[0001]
　TECHNICAL FIELD The present invention relates to a brake disk for a railroad vehicle which is fastened to a wheel of a railway car and generates a braking force by pressing a sliding contact member against a sliding portion.
BACKGROUND ART
[0002]
　In the past, there is a braking system that brakes the rotation of the wheel by fastening the brake disc to the wheel of the railway car and pressing the sliding contact member against the brake disc. In such a brake system, a large frictional heat is generated in the brake disc during braking. For this reason, a structure is adopted in which a plurality of vertical fins extending in the radial direction are provided on the back surface of the brake disc, and air is caused to flow between the brake disc and the wheels by the rotation of the brake disc so that the brake disc radiates heat is there.
　In a brake disk having a plurality of vertical fins, when mounted on a high-speed rail and the wheel rotates at a high speed, a large amount of air flows between the brake disk and the wheel, resulting in a large noise. Therefore, in Patent Document 1, a transverse rib that gives resistance to the air flowing between the plurality of vertical fins is provided, and by adjusting the opening area between the vertical fins by the transverse rib, it flows between a plurality of the vertical fins Proposals have been made to reduce the amount of air and reduce noise.
Prior Art Document
Patent literature
[0003]
Patent Document 1: JP-A-2007-205428
Summary of the invention
Problem to be Solved by Invention
[0004]
　As shown in Patent Document 1, by providing a transverse rib on a brake disc having a plurality of longitudinal fins, noise can be reduced as compared with a case where no lateral rib is provided. However, in the brake disc described in Patent Document 1, it is possible to reduce the noise due to the disturbance of the airflow passing through the flow path on the back surface of the brake disc, but the brake disc on the surface of the brake disc is fixed to the wheel There is a problem that the noise due to the through hole through which the bolt is passed can not be reduced.
[0005]
　In order to develop a low noise brake disc, the inventors of the present invention conducted a test to check the sound source of the brake disc.
　Firstly, we investigated the brake disk that rotates at high speed using the microphone array sound source exploration system and the surrounding sound source. As a result, it turned out that the sound source is in the vicinity of the brake disc or inside the brake disc. Next, we tried to close each part of the brake disc which is supposed to generate turbulence as noise source. Specifically, each part specifically means an entrance (an opening on the inner periphery side of the brake disc) of an air flow path on the rear surface of the disc and an exit (an opening on the outer circumference side of the brake disc) and a brake disk are fastened to the wheel (Sliding portion) side end of the through hole into which the bolt is inserted. As a result of performing the noise test by closing all of them, it was confirmed that the noise generated from the brake disk is reduced to a very low level. Furthermore, one of these was not blocked and the remaining two places were blocked and tested. As a result, it was confirmed that noise of a specific frequency was generated in each part.
　However, even if all of these noises are added up, it was found that the noise level is lower than in a normal state, that is, a state in which all parts are opened. In particular, there was a large difference in the high frequency range of 800 Hz or more.
[0006]
　The inventors of the present invention analyzed the results of these tests and considered that the influence of the noise caused by the through hole through which the bolt passes is large in addition to the noise due to the turbulence of the air flow on the back side of the brake disc and the noise around the through hole By conducting a test in which the form was varied, the present invention was completed.
　SUMMARY OF THE INVENTION The object of the present invention is to remarkably reduce the noise generated from a brake disc during high-speed rotation of a wheel in a railway vehicle brake disc.
Means for solving the problem
[0007]
　A brake disc for a railway car according to the present invention
　comprises a disc plate portion having a sliding portion on its surface (a plate portion excluding the following longitudinal fins and lateral ribs of a brake disc is referred to as a disc plate portion)
　A plurality of through holes penetrating from the front surface to the rear surface of the disc plate portion and arranged side by side in the circumferential direction of the disc plate portion and through which a bolt for fastening the disc plate portion and the wheel of the railway vehicle passes, , And
　a groove provided so as to connect the plurality of through holes on the surface side of the disk plate portion
　.
[0008]
　According to such a configuration, the brake disk is fastened to the wheel by tightening the bolt through each of the plurality of through holes. On the other hand, such a through hole can be a sound source of noise when the brake disk is rotated at high speed without any special measures. However, according to the above configuration, the noise generated due to the through hole can be reduced by the groove provided so as to connect the plurality of through holes.
[0009]
　Preferably, the plurality of through holes are respectively provided at a plurality of places on the same diameter of the disc plate portion, and the
　grooves may circulate in a ring shape by connecting the plurality of through holes.
　According to such a configuration, since the groove circulates in an annular shape, even if the disk plate portion rotates at a high speed, the effect of the groove on the surrounding air is reduced, and the noise due to the groove can be made extremely small.
[0010]
　More preferably, the width of the groove in the radial direction of the disk plate portion is shorter than the diameter of the opening portion on the front surface side of the through hole.
　With such a configuration, it is possible to suppress the sliding area of ​​the disk plate portion from decreasing due to the groove. Further, it is also possible to suppress a decrease in the strength of the disc plate portion due to the groove. Accordingly, it is possible to avoid the reduction in the braking performance and the strength of the brake disc while reducing the noise generated in the through hole portion.
[0011]
　More preferably, the opening portion on the surface side of the disk plate portion of the pair of through holes among the plurality of through holes is defined as a pair of openings, and the portion connecting the pair of openings in the groove is defined as one section groove, the inner peripheral portion from the inner peripheral side of the three portions of the each unit disc plate at equal intervals in the radial direction of the pair of each of the disc plate portion of the opening portion, the central portion, as the outer peripheral portion,
　the said groove The width of the disc plate portion in the radial direction is equal to or less than half of the diameter of the opening portion and
　the groove of the one section includes at least one of the pair of opening portions excluding the inner circumferential portion As shown in FIG.
　With such a configuration, while reducing the width of the groove, the effect of reducing noise generated in the through hole portion can be further improved.
[0012]
　It is also preferable that an opening portion on a surface side of the disc plate portion of a pair of adjacent through holes among the plurality of through holes is defined as a pair of openings and a portion connecting the pair of openings in the groove to one side as a groove,
　the width in the radial direction of the disc plate portion of the groove is greater than half the diameter of the opening,
　the groove of the one section, in at least one of said pair of openings, one of the openings the But may be connected to a portion other than the end on the inner peripheral side along the radial direction of the disk plate portion.
　With such a configuration, it is possible to improve the noise reduction effect occurring in the through hole portion.
Effect of the invention
[0013]
　According to the present invention, noise generated from the brake disc during high-speed rotation of the wheel can be greatly reduced in the brake disc for a railway car.
Brief Description of the Drawings
[0014]
FIG. 1 is a perspective view showing an example of a brake system in a railway car.
2 is a plan view showing a rear surface of the brake disc of the first embodiment. FIG.
3A is a cross-sectional view of each part of the brake disc, taken along the line A - A of FIG. 2. FIG.
3B is a cross-sectional view of each part of the brake disc, taken along the line B - B in FIG. 2.
3C is a cross-sectional view of each part of the brake disc, taken along the line B - B in FIG. 2, showing a modified example of the transverse rib.
FIG. 4A is a plan view of the brake disc of the second embodiment, showing the front side of the brake disc.
4B is a cross-sectional view taken along the line C - C in FIG. 4A, showing the brake disc of the second embodiment.
FIG. 5 is a graph showing test results of noise related to longitudinal fins and transverse ribs.
FIG. 6 is a graph showing a test result of noise related to a through hole for a bolt.
FIG. 7 is a view for explaining an average inclination angle of gradual inclination.
FIG. 8 is a graph showing the relationship between the volume of transverse ribs and the bolt stress range.
9 is a table illustrating first to fifth forms L 5 and L 6 of the lateral rib shown in FIG. 8. FIG.
FIG. 10 is a view for explaining a lateral rib according to a second embodiment.
FIG. 11 is a frequency graph showing a comparison of noise levels between a lateral rib of the second embodiment and a conventional lateral rib.
12 is a table showing the form of transverse ribs compared in FIG. 11. FIG.
FIG. 13 is a graph comparing the total noise levels in a predetermined frequency range.
14 is a view for explaining a form of a groove provided on a surface of a disk plate portion, and FIGS. 14A to 14E show a first mode to a fifth mode, respectively.
FIG. 15 is a frequency graph showing the relationship between the groove width and the noise level.
FIG. 16 is a frequency graph showing the relationship between the connecting portion of the groove and the noise level.
FIG. 17 is a graph showing a relationship between a connection form of a groove and a total noise level in a predetermined frequency range.
MODE FOR CARRYING OUT THE INVENTION
[0015]
　Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings.
　(First Embodiment)
　FIG. 1 is a perspective view showing an example of a brake system in a railway car. FIG. 2 is a plan view showing the rear surface of the brake disc according to the first embodiment. 3B is a cross-sectional view taken along the line B - B of FIG. 2, and FIG. 3C is a cross sectional view taken along the line A - A of FIG. 2 2 is a cross-sectional view taken along the line B - B of FIG. 2 showing an example.
　Hereinafter, the direction facing the outer periphery along the radial direction of the brake disc 10 is defined as "outer peripheral side", and the side facing the inner periphery as "inner peripheral side".
　The brake system according to the first embodiment of the present invention is mounted on a high-speed railroad. This brake system comprises a brake disc 10 fastened to a side portion of a wheel 100 of a railway car, a slidable contact member 200 which contacts the brake disc 10 to generate a braking force, a sliding contact member 200 which is in contact with the brake disc 10 And a movable part 210 which can be pressed against the one to be brought into contact. Although not particularly limited, the brake disc 10 and the slidable contact member 200 are respectively provided on both side surfaces of one wheel 100, and the movable portion 210 is configured to sandwich the wheel 100 with the two sliding contact members 200.
[0016]
　The brake disk 10 is an annular disk, and a surface 10 f of the disk plate portion is a sliding portion. On the back surface 10 r of the disk plate portion, a plurality of longitudinal fins 11 a, 11 b and a plurality of lateral ribs 13 are provided. In the brake disc 10, a plate-like portion excluding the vertical fins 11a and 11b and the transverse rib 13 is called a disc plate portion.
　In addition, the brake disc 10 is provided with a plurality of through holes 12 for passing bolts from the front surface to the rear surface. In FIG. 2, in order to avoid complication, the reference numerals of the vertical fins 11 a and 11 b, the through hole 12, and the lateral rib 13 are only partially attached.
　The vertical fins 11 a and 11 b are portions extending in the radial direction of the disc plate portion and protruding from the back surface of the disc plate portion toward the plate portion of the wheel 100. The plurality of vertical fins 11a, 11b are provided at substantially equal intervals in the circumferential direction of the disc plate portion.
[0017]
　The transverse rib 13 has a shape extending in the circumferential direction of the disc plate portion and connects a pair of vertical fins 11 a and 11 b between each pair of adjacent vertical fins 11 a and 11 b among the plurality of vertical fins 11 a and 11 b As shown in FIG.
　The plurality of through holes 12 are provided on the same diameter of the disk plate portion and are arranged at equal intervals in the circumferential direction of the disk plate portion.
　As shown in FIG. 3A, the heads of the vertical fins 11 a and 11 b contact the side surface of the wheel 100. The lateral ribs 13 have a height such that the head has gaps between the wheels 100. With such a configuration, when the brake disc 10 is fastened to the wheel 100, a flow path of air surrounded by the vertical fins 11 a and 11 b, the back surface 10 r of the disk plate portion, and the plate portion of the wheel 100 is formed. When the wheel 100 and the brake disc 10 rotate, the air flows from the inner circumference side to the outer circumference side in this flow passage, whereby the heat of the brake disc 10 is released.
[0018]
　In the present embodiment, a gentle slope is formed on the inner circumferential side surface 13 a and the outer circumferential side surface 13 b of the lateral rib 13. The gradual inclination is formed such that the inclination angle is smaller than the draft angle of casting, preferably the average inclination angle is 50 ° or less, more preferably the average inclination angle is 45 ° or less. The draft angle means a gradient closest to 90 ° in a gradient in which the transverse rib 13 can be molded without pulling out the undercut process and can be pulled out from the mold when casting the brake disc 10. In FIG. 3B and FIG. 3C, draft slopes are indicated by imaginary lines. The average inclination angle of the transverse rib 13 is smaller than the gradient of the side faces of the vertical fins 11a and 11b. Here, as shown in FIG. 7, the average inclination angle is a straight line AB connecting the end point A of the rounding on the root side of the side surface 13 a of the transverse rib 13 and the end point B of the rounding of the tip side , And a straight line A - C parallel to the plate surface of the brake disc 10.
　The side faces 13 a, 13 b having the gentle inclination of the transverse ribs 13 may have a curved shape having a bulge, a curved shape having a recessed shape, a flat face or a conical face shape.
　The operation of the brake disc 10 of the first embodiment will be described later.
[0019]
　(Second Embodiment)
　FIG. 4 shows the brake disk of the second embodiment, FIG. 4A is a plan view of the surface side of the brake disc (sliding side), the arrow C in FIG. 4B Figure 4A FIG.
　The brake system according to the second embodiment of the present invention is mounted on a high-speed railway as in the first embodiment. In this brake system, the brake disc 10A is fastened to the side portion of the wheel 100 (FIG. 1) of the railway car and the slide contact member 200 (FIG. 1) is pushed against the surface of the brake disc 10A to generate a braking force.
　The brake disk 10A is provided with a plurality of through holes 12 penetrating from the front face 10f to the rear face and a groove 15 connecting the plurality of through holes 12 with the front face 10f.
[0020]
　The plurality of through holes 12 are provided on the same diameter of the brake disc 10 A and are provided at equal intervals in the circumferential direction of the brake disc 10 A. As shown in FIG. 4B, each through hole 12 has a small diameter portion 12 t having a small diameter through which the shaft portion of the bolt passes and a large diameter portion 12 w having a large diameter in which the head portion or nut of the bolt is disposed There. The large diameter portion 12 w may have a depth at which the head or nut of the bolt sinks down or has a depth shorter than the height of the head or nut of the bolt and one of the bolt head or nut May protrude into the groove 15. The depth of the large diameter portion 12 w may be equal to the height of the head portion or nut of the bolt. In either case, the head or nut of the bolt does not protrude outward from the surface 10 f of the brake disc 10.
[0021]
　The groove 15 is annularly formed so as to connect the plurality of through holes 12 in the surface portion of the brake disk 10 A. The groove 15 is provided, for example, in a shape along the concentric circle of the brake disc 10A.
　The structure in which the plurality of through holes 12 are connected by the grooves 15 may be adopted for the brake disc 10 having the vertical fins 11 a, 11 b and the lateral ribs 13 of the first embodiment, or a structure different from the first embodiment As shown in FIG.
[0022]
　
　FIG. 5 is a graph showing test results of noise related to longitudinal fins and lateral ribs. FIG. 6 is a graph showing a test result of noise related to a through hole for a bolt.
　5 and 6 show test results for a conventional brake disc. The conventional brake disc has through holes for longitudinal fins, lateral ribs, and bolts, the transverse ribs have the shape shown by the two-dot chain line in FIG. 3B, the grooves 15 are provided on the surface portion of the disc plate portion It means a brake disc which is not. In FIGS. 5 and 6, the graph line E shows the noise level when the conventional brake disc is rotated at high speed together with the wheel. The graph line L shows the noise level when the conventional brake disk is rotated at high speed together with the wheel by blocking only the through hole for the bolt. The graph line H in FIG. 5 shows the noise level when closing other than the opening on the outer periphery side of the air flow path between a pair of adjacent vertical fins and rotating at high speed together with the wheel. The graph line I in FIG. 5 shows the noise level when closing other than the opening on the inner periphery side of the flow path of air and rotating it together with the wheel at high speed. The graph line F in FIG. 6 shows the noise level when closing the inner circumference side and the outer circumference side opening of the air flow path and the through hole for the bolt and rotating it together with the wheel at high speed as the graph line G Shows the noise level at the time of high-speed rotation together with the wheel by blocking other than the through hole for the bolt.
[0023]
　As a result of the test, the noise of the conventional brake disc includes the noise generated due to the longitudinal fins at the opening on the outer circumferential side or the inner circumferential side of the air flow passage, and the noise generated in the lateral rib It was found that the noise generated due to the noise and the noise generated by the through hole for the bolt are included.
　The noise in the range W 3 of the graph line I in FIG. 5 is presumed to be the noise caused by the vertical fin at the opening on the inner peripheral side. Further, the noise in the range W 2 of the graph line H in FIG. 5 is presumed to be the noise caused by the vertical fin at the opening on the outer peripheral side. Furthermore, the noise in the range W1 in which the difference between the graph lines E and L is larger than the graph lines H and I is presumed to be the noise generated by turbulence of the air current in the flow passage by the transverse rib. Further, the noise in the range W 4 of the graph line G in FIG. 6 is presumed to be the noise caused by the through hole for the bolt. The noise level of the graph line L when only the bolt through hole is blocked in the range W 4 is reduced by 1 to 2 dB from the graph line E. From this, it can be considered that in the range W 4, the noise caused by the through hole for the bolt is about the same as the noise caused by the airflow flowing through the flow path on the back side of the disk.
[0024]
　As shown in FIG. 5, in the brake disc 10 of the first embodiment, the noise level shown in the range W 1 is greatly reduced as compared with the conventional brake disc. This is believed to be because the turbulence of the airflow passing through the transverse ribs 13 due to the gentle gradient of the transverse ribs 13 is largely suppressed. Therefore, according to the brake disc 10 of the first embodiment, it is understood that the flow rate of the air radiating the brake disc 10 does not decrease greatly and the noise is greatly reduced.
　As shown in FIG. 6, in the brake disc 10 A of the second embodiment, the noise in the range W 4 caused by the through hole is greatly reduced as compared with the graph line G having only the bolt hole. This is considered to be due to the fact that the annular groove 15 is provided so as to connect the plurality of through holes 12. Thus, according to the brake disc 10A of the second embodiment, it is found that the noise level is greatly reduced as compared with the conventional brake disc by reducing the noise caused by the through hole 12 . However, it is a prerequisite that the noise in the same frequency range generated due to other factors such as the airflow flowing through the flow path on the back surface of the disc plate portion is reduced.
[0025]
　Although the first and second embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, the arrangement of the transverse ribs 13 can be varied in various ways, such as the inner circumferential portion, the outer circumferential portion, or the middle between the inner circumferential portion and the outer circumferential portion of the disc plate portion. The structure for narrowing the flow path of air between the pair of longitudinal fins by the transverse rib is not limited to the one shown in the above embodiment. The lateral rib 13 of the above embodiment connects a pair of adjacent longitudinal fins and has a structure in which the height in the direction of the rotation axis of the disc plate portion is lower than that of the longitudinal fins. However, for example, the lateral ribs have the same height as the longitudinal fins, whereas the transverse spread of the transverse ribs (spreading in the circumferential direction of the disk plate portion) is not the entire region between the pair of longitudinal fins but part May be expanded while leaving the region of FIG. That is, there may be a structure in which there is an air flow path between the vertical fin and the transverse rib, or there is an air flow path between the transverse ribs connected to the longitudinal fins on one side. In this case, the head top portion of the transverse rib corresponds to the end portion in the rotation axis direction of the disc plate portion (the end portion facing the air flow path). Furthermore, even in this case, the transverse ribs may be provided at various positions such as the inner circumferential portion, the outer circumferential portion, the intermediate portion between the inner circumferential portion and the outer circumferential portion of the disc plate portion. In the above-described embodiment, the heads of all the vertical fins are in contact with one surface of the wheel, but even in a structure in which a slight gap is generated between the head of some of the vertical fins and one surface of the wheel Good. Furthermore, in the above-described embodiment, the longitudinal fins have substantially the same length as the radial length of the disk plate portion, but the longitudinal fins may be shorter than the radial length of the disk plate portion. Further, the groove 15 need not have a configuration along the same diameter of the disk plate portion. Even in this case, noise reduction effect can be obtained. Besides, the details shown in the embodiments can be appropriately changed without departing from the gist of the invention.
[0026]
　(Third Embodiment)
　FIG. 8 is a graph showing the relationship between the transverse rib volume and the bolt stress range. Here, the bolt stress range refers to the range of variation from the stress generated in the bolt in a state in which the disc does not expand thermally, to the stress generated in the bolt in the state that the disc is thermally expanded. FIG. 9 is a table for explaining the first embodiment L1 to the fifth form L5 and the comparative form L6 of the lateral rib shown in FIG. 8, respectively.
　Hereinafter, the direction along the plate surface of the brake disc 10 is defined as the horizontal direction, the direction perpendicular to the plate surface is defined as the elevation direction, and the circumferential direction of the brake disc 10 is defined as the circumferential direction of each part.
　During braking of the railway car, the brake disk 10 thermally expands due to frictional heat, thereby changing the tensile stress and bending stress of the bolt. The vertical axis in FIG. 8 shows the stress range (the difference between the maximum value and the minimum value) of tensile stress and bending stress generated in the bolt when a constant temperature change is applied to the brake disc 10. The horizontal axis of FIG. 8 shows the volume of the transverse rib. Each plot of the graph of FIG. 8 shows the stress range with respect to the volume of the transverse rib when adopting the transverse rib 13 of the first embodiment L1 to the fifth form L5 of FIG. 9 and the comparative embodiment L6 (case of no lateral rib) .
[0027]
　The transverse ribs 13 of the first embodiment L1 to the fifth form L5 in FIG. 9 have a constant height, the length of the head horizontal portion Ld, the shape of the head gentle slope SL 0, and the shape of the bottom slope SL 1 are As shown in the table of FIG. The head horizontal portion Ld indicates a horizontal portion provided at the top of the lateral rib 13. The gentle slope SL 0 refers to a gradient portion from the top of the lateral rib 13 to the skirt or interruption. The skirt slope SL 1 indicates the gradient portion of the skirt portion of the lateral rib 13. "R" in the table indicates the radius of curvature [mm]. The head gentle gradient SL 0 and the skirt slope gradient SL 1 are arranged on the inner circumferential side of the lateral rib 13.
[0028]
　As shown in the graph of FIG. 8, the stress range of the bolt varies depending on the volume of the transverse rib 13 located in the vicinity of the bolt. For example, if the lateral ribs 13 are in the form of the first form L1 of FIG. 9 and the volume thereof is large, the rigidity of the lateral ribs 13 is increased, so that the stress range of the bolts is increased. On the other hand, if the lateral rib 13 is in the form of the fifth embodiment L5 of FIG. 9 and its volume is small, the rigidity of the lateral rib 13 becomes relatively small, so that the stress range of the bolt also becomes small. From the graph of FIG. 8, by setting the volume of the lateral ribs 13 to be equal to or less than the fifth form L 5, the stress range of the bolt is equivalent to that in the case of the comparative embodiment L 6 having no lateral rib 13.
　As described above, when the noise is reduced by increasing the volume of the lateral ribs 13, there arises a problem that the stress range of the bolts becomes large. Therefore, the brake disc of the third embodiment has the transverse rib 13A (see FIG. 10) which can reduce noise without increasing the stress range of the bolt so much.
[0029]
　FIG. 10 is a view for explaining the lateral rib of the third embodiment. FIG. 11 is a frequency graph showing a comparison of the noise level between the transverse rib of the third embodiment and the conventional transverse rib. FIG. 12 is a table showing the form of transverse ribs to be compared in FIG. 11.
　The transverse rib 13 A of the third embodiment includes a gentle slope SL 0 on the inner peripheral side. The head gentle slope SL 0 is provided in the range of the section La 1 in the radial direction of the disc plate section on the inner peripheral side of the transverse rib 13 A and in the range of the section La 2 in the rotation axis direction of the disc from the head apex of the transverse rib 13 A. The head gentle gradient SL 0 is provided in a range where at least both the sections La 1 and La 2 are 2 mm or more and is preferably a convex curved surface of R 2 mm or a gentle slope which is looser therefrom. More preferably, the head gentle slope SL 0 is provided in a range of at least the sections La 1 and La 2 of 5 mm or more, and is preferably a convex curved surface of R 5 mm or a gently sloping surface.
[0030]
　The lateral rib 13A of the third embodiment further includes a straight section Lb continuous with the gentle slope of the head and a gentle slope SL1 on the inner periphery side. The straight section Lb may be made close to vertical within a manufacturable range. This makes it possible to reduce the volume of the transverse rib 13 A. Further, the straight section Lb may be inclined as long as there is a margin in the bolt stress range. Further, the straight section Lb may be a curved section having a gentle curvature.
　The skirt slope SL 1 is, for example, a concave curved surface of R 5 mm. However, the slope slope SL1 may be a flat or curved surface with easy manufacturing. In addition, it is not necessary to have the skirt slope SL 1 within the range that can be manufactured.
[0031]
　Further, the transverse rib 13 A of the third embodiment may or may not include the head horizontal portion Ld. In the case where it is included, the head horizontal portion Ld is preferably in the range of about 1 mm to 20 mm. As the head horizontal portion Ld becomes larger, the volume of the transverse rib 13 A increases, and the influence on the stress range of the bolt increases. Therefore, the size of the head horizontal portion Ld may be appropriately set in consideration of the bolt stress range and the necessary strength of the transverse rib 13A. Further, the outer peripheral side of the transverse rib 13 A may have a vertical configuration within a manufacturable range or a loose slope may be provided. When the gradient on the outer circumferential side of the lateral rib 13A becomes loose, the volume of the lateral rib 13A increases, and the bolt stress range increases. Therefore, the outer peripheral side of the transverse rib 13A may be set appropriately within a range where there is a margin in the bolt stress range. Further, the height of the transverse rib 13A can be appropriately adjusted according to the length of the straight section Lb.
[0032]
　
　FIG. 11 is a frequency graph showing a comparison between the noise between the transverse rib of the third embodiment and the conventional transverse rib. FIG. 12 is a table showing the shape of the transverse rib of FIG. 11. FIG. 13 is a graph comparing the overall noise levels in the range of 400 Hz to 5000 Hz.
　Here, a partial model between a pair of adjacent vertical fins 11a, 11b was prepared, and air was flowed at a predetermined wind speed thereon to measure the noise. The air flow path between the vertical fins 11 a and 11 b was pseudo enclosed by one surface of the disk plate portion and one surface of the plate portion of the wheel 100. In addition, the transverse rib 13 A was arranged to block a part of the flow path. The vertical axis of FIG. 11 shows the noise level of each frequency band, and the horizontal axis of FIG. 11 shows the center frequency of the 1/3 octave band. "O.A" in the abscissa indicates overalls and "P - O.A" indicates overalls in the range of 400 Hz to 5000 Hz.
[0033]
　Here, noise was measured for the transverse rib 13 A of the first embodiment P 1 to the seventh embodiment P 7 in FIG. 12. In the table of FIG. 12, "R" represents the radius of curvature [mm], "head gentle slope shape" represents the radius of curvature of the convex curved surface of the head gentle gradient SL 0, "skirt- 10 shows the radius of curvature of the concave curved surface of the skirt slope SL 1 in FIG. 10. In addition, as a comparison target, lateral ribs of the current shape formed in a rectangular cross section by cutting were also tested.
[0034]
　As shown in FIG. 11, when adopting the lateral ribs 13 A of the first embodiment P 1 to the seventh form P 7, it was confirmed that the noise level can be reduced as compared with the lateral rib of the current shape. Further, when comparing the overall noise level in the range of 400 Hz to 5000 Hz, it is confirmed that the noise level can be remarkably reduced in the first embodiment P 1 to the seventh form P 7 as compared with the current shape as shown in FIG. 13.
　When these noises were measured, there was a slight difference in the amount of air (flow rate) passing between the pair of longitudinal fins 11a, 11b due to the difference in shape of the transverse rib 13A. In the actual brake disk 10, the air amount is set to a predetermined value by adjusting the height of the lateral rib 13A so as to obtain a proper cooling effect. Also, the flow velocity affects the noise level. For this reason, the values ​​in the graph of FIG. 13 were corrected so as to eliminate the variation in the noise level due to variations in the flow velocity.
[0035]
　In FIG. 13, it is understood from the comparison of the test results of the third embodiment P 3 and the seventh embodiment P 7 that the gradient of the straight section Lb does not significantly affect the noise level. Further, from the comparison of the test results of the first embodiment P1 to the third embodiment P3, it was confirmed that the section La2 of the head gradient SL0 and the shape influences the noise level.
　In addition, when the head loose gradient SL 0 is the first form P 1 in which both the section La 1 and the section La 2 are 2 mm and the curvature radius is the convex curved surface of R 2 mm, the overall noise level of 400 Hz to 5000 Hz is about It was confirmed that it can be reduced by 10 dB (A). Further, in the second embodiment P2 in which the head slope SL0 is 5 mm in both the section La1 and the section La2 and the curvature radius is a convex curved surface of R5 mm, the overall noise level of 400 to 5000 Hz is about It was confirmed that it can be reduced by 14 dB. In addition, when the head loose gradient SL 0 is 5 mm in both the section La 1 and the section La 2 and the fifth form P 5 in which the radius of curvature is the convex curved face of R 10 mm, the overall noise level of 400 to 5000 Hz is 18 It can be reduced by 5 dB.
[0036]
　From the result of such a test, it is understood that the noise level can be remarkably reduced by the transverse rib 13 A of the third embodiment.
　As described above, according to the brake disc 10 of the third embodiment, it is possible to remarkably reduce the noise level generated at the position of the transverse rib 13 A without excessively increasing the bolt stress range.
[0037]
　Fourth Embodiment
　FIG. 14 is a view for explaining a form of a groove provided on the surface of a disk plate portion, and FIGS. 14A to 14 E show a first mode to a fifth mode of a groove, respectively. It should be noted that FIG. 14 shows a diagram in which the coordinate transformation is performed such that the circumferential direction and the radial direction of the brake disc 10A are in a linear direction orthogonal to each other in one section of the grooves 15A and 15B.
　In the brake disc 10A of the fourth embodiment, instead of the groove 15 of the second embodiment, a groove 15A having a small width is adopted. The width of the groove 15A is smaller than the diameter of the opening 12F on the surface side of the disc plate portion of the through hole 12 (the sliding surface side of the brake disc 10A), specifically, the diameter of the opening portion 12F is, for example, 36 mm, The width of the groove 15A is, for example, 5 mm, 10 mm, 20 mm, or the like. When the opening portion 12F is not circular, the width of the groove 15A is smaller than the width of the opening portion 12F in the radial direction of the disk plate portion. The width of the groove 15 A means the width of the groove 15 A in the radial direction of the disc plate portion.
[0038]
　In order to generate a braking force, the sliding contact member 200 comes into contact with the surface of the brake disc 10A. Therefore, the groove 15 A provided on the sliding surface of the brake disc 10 A reduces the sliding surface. When the sliding surface becomes smaller, when the pressure of the slidable contact member 200 is the same, it acts in a direction to lower the braking force. When the width or the depth of the groove 15A increases, the strength of the brake disc 10A decreases.
　The brake disc 10A of the fourth embodiment employs the narrow groove 15A as described above. Therefore, in the fourth embodiment, it is possible to secure the area of ​​the sliding surface of the brake disc 10A and to maintain the strength while reducing the noise generated in the bolt through-hole 12 by the groove 15A.
[0039]
　In the case of adopting the narrow groove 15A, variation occurs in the connection form between the adjacent pair of the openings 12F and the groove 15A. As a variation, for example, the groove 15A has a pattern (FIG. 14A) connecting the inner peripheral portion Ri of a pair of adjacent openings 12F, a pattern connecting the central portion Rc (FIG. 14B), a pattern connecting the outer peripheral portion Ro (FIG. 14C). Further, there is a pattern (FIG. 14D) in which the groove 15 A is obliquely connected from one outer peripheral portion Ro to the other inner peripheral portion Ri out of a pair of adjacent openings 12 F. Further, there is a pattern (hereinafter referred to as "staggered" in the following) in which a pair of adjacent openings 12F alternately repeat the connection between the inner peripheral portions Ri and the connection between the outer peripheral portions Ro. The inner peripheral portion Ri, the central portion Rc, and the outer peripheral portion Ro are portions obtained by dividing the opening portion 12 F into three at equal intervals in the radial direction of the brake disc 10 A.
　The connection pattern of the groove 15A of the fourth embodiment includes the connection patterns of FIGS. 14B to 14D among the plurality of patterns as described above, and the connection pattern of the groove 15B shown in FIG. 14A and FIG. 14E is It is excluded.
[0040]
　That is, in the fourth embodiment, when the width of the groove 15A is equal to or less than half of the diameter of the opening 12F, the connecting portion between the groove 15A and the opening 12F is formed so as to be in contact with at least one of the pair of openings 12F, 12F In the connection, a connecting portion excluding the inner peripheral portion Ri of the opening 12 F is adopted. The connecting portion excluding the inner peripheral portion Ri means a portion straddling the central portion Rc, the outer peripheral portion Ro, or the central portion Rc and the outer peripheral portion Ro of the opening portion 12F. The width of the groove 15 A corresponds to, for example, 5 mm, 10 mm, or the like
[0041]
　In the fourth embodiment, when the width of the groove 15 A is larger than half the diameter of the opening 12 F, the connecting portion between the groove 15 A and the opening 12 F is at least one of the pair of openings 12 < In the connection, a connecting portion not including the inner peripheral end of the opening 12 F is adopted. The inner peripheral end means an end portion of the opening portion 12F closest to the inner periphery of the brake disc 10A of the opening portion 12F. The case where the width of the groove 15 A is larger than half the diameter of the opening 12 F is a case where the groove width is 20 mm, for example. It is preferable that the groove 15 A has a depth such that the bottom of the groove has the same height as the head top portion of the bolt or nut, regardless of the groove width and the connecting portion.
[0042]
　
　FIG. 15 is a graph showing the relationship between the noise frequency and the noise level for each groove width. FIG. 16 is a graph showing the relationship between the noise frequency and the noise level for each connection point of the groove. FIG. 17 is a graph showing the noise level in the frequency range from the 1250 Hz band to the 5000 Hz band for each groove connection mode. In these figures, the form of a plurality of target grooves is shown in the format of "connection position - groove width". However, since the groove 15A is half or more of the diameter of the opening 12F, the form of "center-20 mm" is also connected to a part of the outer peripheral part Ro of the opening 12F and a part of the inner peripheral part Ri But shows a mode in which the center of the groove 15A is connected so as to overlap the center of the central portion Rc. In FIG. 15 and FIG. 16, the vertical axis shows the noise level for each 1/3 octave band, and the horizontal axis in FIGS. 15 and 16 shows the center frequency for each 1/3 octave band. The vertical axis of FIG. 17 shows the noise level in the frequency range of 1250 Hz to 5000 Hz.
[0043]
　Among the target shapes, patterns of "center-5 mm", "center-10 mm", "center-20 mm", "outer periphery-10 mm", and "diagonal-10 mm" are adopted in the fourth embodiment For example. The pattern of "no groove", "inner circumference-10 mm", "staggered-10 mm" is an example of a comparative example not adopted in the fourth embodiment.
　From the results shown in FIG. 15, it can be seen that the noise reduction effect gradually decreases as the width of the groove 15 A is narrowed. On the other hand, it is understood from the result of FIG. 15 that a noise reduction effect can be obtained even with a groove of about 5 mm compared to the case without a groove. Further, from the result of FIG. 16, it is understood that when the width of the groove 15A is narrow, the noise reduction effect varies depending on the connection portion between the adjacent pair of openings 12F.
[0044]
　Further, from the result of FIG. 17, although the noise is reduced in the pattern of "inner circumference-10 mm" and the pattern of "staggered-10 mm", the effect is small, whereas in the fourth embodiment It can be seen that a remarkable noise reduction effect can be obtained with the pattern. From these results, it can be seen that by adopting the above-mentioned connection form between the groove 15A and the opening 12F, the noise generated at the groove 15A can be remarkably reduced.
　As described above, according to the brake disc 10 A of the fourth embodiment, it is possible to remarkably reduce the noise caused by the bolt through-hole 12 without significantly reducing the sliding area.
Industrial applicability
[0045]
　The present invention can be applied to brake discs for railway vehicles.
Explanation of sign
[0046]

[Claim 1]A disk plate portion having a sliding portion on a surface thereof; a disk plate portion
　penetrating from the front surface to the back surface of the disk plate portion and arranged side by side in the circumferential direction of the disk plate portion, and fastening the disk plate portion and the wheel of the railroad car And
　a groove provided so as to connect the plurality of through holes on the side of the surface of the disk plate portion
　.
[Claim 2]The railway according to claim 1, wherein the plurality of through holes are 　respectively provided at a plurality of places on the same diameter of the disc plate portion, and the groove circulates in a ring shape by connecting the plurality of through holes Brake disc for vehicles.
[Claim 3]
　3. The brake disc for a railway car according to claim 1 or 2, wherein a width of the groove in the radial direction of the disc plate portion is shorter than a diameter of an opening portion on the front surface side of the through hole.
[Claim 4]
　A pair of openings on a surface side of the disc plate portion of a pair of adjacent through holes among the plurality of through holes is defined as a pair of openings, a portion of the groove connecting the pair of openings is a groove in one section, Each of the openings of the disc plate portion being divided into three at equal intervals in the radial direction of the disc plate portion from the inner peripheral side to the inner peripheral portion, the central portion, and the outer peripheral portion of the
　disc plate portion The width in the radial direction is equal to or less than a half of the diameter of the opening portion and
　the groove of the one section is connected to a portion of at least one of the pair of opening portions excluding the inner circumferential portion 4. The brake disc for a railway car according to claim 3, characterized in that it is provided.
[Claim 5]
　Said pair of apertures opening in the surface side of the disc plate portion of an adjacent pair of through holes of the plurality of through holes, as a groove in a section a portion connecting the pair of openings of said grooves,
　said The width of the groove in the radial direction of the disk plate portion is larger than half the diameter of the opening portion and
　the groove of the one section is formed in at least one of the pair of opening portions of the disk plate portion Wherein the brake disc is connected to a portion excluding an end on the inner peripheral side along the radial direction.