disc brake device

Abstract

This disc brake device (100, 100A) comprises a rotary member (10), a brake disc (20), and an air flow restriction member (30, 30A). The brake disc (20) includes a disc body (21) and a plurality of fins (22). The air flow restriction member (30, 30A) includes a base plate (31) and a projection (32). The base plate (31) is sandwiched between the rotary member (10) and the fins (22). The projection (32) is located inward from the fins (22) along the radial direction of the disc body (21). The projection (32) protrudes from the base plate (31) toward the disc body (21). The projection (32) extends in the circumferential direction of the disc body (21).

Description

[Technical Field]

[0001] The present disclosure relates to a disc brake device for a rail vehicle. [Background technology]

[0002] Disc brake devices are widely used as braking devices for railway vehicles. Disc brake devices include an annular brake disc and a brake lining. The brake disc is fastened to, for example, a wheel of the railway vehicle 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] Brake discs in disc brake devices require sufficient cooling performance to ensure their durability. To ensure cooling performance during braking, a brake disc typically has multiple fins arranged radially on its rear surface. When the brake disc is fastened to a wheel with each fin in contact with the wheel, an air passage is formed between adjacent fins, the brake disc, and the wheel. When the brake disc rotates with the wheel, the air passage allows air to pass from the inner periphery of the brake disc to the outer periphery. The air flowing through the air passage cools the brake disc.

[0004] However, when a railway vehicle is running, air flows through the air passage between the brake disc and the wheel, generating aerodynamic noise. Particularly when the railway vehicle is running at high speed, the amount of air passing through the air passage increases, generating loud aerodynamic noise.

[0005] In response to this, Patent Document 1 discloses a disc brake device in which adjacent fins in the circumferential direction are connected by a connecting portion. In this disc brake device, the connecting portion forms a portion in each of the air passages between the fins where the cross-sectional area is minimum. According to Patent Document 1, the total minimum cross-sectional area of ​​the air passages is set to 18,000 mm 2By setting the following, it is possible to reduce aerodynamic noise during high-speed driving.

[0006] In Patent Document 1, the connecting portion for reducing aerodynamic noise is formed integrally with the brake disc. As a result, the rigidity of the portion of the brake disc near the connecting portion is greater than the rigidity of other portions. Therefore, when the brake lining slides against the brake disc during braking and frictional heat is generated, the portion near the connecting portion is less susceptible to thermal deformation than other portions, causing the brake disc to warp. As a result, the load on the fastening members that fasten the brake disc to the wheel increases.

[0007] In Patent Document 1, the connecting portion is integrated with the brake disc body and the fins, which reduces the degree of freedom in designing the disc body or the fins. Also, when manufacturing brake discs by forging, for example, it is difficult to form the connecting portion, which can reduce the yield of brake discs.

[0008] In response to this, Patent Document 2 proposes a technology in which an aerodynamic noise reduction member that is separate from the brake disc is provided in a disc brake device. The aerodynamic noise reduction member has a plate-shaped support portion and multiple protrusions that protrude from this support portion. According to Patent Document 2, by blocking part of the air passage with each protrusion, the flow of air in the air passage is suppressed, and aerodynamic noise generated while the railway vehicle is in motion can be reduced. Furthermore, because the brake disc and the aerodynamic noise reduction member are separate components, the protrusions of the aerodynamic noise reduction member do not affect the rigidity of the brake disc. This makes it possible to prevent the brake disc from warping due to the protrusions.

[0009] In Patent Document 2, the brake disc and the aerodynamic noise reduction member are separate components, ensuring a high degree of design freedom for the brake disc. In addition, the aerodynamic noise reduction member does not result in a decrease in yield of the brake disc.

[0010] Similarly to Patent Document 2, Patent Document 3 also proposes a technique in which a member for reducing aerodynamic noise is provided in a disc brake device separately from the brake disc. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-205428 [Patent Document 2] International Publication No. 2019 / 194203 [Patent Document 3] Patent Publication No. 2021-81034 Summary of the Invention [Problem to be solved by the invention]

[0012] In Patent Document 1, a connecting portion for reducing aerodynamic noise is provided integrally with the brake disc body and fins. The flow rate of air in the air passage is limited by the size of the gap between the connecting portion and the wheel. However, it is difficult to form the connecting portion, which is integrated with the disc body and fins, with high dimensional accuracy. For example, if the gap between the connecting portion and the wheel becomes small, the cooling performance of the brake disc may deteriorate. In order to ensure the cooling performance of the brake disc, it is necessary to strictly control the size of the gap between the connecting portion and the wheel, in other words, the height of the connecting portion.

[0013] In Patent Documents 2 and 3, the protrusions for reducing aerodynamic noise are included in a separate component from the brake disc, allowing the protrusions to be formed with high dimensional accuracy. However, the protrusions are disposed between a rotating member such as a wheel and the disc body. Generally, the manufacturing tolerance for the distance from the rotating member to the disc body, i.e., the height of the fins, is relatively large. This makes it difficult to precisely adjust the gap between the protrusions and the disc body. To ensure the cooling performance of the brake disc, it is necessary to increase the precision of the size of the gap between the protrusions and the disc body.

[0014] Furthermore, in Patent Documents 2 and 3, multiple fins are provided radially on the wheel-side surface (back surface) of the disc body. To prevent the protrusions from interfering with each fin, it is necessary to divide the protrusions in the circumferential direction of the disc body as in Patent Document 2, or to provide recesses in the fins as in Patent Document 3. In this case, the number of manufacturing steps for the disc brake device increases.

[0015] An object of the present disclosure is to provide a disc brake device for railway vehicles that can be easily manufactured and that allows for easy management of the gap between a protrusion for reducing aerodynamic noise and the brake disc. [Means for solving the problem]

[0016] The disc brake device according to the present disclosure is a disc brake device for a railway vehicle. The disc brake device includes a rotating member, a brake disc, and an airflow restriction member. The rotating member is attached to an axle of the railway vehicle. The brake disc includes an annular disc body and a plurality of fins. The disc body has a back surface facing the rotating member. The plurality of fins are radially arranged on the back surface. Each of the plurality of fins extends in the radial direction of the disc body. The airflow restriction member restricts the amount of airflow between the rotating member and the disc body. The airflow restriction member includes a base plate and a protrusion. The base plate is sandwiched between the rotating member and the fins. The protrusion is arranged radially inward from the fins. The protrusion protrudes from the base plate toward the disc body. The protrusion extends in the circumferential direction of the disc body. [Effects of the Invention]

[0017] The disc brake device for a railway vehicle according to the present disclosure allows for easy management of the gap between the protrusion for reducing aerodynamic noise and the brake disc, and can be manufactured easily. [Brief explanation of the drawings]

[0018] [Figure 1]FIG. 1 is a vertical cross-sectional view showing a schematic configuration of a railway vehicle disc brake device according to a first embodiment. [Figure 2] FIG. 2 is a rear view of the brake disc included in the disc brake device shown in FIG. [Figure 3] FIG. 3 is a partially enlarged view of the disc brake device shown in FIG. [Figure 4] FIG. 4 is a partial vertical cross-sectional view of a railway vehicle disc brake device according to the second embodiment. [Figure 5] FIG. 5 is a partial vertical cross-sectional view of a disc brake device according to a modified example of the first embodiment. [Figure 6] FIG. 6 is a partial vertical cross-sectional view of a disc brake device according to a modified example of the first embodiment. [Figure 7] FIG. 7 is a diagram showing the results of a test using a model of the disc brake device according to the first embodiment. [Figure 8] FIG. 8 is another diagram showing the results of a test using a model of the disc brake device according to the first embodiment. [Figure 9] FIG. 9 is yet another diagram showing the results of a test using a model of the disc brake device according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] The disc brake device according to the embodiment is a disc brake device for a railway vehicle. The disc brake device includes a rotating member, a brake disc, and an airflow restriction member. The rotating member is attached to an axle of the railway vehicle. The brake disc includes an annular disc body and a plurality of fins. The disc body has a back surface facing the rotating member. The plurality of fins are radially arranged on the back surface. Each of the plurality of fins extends in the radial direction of the disc body. The airflow restriction member restricts the amount of airflow between the rotating member and the disc body. The airflow restriction member includes a base plate and a protrusion. The base plate is sandwiched between the rotating member and the fins. The protrusion is arranged radially inward from the fins. The protrusion protrudes from the base plate toward the disc body. The protrusion extends in the circumferential direction of the disc body (first configuration).

[0020] In the disc brake device according to the first configuration, an airflow restriction member separate from the brake disc restricts the amount of airflow between the rotating member and the disc body. More specifically, a protrusion provided on the airflow restriction member restricts the amount of air passing between the rotating member and the disc body, thereby reducing aerodynamic noise. The protrusion is disposed radially inward relative to multiple fins provided on the rear surface of the disc body. This facilitates control of the gap between the brake disc and the protrusion. Furthermore, because the protrusion is disposed on the inner periphery of the fins, there is no need to divide the protrusion in the circumferential direction of the disc body to avoid interference with the fins, and there is no need to provide recesses in each fin for locating the protrusion. This simplifies the manufacturing process of the brake disc.

[0021] Therefore, the disc brake device according to the first configuration allows for easy management of the gap between the protrusion for reducing aerodynamic noise and the brake disc, and can be manufactured easily.

[0022] The protrusion may include a curved surface. The curved surface is disposed, for example, on a portion of the surface of the protrusion that faces the brake disc. When the disc brake device is viewed in a cross section that includes the central axis of the disc body, the curved surface may have a convex arc shape that extends outward from the protrusion (second configuration).

[0023] According to the second configuration, the protruding portion of the airflow restriction member includes a curved surface on its surface. When the disc brake device is viewed in a cross section including the central axis of the disc body, the curved surface has a convex arc shape on the outside of the protruding portion. This curved surface allows air to be smoothly guided between the rotating member and the disc body while the railway vehicle is running. Therefore, the amount of airflow between the rotating member and the disc body is not significantly reduced, and the cooling performance of the brake disc can be maintained at a good level.

[0024] The curved surface may have a radius of curvature of 10 mm or more (third configuration).

[0025] In the third configuration, the radius of curvature of the curved surface is 10 mm or more, which makes it possible to achieve a good balance between ensuring the cooling performance of the brake disc and reducing aerodynamic noise.

[0026] The protruding height of the protrusion may be equal to or less than the height of the fin. In this case, the length of the gap between the protrusion and the fin in the radial direction may be less than 10 mm (fourth configuration). The protruding height of the protrusion may be greater than the height of the fin. In this case, the length of the gap between the protrusion and the disc body in the radial direction may be less than 10 mm (fifth configuration).

[0027] In the fourth and fifth configurations, the length of the gap between the protrusion of the airflow restriction member and the fin or the disc body is less than 10 mm, which makes it possible to appropriately restrict the amount of airflow between the rotating member and the disc body, and more effectively reduce aerodynamic noise.

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or equivalent components are designated by the same reference numerals, and the same description will not be repeated.

[0029] First Embodiment [Disc brake device configuration] 1 is a longitudinal cross-sectional view showing a schematic configuration of a railway vehicle disc brake device 100 according to a first embodiment. The longitudinal cross-section refers to a cross-section of the disc brake device 100 cut along a plane including a central axis X. The central axis X is the axis of an axle 200 of the railway vehicle. Hereinafter, the direction in which the central axis X extends will be referred to as the axial direction.

[0030] As shown in FIG. 1, the disc brake device 100 includes a rotating member 10, a brake disc 20, and an airflow restriction member 30.

[0031] The rotating member 10 is attached to the axle 200 and rotates integrally with the axle 200 around the central axis X. In this embodiment, the rotating member 10 is a wheel of a railway vehicle. However, the rotating member 10 may be a disk body other than a wheel. In the example of FIG. 1 , the rotating member 10 includes a boss portion 11, a rim portion 12, and a plate portion 13. The axle 200 is inserted into the boss portion 11. The rim portion 12 forms the outer periphery of the wheel. The plate portion 13 connects the boss portion 11 and the rim portion 12.

[0032] The brake discs 20 are arranged on both sides of the rotating member 10 in the axial direction. Each brake disc 20 is fastened to the plate portion 13 of the rotating member 10 by a fastening member 40 formed, for example, of a bolt and a nut. A brake lining 50 is arranged on the axially outer side of each brake disc 20. An airflow restriction member 30 is arranged between the rotating member 10 and each brake disc 20.

[0033] Fig. 2 is a view (rear view) of the brake disc 20 as seen from the rotating member 10 side. Fig. 2 shows a quarter circumference portion of the brake disc 20. In Fig. 2, the airflow restriction member 30 is indicated by a two-dot chain line together with the brake disc 20.

[0034] Referring to FIG. 2, the brake disc 20 includes a disc body 21 and a plurality of fins 22.

[0035] The disc body 21 has an annular shape. More specifically, the disc body 21 has an annular plate shape centered on a central axis X. Hereinafter, the circumferential direction and the radial direction of the disc body 21 will simply be referred to as the circumferential direction and the radial direction.

[0036] The disc body 21 includes a back surface 211. The back surface 211 is a surface provided on one axial side of the disc body 21. The back surface 211 faces the rotating member 10 (FIG. 1). A sliding surface is provided on the other axial side of the disc body 21. A brake lining 50 (FIG. 1) is pressed against the sliding surface to generate a braking force.

[0037] The multiple fins 22 are arranged radially on the back surface 211 of the disc body 21. The fins 22 each extend in the radial direction. Each fin 22 protrudes from the back surface 211 toward the rotating member 10 (FIG. 1). This forms spaces between the rotating member 10, adjacent fins 22 in the circumferential direction, and the disc body 21. These spaces serve as ventilation paths through which air passes when the brake disc 20 rotates together with the rotating member 10.

[0038] Each of the fins 22 includes a top surface 221 and an inner circumferential surface 222. The top surface 221 is the surface of each fin 22 that faces the rotating member 10 (FIG. 1). The top surface 221 extends in the radial direction. The inner circumferential surface 222 is the end surface of each fin 22 that is located radially inward. The inner circumferential surface 222 is continuous with the top surface 221. The inner circumferential surface 222 extends from the top surface 221 to the back surface 211 of the disk body 21.

[0039] Each fin 22 may have a fastening hole 23 or a key groove (not shown). The fastening hole 23 penetrates the fin 22 and the disc body 21. A fastening member 40 (FIG. 1) is inserted into the fastening hole 23. A key groove is formed in the top surface 221 of the fin 22. A key (not shown) is fitted into the key groove to regulate relative rotation between the brake disc 20 and the rotating member 10 (FIG. 1). The number of fastening holes 23 and key grooves can be determined appropriately. In the brake disc 20, all fins 22 may have fastening holes 23 or key grooves, or there may be fins 22 that do not have fastening holes 23 or key grooves.

[0040] The airflow restriction member 30 is a member separate from the brake disc 20 and is a member independent from the brake disc 20. The airflow restriction member 30 includes a base plate 31 and a protrusion 32.

[0041] The base plate 31 has, for example, an annular shape. In this embodiment, the base plate 31 has a substantially circular annular shape. The base plate 31 is disposed substantially coaxially with the disc body 21.

[0042] The protrusion 32 is disposed radially inward relative to the plurality of fins 22 of the brake disc 20. The protrusion 32 protrudes from the base plate 31 toward the disc body 21. The protrusion 32 extends in the circumferential direction. In this embodiment, the protrusion 32 extends around the entire circumference of the base plate 31. That is, the protrusion 32 has a substantially annular shape, similar to the base plate 31.

[0043] Figure 3 is a partially enlarged view of the disc brake device 100 shown in Figure 1. The configuration of the airflow restriction member 30 will be described in more detail below with reference to Figure 3. To simplify the drawing, the fastening member 40 is omitted from Figure 3.

[0044] 3, the base plate 31 of the airflow restriction member 30 is sandwiched between the rotating member 10 and the plurality of fins 22 provided on the brake disc 20. The top surface 221 of each fin 22 contacts the outer periphery 311 of the base plate 31. The outer periphery 311 is a portion of the base plate 31 that is located radially outward from the protruding portion 32.

[0045] In a vertical cross-sectional view of the disc brake device 100, the outer circumferential portion 311 of the base plate 31 extends in the radial direction. The outer circumferential portion 311 extends from the protruding portion 32, for example, to an outer side beyond the fastening hole 23. The outer circumferential portion 311 may extend to or beyond the radially outer end of the top surface 221 of the fin 22. The length of the outer circumferential portion 311 along the radial direction is not particularly limited and can be determined as appropriate.

[0046] The base plate 31 includes an outer circumferential portion 311 and an inner circumferential portion 312. The inner circumferential portion 312 is a portion of the base plate 31 that is located radially inward from the protruding portion 32. In a vertical cross-sectional view of the disc brake device 100, the inner circumferential portion 312 is, for example, shorter than the outer circumferential portion 311. The length of the inner circumferential portion 312 along the radial direction can be determined as appropriate.

[0047] In this embodiment, the inner circumferential surface 222 of each fin 22 has a shape such that the end portion on the disk body 21 side is located radially inward relative to the end portion on the top surface 221 side. The protrusion 32 is located radially inward relative to the inner circumferential surface 222 of the fin 22 so as not to interfere with the fin 22. The protrusion 32 includes an outer circumferential surface 321 and an inner circumferential surface 322. The inner circumferential surface 322 is the portion of the surface of the protrusion 32 that faces inward in the radial direction. The outer circumferential surface 321 is the portion of the surface of the protrusion 32 other than the inner circumferential surface 322.

[0048] The outer peripheral surface 321 includes curved surfaces 321a and 321b. In a vertical cross-sectional view of the disc brake device 100, the curved surfaces 321a and 321b each have an arc shape that convex toward the outside of the protruding portion 32. The curved surfaces 321a and 321b are disposed at the top of the protruding portion 32. The curved surface 321a is disposed at a portion of the outer peripheral surface 321 that is adjacent to the inner peripheral surface 322. The curved surface 321b is disposed radially outward from the curved surface 321a. The curved surface 321b is connected to the curved surface 321a, for example, via a portion 321c that has a linear shape in a vertical cross-sectional view of the disc brake device 100.

[0049] As described above, the curved surface 321b has an arc-like shape that is convex toward the outside of the protruding portion 32 in a vertical cross-sectional view of the disc brake device 100. In the present embodiment, the curved surface 321b has an arc-like shape that is convex toward the fin 22 in a vertical cross-sectional view of the disc brake device 100. The curved surface 321b is provided on the protruding portion 32 so as to face, for example, the inner circumferential surface 222 of the fin 22. The radius of curvature of the curved surface 321b is preferably 10 mm or more.

[0050] The outer circumferential surface 321 may further include a curved surface 321d. Similarly, the inner circumferential surface 322 may include a curved surface 322a. The curved surfaces 321d and 322a are disposed at the base of the protruding portion 32. The curved surfaces 321d and 322a may have a concave arc shape toward the inside of the protruding portion 32 in a vertical cross-sectional view of the disc brake device 100.

[0051] A gap G1 exists between the protrusion 32 and the fin 22. The length of the gap G1 in the radial direction is preferably less than 10 mm, and more preferably 7 mm or less. The length of the gap G1 is the radial distance from the protrusion 32 to the fin 22 in a vertical cross-sectional view of the disc brake device 100. The length of the gap G1 can be, for example, the radial distance from the end of the R on the radially inner side (toward the straight portion 321c) of the curved surface 321b of the protrusion 32 to the inner circumferential surface 222 of the fin 22. In other words, the length of the gap G1 can be the radial distance from the apex of the protrusion 32 to the fin 22 in a vertical cross-sectional view of the disc brake device 100.

[0052] The airflow restriction member 30 can be made of, for example, a metal plate. The metal plate preferably has a thickness of 1.0 mm or more and 3.0 mm or less. The airflow restriction member 30 is formed, for example, by pressing the metal plate. In this case, the base plate 31 and the protrusion 32 are integrally formed. However, the base plate 31 and the protrusion 32 can also be formed separately, and then the protrusion 32 can be fixed to the base plate 31 by welding or the like.

[0053] [effect] In the disc brake device 100 according to this embodiment, the amount of airflow between the rotating member 10 and the disc body 21 is restricted by an airflow restriction member 30 that is separate from the brake disc 20. More specifically, a protrusion 32 provided on the airflow restriction member 30 partially blocks the opening of the air passage defined by the rotating member 10, the disc body 21, and each of the fins 22. This restricts the amount of airflow in the air passage, thereby reducing aerodynamic noise generated when the railway vehicle is running.

[0054] If the protruding portion 32 of the airflow restriction member 30 were to be disposed between the rotating member 10 and the disc body 21, it would be necessary to strictly manage the gap between the protruding portion 32 and the disc body 21 and ensure the gap with high precision in order to achieve a predetermined cooling performance for the brake disc 20. However, in the disc brake device 100 according to this embodiment, the protruding portion 32 of the airflow restriction member 30 is not disposed between the rotating member 10 and the disc body 21. The protruding portion 32 is disposed radially inward relative to the multiple fins 22. Therefore, it is not necessary to strictly manage the gap between the protruding portion 32 and the brake disc 20 during manufacturing of the disc brake device 100. Furthermore, it is not necessary to divide the protruding portion 32 circumferentially to avoid interference with the fins 22, and it is also not necessary to provide recesses in each fin 22 for locating the protruding portion 32. This simplifies the manufacturing process for the brake disc 20.

[0055] In this way, the disc brake device 100 according to this embodiment allows for easy management of the gap between the protrusion 32 for reducing aerodynamic noise and the brake disc 20, and can be manufactured easily.

[0056] In this embodiment, the surface of the protrusion 32 of the airflow restriction member 30 includes a curved surface 321b. In a vertical cross-sectional view of the disc brake device 100, the curved surface 321b has a convex arc shape facing the fin 22. This curved surface 321b allows air to be smoothly guided into the air passage when the railway vehicle is traveling. Therefore, the amount of airflow in the air passage is not significantly reduced, and the cooling performance of the brake disc 20 can be maintained at a good level.

[0057] It is preferable that the curved surface 321b of the protrusion 32 has a radius of curvature of 10 mm or more, which makes it possible to achieve a good balance between ensuring the cooling performance of the brake disc 20 and reducing aerodynamic noise.

[0058] In the disc brake device 100 according to this embodiment, a gap G1 exists between the protrusion 32 of the airflow restriction member 30 and the fins 22 of the brake disc 20. The length of the gap G1 along the radial direction is preferably less than 10 mm. In this case, the air flowing into the air passage can be appropriately restricted, and aerodynamic noise can be more effectively reduced.

[0059] Second Embodiment 4 is a partial vertical cross-sectional view of a railway vehicle disc brake device 100A according to the second embodiment. The disc brake device 100A according to this embodiment has almost the same configuration as the disc brake device 100 according to the first embodiment. However, the disc brake device 100A differs from the disc brake device 100 according to the first embodiment in the configuration of the airflow restriction member 30A.

[0060] In the disc brake device 100 according to the first embodiment, the protruding height of the protruding portion 32 of the airflow restriction member 30 is equal to or less than the height of the fins 22 (FIG. 3). On the other hand, as shown in FIG. 4, in the disc brake device 100A according to this embodiment, the protruding height of the protruding portion 32 of the airflow restriction member 30A is greater than the height of the fins 22. The height of the fin 22 refers to the distance along the axial direction from the top surface 221 of the fin 22 to the back surface 211 of the disc body 21. The protruding height of the protruding portion 32 refers to the distance along the axial direction from the surface of the outer circumferential portion 311 of the base plate 31 on the fin 22 side to the apex of the protruding portion 32.

[0061] In a vertical cross-sectional view of the disc brake device 100A, the protrusion 32 protrudes in the axial direction from the base plate 31 to a position that reaches the disc body 21. A gap G2 exists between the protrusion 32 and the disc body 21. The length of the gap G2 in the radial direction is preferably less than 10 mm, and more preferably 7 mm or less. The length of the gap G2 is the radial distance from the protrusion 32 to the disc body 21 in a vertical cross-sectional view of the disc brake device 100A. The length of the gap G2 can be the radial distance from the apex of the protrusion 32 to the disc body 21 in a vertical cross-sectional view of the disc brake device 100A.

[0062] As in the first embodiment, the protrusion 32 is positioned slightly away from the brake disc 20 so that air can be introduced into the air passage defined by the rotating member 10, the disc body 21, and each fin 22. The protrusion 32 limits the amount of air passing through the air passage, thereby reducing aerodynamic noise. As in the first embodiment, the disc brake device 100A according to this embodiment also makes it easy to manage the gap between the protrusion 32 and the brake disc 20, and simplifies the manufacturing process. Furthermore, by setting the radial length of the gap G2 between the protrusion 32 and the disc body 21 to less than 10 mm, the air flowing into the air passage can be appropriately restricted, thereby more effectively reducing aerodynamic noise.

[0063] 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.

[0064] In the first embodiment described above, the protruding portion 32 of the airflow restriction member 30 is hollow when viewed in vertical cross section of the disc brake device 100. However, as shown in FIG. 5 , the protruding portion 32 may be solid when viewed in vertical cross section of the disc brake device 100. Similarly, in the second embodiment, the protruding portion 32 of the airflow restriction member 30A may be solid when viewed in vertical cross section of the disc brake device 100A. In these cases as well, the protruding portion 32 may be molded integrally with the base plate 31, or may be molded separately from the base plate 31.

[0065] In the first embodiment, the inner circumferential surface 322 of the protruding portion 32 of the airflow restriction member 30 is generally linear in a vertical cross section of the disc brake device 100. That is, in the protruding portion 32, the radius of curvature of the curved surface 321a continuing from the inner circumferential surface 322 is significantly smaller than the radius of curvature of the curved surface 321b on the disc body 21 side. However, as shown in FIG. 6 , as with the airflow restriction member 30A according to the second embodiment, the radius of curvature of the curved surface 321a on the inner circumferential surface 322 side can be increased to make part or all of the inner circumferential surface 322 curved. Meanwhile, in the airflow restriction member 30A according to the second embodiment, the inner circumferential surface 322 of the protruding portion 32 may be generally linear in a vertical cross section of the disc brake device 100A.

[0066] In the above embodiment, the protrusion 32 of the airflow restriction member 30, 30A includes the curved surfaces 321a, 321b, 321d, and 322a on its surface. However, the surface of the protrusion 32 does not have to include some or all of the curved surfaces 321a, 321b, 321d, and 322a. The protrusion 32 may also have, for example, a triangular or rectangular shape in a vertical cross-sectional view of the disc brake device 100, 100A. The shape of the protrusion 32 is not limited to the example in the above embodiment.

[0067] In the above embodiment, the airflow restriction member 30, 30A has an annular shape. However, the airflow restriction member 30, 30A does not necessarily have to be a continuous annular shape. The airflow restriction member 30, 30A may be divided into multiple parts in the circumferential direction. The airflow restriction member 30, 30A may be divided into, for example, two or four parts. Furthermore, the airflow restriction member 30, 30A does not necessarily have to be provided around the entire circumference of the brake disc 20. [Example]

[0068] 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.

[0069] To confirm the effects of the disc brake device according to the present disclosure, a test was conducted using a model of the brake disc 20 and the airflow restriction member 30 according to the first embodiment. In this test, a model cut out of a 15° section of the brake disc 20 and the airflow restriction member 30 was created using a 3D printer, and air was made to flow from the inner periphery to the outer periphery of the model using a commercially available suction device. The sound pressure level and air flow velocity generated when the air was flowing were then measured using a commercially available precision sound level meter and hot wire anemometer, respectively. A higher sound pressure level indicates a higher noise (aerodynamic sound), and a higher air flow velocity indicates better cooling performance of the brake disc 20.

[0070] In this test, the sound pressure level and air flow velocity were confirmed while changing the radius of curvature R1 of curved surface 321a of protrusion 32 of airflow restricting member 30, the radius of curvature R2 of curved surface 321b, and the length L1 along the radial direction of gap G1 between protrusion 32 and fin 22. The test results are shown in Figures 7 to 9.

[0071] 7 and 8, when the length L1 of the gap G1 is 5 mm or 7 mm, the radius of curvature R2 of the curved surface 321b has a strong effect on the sound pressure level and the air flow velocity. As shown in FIGS. 7 and 8, when the radius of curvature R2 of the curved surface 321b is 0 mm (right angle), the sound pressure level is low, but the air flow velocity is low, and the cooling performance of the brake disc 20 is relatively low. When the radius of curvature R2 of the curved surface 321b is 2 mm or 5 mm, the air flow velocity is ensured, and the cooling performance of the brake disc 20 is high, but the sound pressure level is relatively high. When the radius of curvature R2 is 5 mm, the sound pressure level is high compared to when the radius of curvature R2 is 2 mm. When the curvature radius R2 of the curved surface 321b is 10 mm or 15 mm, the air flow velocity is approximately the same as when the curvature radius R2 is 2 mm, ensuring the cooling performance of the brake disc 20, while reducing the sound pressure level compared to when the curvature radius R2 is 2 mm. In other words, it was confirmed that when the curvature radius R2 of the curved surface 321b is 10 mm or greater, a good balance is achieved between ensuring the cooling performance of the brake disc 20 and reducing noise.

[0072] 9, when the length L1 of gap G1 is 10 mm, the radius of curvature R2 of curved surface 321b has almost no effect on the sound pressure level and air flow velocity. When the length L1 of gap G1 is 10 mm, even if the radius of curvature R2 of curved surface 321b is changed, the sound pressure level and air flow velocity do not change much. Therefore, in order to obtain the effect of setting the radius of curvature R2 of curved surface 321b to 10 mm or more, it can be said that it is preferable that the length L1 of gap G1 is less than 10 mm.

[0073] In this test, the radius of curvature R1 of the curved surface 321a was also changed to 0 mm (right angle), 2 mm, 4 mm, and 5 mm, but the radius of curvature R1 did not have much effect on the sound pressure level and air flow velocity. [Explanation of symbols]

[0074] 100, 100A: Disc brake device 10: Rotating member 20: Brake disc 21:Disc body 211: Back side 22: Finn 30, 30A: Airflow restriction member 31: Base plate 32:Protrusion 321b: Curved surface

Claims

1. A disc brake device for a railway vehicle, a rotating member attached to an axle of the railcar; a brake disc including an annular disc body having a back surface facing the rotating member, and a plurality of fins arranged radially on the back surface, each fin extending in a radial direction of the disc body; an airflow restriction member that restricts the amount of airflow between the rotating member and the disk body; Equipped with The airflow restriction member is a base plate sandwiched between the rotating member and the fins; a protrusion disposed radially inward of the fin, protruding from the base plate toward the disk body, and extending in a circumferential direction of the disk body; A disc brake device comprising:

2. 2. The disc brake device according to claim 1, The protrusion is a curved surface that is disposed on the brake disc side of the surface of the protrusion and has a convex arc shape on the outside of the protrusion when the disc brake device is viewed in a cross section including the central axis of the disc body; A disc brake device comprising:

3. 3. The disc brake device according to claim 2, The curved surface has a radius of curvature of 10 mm or more.

4. 4. The disc brake device according to claim 1, a protruding height of the protruding portion is equal to or less than a height of the fin, A disc brake device, wherein the length of the gap between the protrusion and the fin in the radial direction is less than 10 mm.

5. 4. The disc brake device according to claim 1, The protrusion height is greater than the height of the fin, A disc brake device, wherein the length of a gap between the protrusion and the disc body in the radial direction is less than 10 mm.

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