Brake disk

Abstract

To provide a brake disk for a railway vehicle which can reduce an aerodynamic noise while maintaining a cooling performance.SOLUTION: A brake disk (100) includes a disk body (10) and a plurality of fins (20). The plurality of fins (20) are provided on one face (12) of the disk body (10) such that each of the fins (20) extends from an inner peripheral side of the disk body (10) toward an outer peripheral side. Each of the fins (20) includes two side faces (221, 222) and a top face (21). One or more fins (20) of the plurality of fins (20) include a plurality of projections (25). The plurality of projections (25) align in a radial direction of the disk body (10) at least on one side face of the two side faces (221, 222) of the fins (20). Each of the projections (25) extends between the disk body (10) and the top face (21) of the fins (20).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to brake discs for rail vehicles. [Background technology]

[0002] Disc brake devices are widely used as braking devices for railway vehicles. Disc brake devices include a brake disc and a brake lining. The brake disc is fastened to, for example, a wheel and rotates together with the wheel. The brake lining is pressed against the brake disc. The railway vehicle is braked by friction between the brake lining and the brake disc.

[0003] The brake disc includes, for example, a circular disk-shaped disc body and a plurality of fins. The fins are arranged radially on one side of the disc body. These fins ensure the cooling performance of the brake disc. More specifically, when the brake disc is fastened to a wheel with the fins facing the wheel, an air passage is formed by the wheel, the disc body, and adjacent fins. When the brake disc rotates with the wheel, the air passage allows air to pass from the inner periphery of the disc body to the outer periphery. This cools the brake disc.

[0004] In this way, the brake disc can be cooled by air flowing through the air passage defined by the wheel, the disc body, and the adjacent fins. However, the air flowing through the air passage generates aerodynamic noise. In particular, when a railway vehicle travels at high speed, the amount of air flowing through the air passage increases, generating louder aerodynamic noise. In addition to ensuring cooling performance, brake discs for railway vehicles are also required to reduce aerodynamic noise.

[0005] For example, Patent Document 1 discloses a brake disc for reducing aerodynamic noise during high-speed driving and improving cooling performance during braking. In the brake disc of Patent Document 1, some fins are provided with fastening holes for inserting fastening members. These fins have grooves formed on the outer and / or inner sides of the fastening holes, extending circumferentially along the disc body. According to Patent Document 1, the corners and wall surfaces of these grooves cause pressure loss in the air flowing through the air passage defined by the wheel, disc body, and fins. This reduces the amount of airflow in the air passage, resulting in reduced aerodynamic noise during high-speed driving. Furthermore, Patent Document 1 also discloses that the grooves in the fins create pressure loss areas on the brake disc that increase the heat transfer coefficient with the air, thereby improving cooling performance during braking. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 038621 Summary of the Invention [Problem to be solved by the invention]

[0007] As described in Patent Document 1, there is a strong correlation between the airflow rate in the air passage and the aerodynamic noise level of brake discs for railway vehicles. That is, an increase in the airflow rate in the air passage increases the aerodynamic noise, while a decrease in the airflow rate in the air passage reduces the aerodynamic noise. In order to reduce the aerodynamic noise generated while a railway vehicle is running, it is sufficient to limit the airflow rate in the air passage. However, when the aerodynamic noise is reduced by limiting the airflow rate, the cooling performance of the brake disc is usually reduced.

[0008] An object of the present disclosure is to provide a brake disc for a railway vehicle that can reduce aerodynamic noise while ensuring cooling performance. [Means for solving the problem]

[0009] The brake disc according to the present disclosure is a brake disc for a railway vehicle. The brake disc includes a disc body and a plurality of fins. The disc body has an annular plate shape. The plurality of fins are arranged on one surface of the disc body so that each fin extends from the inner circumferential side of the disc body toward the outer circumferential side. Each of the plurality of fins includes two side surfaces aligned in the circumferential direction of the disc body and a top surface connecting the two side surfaces. One or more of the plurality of fins includes a plurality of protrusions. The plurality of protrusions are arranged in the radial direction of the disc body on at least one of the two side surfaces of the fin. Each of the protrusions extends between the disc body and the top surface of the fin. [Effects of the Invention]

[0010] According to the railway vehicle brake disc of the present disclosure, aerodynamic noise can be reduced while ensuring cooling performance. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a rear view of a brake disc for a railway vehicle according to a first embodiment. [Figure 2] FIG. 2 is a partial perspective view of the brake disc shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view of the brake disc shown in FIG. 1 taken along line III-III. [Figure 4] FIG. 4 is a cross-sectional view of the brake disc shown in FIG. 1 taken along line IV-IV. [Figure 5] FIG. 5 is a rear view of the railway vehicle brake disc according to the second embodiment. [Figure 6] FIG. 6 is a rear view of the railway vehicle brake disc according to the third embodiment. [Figure 7] FIG. 7 is a rear view of the railway vehicle brake disc according to the fourth embodiment. [Figure 8] FIG. 8 is a rear view of the railway vehicle brake disc according to the fifth embodiment. [Figure 9] FIG. 9 is a rear view of the railway vehicle brake disc according to the sixth embodiment. [Figure 10] FIG. 10 is a rear view of the railway vehicle brake disc according to the seventh embodiment. [Figure 11] FIG. 11 is a rear view of the railway vehicle brake disc according to the eighth embodiment. [Figure 12] FIG. 12 is a partial perspective view of the brake disc shown in FIG. [Figure 13] FIG. 13 is a partially enlarged view of the rear surface of the brake disc shown in FIG. [Figure 14] FIG. 14 is a graph showing the evaluation results of the analysis of the brake discs according to the examples and comparative examples. [Figure 15] FIG. 15 is a diagram showing the results of a rotation test using models of brake discs according to the example and the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0012] The brake disc according to the embodiment is a brake disc for use in a railway vehicle. The brake disc includes a disc body and a plurality of fins. The disc body has an annular plate shape. The plurality of fins are arranged on one side of the disc body so that each fin extends from the inner circumferential side of the disc body toward the outer circumferential side. Each of the plurality of fins includes two side surfaces aligned in the circumferential direction of the disc body and a top surface connecting the two side surfaces. One or more of the plurality of fins includes a plurality of protrusions. The plurality of protrusions are arranged in the radial direction of the disc body on at least one of the two side surfaces of the fin. Each of the protrusions extends between the disc body and the top surface of the fin (first configuration).

[0013] In the brake disc according to the first configuration, a plurality of fins are arranged on one surface of the disc body, and one or more of the fins have a plurality of protrusions on their side surfaces. When the brake disc is attached to a rotating member such as a wheel and an air passage is formed by the rotating member, the disc body, and adjacent fins, these protrusions can reduce the cross-sectional area of ​​the air passage in the circumferential direction of the disc body. This can limit the amount of air passing through the air passage (airflow rate) while the railway vehicle is running. This can reduce aerodynamic noise.

[0014] In the brake disc according to the first configuration, the multiple protrusions provided on the side surfaces of the fins can also increase the surface area of ​​the brake disc. Furthermore, since air flowing into the air passage from the inner periphery of the disc body during travel of the railway vehicle flows along the side surfaces of the fins, providing multiple protrusions on the side surfaces of the fins can increase the heat transfer coefficient between the brake disc and the air. As a result, the cooling performance of the brake disc during braking can be improved. Therefore, the brake disc according to the first configuration can efficiently limit the amount of air flowing through the air passages while maintaining cooling performance, thereby reducing aerodynamic noise.

[0015] In the brake disc according to the embodiment, each of the fins may further include an inner peripheral surface. The inner peripheral surface of each fin is connected to inner ends of the top surface and the two side surfaces in the radial direction of the disc body. The protrusions are preferably arranged outward from the inner peripheral surfaces of the fins in the radial direction of the disc body (second configuration).

[0016] In the second configuration, the multiple protrusions are located radially outward of the inner circumferential surface of the fins. This ensures corners between the inner circumferential surface and both side surfaces of each fin. These corners efficiently draw air into the air passages formed between adjacent fins and maintain a high local heat transfer rate in these areas. This ensures the cooling performance of the brake disc.

[0017] In the brake disc according to the embodiment, one or more of the plurality of fins may have a plurality of protrusions on each of two side surfaces (third configuration).

[0018] According to the third configuration, a plurality of protrusions are provided on both sides of the fin, which can further enhance the effects of reducing aerodynamic noise and improving cooling performance.

[0019] In the brake disc according to the embodiment, each of the plurality of fins may include a plurality of protrusions (fourth configuration).

[0020] According to the fourth configuration, a plurality of protrusions are provided on the side surfaces of all of the fins, which can further enhance the effects of reducing aerodynamic noise and improving cooling performance.

[0021] The plurality of ridges may include one or more first ridges and one or more second ridges. The second ridges are disposed at different positions in the radial direction of the disc body from the first ridges. The length of the first ridges in the circumferential direction of the disc body is greater than the length of the second ridges in the circumferential direction (fifth configuration).

[0022] According to the fifth configuration, the first and second protrusions are provided on the side surfaces of the fins. The length of the first protrusions is greater than the length of the second protrusions in the circumferential direction of the disk body. In this case, the cross-sectional area of ​​the air passage can be particularly reduced at the location of the first protrusions, effectively limiting the amount of air passing through the air passage. This further reduces aerodynamic noise.

[0023] Furthermore, by providing the first protrusions, which are relatively long in the circumferential direction of the disc body, on the side surfaces of the fins, the surface area of ​​the brake disc can be further increased, thereby improving the cooling performance of the brake disc during braking. This allows the amount of air passing through the air passage to be more efficiently restricted while maintaining cooling performance.

[0024] Among the multiple fins, adjacent fins in the circumferential direction of the disc body may each include a first protrusion portion and a second protrusion portion, in which case the first protrusion portion of one of the adjacent fins faces the first protrusion portion of the other adjacent fin in the circumferential direction (sixth configuration).

[0025] The first protrusions may be disposed on the outer periphery of the disc body (seventh configuration). The first protrusions may be disposed on the inner periphery of the disc body (eighth configuration). The first protrusions may be disposed in the center of the disc body in the radial direction (ninth configuration).

[0026] In a brake disc according to an embodiment, among the plurality of fins, fins adjacent to each other in the circumferential direction of the disc body may each include a plurality of protrusions. The plurality of protrusions may include at least one first protrusion. The first protrusion on one of the adjacent fins may be positioned radially offset from the first protrusion on the other adjacent fin so as to bend the air passage formed between the adjacent fins (tenth configuration).

[0027] In a tenth configuration, among the multiple fins arranged on one surface of the disc body, multiple protrusions are provided on the side surfaces of adjacent fins. When the brake disc is attached to a rotating member such as a wheel and an air passage is formed by the rotating member, the disc body, and adjacent fins, these protrusions can reduce the cross-sectional area of ​​the air passage in the circumferential direction of the disc body. This makes it possible to limit the amount of air passing through the air passage (airflow rate) while the railway vehicle is running. Furthermore, the multiple protrusions include first protrusions. The positions of the first protrusions of adjacent fins are offset in the radial direction of the disc body, causing the air passage formed between the adjacent fins to bend. By bending the air passage in this way, it is possible to increase the flow resistance of the air passing through the air passage. This effectively reduces aerodynamic noise.

[0028] In the tenth configuration, the multiple protrusions provided on the side surfaces of the fins can also increase the surface area of ​​the brake disc. Furthermore, since air flowing into the air passage from the inner periphery of the disc body during travel of the railway vehicle tends to flow along the side surfaces of the fins, providing first protrusions on the side surfaces of the fins bends the air passage and lengthens its length, allowing the air flowing through the air passage to sufficiently contact the rear surface of the disc body and the side surfaces of the fins. Furthermore, the bends in the air passage abruptly change the direction of the air flow, thereby increasing the heat transfer coefficient at the bends between the brake disc and the air. As a result, the cooling performance of the brake disc during braking can be improved. Therefore, while maintaining cooling performance, the amount of air flowing through the air passage can be efficiently restricted, reducing aerodynamic noise.

[0029] In the brake disc according to the tenth configuration, the plurality of ridges may further include second ridges. The second ridges are disposed at different positions in the radial direction of the disc body from the first ridges. The length of the first ridges in the circumferential direction of the disc body is greater than the length of the second ridges in the circumferential direction (eleventh configuration).

[0030] The first protrusions on one of the adjacent fins may face the second protrusions on the other of the adjacent fins across a gap in the circumferential direction of the disc body. The second protrusions on one of the adjacent fins may face the first protrusions on the other of the adjacent fins across a gap in the circumferential direction of the disc body (twelfth configuration).

[0031] According to the twelfth configuration, the first protrusions, which are relatively long in the circumferential direction of the disc body, and the second protrusions, which are relatively short in the circumferential direction of the disc body, face each other with a gap between them. In this case, the cross-sectional area of ​​the air passage can be particularly reduced at the position where the first protrusions and the second protrusions face each other, effectively restricting the amount of air passing through the air passage. This allows for efficient reduction of aerodynamic noise.

[0032] In the brake disc according to the embodiment, one or more of the plurality of fins may include a groove that crosses the fin (thirteenth configuration).

[0033] According to a thirteenth configuration, one or more fins include grooves that cross the fin. These grooves reduce the amount of air flowing through the air passage by creating a pressure loss in the air flowing through the passage, and increase the heat transfer coefficient between the brake disc and the air. Furthermore, by providing grooves in the fins, the surface area of ​​the fins can be increased. Therefore, according to the thirteenth configuration, aerodynamic noise can be further reduced and cooling performance can be further improved.

[0034] In a brake disc according to an embodiment, one or more of the fins may include a fastening hole for inserting a fastening member. The groove may be located in at least one of a portion on the outer side and a portion on the inner side of the fastening hole in the radial direction of the disc body in the fin including the fastening hole (fourteenth configuration). It is preferable that the groove be located in each of a portion on the outer side and a portion on the inner side of the fastening hole in the radial direction of the disc body in the fin including the fastening hole (fifteenth configuration).

[0035] According to the fourteenth or fifteenth configuration, grooves are formed in the fins with fastening holes, allowing the fins to thermally expand and contract in the radial direction of the disc body. This reduces the constraint of the fins against thermal expansion during braking of the railway vehicle, reducing deformation of the brake disc due to thermal expansion. As a result, stress loads on the fastening members inserted into the fastening holes and on the brake disc can be reduced, improving the durability of the brake disc.

[0036] A brake disc according to an embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, identical or equivalent components are designated by the same reference numerals, and the same description will not be repeated. Each drawing is a schematic diagram for explaining the main components of the brake disc according to the embodiment. Therefore, the detailed shape or dimensional ratio of the brake disc shown in each drawing may differ from those of an actual brake disc.

[0037] First Embodiment [Brake disc configuration] FIG. 1 is a back view of a railway vehicle brake disc 100 according to a first embodiment. FIG. 2 is a partial perspective view of the brake disc 100 shown in FIG. 1. The brake disc 100 is fastened to a rotating member (not shown) of the railway vehicle. The rotating member is an annular disk that is fixed to an axle of the railway vehicle and rotates together with the axle. The rotating member is, for example, a wheel. The brake disc 100 is typically made of steel and can be formed, for example, by forging.

[0038] 1 and 2, a brake disc 100 includes a disc body 10 and a plurality of fins 20.

[0039] The disc body 10 has a substantially annular plate shape. The disc body 10 includes a front surface 11 and a back surface 12. The front surface 11 includes a sliding surface against which a brake lining (not shown) is pressed. The back surface 12 is the surface facing opposite to the front surface 11. When the brake disc 100 is fastened to a rotating member, the back surface 12 faces the rotating member. Hereinafter, for convenience of explanation, the radial direction and circumferential direction of the disc body 10 may be simply referred to as the radial direction and the circumferential direction. Furthermore, the direction of the central axis of the disc body 10 is referred to as the thickness direction.

[0040] The multiple fins 20 are provided on the back surface 12, which is one surface of the disc body 10. More specifically, the multiple fins 20 are arranged on the back surface 12 of the disc body 10 so that each fin 20 extends from the inner circumferential side toward the outer circumferential side of the disc body 10. Each fin 20 includes a top surface 21 and two side surfaces 221, 222. In each fin 20, the side surfaces 221, 222 are aligned substantially in the circumferential direction. The top surface 21 connects the side surfaces 221, 222. When the brake disc 100 is fastened to a rotating member, the top surface 21 comes into contact with the rotating member. This forms a space between the rotating member, the disc body 10, and adjacent fins 20. This space serves as an air passage through which air passes when the brake disc 100 rotates together with the rotating member.

[0041] At least one of the multiple fins 20 includes a fastening hole 23. In this embodiment, two or more fins 20 each include a fastening hole 23. A fastening member such as a bolt is inserted into the fastening hole 23 when the brake disc 100 is fastened to a rotating member. The fastening hole 23 penetrates the fin 20 in which the fastening hole 23 is provided and the disc body 10 in the thickness direction. The fastening hole 23 is disposed in the radial center of the annular sliding surface 11 (FIG. 2). Therefore, the brake disc 100 is fastened to a rotating member such as a wheel at the radial center of the sliding surface 11 by the fastening member.

[0042] In this embodiment, each of the fins 20 including the fastening holes 23 includes grooves 241 and 242. In this embodiment, the fins 20 without the fastening holes 23 also include the grooves 241 and 242. The grooves 241 and 242 have a concave shape extending from the top surface 21 of the fin 20 toward the disk body 10. The grooves 241 and 242 extend substantially in the circumferential direction and traverse the fin 20. One groove 241 is located in a portion of each fin 20 that is radially outer than the fastening holes 23. The other groove 242 is located in a portion of each fin 20 that is radially inner than the fastening holes 23. Therefore, in the fins 20 that have the fastening holes 23, the fastening holes 23 are positioned between the grooves 241 and 242.

[0043] There are no particular limitations on the shapes of the grooves 241 and 242. For example, the wall surfaces and bottom surfaces of the grooves 241 and 242 may each be flat, convex, or concave. The wall surfaces and bottom surfaces of the grooves 241 and 242 may each be configured by a combination of two or more types of surfaces.

[0044] In this embodiment, each of the fins 20 includes a plurality of protrusions 25 provided on both side surfaces 221, 222 thereof. The plurality of protrusions 25 are arranged substantially in the radial direction (longitudinal direction of the side surface 221) on one side surface 221 of each fin 20. A plurality of protrusions 25 are also arranged substantially in the radial direction (longitudinal direction of the side surface 222) on the other side surface 222 of each fin 20. The protrusions 25 are provided in a pleated shape on each of the side surfaces 221, 222. The protrusions 25 are formed integrally with the side surfaces 221, 222.

[0045] Fig. 3 is a cross-sectional view taken along line III-III of the brake disc 100 shown in Fig. 1. Fig. 4 is a cross-sectional view taken along line IV-IV of the brake disc 100 shown in Fig. 1. The protrusion 25 will be described in more detail below with reference to Figs. 3 and 4.

[0046] As shown in Fig. 3, on one side 221 of the fin 20, the protrusions 25 each extend between the disk body 10 and the top surface 21 of the fin 20. Similarly, as shown in Fig. 4, on the other side 222 of the fin 20, the protrusions 25 each extend between the disk body 10 and the top surface 21 of the fin 20. In this embodiment, when viewed from the side 221 and side 222 of the fin 20, each of the protrusions 25 extends substantially in the thickness direction of the disk body 10. However, when viewed from the side 221 and side 222 of the fin 20, at least some of the protrusions 25 may be inclined with respect to the thickness direction.

[0047] One end of each protrusion 25 contacts the back surface 12 of the disc body 10. In the example shown in FIGS. 3 and 4, the other end of each protrusion 25 reaches the top surface 21 of the fin 20. However, the other end of each protrusion 25 does not necessarily have to reach the top surface 21 of the fin 20. In other words, the length L (length in the thickness direction) of each protrusion 25 can be equal to or less than the height (length in the thickness direction) of the fin 20 protruding from the back surface 12 of the disc body 10. Each protrusion 25 may extend from the back surface 12 of the disc body 10 to near the top surface 21 of the fin 20 without reaching the top surface 21.

[0048] In this embodiment, as shown in FIG. 3 , the protrusions 25 are arranged at equal intervals over substantially the entirety of one side surface 221 of the fin 20. Furthermore, as shown in FIG. 4 , the protrusions 25 are arranged at equal intervals over substantially the entirety of the other side surface 222 of the fin 20. However, the arrangement of the protrusions 25 on the side surfaces 221, 222 of the fin 20 is not limited to this. For example, multiple protrusions 25 may be arranged at unequal intervals on at least one of the side surfaces 221, 222 of the fin 20. At least one of the side surfaces 221, 222 of the fin 20 may have an area where the protrusions 25 are arranged and an area where the protrusions 25 are not arranged. The number of protrusions 25 on each of the side surfaces 221, 222 may be two or more and can be determined appropriately. However, it is preferable that each of the side surfaces 221, 222 has three or more protrusions 25.

[0049] In this embodiment, the region where the protrusions 25 are arranged on one side surface 221 of the fin 20 corresponds to the region where the protrusions 25 are arranged on the other side surface 222 of the fin 20. That is, in the longitudinal direction (radial direction) of each fin 20, the position where each protrusion 25 is provided on one side surface 221 substantially coincides with the position where each protrusion 25 is provided on the other side surface 222. However, the region where the protrusions 25 are arranged on one side surface 221 of the fin 20 does not necessarily have to correspond to the region where the protrusions 25 are arranged on the other side surface 222 of the fin 20. For example, the protrusions 25 may be provided on one of the side surfaces 221, 222 in a region that is more inward than the center of the fastening hole 23 ( FIGS. 1 and 2 ), and the protrusions 25 may be provided on the other side surface 221, 222 in a region that is more outward than the center of the fastening hole 23.

[0050] Each protrusion 25 protrudes substantially in the circumferential direction from the side surface 221 or the side surface 222. In this embodiment, the protrusion amounts of all the protrusions 25 provided on one side surface 221 of the fin 20 are substantially the same. Also, in this embodiment, the protrusion amounts of all the protrusions 25 provided on the other side surface 222 of the fin 20 are substantially the same. The protrusion amount of the protrusion 25 is the length of the protrusion 25 in the circumferential direction of the disc body 10.

[0051] The protrusion amount of each protrusion 25 on each of the side surfaces 221, 222 of the fin 20 can be determined as appropriate. However, the protrusion amount of each protrusion 25 is set to a size that prevents the protrusions 25 of adjacent fins 20 from interfering with each other in the circumferential direction. The protrusion amount of the protrusion 25 can be determined, for example, based on the thickness of the fin 20. The thickness of each fin 20 refers to the length of the fin 20 in a direction substantially perpendicular to the longitudinal direction (radial direction of the disc body 10) and height direction (thickness direction of the disc body 10) of the fin 20. For example, when the thickness of the fin 20 with the smallest thickness among the multiple fins 20 provided on the disc body 10 is T, the protrusion amount of each protrusion 25 can be 1 / 3 × T or more.

[0052] In this embodiment, all of the protrusions 25 on each of the side surfaces 221, 222 of the fin 20 have the same protrusion amount. However, one side surface 221 of the fin 20 may be divided into a plurality of regions in the radial direction, and the protrusion amounts of the protrusions 25 may be varied for each region. For example, the protrusion amounts of the protrusions 25 may be relatively small in regions of the side surface 221 of the fin 20 adjacent to the fastening holes 23 (FIGS. 1 and 2), and relatively large in regions radially inward and outward from the aforementioned regions. Alternatively, conversely, the protrusion amounts of the protrusions 25 may be relatively large in regions of the side surface 221 of the fin 20 adjacent to the fastening holes 23, and relatively small in regions radially inward and outward from the aforementioned regions.

[0053] Similarly, the other side surface 222 of the fin 20 may be divided into a plurality of regions in the radial direction, and the amount of protrusion of the protrusion 25 may be changed for each region. For example, the amount of protrusion of the protrusion 25 may be relatively small in a region of the side surface 222 of the fin 20 adjacent to the fastening hole 23, and the amount of protrusion of the protrusion 25 may be relatively large in regions radially inward and outward from the region. Alternatively, conversely, the amount of protrusion of the protrusion 25 may be relatively large in a region of the side surface 222 of the fin 20 adjacent to the fastening hole 23, and the amount of protrusion of the protrusion 25 may be relatively small in regions radially inward and outward from the region.

[0054] The width W of each protrusion 25 (the length in the longitudinal direction of the side surface 221 or the side surface 222 of the fin 20) may also be determined appropriately. Of the two side surfaces 221, 222 of the fin 20, on one side surface 221, all of the protrusions 25 may have the same width, or protrusions 25 with different widths may be mixed. Similarly, on the other side surface 222, all of the protrusions 25 may have the same width, or protrusions 25 with different widths may be mixed.

[0055] Each protrusion 25 can have various cross-sectional shapes. For example, each protrusion 25 can have a cross-sectional shape that is semicircular, semi-elliptical, semi-oval, or polygonal, such as triangular or rectangular. On one of the two side surfaces 221, 222 of the fin 20, all of the protrusions 25 may have the same cross-sectional shape, or protrusions 25 with different cross-sectional shapes may be present. Similarly, on the other side surface 222, all of the protrusions 25 may have the same cross-sectional shape, or protrusions 25 with different cross-sectional shapes may be present. The cross-section of a protrusion 25 refers to a cross section of the protrusion 25 cut along a plane substantially perpendicular to its extension direction.

[0056] 3 and 4, in the brake disc 100 according to this embodiment, the sliding surface (surface 11 of the disc body 10) against which the brake lining is pressed is provided only on one side in the thickness direction. On each of the side surfaces 221, 222 of the fin 20, the plurality of protrusions 25 are arranged between the inner peripheral end and the outer peripheral end of the annular sliding surface 11 (within the range of the sliding width). The plurality of protrusions 25 are preferably arranged radially within the range of the top surface 21 of the fin 20. The plurality of protrusions 25 are arranged radially outward from the inner peripheral surface 27 of the fin 20. The plurality of protrusions 25 are also arranged radially inward from the outer peripheral surface 28 of the fin 20. In each fin 20, the inner peripheral surface 27 is connected to the inner end of the top surface 21 and the side surfaces 221, 222 in the radial direction. In each fin 20, the outer peripheral surface 28 is connected to the outer end of the top surface 21 and the side surfaces 221, 222 in the radial direction. In this embodiment, the outer peripheral surface 28 is inclined with respect to the thickness direction of the disk body 10 so that the height of the fin 20 decreases radially outward. The inner peripheral surface 27 may be inclined with respect to the thickness direction of the disk body 10 so that the height of the fin 20 increases radially outward. In the range of the top surface 21 between the inner peripheral surface 27 and the outer peripheral surface 28, the height of the fin 20 is substantially constant.

[0057] [effect] According to the brake disc 100 of this embodiment, a plurality of protrusions 25 are provided on each of a plurality of fins 20 arranged on the rear surface 12 of the disc body 10. The plurality of protrusions 25 are provided on the side surfaces 221, 222 of each fin 20. When the brake disc 100 is fastened to a rotating member of a railway vehicle and an air passage is formed by the rotating member, the disc body 10, and the side surfaces 221, 222 of adjacent fins 20, these protrusions 25 can reduce the cross-sectional area of ​​the air passage in the circumferential direction. This makes it possible to limit the amount of air passing through the air passage (airflow rate) while the railway vehicle is traveling. This, in turn, makes it possible to reduce aerodynamic noise.

[0058] Meanwhile, the protrusions 25 provided on the side surfaces 221, 222 of each fin 20 can also increase the surface area of ​​the brake disc 100. Furthermore, since air flowing into the air passage from the inner circumferential side of the disc body 10 while the railway vehicle is running flows along the side surfaces 221, 222 of each fin 20, the protrusions 25 provided on the side surfaces 221, 222 of each fin 20 can increase the heat transfer coefficient between the brake disc 100 and the air. As a result, the cooling performance of the brake disc 100 during braking can be improved. Therefore, with the brake disc 100 according to this embodiment, it is possible to efficiently limit the amount of air flowing through the air passage and reduce aerodynamic noise while ensuring cooling performance.

[0059] In the brake disc 100 according to this embodiment, two or more fins 20 are provided with fastening holes 23 for inserting fastening members. Each of the fins 20 having the fastening holes 23 includes grooves 241, 242 that cross the fin. Furthermore, each of the fins 20 that do not have the fastening holes 23 also includes grooves 241, 242. These grooves 241, 242 reduce the amount of airflow in the air passages by causing a pressure loss in the air flowing through the passages, and increase the heat transfer coefficient between the brake disc 100 and the air. The grooves 241, 242 also increase the surface area of ​​each fin 20. Therefore, by providing the grooves 241, 242 in each fin 20, aerodynamic noise can be further reduced and cooling performance can be further improved.

[0060] Furthermore, the grooves 241, 242 formed in the fins 20 including the fastening holes 23 allow thermal expansion and contraction in the radial direction of the fins 20. This alleviates the constraint on the fins 20 against thermal expansion during braking of the railway vehicle, reducing deformation of the brake disc 100 due to thermal expansion. As a result, the stress load on the fastening members inserted into the fastening holes 23 and on the brake disc 100 can be reduced, and the durability of the brake disc 100 can be improved.

[0061] In the brake disc 100 according to this embodiment, the multiple protrusions 25 are disposed radially outward of the inner peripheral surface 27 of the fins 20. In this case, corners can be formed between the inner peripheral surface 27 and the side surfaces 221, 222 of each fin 20. These corners allow air to be efficiently drawn into the air passages formed between adjacent fins 20, and a high local heat transfer coefficient can be maintained in this region. This allows the cooling performance of the brake disc 100 to be maintained at a good level.

[0062] In the brake disc 100 according to this embodiment, the outer peripheral surface 28 of each fin 20 is inclined relative to the thickness direction of the disc body 10 so that the height of the fin 20 decreases radially outward. The multiple protrusions 25 are arranged radially inward of the outer peripheral surface 28. This makes it possible to prevent the outer peripheral sides of the fins 20 and the protrusions 25 from interfering with rotating members such as wheels when the brake disc 100 is deformed into a convex arch shape toward the brake lining due to frictional heat generated between the brake lining and the sliding surface 11 of the disc body 10 during braking.

[0063] Second Embodiment Fig. 5 is a rear view of a railway vehicle brake disc 100A according to the second embodiment. Fig. 5 shows a portion of the brake disc 100A. The brake disc 100A according to this embodiment differs from the brake disc 100 according to the first embodiment in the configuration of the protrusions 26.

[0064] 5, each of the multiple fins 20 includes multiple protrusions 26. The multiple protrusions 26 are provided on both side surfaces 221, 222 of each fin 20. On each of the side surfaces 221, 222, the multiple protrusions 26 include one or more first protrusions 261 and one or more second protrusions 262. In this embodiment, each of the side surfaces 221, 222 includes multiple first protrusions 261 and multiple second protrusions 262. It is preferable that the total number of protrusions 261, 262 on each of the side surfaces 221, 222 is three or more.

[0065] The first protrusions 261 are disposed on the inner and outer circumferential sides of the disc body 10. That is, the first protrusions 261 are provided on the inner and outer sides of the fastening holes 23 in the radial direction of the disc body 10. The second protrusions 262 are disposed at positions different from the first protrusions 261 in the radial direction. In this embodiment, a plurality of second protrusions 262 are disposed between the first protrusion 261 on the inner circumferential side of the disc body 10 and the first protrusion 261 on the outer circumferential side of the disc body 10. These second protrusions 262 are arranged in the radial direction.

[0066] Like the protrusion 25 in the first embodiment, the protrusions 261, 262 each extend between the disc body 10 and the top surface 21 of the fin 20. The protrusions 261, 262 protrude from the side surface 221 or 222 of the fin 20 substantially in the circumferential direction of the disc body 10. The protrusion amount P1 of the first protrusion 261 is greater than the protrusion amount P2 of the second protrusion 262. The protrusion amounts P1, P2 are the lengths of the protrusions 261, 262 in the circumferential direction, respectively. On each of the side surfaces 221, 222 of the fin 20, the protrusion amount P1 of the first protrusion 261 can be, for example, 2.0 times or more the protrusion amount P2 of the second protrusion 262. As with the protrusion 25 in the first embodiment, the protrusion amount P2 of the second protrusion 262 can be set to 1 / 3×T or more, where T is the thickness of the fin 20 having the smallest thickness among the multiple fins 20.

[0067] The positions of the first protrusions 261 in the radial direction of the disc body 10 are substantially the same for all fins 20. Therefore, of adjacent fins 20, the first protrusions 261 of one fin 20 face the first protrusions 261 of the other fin 20 in the circumferential direction. The first protrusions 261 of adjacent fins 20 do not interfere with each other. That is, a gap S1 exists between the first protrusions 261 that face each other in the circumferential direction. The size of the gap S1 in the circumferential direction can be 0.7 × T or more and 5.0 × T or less, where T is the thickness of the fin 20 that has the smallest thickness among the multiple fins 20.

[0068] In this embodiment, a first protrusion 261 and a second protrusion 262 are provided on the side surfaces 221, 222 of each fin 20, and the protrusion amount P1 of the first protrusion 261 is greater than the protrusion amount P2 of the second protrusion 262. This makes it possible to particularly reduce the cross-sectional area of ​​the air passage at the position of the first protrusion 261, effectively restricting the amount of air passing through the air passage. This therefore makes it possible to further reduce aerodynamic noise.

[0069] In this embodiment, the first protrusions 261, each having a relatively large protrusion amount P1, are provided on the side surfaces 221, 222 of each fin 20. This allows the surface area of ​​the brake disc 100A to be further increased, thereby improving the cooling performance of the brake disc 100A during braking.

[0070] Therefore, like the first embodiment, the brake disc 100A according to this embodiment can also efficiently limit the amount of air passing through the air passages, thereby reducing aerodynamic noise, while ensuring cooling performance.

[0071] Third Embodiment Fig. 6 is a back view of a railway vehicle brake disc 100B according to the third embodiment. Fig. 6 shows a portion of the brake disc 100B. In the brake disc 100B according to this embodiment, each fin 20 includes protrusions 26 on both side surfaces 221, 222 thereof, similar to those in the second embodiment. That is, the side surfaces 221, 222 of each fin 20 are provided with first protrusions 261 having a relatively large protrusion amount P1 and second protrusions 262 having a relatively small protrusion amount P2.

[0072] However, in this embodiment, the first protrusions 261 are arranged only on the outer circumferential side of the disc body 10. That is, the first protrusions 261 are provided only on the outer side of the fastening holes 23 in the radial direction of the disc body 10. In the example shown in Fig. 6, of the first protrusions 261 and the multiple second protrusions 262 provided on the side surface 221 or the side surface 222 of each fin 20, the first protrusions 261 are positioned outermost in the radial direction.

[0073] As with the above-described embodiments, the configuration of the brake disc 100B according to this embodiment also makes it possible to efficiently limit the amount of air passing through the air passages and reduce aerodynamic noise while ensuring cooling performance.

[0074] <Fourth embodiment> Fig. 7 is a back view of a railway vehicle brake disc 100C according to the fourth embodiment. Fig. 7 shows a portion of the brake disc 100C. In the brake disc 100C according to this embodiment, each fin 20 includes protrusions 26 on both side surfaces 221, 222 thereof, similar to those of the second embodiment. That is, the side surfaces 221, 222 of each fin 20 are provided with first protrusions 261 having a relatively large protrusion amount P1 and second protrusions 262 having a relatively small protrusion amount P2.

[0075] However, in this embodiment, the first protrusion 261 is disposed only on the inner peripheral side of the disc body 10. In other words, the first protrusion 261 is provided only radially inward of the fastening holes 23 of the disc body 10. In the example shown in Fig. 7, of the first protrusion 261 and the multiple second protrusions 262 provided on the side surface 221 or the side surface 222 of each fin 20, the first protrusion 261 is positioned innermost in the radial direction.

[0076] As with the above embodiments, the configuration of the brake disc 100C according to this embodiment also makes it possible to efficiently limit the amount of air passing through the air passages and reduce aerodynamic noise while ensuring cooling performance.

[0077] In this embodiment, the first protrusions 261 are arranged on the inner circumferential side of the disc body 10. In this case, maintenance is easier when dust or the like gets stuck between the first protrusions 261 that face each other in the circumferential direction of the disc body 10, compared to when the first protrusions 261 are arranged on the outer circumferential side of the disc body 10. Furthermore, arranging the first protrusions 261 on the inner circumferential side of the disc body 10 is advantageous in terms of formability by forging the brake disc 100C.

[0078] Fifth Embodiment Fig. 8 is a back view of a railway vehicle brake disc 100D according to the fifth embodiment. Fig. 8 shows a portion of the brake disc 100D. In the brake disc 100D according to this embodiment, each fin 20 includes protrusions 26 on both side surfaces 221, 222 thereof, similar to those of the second embodiment. That is, the side surfaces 221, 222 of each fin 20 are provided with first protrusions 261 having a relatively large protrusion amount P1 and second protrusions 262 having a relatively small protrusion amount P2.

[0079] However, in this embodiment, the first protrusion 261 is disposed in the center of the disc body 10 in the radial direction. The first protrusion 261 is disposed, for example, at substantially or approximately the same position as the fastening hole 23 in the radial direction of the disc body 10. The second protrusion 262 is disposed inward and outward of the first protrusion 261 in the radial direction. In the example shown in FIG. 8 , a plurality of second protrusions 262 are provided on each of the side surfaces 221, 222 of the fin 20, radially inward of the first protrusion 261. Furthermore, a plurality of second protrusions 262 are provided on each of the side surfaces 221, 222 of the fin 20, radially outward of the first protrusion 261.

[0080] As with the above embodiments, the configuration of the brake disc 100D according to this embodiment also makes it possible to efficiently limit the amount of air passing through the air passages and reduce aerodynamic noise while ensuring cooling performance.

[0081] Sixth Embodiment Fig. 9 is a back view of a railway vehicle brake disc 100E according to the sixth embodiment. Fig. 9 shows a portion of the brake disc 100E. In the brake disc 100E according to this embodiment, each fin 20 includes protrusions 26 on both side surfaces 221, 222 thereof, similar to those of the second embodiment. That is, the side surfaces 221, 222 of each fin 20 are provided with first protrusions 261 having a relatively large protrusion amount P1 and second protrusions 262 having a relatively small protrusion amount P2.

[0082] In this embodiment, as in the fourth embodiment, the first protrusions 261 are arranged on the inner circumferential side of the disc body 10. Also, in this embodiment, as in the fifth embodiment, the first protrusions 261 are arranged in the radial center of the disc body 10. In the example shown in FIG. 9, one second protrusion 262 is arranged between two first protrusions 261 on each of the side surfaces 221, 222 of the fin 20. Second protrusions 262 are also provided on the radially outer side of the first protrusions 261 on each of the side surfaces 221, 222 of the fin 20.

[0083] As with the above embodiments, the configuration of the brake disc 100E according to this embodiment also makes it possible to efficiently limit the amount of air passing through the air passages and reduce aerodynamic noise while ensuring cooling performance.

[0084] In this embodiment, the first protrusions 261 are arranged on the side surfaces 221, 222 of each fin 20 on the inner circumferential side of the disc body 10 and in the radial center. However, the first protrusions 261 may also be arranged on the side surfaces 221, 222 of each fin 20 on the outer circumferential side of the disc body 10 and in the radial center.

[0085] Seventh Embodiment Fig. 10 is a rear view of a railway vehicle brake disc 100F according to the seventh embodiment. Fig. 10 shows a portion of the brake disc 100F. In the brake disc 100F according to this embodiment, a plurality of the above-mentioned first protrusions 261 are provided on both side surfaces 221, 222 of each fin 20. In this embodiment, no second protrusions 262 are provided on both side surfaces 221, 222 of each fin 20. On the side surfaces 221, 222 of each fin 20, only first protrusions 261 having a relatively large protrusion amount P1 are arranged in the radial direction of the disc body 10.

[0086] As with the above-described embodiments, the brake disc 100F according to this embodiment can also efficiently limit the amount of air passing through the air passages, thereby reducing aerodynamic noise, while ensuring cooling performance.

[0087] Eighth Embodiment Fig. 11 is a back view of a railway vehicle brake disc 100G according to an eighth embodiment. Fig. 12 is a partial perspective view of the brake disc 100G shown in Fig. 11. As shown in Figs. 11 and 12, the brake disc 100G according to this embodiment has a configuration substantially similar to that of the brake disc 100 according to the first embodiment (Figs. 1 and 2). However, the brake disc 100G according to this embodiment differs from the brake disc 100 according to the first embodiment in the configuration of the protrusions 29.

[0088] As in the above-described embodiments, each of the fins 20 includes a plurality of protrusions 29. More specifically, a plurality of protrusions 29 are provided on one side surface 221 of each fin 20. The plurality of protrusions 29 are arranged on the side surface 221 of each fin 20 in a substantially radial direction (the longitudinal direction of the side surface 221). A plurality of protrusions 29 are also provided on the other side surface 222 of each fin 20. The plurality of protrusions 29 are arranged on the side surface 222 of each fin 20 in a substantially radial direction (the longitudinal direction of the side surface 222). The protrusions 29 are provided in a pleated shape on each of the side surfaces 221, 222. The protrusions 29 are formed integrally with the side surfaces 221, 222.

[0089] The plurality of protrusions 29 include a plurality of protrusions 29L and a plurality of protrusions 29S. Each of the protrusions 29L, 29S protrudes substantially in the circumferential direction from the side surface 221 or the side surface 222 of the fin 20. However, in each of the fins 20, the protrusion amount of the protrusion 29L is greater than the protrusion amount of the protrusion 29S. In each fin 20, protrusions 29L having a relatively large protrusion amount and protrusions 29S having a relatively small protrusion amount are mixed. The protrusion amount of the protrusions 29L, 29S refers to the length of the protrusions 29L, 29S in the circumferential direction of the disc body 10.

[0090] In this embodiment, protrusions 29L having a relatively large protrusion amount and protrusions 29S having a relatively small protrusion amount are alternately arranged on each of the side surfaces 221, 222 of the fin 20. The protrusions 29L, 29S are arranged, for example, at equal intervals across the entire side surfaces 221, 222 of the fin 20. However, the protrusions 29L, 29S may also be arranged at unequal intervals on at least one of the side surfaces 221, 222 of the fin 20.

[0091] Each of the protrusions 29L, 29S extends between the disc body 10 and the top surface 21 of the fin 20. Each of the protrusions 29L, 29S extends, for example, substantially in the thickness direction of the disc body 10. However, the protrusions 29L, 29S may be inclined with respect to the thickness direction of the fin 20 in a side view.

[0092] In each fin 20, one end of the protrusions 29L, 29S contacts the back surface 12 of the disc body 10. The other end of the protrusions 29L, 29S may or may not reach the top surface 21 of the fin 20. In other words, the length of the protrusions 29L, 29S in the thickness direction of the disc body 10 can be equal to or less than the distance from the back surface 12 of the disc body 10 to the top surface 21 of the fin 20.

[0093] 13 is a partially enlarged view of the rear surface of the brake disc 100G. The protrusions 29L and 29S will be described in more detail below with reference to FIG.

[0094] Referring to FIG. 13 , when two adjacent fins 20 among the plurality of fins 20 are designated as fins 20a and 20b, the radial positions of the protrusions 29L, which have a relatively large protrusion amount, differ between fins 20a and 20b. The protrusions 29L of fin 20a are radially offset from the protrusions 29L of fin 20b so as to bend the air passage formed between fins 20a and 20b. That is, the protrusions 29L protruding from the side surface 222 of one fin 20a do not face the protrusions 29L protruding from the side surface 221 of the other fin 20b in the circumferential direction. As a result, a zigzag-shaped air passage is formed between the adjacent fins 20a and 20b, as indicated by the two-dot chain arrows in FIG. 13 . This air passage has one or more locations where the air flow is bent. It is preferable that the air passage have multiple locations where the air flow is bent. In order to ensure that the air flow is bent, it is preferable that the air passage has a shape such that the air outlet side cannot be seen from the air inlet side.

[0095] A gap S1 is formed between the protrusion 29L of the fin 20a and the fin 20b. More specifically, the protrusion 29L of the fin 20a faces the protrusion 29S of the fin 20b with the gap S1 in the circumferential direction. Similarly, a gap S2 is formed between the fin 20a and the protrusion 29L of the fin 20b. More specifically, the protrusion 29S of the fin 20a faces the protrusion 29L of the fin 20b with the gap S2 in the circumferential direction. The position of the gap S1 between the protrusion 29L of the fin 20a and the fin 20b is shifted in the circumferential direction from the position of the gap S2 between the protrusion 29L of the fin 20b and the fin 20a.

[0096] The size of the gaps S1 and S2 in the circumferential direction can be determined, for example, based on the thickness of the fin 20. The thickness of the fin 20 is the length of the fin 20 in a direction substantially perpendicular to the radial and thickness directions of the disk body 10. The size of the gaps S1 and S2 in the circumferential direction can be set to 0.7×T or more and 5.0×T or less, where T is the thickness of the fin 20 with the smallest thickness among the multiple fins 20 provided on the disk body 10. The size of the gap S1 is, for example, substantially equal to the size of the gap S2. However, the size of the gap S1 may be different from the size of the gap S2.

[0097] The protrusions 29L and 29S each have a protrusion amount A L ,A S Protrusion amount A L ,A S The protrusion amount A of the protruding portion 29L can be determined based on the thickness of the fin 20, for example. L For example, the protrusion amount A of the protruding portion 29L can be set to 1.0×T or more, where T is the thickness of the fin 20 having the smallest thickness among the plurality of fins 20. L is set to a size that does not interfere with the circumferentially opposing protrusions 29S. S For example, the protrusion amount A of the protrusion portion 29L L is less than 0.85 times.

[0098] The protruding ends of the protruding ridges 29L, 29S have, for example, a semicircular cross section. However, the protruding ends of the protruding ridges 29L, 29S may also have, for example, a semi-elliptical or polygonal cross section such as a triangular or rectangular shape. On each of the side surfaces 221, 222 of the fin 20, the protruding ends of the multiple protruding ridges 29L, 29S may all have the same cross section, or protruding ridges 29L, 29S having protruding ends with different cross sections may be mixed. Here, the cross section refers to a cross section of the protruding ridges 29L, 29S cut along a plane substantially perpendicular to the thickness direction of the disc body 10.

[0099] The width of each of the protrusions 29L, 29S (the length in the longitudinal direction of the side surfaces 221, 222 of the fin 20) can be determined appropriately. On each of the side surfaces 221, 222 of the fin 20, all of the multiple protrusions 29L, 29S may have the same width, or protrusions 29L, 29S with different widths may be mixed.

[0100] According to the brake disc 100G of this embodiment, a plurality of protrusions 29 are provided on each of a plurality of fins 20 arranged on the back surface 12 of the disc body 10. The plurality of protrusions 29 are provided on the side surfaces 221, 222 of each fin 20. When the brake disc 100G is fastened to a rotating member of a railway vehicle and an air passage is formed by the rotating member, the disc body 10, and adjacent fins 20, these protrusions 29 can reduce the cross-sectional area of ​​the air passage in the circumferential direction. This makes it possible to limit the amount of air passing through the air passage (airflow rate) while the railway vehicle is running. Furthermore, in this embodiment, the plurality of protrusions 29 include protrusions 29L, 29S. A relatively large protrusion amount A L The positions of the protrusions 29L having the protrusions 29L are shifted in the radial direction of the disk body 10 between adjacent fins 20. As a result, the air passages formed between adjacent fins 20 are bent, which increases the flow resistance of air passing through the air passages, thereby reducing aerodynamic noise.

[0101] In the brake disc 100G according to this embodiment, the protrusions 29L, 29S provided on the side surfaces 221, 222 of each fin 20 can also increase the surface area of ​​the brake disc 100G. Furthermore, during the running of a railway vehicle, air flowing into the air passage from the inner circumferential side of the disc body 10 tends to flow along the side surfaces 221, 222 of each fin 20. Therefore, the protrusions 29L on the side surfaces 221, 222 bend the air passage and increase its length, allowing the air flowing through the air passage to sufficiently contact the rear surface 12 of the disc body 10 and the side surfaces 221, 222 of each fin 20. Furthermore, the bent portions of the air passage abruptly change the direction of the air flow, thereby increasing the heat transfer coefficient between the brake disc 100G and the air at the bent portions. As a result, the cooling performance of the brake disc 100G during braking can be improved. Therefore, with the brake disc 100G according to this embodiment, it is possible to efficiently limit the amount of air passing through the air passages and reduce aerodynamic noise while ensuring cooling performance.

[0102] In this embodiment, the adjacent fins 20 have a relatively large protrusion amount A L and a relatively small protrusion amount A S The protrusions 29L and 29S face each other with gaps S1 and S2 between them. In this case, the cross-sectional area of ​​the air passage can be particularly reduced at the positions where the protrusions 29L and 29S face each other, further increasing the flow resistance of the air passing through the air passage. This effectively limits the amount of air passing through the air passage, reducing aerodynamic noise.

[0103] In this embodiment, the protrusions 29L, 29S are disposed on each of the side surfaces 221, 222 of the fin 20 between the inner and outer circumferential ends of the annular sliding surface 11 (within the sliding width range). As in the above embodiments, the protrusions 29L, 29S are preferably disposed radially within the range of the top surface 21 of the fin 20. For example, the protrusions 29L, 29S are disposed radially outward from the inner circumferential surface 27 of the fin 20. Therefore, as in the above embodiments, air can be efficiently drawn into the air passages formed between adjacent fins 20, and a high local heat transfer coefficient can be maintained in this region. This allows the cooling performance of the brake disc 100G to be maintained favorably. Furthermore, the protrusions 29L, 29S are disposed radially outward from the outer circumferential surface 28 of the fin 20. Therefore, similarly to the above-described embodiments, when the brake disc 100G is applied, the outer periphery of the fin 20 and the protruding portions 29L, 29S can be prevented from interfering with a rotating member such as a wheel.

[0104] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure.

[0105] For example, in the brake discs 100, 100A to 100F according to the first to seventh embodiments, all of the fins 20 arranged on the back surface 12 of the disc body 10 each include a plurality of protrusions 25 or a plurality of protrusions 26. However, it is also possible for a plurality of protrusions 25 or a plurality of protrusions 26 to be formed on only some of the fins 20 arranged on the back surface 12 of the disc body 10. That is, it is sufficient that one or more of the fins 20 include a protrusion 25 or a protrusion 26. However, in order to achieve a greater effect in reducing aerodynamic noise and improving cooling performance, it is preferable that two or more of the fins 20 include a protrusion 25 or a protrusion 26, and it is more preferable that all of the fins 20 include a protrusion 25 or a protrusion 26.

[0106] In the brake discs 100, 100A to 100F according to the first to seventh embodiments, the fins 20 each have a protrusion 25 or a protrusion 26 on both side surfaces 221, 222. However, each fin 20 may have a plurality of protrusions 25 or a plurality of protrusions 26 formed on only one of the two side surfaces 221, 222. The brake discs 100, 100A to 100F may have a mixture of two or more types of fins 20 including protrusions 25 or protrusions 26 provided on both side surfaces 221, 222, fins 20 including protrusions 25 or protrusions 26 provided on only one of the side surfaces 221, 222, and fins 20 that do not have any protrusions 25, 26.

[0107] In the eighth embodiment, the side surfaces 221 and 222 of each fin 20 have a relatively large protrusion amount A L and a relatively small protrusion amount A S 10. However, each fin 20 does not have to have the protrusion 29S. For example, adjacent fins 20 may each have only the protrusion 29L. Alternatively, one of the adjacent fins 20 may have the protrusions 29L and 29S, and the other of the adjacent fins 20 may have only the protrusion 29L. Even in such a case, as in the above-described eighth embodiment, the air passage between adjacent fins 20 can be bent by shifting the positions of the protrusions 29L of the adjacent fins 20 in the radial direction of the disc body 10. When the fin 20 does not have the protrusion 29S on its side surface 221 or 222, two or more protrusions 29L, more preferably three or more protrusions 29L, are provided on the side surface 221 or 222.

[0108] In the eighth embodiment, all of the fins 20 arranged on the back surface 12 of the disk body 10 each include a plurality of protrusions 29. However, a plurality of protrusions 29 may be formed on only some of the fins 20 arranged on the back surface 12 of the disk body 10. That is, it is sufficient that a plurality of protrusions 29 including the protrusion 29L are formed on at least two adjacent fins 20 among the plurality of fins 20. However, in order to obtain a greater effect in reducing aerodynamic noise and improving cooling performance, it is preferable that three or more fins 20 among the plurality of fins 20 include the protrusions 29, and it is more preferable that all fins 20 include the protrusions 29.

[0109] In the eighth embodiment, the fin 20 has a relatively large protrusion amount A over substantially the entire side surface 221, 222. L The protrusions 29L having the protrusions 29L are arranged on the side surfaces 221 and / or 222. However, it is also possible to provide regions on the side surfaces 221 and / or 222 where the protrusions 29L are not arranged. For example, the protrusions 29L may be arranged only in regions on the inner periphery side of the centers of the fastening holes 23 between adjacent fins 20, so that the protrusions 29L bend the air passages only on the inner periphery side of the centers of the fastening holes 23. Furthermore, for example, the protrusions 29L may be arranged only in regions on the outer periphery side of the centers of the fastening holes 23 between adjacent fins 20, so that the protrusions 29L bend the air passages only on the outer periphery side of the centers of the fastening holes 23. Alternatively, the protrusions 29L may be arranged only in regions near the fastening holes 23 between adjacent fins 20, so that the protrusions 29L bend the air passages only in the center in the radial direction. In each fin 20, a relatively small protrusion amount A may be provided in the regions where the protrusions 29L are present and the regions where the protrusions 29L are not present. S When each fin 20 has both the protrusions 29L and 29S, the total number of the protrusions 29L and 29S is preferably three or more.

[0110] In the brake discs 100, 100A to 100G according to the above embodiments, each fin 20 includes grooves 241, 242. However, each fin 20 may include only one of the grooves 241, 242. Alternatively, each fin 20 may not include either of the grooves 241, 242. In the brake discs 100, 100A to 100G, fins 20 including at least one of the grooves 241, 242 and fins 20 not including the grooves 241, 242 may be mixed. For example, among the multiple fins 20 arranged on the rear surface 12 of the disc body 10, only the fins 20 including the fastening holes 23 may be provided with at least one of the grooves 241, 242, while the other fins 20 may not be provided with the grooves 241, 242. Alternatively, the fins 20 including the fastening holes 23 may not be provided with the grooves 241, 242, and the other fins 20 may be provided with at least one of the grooves 241, 242. The grooves 241, 242 may not be provided in any of the fins 20 arranged on the rear surface 12 of the disk body 10. When at least one of the grooves 241, 242 is provided in a fin 20 that does not include a fastening hole 23, the grooves 241 and / or 242 can be positioned freely in the radial direction of the fin 20 without being restricted by the fastening hole 23. [Example]

[0111] The present disclosure will be described in more detail below with reference to examples, although the present disclosure is not limited to the following examples.

[0112] [First Example] In order to verify the effects of the present disclosure, as Example 1, a brake disc having a shape similar to that of the brake disc 100 according to the first embodiment (FIGS. 1 and 2) was subjected to a three-dimensional thermal fluid analysis using general-purpose thermal fluid analysis software (product name: ANSYS Fluent, manufactured by ANSYS, Inc.) assuming a railway vehicle running steadily at 330 km / h. Furthermore, as Examples 2 to 7, the same analysis as above was performed on the brake discs 100A to 100F according to the second to seventh embodiments (FIGS. 5 to 10), respectively. As a comparative example, the same analysis as above was performed on a brake disc obtained by removing the protrusions on the side surfaces of the fins from the brake disc according to Example 1. Each of the brake discs according to the examples and comparative examples has 33 fins.

[0113] The aerodynamic noise level and cooling performance were evaluated for the brake discs of each example and comparative example. The airflow rate [kg / s] obtained by gas isothermal flow analysis was used as an evaluation index for the aerodynamic noise level. This airflow rate is the amount of air passing between the brake disc and the rotating member (wheel) per brake disc. As mentioned above, in brake discs for railway vehicles, there is a strong correlation between the amount of air passing through the air passage and the aerodynamic noise level. Therefore, it can be said that the greater the airflow rate, the greater the aerodynamic noise level.

[0114] The heat release index [W / K] obtained through non-isothermal gas flow analysis was used as an evaluation index for the cooling performance of the brake disc. This heat release index is the product of the average heat transfer coefficient of the disc surface and the disc surface area per brake disc. The higher the heat release index, the better the cooling performance of the brake disc.

[0115] Heat dissipation efficiency was used as an evaluation index to show the efficiency of aerodynamic noise reduction. Heat dissipation efficiency is the value obtained by dividing the heat dissipation index by the amount of airflow. The higher the heat dissipation efficiency, the more successfully the amount of airflow could be restricted without impairing the cooling performance of the brake disc, meaning that aerodynamic noise was reduced more efficiently.

[0116] The evaluation results of the brake discs according to the examples and comparative examples are shown in Table 1 and FIG.

[0117] [Table 1]

[0118] As shown in Table 1 and FIG. 14, it can be seen that the comparative example has a high heat dissipation index and provides excellent cooling performance. On the other hand, the heat dissipation index of Example 1 is similar to that of the comparative example, and it can also be seen that excellent cooling performance is provided. Furthermore, the amount of airflow in Example 1 was reduced compared to the comparative example. In other words, Example 1 was able to reduce the level of aerodynamic noise while maintaining excellent cooling performance equivalent to that of the comparative example. When comparing heat dissipation efficiency, Example 1 is significantly greater than the comparative example. Therefore, it can be said that Example 1 efficiently reduced aerodynamic noise while maintaining the cooling performance of the brake disc compared to the comparative example.

[0119] In Examples 2 to 7, in which protrusions with relatively large protrusions were provided on both sides of each fin, the amount of airflow was reduced and the level of aerodynamic noise was reduced compared to the comparative example. Meanwhile, with regard to the heat dissipation index, only Example 3 was higher than the comparative example, while Examples 2 and 4 to 7 were slightly lower than the comparative example. However, all of Examples 2 to 7 showed a significant improvement in heat dissipation efficiency compared to the comparative example. Therefore, it can be said that Examples 2 to 7 also efficiently reduced aerodynamic noise while maintaining the cooling performance of the brake disc.

[0120] This analysis confirmed that by providing multiple protrusions on the sides of the fins, it is possible to reduce aerodynamic noise while maintaining cooling performance for railway vehicle brake discs.

[0121] [Second Example] In order to verify the effects of the present disclosure, a three-dimensional thermal fluid analysis similar to that of the first example was carried out on a brake disc having a shape similar to that of the brake disc 100G according to the eighth embodiment (FIGS. 11 to 13) as Example 8. The evaluation results of the brake discs according to Example 8 and the comparative example are shown in Table 2. The comparative example is the same as the comparative example in the first example.

[0122] [Table 2]

[0123] As shown in Table 2, in Example 8, the amount of airflow was significantly reduced compared to the comparative example. On the other hand, in Example 8, the heat dissipation index was slightly reduced compared to the comparative example. However, in Example 8, the heat dissipation efficiency was significantly higher than in the comparative example. Therefore, in Example 8, it can be said that the deterioration of the cooling performance of the brake disc was suppressed despite the significant reduction in aerodynamic noise.

[0124] This analysis confirmed that by providing multiple protrusions on each of adjacent fins and using these protrusions to bend the air passage between adjacent fins, it is possible to efficiently reduce aerodynamic noise while maintaining cooling performance for railway vehicle brake discs.

[0125] [Third Example] Brake disc models (disc test specimens) according to Examples 1 to 8 were prepared, and a rotation test was conducted using each model. In this test, the disc test specimens according to Examples 1 to 8 were attached to wheel models (wheel test specimens) and rotated at a predetermined rotation speed, and the sound pressure level was measured using a sound level meter installed 70 cm away from the surface of each disc test specimen. For comparison, similar rotation tests were also conducted on wheel test specimens to which no disc test specimens were attached, and on brake disc models (disc test specimens) according to the comparative examples. The results of the rotation test are shown in Figure 15. Figure 15 shows the sound pressure level measured in the rotation test (the sum of noise components in the frequency range of 2700 Hz to 3300 Hz, where no peaks presumably originating from the testing machine were present), as well as the airflow rates obtained by the analysis of Examples 1 and 2.

[0126] As shown in Figure 15, in Examples 1 to 8, in which protrusions were provided on each fin, the sound pressure level was reduced compared to the wheel test specimen and the comparative example in which no protrusions were provided on each fin. In Example 8, in which the air passage between adjacent fins was bent, the sound pressure level was particularly low. The trend in sound pressure levels obtained in this rotation test matches the trend in airflow rates obtained in the analysis of Examples 1 and 2 above. In other words, the magnitude relationship of the airflow rates in the analysis corresponds to the magnitude relationship of the sound pressure levels, and it can be said that the evaluation of the aerodynamic noise reduction effect in the analysis is accurate.

[0127] This rotation test confirmed that providing multiple ridges on the side of the fins actually reduces the sound pressure level (aerodynamic noise) of railway vehicle brake discs. Aerodynamic noise was particularly reduced when the ridges bent the air passage between adjacent fins. [Explanation of symbols]

[0128] 100, 100A~100G: Brake disc 10:Disc body 20, 20a, 20b: Fins 21:Top surface 221, 222: Side 27: Inner surface 23:Conclusion hole 241,242: ditch 25,26,261,262,29,29L,29S: protrusion S1, S2: gap

Claims

1. A brake disc for a railway vehicle, a disk body having an annular plate shape; a plurality of fins arranged on one surface of the disk body so as to extend from the inner circumferential side toward the outer circumferential side of the disk body, each fin including two side surfaces aligned in the circumferential direction of the disk body and a top surface connecting the two side surfaces; Equipped with One or more of the fins of the plurality of fins are a plurality of ridges arranged on at least one of the two side surfaces in a radial direction of the disk body, each ridge extending between the disk body and the top surface; Including brake discs.

2. 2. A brake disc according to claim 1, Each of the plurality of fins further includes an inner circumferential surface connected to inner ends of the top surface and the two side surfaces in the radial direction, The brake disc, wherein the plurality of protrusions are arranged radially outward from the inner circumferential surface.

3. A brake disc according to claim 1 or 2, A brake disc, wherein the plurality of protrusions are provided on each of the two side surfaces of one or more of the plurality of fins.

4. A brake disc according to any one of claims 1 to 3, A brake disc, wherein each of the plurality of fins includes the plurality of ridges.

5. A brake disc according to any one of claims 1 to 4, the plurality of protrusions include one or more first protrusions and one or more second protrusions arranged at positions different from the first protrusions in the radial direction, A brake disc, wherein a length of the first protrusion portion in the circumferential direction is greater than a length of the second protrusion portion in the circumferential direction.

6. 6. A brake disc according to claim 5, Among the plurality of fins, fins adjacent to each other in the circumferential direction each include the first protrusion portion and the second protrusion portion, The first protrusion portion of one of the adjacent fins faces the first protrusion portion of the other of the adjacent fins in the circumferential direction.

7. A brake disc according to claim 5 or 6, A brake disc, wherein the first protrusion portion is disposed on an outer circumferential side of the disc body.

8. A brake disc according to any one of claims 5 to 7, A brake disc, wherein the first protrusion portion is disposed on the inner peripheral side of the disc body.

9. A brake disc according to any one of claims 5 to 8, a brake disc, wherein the first protrusion is disposed at a central portion in the radial direction of the disc body;

10. A brake disc according to any one of claims 1 to 4, Among the plurality of fins, fins adjacent to each other in the circumferential direction each include the plurality of protrusions, the plurality of protrusions include at least one first protrusion, a brake disc in which the first protrusion portion on one of the adjacent fins is positioned radially offset from the first protrusion portion on the other of the adjacent fins so as to bend an air passage formed between the adjacent fins.

11. A brake disc according to claim 10, The plurality of protrusions further include a second protrusion portion disposed at a position different from the first protrusion portion in the radial direction; Including, A brake disc, wherein a length of the first protrusion portion in the circumferential direction is greater than a length of the second protrusion portion in the circumferential direction.

12. A brake disc according to claim 11, the first protrusion portion of one of the adjacent fins faces the second protrusion portion of the other of the adjacent fins across a gap in the circumferential direction, The second protrusion portion of one of the adjacent fins faces the first protrusion portion of the other of the adjacent fins across a gap in the circumferential direction.

13. A brake disc according to any one of claims 1 to 12, A brake disc, wherein one or more of the fins includes a groove extending across the fin.

14. 14. A brake disc according to claim 13, At least one of the plurality of fins includes a fastening hole for inserting a fastening member, A brake disc, wherein the groove is arranged in at least one of an outer portion and an inner portion of the fin including the fastening hole in the radial direction relative to the fastening hole.

15. 15. A brake disc according to claim 14, A brake disc, wherein the grooves are arranged in the fin including the fastening hole at portions radially outward and inward from the fastening hole.

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