JP6515872B2 - brake disc - Google Patents

Description

  The present invention relates to a brake disc.

  According to Patent Document 1, for the purpose of “obtaining a brake disc free of noise generation”, “at least two discs of different frequencies are superposed and dispersed so that both can give freedom to each other. It is described that "we bond together in multiple places." Specifically, it is described that two disks are integrally joined by a rivet at a portion sliding with the brake pad.

  In the brake disc described in Patent Document 1, two discs are fixed by a large number of rivets at a portion in contact with a brake pad (also referred to as a "friction pad"). This complicates the structure. Further, since the wear powder of the friction pad is accumulated in the through holes for rivets, there is a concern that noise (brake noise) caused by the wear powder.

Japanese Patent Publication No. 50-035179

  An object of the present invention is to provide a brake disc in which at least two discs are superimposed, the assembly of which is simplified and the brake noise can be reliably reduced.

The brake disc (BRD) according to the present invention applies braking torque to the wheel (WH) by sliding with the friction pad (MPO, MPI), and at least one auxiliary that slides with the friction pad (MPO, MPI) The auxiliary (Mhq, Mhr) on the side (Mhq, Mhr) opposite to the side (Mhp, Mhs) on which the disc (BDH, BDI), the auxiliary disc (BDH, BDI) and the friction pad (MPO, MPI) slide A main disk (BDS) in surface contact with a disk (BDH, BDI), and a hat member (HTB) for fixing the main disk (BDS) and the auxiliary disk (BDH, BDI) in a mutually microdisplaceable state Composed of The minute displacement is a displacement that is larger than the amplitude of the brake noise when the brake noise occurs.

  According to the above configuration, since friction is present on the contact surface between the main disk BDS and the auxiliary disk (at least one of BDH and BDI), brake noise is reduced by friction damping when rubbed together. Be done. Also, the brake disc is not composed of one member, but is composed of two separate members of the main disc BDS and the hat member HTB. Since the main disc BDS and the auxiliary discs BDH and BDI are fixed to the hat member HTB, the assemblability of the entire brake disc BRD can be improved.

FIG. 1 is a cross-sectional view for explaining a first embodiment of a brake disc according to the present invention. It is a sectional view for explaining a 2nd embodiment of a brake disc concerning the present invention. It is a sectional view for explaining a 3rd embodiment of a brake disc concerning the present invention. It is a fragmentary sectional view for explaining the example of an auxiliary disk. It is the schematic for demonstrating the other example of an auxiliary | assistant disk.

<First Embodiment of Brake Disc according to the Present Invention>
A first embodiment of a brake disc BRD according to the present invention will be described with reference to the sectional view of FIG. The brake disc BRD is a friction disc of a disc brake employed for braking the wheel WH in a vehicle.

  The brake disc BRD is fixed to rotate integrally with the wheel WH by a hub bolt HBB embedded in the hub unit HUB. Specifically, the hub bolt HBB extended from the hub unit HUB penetrates the mounting hole Ahb opened in the brake disc BRD and the wheel disc portion Whd of the wheel WH, and is fastened by the wheel nut WHN.

  The brake disc BRD is sandwiched by two friction pads MPO, MPI. Here, the outer pad MPO located on the side closer to the wheel disc portion Whd of the wheel WH (that is, the outer side in the lateral direction of the vehicle) is the side farther than the wheel disc portion Whd of the wheel WH (ie, The inner pad MPI is located inward in the left-right direction of the vehicle. At the time of braking, the brake disc BRD is pinched by the friction pads MPO and MPI to generate a frictional force. The wheel WH exerts a braking force by this frictional force.

  The brake disc BRD includes a main disc BDS, an auxiliary disc BDH, a hat member HTB, and a fastening member TKB. Note that "outer side" indicates the outer side in the left and right direction of the vehicle, and "inner side" indicates the inner side in the left and right direction of the vehicle.

  The main disc BDS is an annularly formed member. The main disc BDS is in sliding contact with the inner friction pad MPI on the main disc inner surface Mse (flat surface) located at the outer peripheral portion so that the wheel WH (tire) generates a braking force. Further, the main disk BDS has a plurality of vents (passages of air) Avn inside for heat dissipation. The main disk BDS is a so-called vented disk. For example, cast iron may be adopted for the main disc BDS. Cast iron is due to its high damping property.

  The auxiliary disc BDH is an annularly shaped thin plate-shaped member, and is superposed so as to be in surface contact with the main disc BDS. Thus, the contact between the main disc BDS and the auxiliary disc BDH is not a point or line contact. The auxiliary disc BDH rotates integrally with the wheel WH in the same manner as the main disc BDS. The auxiliary disc BDH is in sliding contact with the outer friction pad MPO at the auxiliary disc outer surface Mhp (flat surface) located at the outer peripheral portion so that the wheel WH (tire) generates a braking force. Here, when the brake disk BRD rotates, the portion where the auxiliary disk BDH and the friction pad MPO slide is the sliding range Hms. For example, a steel plate may be employed as the auxiliary disc BDH. The auxiliary disk BDH is not provided with a vent.

  The respective planes of the main disk BDS and the auxiliary disk BDH will be described. In the main disk BDS, the plane (sliding surface) in contact with the inner pad MPI is the main disk inner surface Mse. The plane opposite to the main disk inner surface Mse (back side) is the main disk outer surface Msd. In the auxiliary disk BDH, a plane (sliding surface) in contact with the outer pad MPO is the auxiliary disk outer surface Mhp. The flat surface on the opposite side (back side) to the auxiliary disc outer surface Mhp is the auxiliary disc inner surface Mhq.

  The main disk BDS and the auxiliary disk BDH are overlapped. For this reason, the main disk outer surface Msd and the auxiliary disk inner surface Mhq come in contact with each other. The main disk outer surface Msd and the auxiliary disk inner surface Mhq are contact surfaces. At the time of braking, the main disc BDS and the auxiliary disc BDH are forced to be sandwiched by the friction pads MPO and MPI. Therefore, at the time of braking, the contact surface pressure between the main disk outer surface Msd and the auxiliary disk inner surface Mhq is increased as compared to the non-braking condition.

  The main disc BDS and the auxiliary disc BDH are provided with a plurality of assembly holes Atk in the inner peripheral portion so as to be assembled to the hat member HTB. The assembly holes Atk are through holes in the respective disk members BDS, BDH. Here, in the main disc BDS, the portion on the outer side (the side farther from the center in the left-right direction of the vehicle) with respect to the vent Avn is extended in the direction of the rotation axis Jbd (that is, the direction of the hat member HTB) An assembly hole Atk is provided in the inner peripheral portion Otb. Accordingly, the outer inner circumferential portion Otb is a connection portion between the hat member HTB and the main disk BDS.

  The hat member HTB has a flange portion Fln at the outer peripheral portion Eng, and is a bottomed cylindrical member extending in the rotation axis direction Jbd of the brake disc (the same as the rotation axis of the wheel WH). A hub unit HUB is provided inside the cylinder of the hat member HTB. A plurality of mounting holes (through holes) Ahb are provided in the bottom portion Skb of the hat member HTB. The hub bolt HBB of the hub unit HUB penetrates the mounting hole Ahb, and is tightened by the wheel nut WHN, sandwiching the wheel disc Whd of the wheel WH. That is, the hub unit HUB, the hat member HTB, and the wheel WH are integrally coupled by the hub bolt HBB and the wheel nut WHN. For example, an aluminum alloy may be employed as the hat member HTB.

  The flange portion Fln of the hat member HTB is provided with a plurality of assembly holes (through holes) Atk so that the main disk BDS and the auxiliary disk BDH can be assembled. The fastening members TKB pass through the assembly holes Atk of the respective members HTB, BDS (in particular, the outer inner circumferential portion Otb) and BDH. Then, these three members HTB, BDS, BDH are fastened by the fastening member TKB. Specifically, the fastening member TKB is a caulking member (for example, a rivet, a grommet), and plastic deformation of the end portion thereof causes the hat member HTB, the auxiliary disk BDH, and the main disk BDS in this order from the outer side. It is fixed. That is, the brake disc BRD is formed as a single disc, in which two discs (main disc BDS and auxiliary disc BDH) are superimposed, fixed by the hat member HTB and the fastening member TKB. The hole diameter of the assembly hole Atk is slightly larger than the diameter of the fastening member TKB at the penetration portion. For this reason, in the state of being fixed in the direction of the disc rotation axis Jbd, the main disc BDS and the auxiliary disc BDH are in a state in which micro displacement can be mutually made in the contact surface. The wheel WH, the hub unit HUB, the hat member HTB, the main disc BDS, and the auxiliary disc BDH are coaxially fixed. Therefore, the disc rotation axis Jbd is a rotation axis of the wheel WH, the hub unit HUB, the hat member HTB, the main disc BDS, and the auxiliary disc BDH.

  The "small displacement" is a displacement larger than the amplitude of the brake noise when the brake noise occurs. The brake noise is at most several tens of μm. Therefore, the minute displacement is within the range of the play in assembling or the elastic deformation of the member. When a brake noise occurs, the main disk BDS (particularly, the main disk outer surface Msd) and the auxiliary disk BDH (particularly, the auxiliary disk inner surface Mhq) are rubbed against each other in any direction of the contact surface (blowing portion See A)). Because friction is present at the contact surfaces of the main disc BDS and the auxiliary disc BDH, the brake noise is reduced by the friction damping that occurs when rubbed together.

  The main disk BDS and the auxiliary disk BDH are fixed to the hat member HTB by the fastening member TKB. The main disk BDS and the auxiliary disk BDH are in a mutually minutely displaceable state. That is, at least one of the main disk BDS and the auxiliary disk BDH can be minutely displaced with respect to the hat member HTB in the surface direction of the disk (vertical direction with respect to the rotation axis Jbd of the brake disk). It is attached. For example, the diameter of the assembly hole (through hole) Atk of the auxiliary disk BDH is made larger than the diameter of the assembly hole (through hole) Atk of the main disk BDS. Thereby, the auxiliary disc BDH is made easy to move with respect to the hat member HTB in the contact surface direction. In this manner, by fixing each of the disk members BDS and BDH via the hat member HTB which is a separate member from the disks, the assemblability of the entire brake disk BRD can be improved.

  Here, in the main disc BDS, the portion on the outer side is extended in the rotation axis direction (toward the hat member HTB) with reference to the vent hole Avn, and fixed at the inner peripheral portion (outer inner peripheral portion) Otb In this case, the auxiliary disk BDH is provided on the outer side of the main disk BDS. By this arrangement, the shapes of the disks BDS and DBH can be simplified and the assemblability can be further improved.

  Furthermore, the portion where the main disk BDS and the auxiliary disk BDH are fixed to the hat member HTB (that is, the fastening point by the fastening member TKB) removes the sliding range Hms between the auxiliary disk BDH and the friction pad MPO , Disks BDH and BDS are positioned close to the rotational axis Jbd. Here, the sliding range Hms is a band-like region in which the auxiliary disc BDH and the friction pad MPO are in contact when the auxiliary disc BDH is rotated (see the shaded portion). Since the discs BDH and BDS are fixed by removing the sliding range Hms, the contact between the fastening member TKB and the friction pad MPO is avoided. Therefore, it is difficult for the abrasive powder of the friction pad to adhere to the disc, and the brake noise caused by the abrasive powder can be suppressed. Furthermore, since the disk fixation is performed on the side close to the rotation axis Jbd, the brake disk BRD can be miniaturized.

  At the time of non-braking where the wheel WH does not generate a braking force, the main disc BDS and the auxiliary disc BDH do not move relative to each other and rotate completely in unison. Further, even during braking, when the brake noise does not occur, relative displacement between the main disk BDS and the auxiliary disk BDH does not occur. However, when a brake noise occurs on either one of the main disk BDS and the auxiliary disk BDH at the time of braking, the cyclic relative displacement between the disk where the brake noise does not occur and the disk where the brake noise does not occur is It occurs. The relative movement between the main disk BDS and the auxiliary disk BDH generates a frictional force between the main disk outer surface Msd and the auxiliary disk inner surface Mhq. This frictional force can suppress the generated brake noise.

  It is adopted that the main disc BDS and the auxiliary disc BDH have respectively different vibration characteristics (for example, natural frequency) so as not to generate brake noise at the same time. Therefore, when a brake noise occurs on any one of the main disk BDS and the auxiliary disk BDH, amplification of vibration by the other disk (that is, resonance phenomenon) is avoided.

<Second Embodiment of Brake Disc according to the Present Invention>
A second embodiment of a brake disc BRD according to the present invention will be described with reference to the sectional view of FIG. The difference is that in the first embodiment, the main disk BDS is fixed to the hat member HTB at the outer inner peripheral portion Otb, while in the second embodiment the main disk BDS is at the inner inner peripheral portion Inb , Is fixed to the hat member HTB.

  The respective planes of the main disk BDS and the auxiliary disk BDI in the second embodiment will be described. In the main disk BDS, the plane (sliding surface) in contact with the outer pad MPO is the main disk outer surface Msd. The plane opposite to the main disk outer surface Msd (back side) is the main disk inner surface Mse. In the auxiliary disk BDI, the plane (sliding surface) in contact with the inner pad MPI is the auxiliary disk inner surface Mhs. The plane opposite to the auxiliary disc inner surface Mhs (back side) is the auxiliary disc outer surface Mhr.

  The main disc BDS and the auxiliary disc BDI are overlapped and fixed to the hat member HTB by the fastening member TKB. The main disk inner surface Mse and the auxiliary disk outer surface Mhr are in contact with each other and are in a state where they can be slightly displaced from each other. The main disk inner surface Mse and the auxiliary disk outer surface Mhr are contact surfaces. At the time of braking, the main disc BDS and the auxiliary disc BDI are forced to be pinched by the friction pads MPO and MPI. Therefore, at the time of braking, the contact surface pressure between the main disk inner surface Mse and the auxiliary disk outer surface Mhr is increased as compared to the non-braking condition.

  As in the first embodiment, when the brake noise occurs, minute mutual movement occurs between the main disk BDS and the auxiliary disk BDI. At this time, a frictional force is generated between the main disk BDS and the auxiliary disk BDI. This frictional force can dampen the brake noise.

  The main disc BDS and the auxiliary disc BDI are provided with a plurality of assembly holes Atk on the inner peripheral portion so as to be assembled to the hat member HTB. The assembly holes Atk of the respective members are through holes. The assembly hole Atk of the main disc BDS is extended in the direction of the rotation axis Jbd (that is, the direction of the hat member HTB) on the inner side (the side closer to the center in the left and right direction of the vehicle) with respect to the vent Avn. , And the inner periphery Inb. That is, the connection portion between the main disk BDS and the hat member HTB is the inner inner peripheral portion Inb. The auxiliary disk BDI is disposed on the inner side of the main disk BDS, and the main disk inner surface Mse and the auxiliary disk outer surface Mhr are in contact with each other.

  In the main disc BDS, the portion on the inner side with respect to the vent hole Avn is extended to the hat member HTB, and the disc BDS, BDI is adopted by adopting the above arrangement in the inner peripheral portion Inb fixed thereto. Is simplified and the assemblability is further improved. In addition, the portion where the main disk BDS and the auxiliary disk BDI are fixed to the hat member HTB (i.e., the fastening point by the fastening member TKB) is outside the sliding range Hms and close to the disc rotation axis Jbd Located on the side. Here, the sliding range Hms corresponds to the sliding portion between the auxiliary disk BDI (in particular, the auxiliary disk inner surface Mhs) and the friction pad MPI.

  Further, the diameter of the assembly hole Atk of the auxiliary disk BDI can be set larger than the diameter of the assembly hole Atk of the main disk BDS so that the auxiliary disk BDI can be easily displaced. Furthermore, in order to avoid brake noise due to resonance, the shape, material, and the like of the main disk BDS and the auxiliary disk BDI are selected so as to have different vibration characteristics (for example, natural frequency).

<Third Embodiment of Brake Disc according to the Present Invention>
A third embodiment of a brake disc BRD according to the present invention will be described with reference to the sectional view of FIG. In the first and second embodiments, one main disk BDS and one auxiliary disk BDH are configured, but in the third embodiment, one main disk BDS and two auxiliary disks BDH, Composed of BDI and Members (components) and the like given the same symbols, such as “BDS” and the like, have the same functions in the third embodiment. Therefore, the differences will be mainly described.

  In the brake disk BRD according to the third embodiment, a second auxiliary disk BDI is provided in addition to the first auxiliary disk BDH. Specifically, the second auxiliary disk BDI is provided on the inner side of the main disk BDS, which is the opposite side to the outer side with which the first auxiliary disk BDH contacts the main disk BDS. Similar to the first auxiliary disk BDH, the second auxiliary disk BDI is also provided with an assembly hole (through hole) Atk, and is fixed to the flange portion Fln of the hat member HTB by the fastening member TKB. Here, the auxiliary disk BDI (in particular, the auxiliary disk outer surface Mhr) and the main disk BDS (in particular, the main disk inner surface Mse) are in surface contact (not point contact, not line contact), mutually mutually minute displacement (brake For example, it is fixed in a state where it can be larger than the amplitude of the noise, for example, in the assembly play or in the elastic deformation range of the member. In the third embodiment of the brake disc BRD, the two auxiliary discs BDH, BDI are in sliding contact with the friction pads MPI, MPO and the main disc BDS does not slide directly with the friction pads.

  As in the first and second embodiments, the main disk BDS and the auxiliary disks BDH and BDI have different vibration characteristics (for example, natural frequencies). This is to prevent the brake noise caused by the resonance phenomenon.

  Also in the third embodiment, the same effects as in the first and second embodiments can be obtained. That is, when a brake noise occurs, the friction between the main disk BDS and the first and second auxiliary disks BDH and BDI attenuates the brake noise. Further, since the hat member HTB is adopted and the disks BDS, BDH and BDI are assembled to the hat member HTB, the assemblability of the entire brake disk BRD can be improved. Further, a fastening point by the fastening member TKB is provided at a position close to the rotation axis Jbd while avoiding the sliding range Hms. For this reason, while the brake noise resulting from the abrasion powder of a friction pad is suppressed, brake disc BRD (especially outer-diameter shape) may be miniaturized.

<Example of auxiliary disk>
An example (first example) of the auxiliary disks BDH and BDI will be described with reference to the partial cross-sectional view of FIG. 4. Since the auxiliary disk BDH and the auxiliary disk BDI are basically the same, the auxiliary disk BDH will be described as an example.

  The auxiliary disc BDH is a thin plate (for example, a steel plate), and is fixed to the hat member HTB at a position relatively close to the rotation axis Jbd. When braking is performed, the friction pads MPO (outer side) and MPI (inner side) are pressed, so that the main disc BDS and the auxiliary disc BDH are in firm contact with each other at the surface. However, when the main disk BDS and the auxiliary disk BDH are not fixed at the outer peripheral portion (outer diameter portion) at the time of non-braking, a situation may occur where the main disk BDS and the auxiliary disk BDH are not in contact. At this time, if foreign matter such as sand gets into the gap between the main disc BDS and the auxiliary disc BDH, the expected friction damping effect may not be obtained. In order to avoid this, a pressure (preload) is applied to the contact surface in advance so that the main disk BDS and the auxiliary disk BDH contact (contact surface pressure) with certainty.

  Specifically, a “disc spring” shape is adopted as the shape of the auxiliary disk BDH before assembly. The disc spring is a spring in which a disc-like plate with a hole at its center is formed in a conical shape (round shape with a base in a conical shape), and is also called a diaphragm spring. In the disc spring shape (conical shape) of the auxiliary disk BDH, a load is applied to the outer peripheral portion Gsh on the bottom side and the inner peripheral portion Nsh on the crest side, and is bent and assembled in a direction to lower the conical height. Therefore, the auxiliary disk inner surface Mhq of the auxiliary disk BDH is fixed with the preload maintained so as to always be pressed against the main disk outer surface Msd of the main disk BDS.

  Since the main disk BDS and the auxiliary disk BDH are brought into close contact with each other with surface pressure by the spring action of the auxiliary disk BDH, the above-mentioned gap does not occur at the time of non-braking. For this reason, in the brake disc BRD, the suppression effect of the brake noise by friction damping can be maintained over a long period of time.

  The disc spring shape similar to that of the auxiliary disc BDH is also adopted for the auxiliary disc BDI. The auxiliary disk outer surface Mhr of the auxiliary disk BDI is fixed with a preload maintained so as to always be pressed against the main disk inner surface Mse of the main disk BDS. As a result, the friction damping effect can be maintained.

<Another Example of Auxiliary Disk>
Another example (second example) of the auxiliary disks BDH and BDI will be described with reference to the schematic view of FIG. As in the first example, since the auxiliary disk BDH and the auxiliary disk BDI are basically the same, the auxiliary disk BDH will be described as an example in the second example as well. The figure shows the shape of the auxiliary disk BDH before assembly.

  A pawl portion Tsu is provided on the outer peripheral portion of the auxiliary disk BDH in order to prevent the main disk BDS and the auxiliary disk BDH from being separated and causing a gap when braking is not performed. When assembling the brake disc, the claw portion Tsu is bent and hooked on the outer peripheral portion of the main disc BDS. Since the outer peripheral portion of the auxiliary disk BDH is fixed to the outer peripheral portion of the main disk BDS by the claw portion Tsu, the generation of the gap can be suppressed. Furthermore, after adopting the disc spring shape shown in the first example of the auxiliary disk BDH, the auxiliary disk BDH is provided with the claw portion Tsu and is fastened to the outer peripheral portion of the main disk BDS. The surface contact between the main disc BDS and the auxiliary disc BDH can be made more rigid.

<Operation and effect>
Hereinafter, the operation and effects of the embodiment of the present invention will be described. The brake disc BRD applies a braking torque to the wheel WH by sliding with the friction pads MPO and MPI. The brake disc BRD includes a main disc BDS, at least one auxiliary disc (one or more of the auxiliary discs BDH and BDI), and a hat member HTB.

  The auxiliary disc BDH (auxiliary disc BDI) slides on the friction pad MPO (friction pad MPI). The sliding plane between the auxiliary disk BDH (BDI) and the friction pad MPO (MPI) is a sliding surface Mhp (Mhs). The main disk BDS makes surface contact with the auxiliary disk BDH (BDI) at the contact surface Mhq (Mhr) on the opposite side (back side) to the sliding surface Mhp (Mhs). Then, the hat member HTB fixes the main disk BDS and the auxiliary disk BDH (BDI) together so as to be able to be mutually finely displaced so as to integrally rotate via the fastening member TKB. Specifically, the wheel WH, the hub unit HUB, the hat member HTB, the main disc BDS, and the auxiliary disc BDH (BDI) are coaxially fixed. Therefore, the disc rotation axis Jbd is a rotation axis of at least one of the wheel WH, the hub unit HUB, the hat member HTB, the main disc BDS, and the auxiliary disc BDH (BDI).

  The "smallly displaceable state" means that a displacement larger than the amplitude of the brake noise is mutually permitted when the brake noise occurs. This amplitude is so small that it is in the range of looseness in fastening, elastic deformation of the member. Since a small displacement is possible between the disks, when the brake noise occurs, the brake noise is attenuated by the main disk BDS and the auxiliary disk BDH (BDI) sliding with friction.

  The main disc BDS is not constituted as one member, but is constituted by two separate members of the main disc BDS (sliding member with friction pad) and the hat member HTB (fixing member to the wheel) Ru. Thus, since the hat member HTB is adopted to fix the main disk BDS and at least one auxiliary disk (BDH and / or BDI), the assemblability in the brake disk BRD can be improved.

  Furthermore, when the brake disc BRD is configured of one main disc BDS and one auxiliary disc BDH, the attachment of the main disc BDS to the hat member HTB is on the outer side with respect to the vent hole Avn (in the vehicle left-right direction In the configuration performed on the inner peripheral portion (connection portion) Obb on the side far from the center, that is, the outer side, the auxiliary disk BDH is disposed on the outer side of the main disk BDS (see FIG. 1). On the other hand, when the main disk BDS is attached to the hat member HTB at the inner peripheral portion (connection portion) Inb on the inner side (the side closer to the center in the vehicle left-right direction, ie, the inner side) with respect to the vent hole Avn, The auxiliary disk BDI is disposed on the inner side of the main disk BDS (see FIG. 2). The shape of each disk is simplified and the assemblability is further improved by the relationship between the attachment of the main disk BDS (the positions of the connection portions Otb and Inb) and the arrangement of the auxiliary disks BDH and BDI.

  Fastening of the main disc BDS and the auxiliary discs BDH and BDI to the hat member HTB removes the sliding range Hms between the friction pads MPO and MPI and the auxiliary discs BDH and BDI, and brakes based on the sliding range Hms It is performed on the side close to the disk rotation axis Jbd. Since the fastening portion by the fastening member TKB does not overlap with the sliding range Hms, wear powder of the friction pad is not accumulated in this fastening portion. For this reason, the brake noise resulting from wear powder can be avoided. Furthermore, since the fastening portion is on the side closer to the disc rotation axis Jbd, the outer diameter of the brake disc BRD can be miniaturized.

  In order to improve the cooling performance of the brake disc BRD, the main disc BDS is provided with an air vent Avn. The above-mentioned fastening point avoids the sliding range Hms, and is arranged near the disc rotation axis Jbd. Thus, when the main disk BDS is provided with the vent holes Avn, interference between the fastening portion and the vent holes Avn is avoided, so that the cooling performance of the disc can be secured. In the case where a vent hole is adopted in the one described in Patent Document 1, the rivet for assembly interferes with the vent hole, so that it is difficult to assemble the main disc and the auxiliary disc. Alternatively, the cooling performance may be impaired even if assembled.

  Among the materials and shapes of the main disk BDS and the auxiliary disks BDH and BDI, those having different vibration characteristics such as natural frequency may be employed. Thereby, the brake noise due to the resonance between the disks can be avoided.

  As a shape of the auxiliary disks BDH and BDI before assembly, a “disc spring” shape is adopted (see FIG. 4). By the spring action of the auxiliary disks BDH and BDI, the main disk BDS and the auxiliary disks BDH and BDI are brought into close contact with each other while maintaining the preload. Therefore, no gap is generated between the main disk BDS and the auxiliary disks BDH and BDI at the time of non-braking. As a result, the suppression effect of the brake noise by friction damping can be maintained over a long period of time.

  The claw portion Tsu is provided on the outer peripheral portion of the auxiliary disks BDH and BDI, and the claw portion Tsu is bent at the time of assembly and hooked on the outer peripheral portion of the main disk BDS (see FIG. 5). According to this configuration, when braking is not performed, surface contact between the main disk BDS and the auxiliary disks BDH and BDI is released, and generation of a gap can be avoided.

<Modification>
As the main disk BDS, instead of a ventilated type having a cooling vent Avn, a solid type having no vent Avn is adopted. Even when a solid type disc is employed, the same effect as described above is obtained.

  Although caulking fixing was illustrated in connection with the main disk BDS and the auxiliary disks BDH and BDI, instead of caulking fixing, a combination of a bolt and a nut may be employed. Also, it may be fixed by welding (eg, spot welding) instead of caulking. Furthermore, when any one of the main disc BDS and the hat member HTB is a cast, the auxiliary discs BDH and BDI can be cast and fixed thereto. Also in such a fixing method, mutual minute displacement is secured, and the same effect as described above is obtained.

BRD: brake disk, MPO, MPI: friction pad, BDS: main disk, BDH, BDI: auxiliary disk, HTB: hat member, TKB: fastening member, Avn: air hole.

Claims (1)

In a brake disc that applies a braking torque to a wheel by sliding with a friction pad,
At least one auxiliary disc sliding with the friction pad;
A main disk in surface contact with the auxiliary disk on the side opposite to the side on which the auxiliary disk and the friction pad slide;
A hat member for fixing the main disc and the auxiliary disc in such a manner that they can be displaced from each other in a minutely manner;
Consists of
The brake disc, wherein the minute displacement is a displacement larger than an amplitude of the brake noise when a brake noise occurs .