JP6921024B2 - Disc brake - Google Patents

Description

The present invention relates to a disc brake.

A groove is provided inside the open end of the piston, and a shim is provided with a locking claw that elastically engages with the groove (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 10-184744

It is desired to suppress the dragging of the friction pad and to prevent the return amount of the piston after braking from becoming excessive.

An object of the present invention is to provide a disc brake capable of suppressing an excessive return amount of a piston after braking while suppressing dragging of a friction pad.

In order to achieve the above object, the present invention comprises a configuration in which the pad and the piston are provided with a regulating unit that allows the pad and the piston to be separated within a predetermined distance and regulates the separation exceeding a predetermined distance. bottom.

According to the present invention, it is possible to suppress the dragging of the friction pad and the excessive return amount of the piston after braking.

The cross-sectional view which shows the disc brake of 1st Embodiment. A partially enlarged cross-sectional view showing a caliper body, a piston and a seal member of the disc brake of the first embodiment. The cross-sectional view which shows the piston of the disc brake of 1st Embodiment. The rear view which shows the friction pad of the disc brake of 1st Embodiment. The plan view which shows the friction pad of the disc brake of 1st Embodiment. The perspective view which shows the friction pad of the disc brake of 1st Embodiment. FIG. 5 is a cross-sectional view schematically showing a main part of the disc brake of the first embodiment. FIG. 5 is a cross-sectional view schematically showing a main part of the disc brake of the first embodiment. FIG. 5 is a cross-sectional view schematically showing a main part of the disc brake of the first embodiment. The cross-sectional view which shows the piston of the disc brake of 2nd Embodiment. The plan view which shows the friction pad of the disc brake of the 2nd Embodiment. The perspective view which shows the friction pad of the disc brake of the 2nd Embodiment. FIG. 5 is a cross-sectional view schematically showing a main part of a disc brake according to a second embodiment. FIG. 5 is a cross-sectional view schematically showing a main part of a disc brake according to a second embodiment. FIG. 5 is a cross-sectional view schematically showing a main part of a disc brake according to a second embodiment.

[First Embodiment]
The first embodiment will be described below with reference to FIGS. 1 to 9. The disc brake 10 of the first embodiment shown in FIG. 1 brakes the vehicle by stopping the rotation of the disc-shaped disc 11 that rotates together with the wheels (not shown). Hereinafter, the direction of the central axis of the disk 11 is referred to as the disk axial direction, the radial direction of the disk 11 is referred to as the disk radial direction, and the circumferential direction of the disk 11, that is, the rotation direction is referred to as the disk circumferential direction. Further, the center side of the disk 11 in the disk radial direction is referred to as the inside in the disk radial direction, and the side opposite to the center of the disk 11 in the disk radial direction is referred to as the outside in the disk radial direction.

As shown in FIG. 1, the disc brake 10 includes a pair of friction pads 13 and 14, a caliper 15, and a mounting member (not shown). In the disc brake 10, a mounting member (not shown) is arranged so as to straddle the outer peripheral side of the disc 11 and is mounted on a non-rotating portion of the vehicle. The structure is such that the 14 and the caliper 15 are slidably supported in the disc axial direction.

Each of the pair of friction pads 13 and 14 has a pad body 34 having a metal back plate 31 and a lining 33 which is a friction material attached to a surface 32 on one side of the back plate 31 in the plate thickness direction. It has.

One friction pad 13 is arranged so as to face the disc 11, and the back plate 31 thereof is supported by a mounting member (not shown) in a direction in which the lining 33 faces the disc 11. In this state, the surface 35 of the back plate 31 opposite to the lining 33 of the friction pad 13 faces the side opposite to the disc 11. Further, in this state, the friction pad 13 has a lining 33 facing the disc 11 on a surface 36 opposite to the back plate 31. The friction pad 13 is supported by a mounting member (not shown) via a back plate 31 provided on a surface 37 opposite to the disc 11 of the lining 33. The friction pad 13 is an inner-side friction pad arranged on the inner side, which is inside the vehicle width direction of the vehicle with respect to the disc 11.

Further, the other friction pad 14 is arranged so as to face the disc 11, and the back plate 31 thereof is supported by a mounting member (not shown) in a direction in which the lining 33 faces the disc 11. The friction pad 14 is a friction pad on the outer side arranged on the outer side, which is outside the vehicle width direction of the vehicle with respect to the disc 11.

The friction pads 13 and 14 supported by the mounting members (not shown) are arranged on both sides in the axial direction of the disc 11 and can be moved in the axial direction of the disc 11. When these friction pads 13 and 14 move toward the disc 11 along the disc axial direction, their respective linings 33 come into contact with the disc 11.

The caliper 15 includes a caliper body 40, a piston 41, and a seal member 42. In other words, the piston 41 forms part of the caliper 15 of the disc brake 10.

In the caliper 15, the caliper body 40 is slidably supported in the disc axial direction by a mounting member (not shown). The caliper body 40 has a cylinder 46 arranged on the inner side in the disc axial direction with respect to the disc 11 and a bridge extending along the disc axial direction from the outside of the cylinder 46 in the disc radial direction so as to straddle the outer periphery of the disc 11. It has a portion 47 and a claw portion 48 that extends inward in the disc radial direction from the side of the bridge portion 47 opposite to the cylinder 46 and is arranged on the outer side in the disc axial direction with respect to the disc 11.

The cylinder 46 is formed with a bore portion 51 having a cylinder opening 50 that opens toward the claw portion 48 side and recessing on the side opposite to the disc 11 in the disc axial direction. The bore portion 51 is arranged so that the piston 41 can move in the disk axial direction. The wall surface 52 of the bore portion 51 has a guide inner peripheral surface 53 which is a cylindrical surface for guiding the movement of the piston 41. The wall surface 52 of the bore portion 51 has an annular seal groove 55 recessed radially outward from the guide inner peripheral surface 53 on the cylinder opening 50 side.

As shown in FIG. 2, the seal groove 55 has an annular flat surface in which the radial outer wall surface 57 on the cylinder opening 50 side (left side in FIG. 2) extends in the direction orthogonal to the axis of the guide inner peripheral surface 53. The inside of the wall surface 57 in the radial direction is a tapered surface 58 located on the side of the cylinder opening 50 in the axial direction toward the inside in the radial direction.

As shown in FIG. 1, the piston 41 includes a disk-shaped piston bottom 61 and a cylindrical piston body 62. The piston 41 is formed in a bottomed cylindrical shape in which the end of the piston body 62 opposite to the piston bottom 61 opens. The piston 41 is movably housed in the bore portion 51 in a direction in which the bottom portion 61 of the piston is located in the bore portion 51 on the side opposite to the cylinder opening 50.

As shown in FIG. 3, the piston 41 is formed with an inner flange portion 63 projecting radially inward from the piston body portion 62 at an end portion of the piston body portion 62 opposite to the piston bottom portion 61. There is. The inner flange portion 63 is continuous over the entire circumference of the piston 41 in the circumferential direction and forms an annular shape.

The seal member 42 shown in FIG. 1 has an annular shape and is fitted in the seal groove 55 of the bore portion 51. A piston 41 is fitted on the inner peripheral side of the seal member 42. The inner peripheral side of the seal member 42 comes into contact with the piston 41 over the entire circumference, and the outer peripheral side comes into contact with the groove bottom of the seal groove 55 over the entire circumference. As a result, the sealing member 42 seals the gap between the cylinder 46 and the piston 41, and forms a hydraulic chamber 65 between the piston 41 and the cylinder 46. At the same time, the seal member 42 slidably supports the piston 41 in the disk axial direction with the guide inner peripheral surface 53 of the bore portion 51.

The cylinder 46 is formed with a communication hole 66 for communicating the hydraulic pressure chamber 65 to the outside, and the brake fluid is introduced into the hydraulic pressure chamber 65 from the communication hole 66. The brake fluid introduced into the hydraulic chamber 65 advances the piston 41 toward the claw portion 48.

The friction pad 13 on one inner side is arranged between the piston 41 and the disc 11, and the friction pad 14 on the other outer side is arranged between the claw portion 48 and the disc 11.

The friction pad 13 on the inner side has a pad body 34 having a back plate 31 and a lining 33, and a shim 71 shown in FIGS. 4 to 6 that covers the surface 35 of the back plate 31.

As shown in FIGS. 5 and 6, the back plate 31 has a flat plate shape, and both the central plate portion 75 to which the lining 33 is attached and both ends of the central plate portion 75 in the disk circumferential direction to the disc circumferential direction. It has a pair of ear portions 76 protruding outward. The back plate 31 has a substantially mirror plane symmetry with respect to the center in the width direction. In the back plate 31, a pair of ear portions 76 are supported by mounting members (not shown).

The shim 71 is provided to suppress the heat of the pad body 34 from being transferred to the piston 41 and to suppress the brake squeal of the friction pad 13. As shown in FIG. 5, in the shim 71, the flat plate-shaped main plate portion 81 abuts on the surface 35 of the back plate 31 in surface contact to cover the surface 35. The shim 71 is an integrally molded product formed by pressing from a single plate material. In the shim 71, the main plate portion 81 is attached to the back plate 31 with grease or the like, and is integrally attached to the back plate 31. The shim 71 may be provided with an engaging claw that engages with the back plate 31, and the shim 71 may be elastically attached to the back plate 31.

As shown in FIG. 6, the shim 71 has a plurality of locking claws 91 cut up from the main plate portion 81. The locking claw 91 is a claw portion that projects vertically from the main plate portion 81 and an end portion of the extension portion 92 that is opposite to the main plate portion 81 so as to be parallel to the main plate portion 81. It has 93 and. As shown in FIG. 4, each of the locking claws 91 is curved so that each of the extending portions 92 forms a part of the same cylinder, and as a result, the radius of the curve is the same and the center of the curve is the same. Match. Each of the claw portions 93 of the locking claws 91 projects in a direction opposite to the center of curvature of the extension portion 92 with respect to the extension portion 92 at the base end of the protrusion. As shown in FIG. 5, the claw portion 93 of these locking claws 91 is arranged on the same plane parallel to the main plate portion 81.

As shown in FIG. 1, the diameter of the circumscribed circle of the claw portions 93 of the plurality of locking claws 91 is larger than the inner diameter of the inner flange portion 63 of the piston 41 and slightly smaller than the inner diameter of the piston body portion 62. The diameter of the circumscribed circle of the plurality of extending portions 92 is slightly smaller than the inner diameter of the inner flange portion 63 of the piston 41. The length of the portion between the main plate portion 81 and the claw portion 93 of the extending portion 92 of the plurality of locking claws 91 is a predetermined value longer than the axial length of the inner flange portion 63 of the piston 41.

In the shim 71, a plurality of locking claws 91 are engaged with the inner flange portion 63 of the piston 41. That is, by elastically deforming the extending portions 92 of the plurality of locking claws 91, the diameter of the circumscribing circle of the plurality of claw portions 93 is made smaller than the inner diameter of the inner flange portion 63, and the plurality of locking claws 91 Is inserted into the inner flange portion 63 of the piston 41, and the claw portions 93 of the plurality of locking claws 91 are located closer to the piston bottom portion 61 than the inner flange portion 63. Releases the elastic deformation of. Then, the diameter of the circumscribed circles of the plurality of claw portions 93 becomes larger than the inner diameter of the inner flange portions 63. As a result, the detachment of the shim 71 and the piston 41 is restricted by the plurality of claw portions 93 coming into contact with the inner flange portions 63.

In the axial direction of the piston 41, the shim 71 can separate the main plate portion 81 from the piston 41 to a position where the plurality of claw portions 93 abut on the inner flange portion 63, and the piston 41 of the main plate portion 81 beyond that. Separation from is regulated. Further, in the axial direction of the piston 41, the shim 71 can approach the piston 41 until the main plate portion 81 abuts on the piston 41. In addition, the plurality of claws 93 and the piston 41 are relatively slidable in the axial direction of the piston 41.

Therefore, the plurality of locking claws 91 of the shim 71 and the inner flange portion 63 of the piston 41 are provided on the friction pad 13 and the piston 41 to allow the friction pad 13 and the piston 41 to be separated from each other within a predetermined distance. It constitutes a regulation unit 101 that regulates the separation exceeding a predetermined distance. The regulating unit 101 can hold the friction pad 13 and the piston 41 in a separated state within a range within this predetermined distance. In other words, the regulating unit 101 does not generate a force in the direction of bringing the friction pad 13 and the piston 41 apart from each other within a predetermined distance. In other words, the regulating unit 101 connects the friction pad 13 and the piston 41 so as to be freely movable in the axial direction of the piston 41 within a range within the predetermined distance. The regulating portion 101 is provided on the shim 71 and the piston 41 of the friction pad 13.

In the first embodiment, when the brake hydraulic pressure in the hydraulic chamber 65 of the caliper 15 rises and the brake hydraulic pressure acts on the piston 41, the piston 41 advances toward the disc 11 with respect to the cylinder 46, and the figure shows the figure. As shown in 7, the friction pad 13 is pressed against the disc 11 by abutting against the main plate portion 81 of the shim 71 of the friction pad 13 on the inner side arranged between the piston 41 and the disc 11. As a result, the friction pad 13 on the inner side moves and comes into contact with the disc 11. At this time, in the shim 71 of the friction pad 13, the claw portions 93 of the plurality of locking claws 91 are separated from the inner flange portion 63 of the piston 41 by a predetermined distance δ.

Further, due to the reaction force of this pressing, the caliper body 40 slides with respect to the mounting member (not shown) and moves in the disc axial direction, and the claw portion 48 shown in FIG. 1 is arranged between the claw portion 48 and the disc 11. The friction pad 14 on the outer side is pressed toward the disc 11. As a result, the friction pad 14 on the outer side comes into contact with the disc 11. In this way, the caliper 15 sandwiches the pair of friction pads 13 and 14 between the piston 41 and the claw portion 48 from both sides and presses them against both sides of the disc 11 by the operation of the piston 41. As a result, the pair of friction pads 13 and 14 impart frictional resistance to the disc 11 to generate a braking force. The caliper 15 is a fist type caliper.

Here, as described above, when the piston 41 advances toward the disc 11 with respect to the cylinder 46, the seal member 42 provided on the cylinder 46 has an inner peripheral portion in contact with the piston 41 together with the piston 41. It is elastically deformed in the seal groove 55 so as to move to the disk 11 side. At this time, as shown in FIG. 2, since the tapered surface 58 is formed on the cylinder opening 50 side (left side in FIG. 2) inside the seal groove 55 in the radial direction, the seal member 42 may be more elastically deformed. It is possible.

When the hydraulic pressure of the brake fluid introduced into the hydraulic chamber 65 of the caliper 15 decreases from the braking state shown in FIG. 7, the piston 41 undergoes a restoring force of elastic deformation of the seal member 42, so-called rollback. As shown in FIG. 8, the cylinder 46 is retracted to the side opposite to the disk 11.

At this time, the frictional force of the friction pad 13 with respect to the attachment member (not shown) is set to be sufficiently larger than the rollback force of the seal member 42. Therefore, as shown in FIG. 8, the plurality of claw portions 93 of the shim 71 are attached to the inner flange portion 63 of the piston 41 in a state where the friction pad 13 is restrained from moving with respect to the mounting member (not shown) due to frictional force. It will come into contact and get caught, restricting further retreat of the piston 41. That is, the regulating portion 101 including the plurality of locking claws 91 of the friction pad 13 and the inner flange portion 63 of the piston 41 regulates the distance between the friction pad 13 and the piston 41 exceeding a predetermined distance δ. As a result, the movement of the piston 41 with respect to the cylinder 46 in the direction opposite to that of the disk 11 is restricted within a predetermined distance δ.

Then, the seal member 42 returns to the state before the elastic deformation in the state where the movement of the piston 41 is regulated by the friction pad 13. After that, as shown in FIG. 9, the friction pad 13 moves in the direction away from the disc 11 with respect to the piston 41 and the cylinder 46 within a range of a predetermined distance δ due to the runout of the disc 11.

The regulating portion 101 includes an extending portion 92 in which a part of the shim 71 along the back plate 31 extends in the piston axial direction, and a claw portion 93 (locking) in which the end portion of the extending portion 92 is bent in the piston radial direction. Part) and. When the piston 41 moves relative to the shim 71, the regulating portion 101 locks the claw portion 93 to the inner peripheral portion of the piston 41.

The disc brake described in Patent Document 1 is provided with a groove inside the open end of the piston, and the shim is provided with a locking claw that elastically engages with the groove. In such a configuration, since the friction pad basically moves integrally with the piston, if the amount of rollback by the piston sealing member is small and the piston cannot be sufficiently retracted after braking, the friction pad and the disc will come into contact with each other. The gap becomes narrower, and there is a possibility that the friction pad will be dragged due to the runout of the disc. For example, if the seal member is settled due to aged deterioration or the friction pad is worn, the piston cannot be sufficiently retracted. In order to suppress the dragging of the friction pad, the amount of rollback by the sealing member of the piston may be increased so that the piston can be returned even if the restoring force of the sealing member decreases. However, in this way, the rollback amount becomes too large when the restoring force of the sealing member is not reduced. Then, the amount of retreat of the piston becomes large, the invalid stroke increases, and the responsiveness at the time of the next braking is affected.

On the other hand, the disc brake 10 of the first embodiment allows the friction pad 13 and the piston 41 to be separated from each other within a predetermined distance δ, and regulates the separation exceeding the predetermined distance δ. 101 is provided. Therefore, even if the rollback amount of the piston 41 by the seal member 42 is increased so as to suppress dragging, it is possible to prevent the piston 41 from retreating beyond a predetermined distance δ after braking. Therefore, it is possible to prevent the return amount from becoming excessive while ensuring the return of the piston 41 after braking. Therefore, the responsiveness at the time of the next braking is improved while suppressing the dragging of the friction pad 13. In addition, since abnormal wear of the friction pad 13 can be suppressed, the effects of extending the life of the friction pad 13 and reducing brake squeal can be obtained.

Further, in the disc brake 10 of the first embodiment, since the regulation unit 101 is provided on the shim 71 and the piston 41, it is possible to suppress an increase in cost for providing the regulation unit 101.

A plurality of locking claws 91 may be provided on the back plate 31 instead of the shim 71. For example, it is possible to fix a plurality of locking claws 91, which are separate from the back plate 31, to the back plate 31 by welding or crimping. In that case, the shim 71 and the piston 41 are arranged so as not to come into contact with the welded portion and the crimped portion. Of course, it is easier to manufacture and the cost can be significantly reduced by forming a plurality of locking claws 91 by cutting and raising the shim 71 made of one plate material as in the first embodiment.

[Second Embodiment]
Next, the second embodiment will be described mainly based on FIGS. 10 to 15, focusing on the differences from the first embodiment. The parts common to the first embodiment are represented by the same title and the same reference numerals.

The second embodiment includes a piston 41A that is partially different from the piston 41 of the first embodiment. As shown in FIG. 10, the piston 41A has a small diameter portion 111 having a smaller outer diameter than the other portions on the side of the piston body 62 opposite to the piston bottom 61, and the piston bottom portion of the small diameter portion 111. An outer flange portion 63A that protrudes radially outward from the small diameter portion 111 is formed at an end portion of the piston body portion 62 that is on the opposite side of the piston body portion 62 and that is opposite to the piston bottom portion 61. The small diameter portion 111 and the outer flange portion 63A are continuous over the entire circumference of the piston 41A in the circumferential direction and form an annular shape.

The second embodiment has an inner-side friction pad 13A that is partially different from the inner-side friction pad 13 of the first embodiment. As shown in FIGS. 11 and 12, the friction pad 13A has a pad body 34 similar to that of the first embodiment and a shim 71A that is partially different from the shim 71 of the first embodiment.

The shim 71A is also an integrally molded product formed from a single plate material by press working, and has a plurality of locking claws that are partially different from the first embodiment cut up from the main plate portion 81 similar to the first embodiment. It has 91A. The locking claw 91A has an extension portion 92 similar to that of the first embodiment extending vertically from the main plate portion 81, and is parallel to the main plate portion 81 from the side opposite to the main plate portion 81 of the extension portion 92. It has a claw portion 93A different from that of the first embodiment that protrudes. Each of the claw portions 93A of the locking claws 91A projects in the direction of the center of curvature of the extension portion 92 with respect to the extension portion 92 at the base end of the protrusion. The claw portion 93A of the locking claw 91A is arranged on the same plane parallel to the main plate portion 81.

The diameter of the inscribed circle of the claw portion 93A of the plurality of locking claws 91A is smaller than the outer diameter of the outer flange portion 63A of the piston 41A shown in FIG. 10 and slightly larger than the outer diameter of the small diameter portion 111. The diameter of the inscribed circle of the plurality of extending portions 92 is slightly larger than the outer diameter of the outer flange portion 63A of the piston 41. The length of the portion between the main plate portion 81 and the claw portion 93A of the extending portion 92 of the plurality of locking claws 91A is a predetermined value longer than the axial length of the outer flange portion 63A of the piston 41.

In the shim 71A, a plurality of locking claws 91A are engaged with the outer flange portion 63A of the piston 41A. That is, by elastically deforming the extending portions 92 of the plurality of locking claws 91A, the diameter of the inscribed circle of the plurality of claw portions 93A is made larger than the outer diameter of the outer flange portion 63A, and the plurality of locking claws are locked. The outer flange portion 63A of the piston 41A is inserted inside the claw 91A, and the claw portions 93A of the plurality of locking claws 91A are located closer to the piston bottom 61 than the outer flange portion 63A. The elastic deformation of the extension portion 92 is released. Then, the diameter of the inscribed circle of the plurality of claws 93A becomes smaller than the outer diameter of the outer flange 63A, whereby the shim 71A and the piston 41A are disengaged from each other, and the plurality of claws 93A are attached to the outer flange 63A. It becomes a state of regulation by contacting.

In the axial direction of the piston 41A, the shim 71A can separate the main plate portion 81 from the piston 41A to a position where the plurality of claw portions 93A abut on the outer flange portion 63A, and the piston 41A of the main plate portion 81 beyond that. Separation from is regulated. Further, in the axial direction of the piston 41A, the shim 71A can approach the piston 41A until the main plate portion 81 abuts on the piston 41A. The plurality of claw portions 93A and the piston 41A are relatively slidable in the axial direction of the piston 41A.

Therefore, the plurality of locking claws 91A of the shim 71A and the outer flange portion 63A of the piston 41A are provided on the friction pad 13A and the piston 41A to allow the friction pad 13A and the piston 41A to be separated within a predetermined distance. It constitutes the regulation unit 101A that regulates the separation exceeding the predetermined distance. The regulating unit 101A can hold the friction pad 13A and the piston 41A in a separated state within a range within this predetermined distance. In other words, the regulating unit 101A does not generate a force in the direction of bringing the friction pad 13A and the piston 41A apart from each other within a predetermined distance. In other words, the regulating unit 101A connects the friction pad 13A and the piston 41A so as to be freely movable in the axial direction of the piston 41A within a range within the predetermined distance. The regulating portion 101A is provided on the shim 71A and the piston 41A of the friction pad 13A.

Also in the second embodiment, when the brake hydraulic pressure in the hydraulic chamber 65 of the caliper 15 rises and the brake hydraulic pressure acts on the piston 41A, the piston 41A advances toward the disc 11 with respect to the cylinder 46, and the figure shows the figure. As shown in 13, the friction pad 13A abuts on the main plate 81 of the shim 71A of the inner side friction pad 13A arranged between the piston 41A and the disc 11 and presses the friction pad 13A toward the disc 11. As a result, the friction pad 13A on the inner side moves and comes into contact with the disc 11. At this time, in the shim 71A of the friction pad 13A, the claw portions 93A of the plurality of locking claws 91A are separated from the outer flange portion 63A of the piston 41A by a predetermined distance δ.

Then, when the hydraulic pressure of the brake fluid introduced into the hydraulic chamber 65 of the caliper 15 decreases after braking, the piston 41A and the disc 11 with respect to the cylinder 46 by the restoring force of the elastic deformation of the seal member 42, so-called rollback. Is retracted to the other side. At this time, the movement of the friction pad 13A is suppressed by the frictional force with respect to the mounting member (not shown), and as shown in FIG. 14, the plurality of claw portions 93A of the friction pad 13A hit the outer flange portion 63A of the piston 41A. It touches and restricts further retreat of piston 41A. That is, the regulating portion 101A composed of the plurality of locking claws 91A and the outer flange portion 63A regulates the distance between the friction pad 13A and the piston 41A exceeding a predetermined distance δ. As a result, the movement of the piston 41A with respect to the cylinder 46 in the direction opposite to that of the disc 11 is restricted within a predetermined distance δ. In this way, the seal member 42 returns to the state before elastic deformation in the state where the movement of the piston 41A is restricted. After that, as shown in FIG. 15, the friction pad 13A moves in the direction away from the disc 11 with respect to the piston 41A and the cylinder 46 within a range of a predetermined distance δ due to the runout of the disc 11.

The regulation portion 101A includes an extension portion 92 in which a part of the shim 71A along the back plate 31 extends in the piston axial direction, and a claw portion 93A (locking) in which the end portion of the extension portion 92 is bent in the piston radial direction. Part) and. When the piston 41A moves relative to the shim 71A, the regulating portion 101A locks the claw portion 93A to the outer peripheral portion of the piston 41A.

In the second embodiment, the friction pad 13A and the piston 41A are provided with a regulation unit 101A that allows the friction pad 13A and the piston 41A to be separated within a predetermined distance δ and regulates the separation exceeding a predetermined distance δ. Therefore, as in the first embodiment, it is possible to suppress the dragging of the friction pad 13A and prevent the return amount of the piston 41A after braking from becoming excessive.

The first aspect of the embodiment described above is a friction pad facing the disc, a piston that presses the friction pad against the disc, a cylinder having a bore portion that movably accommodates the piston, and the bore. A disc brake including a seal member arranged in a seal groove of a portion and in contact with the piston, wherein the friction pad and the piston are allowed to be separated from each other within a predetermined distance between the friction pad and the piston. It is characterized in that a regulation unit is provided to regulate the separation exceeding a predetermined distance. As a result, it is possible to suppress the dragging of the friction pad and the excessive return amount of the piston after braking.

In the second aspect, in the first aspect, the friction pad has a lining in contact with the disc, a back plate provided on the surface of the lining opposite to the disc, and the lining of the back plate. It has a shim that covers the opposite surface, and the regulating portion is provided on the shim and the piston.

In a third aspect, in the second aspect, the restricting portion includes an extending portion in which a part of the shim along the back plate extends in the piston axial direction and an end portion of the extending portion. It has a locking portion bent in the radial direction of the piston, and when the piston moves relative to the shim, the locking portion locks on the inner peripheral portion or the outer peripheral portion of the piston. ..

10 Disc brake 11 Disc 13,13A Friction pad 31 Back plate 33 Lining 36 Face 41,41A Piston 42 Seal member 46 Cylinder 51 Bore 55 Seal groove 71,71A Shim 101, 101A Regulator

Claims (3)

The friction pad facing the disc and
A piston that presses the friction pad against the disc,
A cylinder having a bore portion that movably accommodates the piston,
A disc brake including a seal member arranged in the seal groove of the bore portion and in contact with the piston.
The disc brake is characterized in that the friction pad and the piston are provided with a regulating portion that allows the friction pad and the piston to be separated within a predetermined distance and regulates the separation exceeding a predetermined distance. The friction pad is
The lining that contacts the disc and
A back plate provided on the surface of the lining opposite to the disc, and
It has a shim that covers the surface of the back plate opposite to the lining.
The disc brake according to claim 1, wherein the regulating portion is provided on the shim and the piston. The restricting portion includes an extending portion in which a part of the shim along the back plate extends in the piston axial direction, and a locking portion in which an end portion of the extending portion is bent in the piston radial direction. Have and
The disc brake according to claim 2, wherein when the piston moves relative to the shim, the locking portion locks on the inner peripheral portion or the outer peripheral portion of the piston.

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