Ventilated brake disc

Abstract

To provide a ventilated brake disc that can suppress abnormal noise such as brake squeal, improve heat storage and heat dissipation of a brake disc, and suppress occurrence of a thermal inclination phenomenon with a simple structure.SOLUTION: A ventilated brake disc 1 includes: a disc 10 including two disc-shaped metal plates that are inner plate 11 and outer plate 12 disposed so as to face each other; an attachment part 18 to a vehicle body; coupling ribs 13 extending in a radial direction, and coupling respective facing surfaces of the inner plate and the outer plate; and a first circumferential rib 14 provided in a region near an outer edge in a radial direction on a facing surface 12a between the inner plate and the outer plate, protruding from a plate surface of the outer plate toward a facing surface 11a of the inner plate in a direction along a rotation axis Ax of the disc, having a gap with the plate surface of the inner plate, and continuously formed in an annular shape in a circumferential direction on the plate surface of the outer plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a ventilated brake disc used in a disc brake device for a vehicle such as an automobile, and more particularly to a brake disc structure capable of suppressing in-plane vibration. [Background technology]

[0002] In recent years, disc-type brake devices have become common and widely used in brake devices used in vehicles such as automobiles. These brake devices have a metal brake disc (also called a brake rotor or disc rotor) that is attached coaxially with the wheel and rotates with the wheel. The plate surface of the brake disc is clamped from both sides with friction members to suppress the rotation of the wheel, thereby slowing down or stopping the vehicle.

[0003] In this type of disc-type brake device, an abnormal noise known as brake squeal may occur when the brake is applied. It is known that one of the causes of this abnormal noise in a brake device is in-plane vibration of the brake disc (vibration in the circumferential direction of the disc).

[0004] Therefore, in conventional brake devices, various technologies have been proposed, for example, in Patent Publication No. 2005-30471 and Patent Publication No. 2021-514449, to adjust or suppress the generation of abnormal noise when the brakes are activated by changing the shape of the brake disc.

[0005] The technology disclosed in JP 2005-30471 A and other publications measures the natural frequency of a brake disc, and if the measurement result is not within an acceptable range, cuts a portion of the brake disc. This changes the disc shape and adjusts the natural frequency of the in-plane vibration of the brake disc so that it is away from the frequency at which abnormal noise occurs. This prevents the generation of abnormal noise such as brake squeal.

[0006] The brake disc disclosed in JP 2021-514449 A and the like is a ventilated brake disc, in which, among the multiple connecting ribs formed in the radial direction (radial direction) connecting the two plates that make up the brake disc, the connecting ribs within a predetermined circumferential range are provided on at least one of the two plates and have a configuration in which adjacent connecting ribs are connected to each other by a protrusion that extends circumferentially without connecting the two plates. In this way, by providing a connecting rib that connects the two plates and a protrusion that connects some of the connecting ribs to each other in the circumferential direction, the generation of abnormal noise such as brake squeal is suppressed. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-30471 [Patent Document 2] Japanese Patent Publication No. 2021-514449 Summary of the Invention [Problem to be solved by the invention]

[0008] However, according to the prior art disclosed in JP 2005-30471 A, JP 2021-514449 A, and the like, changing the shape of the brake disc changes the mass and rigidity of the brake disc itself, which changes each natural frequency, including in-plane vibration. Therefore, in some cases, in-plane vibration (vibration in the circumferential direction of the disc) and out-of-plane vibration (vibration that oscillates in a direction along the disc's rotation axis) may be coupled, which may worsen brake squeal.

[0009] Generally, in disc-type brake devices, the rotational energy of the brake disc is converted into heat energy through friction when brake pads are pressed against the plate surface of the rotating brake disc. Therefore, when the brake device is activated, heat is generated in the brake disc. However, as the brake disc rotates and comes into contact with the outside air, the heat is dissipated and the brake disc is cooled. In this case, it is known that braking effectiveness is reduced if the heat is not dissipated sufficiently.

[0010] Therefore, in conventional disc-type brake devices, a type called a ventilated brake disc has been put into practical use as a means of efficiently dissipating heat.

[0011] Specifically, the ventilated brake disc is configured by arranging, for example, two circular metal plates together, and connecting the two plates using a plurality of ribs that extend radially (in the radial direction) and are arranged side by side in the circumferential direction. This configuration allows ventilation in the gap between the adjacent ribs between the two plates, thereby enabling efficient heat dissipation from the brake disc.

[0012] However, in this type of conventional ventilated brake disc, the heat storage capacity of the two circular metal plates, the outer plate located on the outside of the vehicle body and the inner plate located inside the vehicle body, is different, and it is well known that this causes the amount of distortion on the outer periphery of the disc to differ between the outer plate and the inner plate.

[0013] This means that when a brake disc is in operation, a difference in heat storage or heat dissipation between the inner plate and the outer plate can occur, which can cause the disc to tilt in the direction along the rotation axis, a phenomenon known as thermal collapse. If this thermal collapse occurs, it can cause uneven wear of the brake pads, which can lead to judder.

[0014] Therefore, in brake devices that use conventional ventilated brake discs, there is a constant demand for measures or structural innovations to prevent the phenomenon of thermal collapse while ensuring more efficient heat dissipation, for example.

[0015] The present invention aims to provide a ventilated brake disc that can suppress abnormal noises such as brake squeal that occur when the brakes are applied in a disc-type brake device, while contributing to improving the heat storage and heat dissipation properties of the brake disc and suppressing the occurrence of thermal collapse with a simple structure. [Means for solving the problem]

[0016] In order to achieve the above object, one embodiment of the ventilated brake disc of the present invention is a ventilated brake disc comprising a disc portion consisting of two circular metal plates, an inner plate and an outer plate, arranged opposite each other, and an attachment portion to a vehicle body, and comprising a plurality of connecting ribs formed to extend radially and connecting the opposing surfaces of the inner plate and the outer plate, and a first circumferential rib provided in an area near the radial outer edge on the opposing surface of the outer plate or the inner plate with the inner plate or the outer plate, protruding from above the plate surface of the outer plate or the inner plate in a direction along the rotation axis of the disc portion toward the opposing surface of the inner plate or the outer plate, with a gap between it and the plate surface of the inner plate or the outer plate, and formed in an annular shape that is continuous circumferentially on the plate surface of the outer plate or the inner plate. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a ventilated brake disc that can suppress abnormal noises such as brake squeal that occur when the brakes are applied in a disc-type brake device, while at the same time contributing to improving the heat storage and heat dissipation properties of the brake disc and suppressing the occurrence of thermal collapse, with a simple structure. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic perspective view showing a ventilated brake disc according to a first embodiment of the present invention; [Figure 2] Plan view from the direction of arrow [2] in Figure 1. [Figure 3] Cross-sectional view along line [3]-[3] in Figure 2; [Figure 4] FIG. 4 is an enlarged cross-sectional view of the main part of the region indicated by the reference numeral [4] in FIG. 3; [Figure 5] 1 is a cross-sectional view of a ventilated brake disc according to a second embodiment of the present invention; [Figure 6] FIG. 6 is an enlarged cross-sectional view of the main part of the region indicated by the reference numeral [6] in FIG. 5; [Figure 7] FIG. 10 is a schematic perspective view showing a ventilated brake disc according to a third embodiment of the present invention; [Figure 8] Cross-sectional view along line [8]-[8] in Figure 7; [Figure 9] 5A and 5B are diagrams showing modified examples of the cross-sectional shapes of the first and second circumferential ribs in the ventilated brake discs according to the first to third embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described below with reference to the illustrated embodiments. The drawings used in the following description are schematic. Therefore, in these drawings, each component is shown at a size that allows it to be recognized on the drawing. For this reason, the dimensional relationships and scales of the components in the drawings may be different for each component. The present invention is not limited to the illustrated embodiments with respect to the quantities, shapes, size ratios, relative positional relationships, etc. of the components shown in the drawings.

[0020] Fig. 1 is a schematic perspective view showing a ventilated brake disc according to a first embodiment of the present invention. Note that Fig. 1 shows a cutaway view of the ventilated brake disc. Fig. 2 is a plan view of the ventilated brake disc according to this embodiment, as seen from the direction of arrow [2] in Fig. 1. Fig. 3 is a cross-sectional view taken along line [3]-[3] in Fig. 2. Fig. 4 is an enlarged cross-sectional view of a main part, showing an enlarged area indicated by reference numeral [4] in Fig. 3.

[0021] First, the general configuration of the ventilated brake disc (hereinafter simply referred to as the brake disc) of this embodiment will be described below.

[0022] As shown in Figures 1 to 3, the brake disc 1 of this embodiment is broadly divided into a disc portion 10 and a mounting portion 18. Of these, the disc portion 10 is made up of two circular metal plates arranged opposite each other with a predetermined gap dimension between them.

[0023] Here, the two disk-shaped metal plates are an inner plate 11 and an outer plate 12. The inner plate 11 is a disk-shaped metal plate (plate) that is arranged inside the vehicle body. The outer plate 12 is a disk-shaped metal plate (plate) that is arranged outside the vehicle body.

[0024] In Fig. 1, the symbol Ax indicates the rotation axis of the brake disc 1. In Fig. 1, the region indicated by the symbol [OUT] is the outer region of the vehicle body, and the region indicated by the symbol [IN] is the inner region of the vehicle body.

[0025] The inner plate 11 and outer plate 12 of the disk portion 10 are integrally connected by a plurality of connecting ribs 13. In this case, the plurality of connecting ribs 13 are rib-shaped portions that connect the opposing surfaces (11a, 12a) of the inner plate 11 and the outer plate 12.

[0026] In other words, the multiple connecting ribs 13 are provided in the gap between the inner plate 11 and the outer plate 12, and are provided as connecting portions that connect the two plates (11, 12). In this case, in the gap space between the inner plate 11 and the outer plate 12, in the portion where the multiple connecting ribs 13 are not arranged, and in the region between adjacent connecting ribs 13 (the region indicated by the symbol [V] in Figure 1 etc.), a space through which air passes in the circumferential direction is formed. This region [V] serves as a flow path for air to circulate. Therefore, in the following description, this region [V] will be referred to as a ventilated portion.

[0027] The multiple connecting ribs 13 are formed to extend in the radial direction (radial direction) of the disk portion 10 (11, 12). The multiple connecting ribs 13 are arranged side by side in the circumferential direction over almost the entire circumference on each opposing surface (11a, 12a) of the disk portion 10 (11, 12).

[0028] With this configuration, the multiple connecting ribs 13 ensure the rigidity of the disk portion 10 (11, 12) in the radial direction (radial direction), and serve to suppress out-of-plane vibration.

[0029] The outer plate 12 is further formed with a first circumferential rib 14 at a predetermined position on the opposing surface 12a. The first circumferential rib 14 is provided in an area on the opposing surface 12a of the outer plate 12 near the outer edge.

[0030] The first circumferential rib 14 is formed to protrude inward (toward the opposing surface 11a of the inner plate 11) from above the opposing surface 12a of the outer plate 12 in a direction along the rotation axis Ax. In this case, the first circumferential rib 14 is formed to protrude by an amount that does not reach the opposing surface 11a of the inner plate 11. In other words, the base end side of the first circumferential rib 14 is formed on the opposing surface 12a of the outer plate 12, and the tip side is formed with a predetermined gap between it and the opposing surface 11a of the inner plate 11. The first circumferential rib 14 is formed in an annular shape that continues in the circumferential direction of the outer plate 12.

[0031] The inner plate 11 is further formed with a second circumferential rib 15 at a predetermined position on the opposing surface 11a. The second circumferential rib 15 is provided in an area on the opposing surface 11a of the inner plate 11 near the inner edge.

[0032] The second circumferential rib 15 is formed to protrude inward (toward the opposing surface 12a of the outer plate 12) from above the opposing surface 11a of the inner plate 11 in a direction along the rotation axis Ax. In this case, the second circumferential rib 15 is formed to protrude by an amount that does not reach the opposing surface 12a of the outer plate 12. In other words, the base end side of the second circumferential rib 15 is formed on the opposing surface 11a of the inner plate 11, and the tip side is formed with a predetermined gap between it and the opposing surface 12a of the outer plate 12. The second circumferential rib 15 is formed in an annular shape that continues in the circumferential direction of the inner plate 11.

[0033] On the other hand, the mounting portion 18 is composed of a hat portion 16 and a flange portion 17. Of these, the hat portion 16 is disposed between the disc portion 10 and the flange portion 17 and is a component for connecting and integrating both the disc portion 10 and the flange portion 17. The hat portion 16 is composed of a cylindrical wall surface that extends from the inner peripheral edge of the outer plate 12 toward the outside of the vehicle body in a direction parallel to the rotation axis Ax.

[0034] The flange portion 17 is a flat portion formed on the vehicle body outer end of the hat portion 16. A plurality of bolt insertion holes 17a are provided in the flange portion 17. The plurality of bolt insertion holes 17a are provided for inserting a plurality of bolts (not shown) for attaching a wheel (not shown) coaxially with the brake disc 1.

[0035] In the brake disc 1 of this embodiment configured as described above, the air flowing through the ventilated portion [V] is, for example, as shown in Figure 4. Here, the symbol [F] in Figure 4 schematically indicates the flow of air passing through the ventilated portion [V]. In this case, the air passing through the ventilated portion [V] flows from the inner diameter side to the outer diameter side of the brake disc 1.

[0036] In the brake disc 1 of this embodiment, the ventilated portion [V] is slightly narrowed near the inlet V1 (see FIG. 4) on the inner diameter side because the second circumferential rib 15 is provided. On the other hand, the ventilated portion [V] is slightly narrowed near the outlet V2 (see FIG. 4) on the outer diameter side because the first circumferential rib 14 is provided.

[0037] In this case, consider the flow of air passing through the ventilated section [V] from the inner diameter side to the outer diameter side.

[0038] First, as shown in Fig. 4, the air flow [F] that flows into the ventilated section [V] through the inlet V1 travels radially within the ventilated section [V] and eventually reaches the first circumferential rib 14. After colliding with the first circumferential rib 14, the air flow [F] temporarily stagnates in a predetermined region (the region indicated by the symbol [R] in Fig. 4) in front of the first circumferential rib 14 and closer to the outer plate 12. Thereafter, the air flow [F] bypasses the first circumferential rib 14 and flows out to the outlet V2.

[0039] As described above, the air flow {F} moving radially inside the ventilated section [V] collides with the first circumferential rib 14 and stagnates in a partial region [R] of the flow path near the outer plate 12. The stagnant air [F] retains heat, and heat dissipation is somewhat hindered in this region [R].

[0040] In general, the outer plate 12 has a larger mass and a larger surface area than the inner plate 11, and therefore tends to have a larger heat storage capacity and a higher heat dissipation capacity than the inner plate 11. This is a factor that causes the thermal collapse phenomenon.

[0041] Therefore, in the brake disc 1 of this embodiment, as described above, the heat dissipation is slightly suppressed by retaining the air flow [F] in a predetermined region [R] near the outer plate 12. This reduces the imbalance in the temperature difference between the inner plate 11 and the outer plate 12.

[0042] As described above, according to the first embodiment, the disk portion 10 is configured such that, in addition to the multiple connecting ribs 13, the two circular metal plates (11, 12) are each provided with a circumferential rib (14, 15). With this simple structural change, it is possible to ensure rigidity against circumferential vibration and significantly change only the circumferential natural frequency. Therefore, it is possible to separate the natural frequency of the in-plane vibration of the brake disk 1 from the frequency at which abnormal noise occurs, thereby suppressing brake squeal.

[0043] The natural frequency of the out-of-plane vibration can also be adjusted by increasing or decreasing the number of connecting ribs 13. Therefore, according to the configuration of this embodiment, the natural frequency of the in-plane vibration and the natural frequency of the out-of-plane vibration can be easily set independently.

[0044] A first circumferential rib 14 is provided on the outer edge of the outer plate 12, and a second circumferential rib 15 is provided on the inner edge of the inner plate 11. This configuration contributes to improving the heat storage capacity of each of the two circular metal plates (11, 12) of the disk portion 10.

[0045] Furthermore, the two circumferential ribs (14, 15) are arranged in staggered positions when viewing the cross section of the ventilated section [V]. That is, the first circumferential rib 14 is provided on the outer edge of one outer plate 12, and the second circumferential rib 15 is provided on the inner edge of the other inner plate 11. This configuration allows the air flow path [F] passing through the ventilated section [V] to be longer. Therefore, this configuration can contribute to improved heat dissipation.

[0046] Furthermore, when air passes through the inside of the ventilated section [V], the air flow [F] is stagnated in a predetermined area [R] near the outer plate 12. This configuration slightly suppresses the heat dissipation of the outer plate 12, reducing the temperature difference between the outer plate 12 and the inner plate 11. This makes it possible to suppress the phenomenon of thermal collapse of the disk section 10.

[0047] In the first embodiment described above, an example is shown in which the inner plate 11 and the outer plate 12 are each provided with circumferential ribs, but the present invention is not limited to this example configuration.

[0048] For example, a configuration example such as the second embodiment shown below can be considered. Fig. 5 is a cross-sectional view of a ventilated brake disc according to the second embodiment of the present invention. Note that Fig. 5 is a cross-sectional view equivalent to a cross-section taken along the line corresponding to the line [3]-[3] in Fig. 2, similar to Fig. 3 in this embodiment. Fig. 6 is an enlarged cross-sectional view of a main part showing an enlarged area indicated by the symbol [6] in Fig. 5.

[0049] The second embodiment of the present invention basically has a configuration substantially similar to that of the first embodiment described above. In this embodiment, only the configuration of the inner plate 11A in the disc portion 10A of the brake disc 1A is slightly different. Therefore, in the following description, components similar to those in the first embodiment described above are assigned the same reference numerals and their description is omitted, and only the different parts will be described in detail below.

[0050] In the brake disc 1A of this embodiment, the disc portion 10A is composed of an inner plate 11A and an outer plate 12. Of these, the outer plate 12 is provided with a first circumferential rib 14, as in the first embodiment described above. On the other hand, in this embodiment, the inner plate 11A is configured not to be provided with a second circumferential rib 15. The other configuration is exactly the same as in the first embodiment described above.

[0051] In the brake disc 1A of this embodiment configured as described above, the air flowing through the ventilated portion [V] is, for example, as shown in Figure 6. Here, the symbol [F1] in Figure 6 schematically indicates the flow of air passing through the ventilated portion [V]. In this case, the air passing through the ventilated portion [V] flows from the inner diameter side to the outer diameter side of the brake disc 1A, as in the first embodiment.

[0052] In the brake disc 1A of this embodiment, the ventilated portion [V] has an inlet V3 (see FIG. 6) on the inner diameter side that is wider than that of the first embodiment described above due to the omission of the second circumferential rib 15. On the other hand, the ventilated portion [V] has an outlet V2 (see FIG. 6) on the outer diameter side that is slightly narrower due to the provision of the first circumferential rib 14, as in the first embodiment described above.

[0053] In this case, consider the flow of air passing through the ventilated section [V] from the inner diameter side to the outer diameter side.

[0054] First, as shown in Fig. 6, the air flow [F1] that flows into the ventilated section [V] through the inlet V3 travels radially within the ventilated section [V] and eventually reaches the vicinity of the first circumferential rib 14. Then, after a portion of the air flow [F1] collides with the first circumferential rib 14, the air flow [F1] temporarily stagnates in a predetermined region (the region indicated by the symbol [R] in Fig. 6) in front of the first circumferential rib 14 and closer to the outer plate 12. Thereafter, the air flow [F1] bypasses the first circumferential rib 14 and flows out to the outlet V2.

[0055] In addition, another part of the air flow [F1] flowing through the ventilated section [V] continues straight to the outlet V2 and flows out.

[0056] Here, as in the first embodiment described above, the air [F1] that stagnates in a partial region [R] of the flow path near the outer plate 12 slightly inhibits heat dissipation in that region [R]. As a result, in the brake disc 1A of this embodiment, the air flow [F] stagnates in a predetermined region [R] near the outer plate 12, which slightly inhibits heat dissipation. This reduces the imbalance in the temperature difference between the inner plate 11A and the outer plate 12.

[0057] As described above, according to the second embodiment, the circumferential rib (14) is provided only on one (the outer plate 12) of the two circular metal plates (11, 12) of the disk portion 10A. This configuration also provides the same effects as those of the first embodiment.

[0058] In addition, in this embodiment, the inner plate 11A does not have circumferential ribs, which slightly reduces the heat storage capacity of the inner plate 11A, thereby reducing the temperature difference between the outer plate 12 and the inner plate 11 and suppressing the thermal collapse of the disk portion 10A.

[0059] The above-described first and second embodiments exemplify a configuration in which the inner peripheral edge of the outer plate 12 is connected to the hat portion 16. In this configuration, the first and second embodiments show a configuration example in which a first circumferential rib 14 is provided on the outer peripheral side of the outer plate 12. Furthermore, the first embodiment shows a configuration example in which a second circumferential rib 15 is further provided on the inner peripheral side of the inner plate 11.

[0060] However, the configuration of the ventilated brake disc is not limited to the configuration examples shown in the first and second embodiments, and there are other configurations as well. For example, the ventilated brake disc shown in the following third embodiment has a configuration in which the inner peripheral edge of the inner plate is connected to the hat portion.

[0061] A ventilated brake disc according to a third embodiment of the present invention will be described below. Fig. 7 is a schematic perspective view showing a ventilated brake disc according to the third embodiment of the present invention. Fig. 7 shows a cutaway view of the ventilated brake disc. Fig. 8 is a cross-sectional view taken along line [8]-[8] in Fig. 7.

[0062] The disc brake of the third embodiment differs in that the inner peripheral edge of the inner plate is connected to the hat portion. Therefore, the same components as those of the first embodiment are given the same reference numerals and their description is omitted, and only the different components will be described in detail below.

[0063] 7 and 8, the brake disc 1B of this embodiment is roughly divided into a disc portion 10B and a mounting portion 18B, and has the same configuration as the first embodiment described above. Of these, the disc portion 10B is made up of two circular metal plates (an inner plate 11B and an outer plate 12B) arranged facing each other with a predetermined gap between them.

[0064] The inner plate 11B and the outer plate 12B are integrally connected by a plurality of connecting ribs 13 (connecting portions).

[0065] Here, the outer plate 12B is further formed to have a second circumferential rib 15B in an area near the inner edge on the opposing surface 12a.

[0066] The second circumferential rib 15B is formed to protrude inward in the direction along the rotation axis Ax (toward the opposing surface 11a of the inner plate 11B) from above the opposing surface 12a of the outer plate 12B. In this case, the second circumferential rib 15B is formed to protrude by an amount that does not reach the opposing surface 11a of the inner plate 11B.

[0067] That is, the base end of the second circumferential rib 15B is formed on the opposing surface 12a of the outer plate 12B, and the tip end is formed with a predetermined gap between it and the opposing surface 11a of the inner plate 11B. The second circumferential rib 15B is formed in an annular shape that continues in the circumferential direction of the outer plate 12B.

[0068] The inner plate 11B is further formed with a first circumferential rib 14B in an area near the outer edge on the opposing surface 11a.

[0069] The first circumferential rib 14B is formed to protrude inward in the direction along the rotation axis Ax (toward the opposing surface 12a of the outer plate 12B) from above the opposing surface 11a of the inner plate 11B. In this case, the first circumferential rib 14B is formed to protrude by an amount that does not reach the opposing surface 12a of the outer plate 12B. In other words, the base end of the first circumferential rib 14B is formed on the opposing surface 11a of the inner plate 11B, and the tip end is formed with a predetermined gap between it and the opposing surface 12a of the outer plate 12B. The first circumferential rib 14B is formed in an annular shape that continues in the circumferential direction of the inner plate 11B.

[0070] On the other hand, the mounting portion 18B is composed of a hat portion 16B and a flange portion 17. Of these, the hat portion 16B is composed of a cylindrical wall surface that extends from the inner peripheral edge of the inner plate 11B toward the outside of the vehicle body in a direction parallel to the rotation axis Ax. The other configurations are substantially the same as those of the first embodiment described above.

[0071] In the brake disc 1B of this embodiment configured in this manner, the air flowing through the ventilated portion [V] collides with the first circumferential rib 14B (not shown), and then temporarily stagnates in front of the first circumferential rib 14B, and then bypasses the first circumferential rib 14B and flows out to the outlet, in a manner similar to that described using Figure 4, for example.

[0072] In the configuration of this embodiment, the outer plate 12B has a higher cooling performance, but the airflow is slower because the air flow path is longer. As a result, the temperature of the outer plate 12B becomes slightly higher (medium temperature) than that of the inner plate 11B.

[0073] On the other hand, the inner plate 11B connected to the hat portion 16B has a larger mass and surface area than the outer plate 12B, and therefore the inner plate 11B has a larger heat storage capacity and higher heat dissipation than the outer plate 12B. On the other hand, the air flow path is shorter, and as a result, the temperature difference between the inner plate 11B and the outer plate 12B is somewhat reduced.

[0074] As described above, the configuration of the third embodiment is designed to somewhat suppress the temperature difference between the inner plate 11B and the outer plate 12B compared to the configurations of the first and second embodiments. However, even with the configuration of the third embodiment, the thermal collapse phenomenon may occur. Note that with this configuration, the thermal collapse phenomenon occurs in the opposite direction compared to the configuration of the first embodiment.

[0075] Therefore, in the brake disc 1B of this embodiment, the air flow is stagnated in a predetermined region of the inner plate 11B (near the first circumferential rib 14B) to slightly suppress heat dissipation, thereby reducing the imbalance in the temperature difference between the inner plate 11 and the outer plate 12.

[0076] As described above, according to the third embodiment, even if the brake disc has a configuration (a configuration in which the hat portion is connected to the inner plate) different from the first and second embodiments (a configuration in which the hat portion is connected to the outer plate) described above, it is possible to obtain substantially the same effects as the first embodiment described above.

[0077] Incidentally, the cross-sectional shape of the first circumferential rib (14, 14B) or the second circumferential rib (15, 15B) formed in the ventilated brake discs of the first to third embodiments described above is not limited to the shapes shown in Figures 3 to 6 and 8, i.e., rectangular cross sections, etc.

[0078] For example, they may be formed into various cross-sectional shapes as shown in Fig. 9. Here, Fig. 9 is a diagram showing modified examples of the cross-sectional shapes of the first and second circumferential ribs in the ventilated brake discs according to the first to third embodiments of the present invention.

[0079] In addition, in FIG. 9, various modified examples (14C, 14D, 14E, 14F) of the first circumferential rib are illustrated, but each of the embodiments can be applied to the second circumferential rib (15) in exactly the same way.

[0080] A first circumferential rib 14C of a first modified example, designated by reference numeral [9A] in FIG. 9, has a recess 14Ca whose cross section at the tip end surface of the rib is recessed in an arc shape.

[0081] A first circumferential rib 14D of a second modified example, designated by the reference numeral [9B] in FIG. 9, has a recess 14Da whose cross section at the tip end surface of the rib is rectangularly recessed.

[0082] In a first circumferential rib 14E of a third modified example indicated by the reference numeral [9C] in FIG. 9, the cross-sectional shape of the peripheral corner of the rib tip surface is formed into a rounded portion 14Eb.

[0083] In a first circumferential rib 14F of a fourth modified example indicated by the reference numeral [9D] in FIG. 9, the cross-sectional shape of the peripheral corner of the rib tip surface is formed into a C-chamfered portion 14Fb.

[0084] In addition, in each of the modified examples indicated by symbols [9C] and [9D] in Figure 9, the R-shaped portion 14Eb or the C-chamfered portion 14Fb may be formed around the entire circumference of the peripheral corner, or may be formed on both or either of the outer and inner sides of the peripheral corner in the disk radial direction (air flow path direction) (not formed on the rib side), and various other configurations are possible.

[0085] According to the various shapes of the first and second circumferential ribs formed in this way, it is possible to change the air flow in the ventilated section [V] and the air retention in the partial area [R] near the first and second circumferential ribs.

[0086] Therefore, by changing the cross-sectional shapes of the first and second circumferential ribs in various ways, it is possible to adjust the air flow in the ventilated portion to a desired form.

[0087] The present invention is not limited to the above-described embodiments, and various modifications and applications can be made without departing from the spirit and scope of the invention. Furthermore, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the disclosed multiple constituent elements. For example, if the problem to be solved by the invention can be solved and the effects of the invention can be obtained even if some constituent elements are deleted from all the constituent elements shown in each of the above embodiments, the configuration from which these constituent elements are deleted can be extracted as the invention. Furthermore, constituent elements from different embodiments may be appropriately combined. The present invention is not limited by specific embodiments other than as limited by the appended claims. [Explanation of symbols]

[0088] 1, 1A, 1B...Ventilated brake disc 10, 10A, 10B...Disc section 11, 11A, 11B...Inner plate 11a, 12a...Opposing surface 12,12B...Outer plate 13...Connecting rib 14, 14B, 14C, 14D, 14E, 14F...First circumferential rib 14Ca, 14Da...concave 14Eb…R shape part 14Fb...C chamfered part 15, 15B...Second circumferential rib 16,16B...Hat section 17...Flange 17a...Bolt insertion hole 18, 18B...Mounting part Ax...rotation axis [V]…Ventilated section V1,V3…Inlet V2… Outlet

Claims

1. A ventilated brake disc comprising: a disc portion made of two circular metal plates, an inner plate and an outer plate, arranged to face each other; and an attachment portion to a vehicle body, a plurality of connecting ribs formed to connect opposing surfaces of the inner plate and the outer plate and extending in a radial direction; a first circumferential rib provided in a region near the radial outer edge on the opposing surface of the outer plate or the inner plate with respect to the inner plate or the outer plate, protruding from above the plate surface of the outer plate or the inner plate in a direction along the rotation axis of the disk portion toward the opposing surface of the inner plate or the outer plate, having a gap between itself and the plate surface of the inner plate or the outer plate, and formed in a circular shape continuously in the circumferential direction on the plate surface of the outer plate or the inner plate; A ventilated brake disc comprising:

2. the inner plate or the outer plate is provided in a region near a radial inner edge on the opposing surface of the inner plate or the outer plate, a second circumferential rib that protrudes from the plate surface of the inner plate or the outer plate in a direction along the rotation axis of the disk portion toward the opposing surface of the outer plate or the inner plate, has a gap between itself and the plate surface of the outer plate or the inner plate, and is formed in a circular shape continuously in the circumferential direction on the plate surface of the inner plate or the outer plate; 2. The ventilated brake disc according to claim 1, further comprising:

3. The plurality of connecting ribs are formed so as to extend in the radial direction of the disk portion, and are arranged in a line in the circumferential direction.

2. The ventilated brake disc according to claim 1.

4. The first circumferential rib is A part of the air flowing through the gap space between the outer plate and the inner plate and between the plurality of connecting ribs is retained in a predetermined area.

2. The ventilated brake disc according to claim 1.

5. The second circumferential rib is A part of an inlet for air flow flowing through a gap space between the outer plate and the inner plate and between the plurality of connecting ribs is narrowed.

2. The ventilated brake disc according to claim 1.

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