JP2020060210A - Brake for vehicle - Google Patents

Abstract

To obtain a brake for a vehicle having an improved and novel constitution such that an opening of a U-shaped structure of, for example, a bridge, a piston and a pressing part accompanied by the pressurization of a linear motion member is suppressed.SOLUTION: This brake for a vehicle comprises: a body having, for example, a piston which moves by fluid pressure in a cylinder, a bridge having a cylinder therein, and straddling the outside in a radial direction of a brake disc which is fixed to the cylinder and rotates around a rotation center toward an axial direction, and a pressing part fixed to the bridge and pressing a pad to the brake disc from a side opposite to the brake disc; and a rotation linear motion conversion mechanism having a rotating member rotating in conjunction with an output shaft of a motor, and a linear motion member linearly moving according to the rotation of the rotating member, and pressing the pad to the brake disc via the piston. A second action point in which the piston is pressed by the linear motion member is farther from the rotation center than a first action point in which the pad is pressed by the piston.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to vehicle brakes.

  BACKGROUND ART Conventionally, there is known a vehicle brake having an electric brake that converts the rotation of a rotating member driven by a motor into a linear motion of a linear motion member and presses a pad against a disc via a piston by the linear motion member ( Patent Document 1). In the vehicle brake of Patent Document 1, the piston and the body operate in mutually opposite directions, and the pressing portion provided on the opposite side of the body from the piston presses the pad in the direction opposite to the pressing direction by the piston. It is configured to be pressed against. The cylinder that accommodates the piston and the pressing portion are connected by a bridge that extends radially outside the peripheral portion of the disc in the axial direction of the disc. That is, the vehicle brake has a U-shaped structure in which the cylinder and the pressing portion project from both sides of the bridge inward in the radial direction of the disc, and the U-shaped structure partially covers the peripheral edge of the disc.

JP, 2014-69739, A

  In the above conventional technique, the further the piston pressing position of the linear motion member is from the bridge, the more the vehicle brake opens the U-shaped structure, that is, the radially inner end of the cylinder and the radially inner part of the pressing portion. It becomes easy to deform so that the other end is separated from each other. It is not preferable that an inconvenient event resulting from such deformation occurs.

  Therefore, one of the problems of the present disclosure is, for example, a vehicle brake having an improved and novel structure in which the opening of the U-shaped structure of the bridge, the cylinder, and the pressing portion due to the pressing of the linear motion member is suppressed. Is to get.

  The vehicle brake of the present disclosure is provided with, for example, a piston that is housed in a cylinder, moves by hydraulic pressure in the cylinder and presses a pad against a brake disc, and the cylinder, and is fixed to the cylinder and rotates around a rotation center. A body having a bridge straddling the outside in the radial direction of the brake disc in the axial direction, and a pressing portion that is fixed to the bridge and presses a pad against the brake disc from the side opposite to the brake disc of the piston, and the output of the motor A rotary member that rotates in conjunction with the shaft, and a rotation-linear motion conversion mechanism that has a linear motion member that linearly moves according to the rotation of the rotary member and presses the pad against the brake disc via the piston, And a second action point where the piston is pressed by the linear motion member is Away from the center of rotation than the first action point that is pressed by the ton.

  In the vehicle brake, the second point of action where the piston is pressed by the linear motion member is farther from the rotation center of the brake disc than the first point of action where the pad is pressed by the piston. Therefore, the second point of action can be set closer to the bridge. Therefore, according to such a configuration, for example, a vehicle brake having an improved new configuration in which the opening of the U-shaped structure of the bridge, the cylinder, and the pressing portion due to the pressing of the linear motion member is suppressed is provided. Obtainable.

FIG. 1 is a schematic and exemplary cross-sectional view of a vehicle brake according to an embodiment, showing a braking state. FIG. 2 is a schematic and exemplifying view of the linear motion member and the piston of the vehicle brake of the embodiment as seen in the direction D1 of FIG.

  Hereinafter, exemplary embodiments of the present invention will be disclosed. The configurations of the embodiments shown below, and the actions and results (effects) provided by the configurations are examples. The present invention can be realized by a configuration other than the configurations disclosed in the following embodiments. Further, according to the present invention, it is possible to obtain at least one of various effects (including derivative effects) obtained by the configuration. Moreover, all drawings are schematic and exemplary.

  In each drawing, the direction in which the linear motion member 52 approaches the pad 45 is indicated by an arrow D1, the direction in which the linear motion member 52 moves away from the pad 45 is indicated by an arrow D2, and the rotation of the rotary member 51 pressing the pad 45 is indicated. The forward rotation direction, which is the direction, is indicated by an arrow Rn, and the reverse rotation direction is indicated by an arrow Rr. The directions D1 and D2 are parallel to the axial direction of the rotation center of the disk D.

  FIG. 1 is a cross-sectional view of a vehicle brake 10 showing a braking state. As illustrated in FIG. 1, the vehicle brake 10 includes a motor 20, a rotation transmission mechanism 30, and a caliper 40 including a rotation / linear motion conversion mechanism 50. The vehicle brake 10 can operate not only as a hydraulic brake but also as an electric brake. The caliper 40 constitutes a hydraulic brake, and the motor 20, the rotation transmission mechanism 30, the rotation / linear motion conversion mechanism 50, and the caliper 40 constitute an electric brake. The electric brake is a so-called electric parking brake. That is, the vehicle brake 10 is configured such that the braking state by the electric brake function is maintained during parking. However, the electric brake may be activated during traveling or during a temporary stop.

  The rotation of the output shaft 20a of the motor 20 is transmitted to the rotating member 51 of the rotation / linear motion converting mechanism 50 via the rotation transmitting mechanism 30 having rotating elements (not shown) such as a plurality of gears. The output shaft 20a may also be called a rotor. The rotation transmission mechanism 30 may also be referred to as a speed reduction mechanism.

  The caliper 40 has a body 41 and a piston 43. Further, the body 41 is provided with a cylinder 42 that movably accommodates the piston 43. The body 41 has a bridge 41a and a pressing portion 41b. The bridge 41a straddles the outer side (upper side in FIG. 1) of the disk D in the radial direction in the axial direction (left-right direction in FIG. 1) of the disk D. The pressing portion 41b is fixed to the bridge 41a on the side of the piston 43 opposite to the disc D. The pressing portion 41b projects inward in the radial direction of the disc D (downward in FIG. 1, opposite to the direction R) from the bridge 41a in a state of being separated from the disc D in the direction D1. Further, the cylinder 42 protrudes inward in the radial direction of the disk D (downward in FIG. 1, opposite to the direction R) from the bridge 41a while being separated from the disk D in the direction D2. Therefore, the bridge 41a, the cylinder 42, and the pressing portion 41b of the caliper 40 form a U-shaped structure that is opened inward in the radial direction of the disk D. The disc D may also be called a brake disc, a disc rotor, or a rotor.

  The cylinder 42 is a bottomed cylindrical hole opened in the direction D1 (rightward in FIG. 1) around the first central axis Ax1. The piston 43 is housed in the cylinder 42 so as to be capable of reciprocating along the first central axis Ax1. The cylinder 42 is provided with a hydraulic chamber Rp. As the hydraulic pressure in the hydraulic chamber Rp rises, the piston 43 pushes the back plate 45a of the pad 45 in the direction D1 and the lining 45b against the disc D. Further, with the movement of the piston 43 in the direction D1, the body 41 moves in the direction D2 (left side in FIG. 1). Therefore, the pressing portion 41b of the body 41 pushes the pad 45 in the direction D2 and pushes the pad 45 against the disc D. As a result, a braking state by the hydraulic brake is obtained in which the wheel (not shown) of the vehicle that rotates integrally with the disc D is braked.

  The piston 43 has a bottomed cylindrical shape, and has a cylindrical wall 43a and a bottom wall 43c. That is, the piston 43 is provided with the recess 44. The cylindrical wall 43a has a cylindrical shape centered on the first central axis Ax1, and the bottom wall 43c intersects the first central axis Ax1. Further, the piston 43 has an outer peripheral surface 43b having a cylindrical outer surface, an inner peripheral surface 43e having a cylindrical inner surface, and an end surface 43c1 opposite to the hydraulic chamber Rp (right side in FIG. 1). . A minute clearance (clearance) is set between the outer peripheral surface 43b and the inner peripheral surface 42a of the cylinder 42, and the outer peripheral surface 43b is in contact with the inner peripheral surface 42a in a lubricated state in which hydraulic fluid exists in the clearance. Slide. The seal 72 is interposed between the outer peripheral surface 43b and the inner peripheral surface 42a and suppresses leakage of the hydraulic fluid from the hydraulic chamber Rp through the gap. Further, the seal 72 is a retract that retracts the end face 43c1 of the piston 43 from the pad 45 by retracting the piston 43 to the hydraulic chamber Rp side (left side in FIG. 1) by the elastic force as the hydraulic pressure in the hydraulic chamber Rp decreases. It has a function. That is, when the pressing of the piston 43 against the back plate 45a is released as the hydraulic pressure in the hydraulic chamber Rp decreases, the pressing of the lining 45b against the disk D by the piston 43 is released, and the hydraulic brake is thereby released. The braking release state by is obtained. In this way, the caliper 40 can operate as a hydraulic brake. The pad 45 is an example of a braking member.

  A rotation / linear motion conversion mechanism 50 is provided in the caliper 40. The rotation / linear motion conversion mechanism 50 includes a rotating member 51 and a linear motion member 52. The rotating member 51 has a coupling portion 51a, a flange 51b, and a shaft 51c, and is supported by the body 41 so as to be rotatable about the second central axis Ax2. The coupling portion 51a rotates integrally with the output shaft (not shown) of the rotation transmission mechanism 30. A thrust bearing 71 is provided between the flange 51b and the body 41 of the caliper 40. The shaft 51c projects from the flange 51b to the side opposite to the coupling portion 51a (rightward in FIG. 1). A male screw portion 51d is provided on the outer peripheral surface of the shaft 51c.

  The linear motion member 52 is located inside the cylindrical wall 43 a of the piston 43. The linear motion member 52 has a tubular portion 52a and a protrusion 52b. The cylindrical portion 52a has a cylindrical shape centered on the second central axis Ax2. A female screw portion 52c is provided on the inner surface of the cylinder of the tubular portion 52a, and the female screw portion 52c and the male screw portion 51d of the rotating member 51 mesh with each other. The protrusion 52b projects outward from the tubular portion 52a in the radial direction of the second central axis Ax2 (hereinafter, simply referred to as the radial direction). The tubular portion 52a may also be referred to as a shaft. The protrusion 52b may also be referred to as an outward protrusion, an outward flange, or a flange.

  The rotation / linear motion converting mechanism 50 is housed in a recess 44 provided in the piston 43. The recess 44 is open toward the hydraulic chamber Rp side (left side in FIG. 1). The linear motion member 52 is provided in the recess 44 so as to be movable in the axial direction of the second central axis Ax2 (hereinafter, simply referred to as the axial direction, the horizontal direction in FIG. 1).

  FIG. 2 is a view of the linear motion member 52 and the piston 43 as viewed in the direction D1 of FIG. The rotation / linear motion conversion mechanism 50 is provided with a rotation stopping mechanism 60 that restricts rotation of the linear motion member 52 around the second central axis Ax2. Specifically, as illustrated in FIG. 2, a recess 43 provided in the piston 43 is provided with a groove 43d extending in the axial direction, and the groove 43d has a projection of the linear motion member 52. 52b is accommodated so as to be movable along the groove 43d. The rotation stop mechanism 60 is configured by the side surface of the groove 43d and the projection 52b of the linear motion member 52. The rotation of the piston 43 about the first central axis Ax1 is limited by the friction between the piston 43 and the seal 72 or the pad 45.

  As described above, in the present embodiment, the male screw portion 51d of the rotary member 51 and the female screw portion 52c of the linear motion member 52 mesh with each other, and the rotation of the projection 52b of the linear motion member 52 causes the rotation of the protrusion 52b of the linear motion member 52 to rotate. Therefore, the linear motion member 52 linearly moves in the axial direction according to the rotation of the rotary member 51. Due to the rotation of the output shaft 20a of the motor 20 in one direction based on the rotation of the output shaft 20a (hereinafter, referred to as normal rotation), the linear motion member 52 moves in the direction D1 (rightward in FIG. 1), and the piston 43 When the back plate 45a is pressed in the direction D1, the piston 43 presses the lining 45b of the pad 45 against the disk D. In this case as well as in the case of the hydraulic brake, the body 41 moves in the direction D2 (left in FIG. 1) as the piston 43 moves in the direction D1. Therefore, the pressing portion 41b of the body 41 pushes the pad 45 in the direction D2 and pushes the pad 45 against the disc D. As a result, a braking state by the electric brake in which the wheel (not shown) of the vehicle that rotates integrally with the disc D is braked is obtained.

  On the other hand, when the rotation member 51 rotates in the opposite direction due to the reverse rotation of the output shaft 20a of the motor 20, the linear motion member 52 moves in the direction D1 and the pressing of the piston 43 against the back plate 45a is released. The pressing of the lining 45b against the disc D by the is released, and the released state of the braking by the electric braking function is obtained. In this way, the motor 20, the rotation transmission mechanism 30, the rotation / linear motion conversion mechanism 50, and the caliper 40 can operate as an electric brake.

  The rotation stopping mechanism 60 has a forward rotation limiting portion 61 that limits the forward rotation of the linear motion member 52. The forward rotation limiting portion 61 has a side surface 52b1 on the forward rotation direction (direction Rn) side of the projection 52b of the linear motion member 52 and a side surface 43d1 on the forward rotation direction side of the groove 43d of the piston 43. The groove 43d of the piston 43 is a circumferential direction (hereinafter, simply referred to as a circumferential direction) of the first central axis Ax1 among the four protrusions 43f (protrusions) that protrude radially inward from the inner circumferential surface 43e of the piston 43. Between the two protrusions 43f facing each other. The protrusion 43f extends along the first central axis Ax1 and has a constant cross-sectional shape orthogonal to the first central axis Ax1. In other words, the side surface 43d1 on the forward rotation direction side of the groove 43d is the side surface on the reverse rotation side of the protrusion 43f. When the linear motion member 52 rotates in the normal direction along with the normal rotation of the rotating member 51, the side surface 52b1 of the linear motion member 52 contacts the side surface 43d1 of the piston 43. The side surface 43d1 of the piston 43 restricts the movement of the side surface 52b1 of the linear motion member 52 in the normal rotation direction, whereby the normal rotation of the linear motion member 52 is restricted. The side surface 52b1 may be referred to as a first pushing portion or a pushing portion, and the side surface 43d1 may be referred to as a first receiving portion or a receiving portion.

  Further, the rotation stopping mechanism 60 has a reverse rotation limiting portion 62 that limits the reverse rotation of the linear motion member 52. The reverse rotation limiting portion 62 has a side surface 52b2 on the reverse rotation direction (direction Rr) side of the projection 52b of the linear motion member 52 and a side surface 43d2 on the reverse direction side of the groove 43d of the piston 43. In other words, the side surface 43d2 on the reverse rotation direction side of the groove 43d is the side surface on the normal rotation direction side of the protrusion 43f. When the linear motion member 52 reverses as the rotary member 51 reverses, the side surface 52b2 of the linear motion member 52 contacts the side surface 43d2 of the piston 43. The side surface 43d2 of the piston 43 limits the movement of the side surface 52b2 of the linear motion member 52 in the reverse rotation direction, whereby the reverse rotation of the linear motion member 52 is limited. The side surface 52b2 may be referred to as a second pushing portion or a pushing portion, and the side surface 43d2 may be referred to as a second receiving portion or a receiving portion.

  The circumferential width of the groove 43d is set to be larger than the circumferential width of the protrusion 52b. Therefore, in the state where the normal rotation of the linear motion member 52 is restricted in the normal rotation restriction part 61 by the normal rotation of the rotation member 51, the side surface 52b2 of the linear motion member 52 of the reverse rotation restriction part 62 and the side surface of the piston 43. 43d2 is separated from each other. When the reverse rotation of the rotary member 51 restricts the reverse rotation of the linear motion member 52 in the reverse rotation restricting portion 62, the side surface 52b1 of the linear motion member 52 of the normal rotation restricting portion 61 and the side surface 43d1 of the piston 43 are separated. Are separated from each other. That is, when the rotating member 51 is in the normal rotation state, only the normal rotation limiting portion 61 of the normal rotation limiting portion 61 and the reverse rotation limiting portion 62 is activated, and when the rotating member 51 is in the reverse rotation state, the forward rotation limiting portion 61 is rotated. Of the section 61 and the reverse rotation limiting section 62, only the reverse rotation limiting section 62 operates.

  Here, as shown in FIGS. 1 and 2, in the present embodiment, the second pressing center P2 with which the piston 43 is pressed by the linear motion member 52 is the first pressing center P1 with which the pad 45 is pressed by the piston 43. Than the rotation center C (FIG. 2) of the disk D. The pressing center is the center of gravity of the pressing surface. In the present embodiment, the first pressing center P1 is, for example, the center (center of gravity, centroid) of the end surface 43c1 of the piston 43, and is a position on the first central axis Ax1. The first pressing center P1 is the force point of the pressing force F1. The second pressing center P2 is, for example, the center (center of gravity, centroid) of the end face 52d of the linear motion member 52 in the direction D1, and is a position on the second central axis Ax2. The second pressing center P2 is the force point of the pressing force F2. The farther the second pressing center P2 is from the bridge 41a, the longer the moment arm from the bridge 41a is, and the U-shaped structure of the bridge 41a, the cylinder 42, and the pressing portion 41b of the caliper 40 is opened, that is, the cylinder 42 of the cylinder 42 is opened. The end portion 42b radially inward (downward in FIG. 1) of the rotation center C and the end portion 41b1 radially inwardly (downward in FIG. 1) of the pressing portion 41b are easily separated from each other, For example, there is a possibility that it may contribute to uneven wear of the lining 45b of the pad 45. In this regard, according to the present embodiment, the second pressing center P2 can be brought closer to the bridge 41a, and the moment arm from the bridge 41a to the second pressing center P2 can be made shorter, so the U-shaped caliper 40 is formed. The opening of the structure is easily suppressed, and an inconvenient event accompanying the opening is less likely to occur. The first pressing center P1 is an example of the first operating point, and the second pressing center P2 is an example of the second operating point. Generally, the pressing forces F1 and F2 by the electric brake are larger than the pressing force F1 by the hydraulic brake.

  Further, the position of the first pressing center P1 may affect a performance different from the uneven wear of the lining 45b, such as prevention of squeal of the brake. In this respect, according to the present embodiment, since the first pressing center P1 and the second pressing center P2 are offset, for example, a merit such as preventing squeal of a brake by setting the position of the first pressing center P1. , And by setting the position of the second pressing center P2, it is possible to obtain advantages such as suppressing uneven wear of the lining 45b.

  Further, in the present embodiment, the second central axis Ax2 is farther from the rotation center C than the first central axis Ax1. With such a configuration, for example, the second central axis Ax2 can be closer to the second pressing center P2 than in the case where the second central axis Ax2 and the first central axis Ax1 overlap. The further the second central axis Ax2 is from the second pressing center P2, the bending acting on the component of the electric brake such as the rotation / linear motion converting mechanism 50 by the reaction force of the pressing force F2 acting from the second pressing center P2. The moment is larger and the component is more likely to be deformed. As a countermeasure, if the rigidity of the component is increased, the structure may be increased in size or weight. In this respect, according to the present embodiment, since the second central axis Ax2 can be brought closer to the second pressing center P2, for example, the bending moment acting on the component of the electric brake can be further reduced, and the bending can be reduced. The occurrence of inconvenient events due to the moment can be suppressed.

  Further, in the present embodiment, the second pressing center P2 is located on the second central axis Ax2. In other words, the second pressing center P2 and the second central axis Ax2 are aligned. With such a configuration, for example, the bending moment acting on the component parts of the electric brake can be further reduced, and the occurrence of inconvenient events due to the bending moment can be further suppressed.

  Further, in the present embodiment, as shown in FIG. 2, the first central axis Ax1 and the second central axis Ax2 are aligned in the radial direction (direction R) of the rotation center C of the disk D. In other words, when viewed in the direction R, the first central axis Ax1 and the second central axis Ax2 overlap. With such a configuration, the first central axis Ax1 and the second central axis Ax2 are different from the case where the first central axis Ax1 and the second central axis Ax2 are not aligned in the radial direction of the rotation center C of the disk D, that is, the second central axis Ax2. The second pressing center P2 on the axis Ax2 can be arranged closer to the bridge 41a. Therefore, for example, the opening of the U-shaped structure of the caliper 40 is more easily suppressed, and the inconvenient phenomenon associated with the opening is further less likely to occur.

  Further, in the present embodiment, the linear motion member 52 has a plurality of protrusions 52ba and 52bb having different radial projection lengths of the rotation center C. Specifically, the lengths of the protrusions 52ba and 52bb are set longer as the distance from the second central axis Ax2 to the inner peripheral surface 43e of the piston 43 is longer. Therefore, for example, the protrusion heights of the plurality of protrusions 43f protruding from the inner peripheral surface 43e of the piston 43 can be set to be the same, and thus the piston 43 can be set to the first central axis Ax1 and the second central axis Ax2. Is offset, and the configuration in which the first central axis Ax1 and the second central axis Ax2 are not offset provides the advantage of being easily shared.

  Further, in the present embodiment, as indicated by a two-dot chain line arc in FIG. 2, the rotation locus Pt of the tip 52bt of the protrusion 52ba around the second central axis Ax2 intersects the inner peripheral surface 43e of the piston 43. ing. Such a protrusion 52ba serves as a structure for suppressing the rotation of the piston 43 around the first central axis Ax1, that is, a rotation stopper. This is because the cylindrical wall 43a of the piston 43 limits the rotation of the protrusion 52ba, that is, the linear motion member 52. In addition, the pressing force Fp exerted on the piston 43 from the projection 52ba generated by the rotation of the linear motion member 52 around the second central axis Ax2 causes a component outward in the radial direction of the first central axis Ax1. The pressing force on the inner peripheral surface 42a of the cylinder 42 by the outer peripheral surface 43b of the piston 43 in the radial direction of the first central axis Ax1 increases, and the outer peripheral surface 43b and the inner peripheral surface 42a move in the circumferential direction of the first central axis Ax1. This is also because the frictional force increases. Therefore, according to such a configuration, the protrusion 52ba of the linear motion member 52 and the tubular wall 43a of the piston 43 construct a rotation stopping structure for the linear motion member 52, and therefore, for example, the tightening force by the seal 72 is further increased. In some cases, it is possible to reduce the resistance of the piston 43 when it is moved, and to reduce the rotation-stopping structure of the pad 45. The rotation trajectory Pt is an example of a trajectory.

  Although the embodiments of the present invention have been illustrated above, the above embodiments are merely examples, and are not intended to limit the scope of the invention. The above-described embodiment can be implemented in various other forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. In addition, specifications such as each configuration and shape (structure, type, direction, shape, size, length, width, thickness, height, number, arrangement, position, material, etc.) may be changed as appropriate. Can be carried out. For example, the rotation / linear motion converting mechanism and the rotation stopping mechanism can be realized in various configurations.

  Further, for example, in the above embodiment, the configuration in which the first central axis and the second central axis are offset has been illustrated, but the present invention is not limited to this, and the first central axis and the second central axis overlap. However, even if the first pressing center and the second pressing center are offset in the radial direction of the rotation center of the disk, the effect of suppressing the opening of the U-shaped structure can be obtained.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle brake, 20 ... Motor, 20a ... Output shaft, 41a ... Bridge, 42 ... Cylinder, 43 ... Piston, 43a ... Cylindrical wall, 43d1 ... Side (reception part), 43d2 ... Side (reception part), 45 ... Pads, 50 ... Rotation / linear motion converting mechanism, 51 ... Rotating member, 52 ... Linear motion member, 52a ... Cylindrical part (shaft), 52b ... Projection, 52b1 ... Side surface (pushing part), 52b2 ... Side surface (pushing part) , 52 bt ... Tip, Ax1 ... First central axis, Ax2 ... Second central axis, C ... Rotation center, D ... Disc (brake disc), P1 ... First pressing center (first action point), P2 ... Second pressing Center (second point of action), Pt ... Rotation locus (trajectory).

Claims (5)

A piston that is housed in the cylinder and moves by the hydraulic pressure in the cylinder to press the pad against the brake disc,
The cylinder is provided, and a bridge that is fixed to the cylinder and axially straddles the radially outer side of a brake disc that rotates around the center of rotation, and a pad that is fixed to the bridge and is opposite to the brake disc of the piston A body having a pressing portion pressed against the brake disc,
Rotation-to-linear motion conversion including a rotating member that rotates in conjunction with the output shaft of the motor, and a linear moving member that linearly moves according to the rotation of the rotating member and presses the pad against the brake disc through the piston. Mechanism,
Equipped with
A vehicle brake in which a second point of action of the piston that is pressed by the linear motion member is farther from the center of rotation than a first point of action that the pad is pressed by the piston.   The vehicle brake according to claim 1, wherein the second central axis of the rotating member is farther from the rotational center than the first central axis of the cylinder.   The vehicle brake according to claim 2, wherein the first central axis and the second central axis are arranged in a radial direction of the rotation center. The piston has a cylindrical wall around the first central axis,
At least a part of the linear motion member is surrounded by the tubular wall,
The linear motion member includes a shaft extending along the second central axis, and a projection that protrudes from the shaft to a radial outside of the second central axis to form a pressing portion,
In the cylinder of the cylindrical wall, a receiving portion is provided that extends along the first central axis and abuts the pressing portion to limit movement of the pressing portion in the circumferential direction of the first central axis.
The vehicle brake according to claim 2, wherein the protrusions include a plurality of protrusions having different protrusion lengths of the second central shaft outward in the radial direction. The piston has a cylindrical wall around the first central axis,
At least a part of the linear motion member is surrounded by the tubular wall,
The linear motion member includes a shaft extending along the second central axis, and a projection that protrudes from the shaft to a radial outside of the second central axis to form a pressing portion,
In the cylinder of the cylindrical wall, a receiving portion is provided that extends along the first central axis and abuts the pressing portion to limit movement of the pressing portion in the circumferential direction of the first central axis.
The vehicle brake according to claim 2 or 3, wherein a locus of a tip of the protrusion that accompanies rotation of the linear motion member around the second central axis intersects an inner peripheral surface of the piston.

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