the web portion 120. In another aspect, the beam portion 110 includes a web portion 120, and four flange portions 130 which are joined to both ends of the web portion 120 has a H-shaped cross section of the. At least one of the four flanges 130 is a specific flange portion 131 including the bending portion 132. In FIGS. 1 to 4, all four flange portions 130 illustrates a case where a specific flange portion 131. As shown in FIG. 4, the bending portion 132, closer to the end portion 132a of the bent portion 132 is bent to be closer to the flange portion 130 opposite to the bent portion 132.
[0064]
　Two flange portions 130 projecting from the upper side of the web portion 120, two spring mounting seat 111 is formed. Two spring mounting seat 111 is disposed on the left and right symmetrical positions at a distance. Spring is arranged in the spring mounting seat 111, a vehicle body (including the engine) is mounted on the spring.
[0065]
　Here, the four specific flange portion 131, and first to fourth specific flange portion 131a-131d. In Figure 4, as an example, the particular flange portion 131 are arranged vertically at the front of the web portion 120, and first and second specific flange portion 131a and 131b. Furthermore, the particular flange portion 131 are arranged vertically at the rear of web portion 120, and the third and fourth particular flange portion 131c and 131d. Note that any particular flange portion or the first to fourth specific flange portion is arbitrary. For example, two specific flange are aligned back and forth across between the vertical line Lct passing through the center of the longitudinal direction HD of the web portion 120 may be a first and second specific flange portion.
[0066]
　Each of the four specific flange portion 131 includes a bend 132. In the first embodiment, a description is given of a case where the bending portion 132 is formed between the two spring mounting seat 111, may bend 132 in the other portion is formed.
[0067]
　In FIGS. 1 to 4, and it illustrates an example is a specific flange portion 131 which contains all the bends 132 of the four flange portions 130. However, at least one flange portion 130 may if it has a bent portion 132. For example, among the four flange portions 130, only two flanges 130 arranged in the vertical direction VD may be a specific flange portion 131. They to the web portion 120 may protrude forward may protrude backward. Alternatively, among the four flange portions 130, only two flanges 130 arranged in the longitudinal direction HD may be a specific flange portion 131. They may be disposed at the upper end of the web portion 120 may be disposed at the lower end of the web portion 120.
[0068]
　(Second Embodiment)
　In the second embodiment, an example of producing a front axle 100 shown in FIGS. 1 to 4 will be described with reference to the drawings. This manufacturing method includes a die forging process and the bending process described below in this order. Die forging step and the bending step is a hot processing carried out by heating the processing target.
[0069]
　In the die forging process, by forging a steel material with a mold to form a predetermined forging. There is no limitation to the die forging step can be carried out by known die forging process. In the die forging process, usually, burrs are formed on the forging. If burrs are formed on the forging, burrs punching step is carried out prior to the bending process. Figure 5A is a perspective view showing a part of a cross-section of the forging 200 after burr punching process is performed.
[0070]
　Forgings 200 includes a coarse beam portion 210 as the beam portion 110. Crude beam unit 210 includes a coarse web portion 220 serving as the web portion 120, and a plate-shaped four coarse flange portion 230 from each of the upper and lower ends protruding toward the front and rear of the coarse web portion 220. All four rough flange portion 230, a specific crude flange portion 231 becomes a specific flange portion 131. The forging 200, the portion 211 comprising a spring mounting seat 111 is formed.
[0071]
　Section forgings 200 (cross section perpendicular to the longitudinal direction LD), shown in Figure 5B. The cross-section of Figure 5B is a cross-section of a portion to be the bent portion 132. Particular crude flange portion 231 is composed of first to fourth specific crude flange 231a-231d to be the first to fourth specific flange portion 131a-131d.
[0072]
　Die forging process, rough flange 230 is performed by moving the mold (forging machine) in the direction (front-rear direction HD (direction orthogonal to the extending direction of the rough web portion 220)) that protrudes. Forging die has a center line of the rough web portion 220 in pairs in the boundary. Therefore, the rough flange portion 230 is provided with a gradient for demolding. FIG 5B, showing the angles Q, Q 'of the draft for stamping direction (front-rear direction HD). For this slope, rough flange portion 230 is thinner closer to its end. In the example shown in FIG. 5B, the boundary portion 230a of the two coarse flange portion 230 adjacent to the front-rear direction HD is in the position of the burr has been removed burr line.
[0073]
　Steel as a material for the die forging process typically has a shape suitable for die forging. Such steel can be formed by preforming a billet which is a starting material in the preforming step. That is, the steel material may be a preform. There is no limitation to the preforming step, it may be applied known preforming process. For example, pre-molding step, and the step of squeezing the billet may include bending beating process. Preforming step is usually hot working.
[0074]
　Bending the process, by pushing at least one first mold certain crude flange portion 231, the vertical direction VD bend 232 is bent inward (see FIG. 6B) a specific crude flange portion of the forged product 200 form to 231. This bending process, the bending portion 232 a bent portion 132 is formed. Bend 232 generally has the shape of a bent portion 132. That is, usually, bend 232 becomes bent portion 132 as it is.
[0075]
　Two examples of bending process (first and second examples) are described below. As described above, the first example, two particular crude flange portion 231 is performed when the are arranged in the vertical direction VD forging. In a first example, moving the first mold in the longitudinal direction HD forging 200. A second example, two particular crude flange portion 231 is performed when the are arranged in the longitudinal direction HD forging. In a second example, moving the first mold in the vertical direction VD forging 200. Incidentally, if all the four crude flange portion 230 is a specific rough flange portion 231, can either be regarded as two specific crude flange portion 231 are aligned in the longitudinal direction HD, the are arranged in the vertical direction VD It can also be considered. Therefore, in this case, none of the method and the second example of the method of the first embodiment are feasible.
[0076]
　(First embodiment)
　The method of the first embodiment will be described with reference to the sectional view of FIG. 6A and 6B. Figures 6A and 6B are sectional views of a portion bend 232 is formed. Here, it defines the first to fourth specific crude flange 231a-231d to be the first to fourth specific flanges 131a-131d as shown in FIGS. 6A and 6B. In this case, the first specific crude flange portion 231a and the second specific crude flange portion 231b, are arranged in the vertical direction VD forging 200.
[0077]
　In the first example, first, as shown in FIG. 6A, placing two first mold 310 so as to sandwich the forgings 200 from the front and rear direction HD forging 200. Normally, the bending step, moving the first mold 310 in the vertical direction (direction of gravity). Therefore, in the method of the first embodiment, normally, by placing the forging 200 as the front-rear direction HD is vertical and parallel to the forging 200, the bending process is performed.
[0078]
　The first mold 310 has a V-shaped recess. Recess of the first mold 310 includes a first inclined surface 310a, and a second inclined surface 310b. Angle P formed between the first inclined surface 310a and the second inclined surface 310b is, for example in the range described above. In the example shown, the first inclined surface 310a and the second inclined surface 310b, respectively, abut at the same angle with respect to two specific crude flange portion 231 arranged in the vertical direction VD. In this case, the angle formed between the direction in which the particular crude flange and their slopes are projecting is P / 2. The direction in which the particular crude flange projecting is a longitudinal direction HD, equal to the moving direction of the first mold 310.
[0079]
　In Figure 6A, but the first inclined surface 310a and the second inclined surface 310b indicates a case is planar, they may be curved. It will be described below such first mold 310.
[0080]
　Next, as shown in FIG. 6B, performing step bending by moving the first mold 310 in the longitudinal direction HD forging 200. The bending process, forging 201 having a bent portion 232 is formed. In a typical example, the forging 200 is mounted on the first mold 310 of the lower, bending process by moving only the first mold 310 of the upper is carried out.
[0081]
　Bending in the step, a vertical direction VD in side by side of the two has a specific rough flange portion 231 of the forging 200, pressing simultaneously by one of the first and second inclined surfaces 310a and 310b of the first mold 310. By carrying out such a bending step, it can be accurately formed two or four curved portions in a single pressure. In the example shown in the figure, four particular crude flange portion 231 pushed simultaneously by the two first inclined surface 310a and two second inclined surface 310b.
[0082]
　The bending process, forging 200 may have burrs. In this case, burrs at the boundary portions 230a of the two coarse flange portion 230 adjacent to the front-rear direction HD, lies along the vertical direction VD (see FIG. 5B). With reference to FIGS. 6A and 6B, when performing the bending process to forgings 200 having a burr, burr suppresses deformation in the vertical direction VD of the crude flange portion 230. Therefore, it can be performed better bending process accuracy.
[0083]
　Bending step may be performed in a state of fixing the forgings 200 by another mold. An example of a first example of a bending process using the other mold, will be described with reference to FIGS. 7A and 7B. Since FIGS. 7A and 7B are views corresponding to FIGS. 6A and 6B, without redundant description.
[0084]
　In the example shown in FIGS. 7A and 7B, bending process in a state where the two second mold 320 is fixed across the forging 200 is performed. Specifically, two second mold 320, and the boundary portions 230a of the two specific crude flange portion 231 that protrudes from the upper end of the rough web portion 220 (crude flange portion 230), projecting from the lower end of the rough web portion 220 two and a boundary portion 230a of a particular crude flange portion 231 (crude flange portion 230) which, sandwich the vertical direction VD forging 200.
[0085]
　By performing the bending process while holding the forging 200 in the second mold 320, it can be performed better bending process accuracy.
[0086]
　(Second embodiment)
　The method of the second embodiment will be described with reference to the sectional view of FIG. 8A and 8B. Figures 8A and 8B are cross-sectional views of a portion bend 232 is formed. Here, it defines the first to fourth specific crude flange 231a-231d to be the first to fourth specific flanges 131a-131d as shown in FIGS. 8A and 8B. In this case, the first specific crude flange portion 231a and the second specific crude flange portion 231b, are arranged in the longitudinal direction HD forging 200.
[0087]
　In the second example, first, as shown in FIG. 8A, placing two first mold 310 as in the vertical direction VD sandwich the forging 200 of forging 200. Normally, the bending step, moving the first mold 310 in the vertical direction (direction of gravity). Therefore, in the method of the second embodiment, typically, as the vertical direction VD of the forged product 200 is vertical and parallel, bending process by placing the forging 200 is performed.
[0088]
　The first mold 310 has a U-shaped recess. Recess of the first mold 310 includes a first inclined surface 310a, and a second inclined surface 310b. In Figure 8A, the first inclined surface 310a and the second inclined surface 310b indicates a case where the curved surface. In this case, the angle formed between the first inclined surface 310a and the second inclined surface 310b is varies by location. However, at least a portion of the first inclined surface 310a which makes contact with a particular crude flange portion 231, the angle P formed between at least a portion of the second inclined surface 310b that makes contact with a particular crude flange portion 231, for example in the range described above.
[0089]
　Next, as shown in FIG. 8B, performing step bending by moving the first mold 310 in the vertical direction VD forging 200. The bending process, the bend portion 232 is formed. In a typical example, the forging 200 is mounted on the first mold 310 of the lower, bending process by moving only the first mold 310 of the upper is carried out.
[0090]
　The bending process, two specific crude flange portion 231 that appears in the forging 200 longitudinal direction HD, pressing simultaneously by one of the first and second inclined surfaces 310a and 310b of the first mold 310. By carrying out such a bending step, it can be accurately formed two or four curved portions in a single pressure. In the example shown in the figure, four particular crude flange portion 231 pushed simultaneously by the two first inclined surface 310a and two second inclined surface 310b.
[0091]
　Bending step may be performed in a state of fixing the forgings 200 by another mold. An example of a second example of a bending process using the other mold, will be described with reference to FIGS. 9A and 9B. 9A is a sectional view before starting the deformation of the first mold 310. 9B is a sectional view of the deformation is completed.
[0092]
　In the example shown in FIGS. 9A and 9B, step bending in a state in which the two second mold 320 is fixed across the forging 200 is performed. Specifically, the crude web portion 220 from the front-rear direction HD forging 200 in a state sandwiched by the two second mold 320, the bending process is performed.
[0093]
　By performing the bending process while holding the crude web portion 220 in the second mold 320, it can be performed better bending process accuracy. Furthermore, the deformation of the coarse web portion 220 in the bending step, it is possible to control by the second die 320.
[0094]
　By the above bending process, forging 201 having substantially the same outer front axle 100 is obtained. The resulting forged product 201 may be subjected to various processes as needed. Examples of these processes, burr punching process, shaping step, drilling process, the heat treatment step, bend-up step, surface treatment step, and the like coating process. In this way, the front axle 100 is manufactured.
[0095]
　In the above manufacturing method, the contour of each cross section of the bending process before forging 200 and bending processes after forging 201, shown superimposed in Figure 10. Further, in FIG. 10 shows a rectangle that encloses the contour of the forged product 200 by a one-dot chain line.
[0096]
　One way to improve the rigidity, it is conceivable to lengthen the flange portion in the front-rear direction. However, just when longer flange portion in the longitudinal direction, the front-rear direction size of the front axle is increased. On the other hand, according to the manufacturing method of this embodiment, as shown in FIG. 10, since the bent flange portion extending in the longitudinal direction, it is possible to reduce the front-rear direction size. That is, according to the manufacturing method of this embodiment, it is possible to suppress an increase in size improves the rigidity.
[0097]
　(Other examples)
　In the above example, has been described a case where all four flange portions 130 to produce a front axle 100 is a specific flange portion 131. However, of the four flange portions 130, even if only the front-rear direction HD or vertical direction two in a row in the VD of the flange portion 130 is a specific flange portion 131 can be similarly prepared. In this case, two specific crude flange portion 231 in a row, may be formed bent portion 232 by pressing one of the first inclined surface 310a and the second inclined surface 310b of the first die 310.
[0098]
　In the following, there is a case where a normal crude flange portion 230 is not a particular rough flange portion 231, referred to as crude flange 230n. If a specific crude flange portion 231 and the rough flange 230n are arranged in the longitudinal direction HD, bend 232 only certain crude flange portion 231 of them in step bending is formed. In that case, a force is applied only to certain rough flange portion 231, a boundary portion between the rough web portion 220 with a particular crude flange portion 231 as a fulcrum, there is a risk that rough flange 230n is displaced. In order to suppress such displacement, it is preferable to perform the bending process while suppressing the displacement of the rough flange 230n. An example of a method of suppressing deformation of the crude flange 230n, shown in the sectional view of FIG. 11.
[0099]
　Sectional view of FIG. 11 shows a state before the start of deformation in bending process. Forging 200 illustrated includes upper and lower two particular crude flange portion 231a and 231b that are aligned in the direction VD, and two coarse flange portion 230n which are arranged in the vertical direction VD. Two coarse flange portion 230n is arranged to fit into the recess of the third mold 330. That is, the third mold 330, recess crude flange 230n is fitted is formed. By using a third die 330, it is possible to suppress the coarse flange 230n is displaced. In the case where the rough flange 230n is displaced in the bending process, crude flange 230n moves outward in the vertical direction VD. Therefore, it may be using a third the mold 330 without third mold to fix only the outer part of the crude flange 230n shown in FIG. 11.
[0100]
　Note that when only one of the four flange portions 130 is the specific flange 131 by using the first mold comprising a single slope, by forming the bent portion 232 to a specific crude flange portion 231 good. In this case, as described above, it is preferred to carry out the bending process in a state of fixing the crude flange 230n adjacent to the front-rear direction HD and certain crude flange portion 231.
Example
[0101]
　Hereinafter, more detailed description of the examples the invention.
[0102]
　In this Example it was evaluated by simulation and rigidity of the beam portion of the present embodiment having the bent portion, and a rigidity of the beam portion of the comparative example having no bent portion. In the simulation, as a model of the beam portion, the cross-sectional shape perpendicular to the longitudinal direction length constant is assumed to 100mm model. The physical properties of samples 1 and 2, assuming a Young's modulus and 210 GPa, and Poisson's ratio was assumed to 0.293. The simulation was carried out by the finite element method. Mass samples 1 and 2 were the same. That is, the vertical cross-sectional area in the longitudinal direction was the same in samples 1 and 2.
[0103]
　Sample 1 of the cross-sectional shape of the present embodiment, and FIG. 12 shows a sample 2 of the cross-sectional shape of comparative example. In cross-section (a cross section perpendicular to the longitudinal direction) shown in FIG. 12, the cross section of Sample 1 and Sample 2 are and vertically symmetrical symmetrical. The flange portion of the sample 2, it was assumed that the projecting horizontally in the longitudinal direction HD from the upper and lower ends of the web portion. Incidentally, (see FIG. 5B) angle Q, Q 'of the draft of the sample 2 was assumed to 5 °.
[0104]
　As shown in FIG. 12, suppose the X and Y coordinates as the origin centroid CT of each sample in the cross section of FIG. 12. X-axis of the X-coordinate is parallel to the longitudinal direction HD of the beam portion, Y-axis of the Y coordinate is parallel to the vertical direction VD of the beam portion. A region X and Y coordinates are both positive, i.e., about one quarter of the cross section was determined centroid. Position of the center of gravity CG1 of samples 1, and shows the position of the center of gravity CG2 of the sample 2 in Figure 12. These coordinates (unit: mm) are shown below.
The center of gravity of the sample 1 CG1: (X, Y) = (22.608,19.973)
Sample 2 of the center of gravity CG2: (X, Y) = (21.388,22.768)
[0105]
　As described above, the X coordinate of the center of gravity CG1 of the sample 1 of this embodiment was greater than the X coordinate of the center of gravity CG2 of sample 2 of Comparative Example. By this X-coordinate is large, the effect of enabling an increase in the polar second moment against torsion and second moment against bending deformation by longitudinal load lightweight obtained.
[0106]
　For Samples 1 and 2, the rigidity when a load is applied as shown in FIG. 13 was obtained by simulation. Specifically, the one end face of one of the two end faces restrained, the load is applied in a direction indicated by an arrow shown in FIG. 13 the other end face. The load of the bending back and forth shown in FIG. 13, to determine the stiffness in the longitudinal direction. The load of the rotation torque shown in FIG. 13, to determine the torsional rigidity. The evaluation results are shown in Table 1.
[0107]
[Table 1]

[0108]
　As shown in Table 1, the longitudinal direction of the stiffness of the sample 1 of the present embodiment was the same equivalent or sample 2 of Comparative Example. Furthermore, the torsional stiffness of the sample 1 was significantly higher than that of sample 2.
[0109]
　As is apparent from the above results, by using a beam portion having a curved portion, the mass have the same predetermined rigidity is high front axle obtained. This indicates that you can weight the front axle without reducing a predetermined rigidity. This further shows that there is a possibility of realizing a conventional equal or rigid conventional products equal to or less than the cross-sectional size.
Industrial Applicability
[0110]
　The present invention can be used in the front axle beam.
DESCRIPTION OF SYMBOLS
[0111]
　100: front axle (front axle
　beam) 110: beam portion
　111: spring mounting seat
　120: web portion
　130: flange portion
　131: a specific flange portion
　132: curved portion
　150: kingpin mounting portion
　210: crude beam part
　220: crude web portion
　230: the crude flange
　231: specific crude flange
　310: first mold
　310a: first inclined surface
　310b: second slope
　320: second mold
　330: third mold
　LD: longitudinal
　HD: longitudinal direction
　VD: vertical direction

WE CLAIM

And the web portion, the method of manufacturing a front axle beam with a beam portion of the H-shaped cross-section of which comprises a flange portion which is joined to the opposite ends of the web portion,
　in the cross section, the center of the web portion forging the material the shaft in a mold paired to the boundary,
　in the transverse section, to bend toward the flange portion facing the flange portion, a method of producing a front axle beam.
[Requested item 2]
　The flange portion bent is curved, the manufacturing method of the front axle beam according to claim 1.
[Requested item 3]
　And the web portion, a front axle beam with a beam portion of the cross section of the H-type and a junction with the flange portion at both ends of the web portion,
　in the cross section, opposite than the length of the web portion and the towards the tip of the spacing of the flange portion is small, the front axle beam.
[Requested item 4]
　In the transverse plane, the flange portion is curved, the front axle beam according to claim 3.
[Requested item 5]
　Comprising at least two spring mounting seat, said transverse plane is a transverse plane between the spring mounting seat, a front axle beam according to claim 3 or claim 4.