JP2014126065A - Disk brake for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk brake for a vehicle including a resin piston, which can prevent abrasion of the piston and reduce the weight of a friction pad, even in a case where the piston contacts with the friction pad in an inclined state by deformation of a caliper body due to brake reaction force.SOLUTION: A length L1 in a disk radial direction of a friction pad 6 is formed so as to become shorter than a diameter L2 of a piston 10. A rear plate 6a is provided with a straight part 6e formed linearly, at an outer end part in the disk radial direction of a surface on which the rear plate 6a contacts with the piston 10.

Description

  The present invention relates to a vehicle disc brake, and more specifically, a vehicle including a pair of friction pads disposed on both sides of a disc rotor and a resin piston inserted into a cylinder hole formed in a caliper body. Disc brake for use.

  A vehicle disc brake having a piston inserted into the cylinder hole of the caliper body and a pair of friction pads disposed on both sides of the disc rotor reduces the weight of the vehicle and improves the operability and fuel consumption of the vehicle. However, resin-made pistons tend to be used. However, resin-made pistons may cause cracks or other defects on the pressing surface (opening end surface) that presses the friction pad.

  In addition, when trying to reduce the weight of the friction pad to be used, a part of the piston may be arranged on the outer side in the disk radial direction from the outer surface in the disk radial direction of the friction pad. When the caliper body is deformed, the friction pad is pushed in a state where the piston is inclined, so that a force is locally applied to the piston and the piston may be worn.

  For this reason, on the bottom side of the cylinder hole, the piston abuts against the piston to suppress tilting of the piston (see, for example, Patent Document 1) or the back plate of the friction pad protrudes toward the outer peripheral side in the disk radial direction. There has been an extension portion formed so that the entire opening end surface of the piston is in contact with the back plate to reduce the surface pressure applied to the tip portion of the piston (see, for example, Patent Document 2).

Japanese Utility Model Publication No. 2-25737 JP 2002-295547 A

  However, in the above-mentioned Patent Document 1, the caliper body provided with the cylinder hole by the braking reaction force has the action portion and the reaction portion in the direction away from each other from the disc rotor, centering on the bridge portion straddling the disc rotor. When deformed into a letter shape, the piston and the friction pad are in contact with each other in an inclined state, and the outer end surface in the disk radial direction of the back plate of the friction pad is curved substantially along the outer periphery of the disk rotor. For this reason, the piston and the back plate are strongly hit at two points or one point, and the piston may be worn.

  Moreover, in the thing of patent document 2, since the extension part was provided in the back plate, the weight of the friction pad was bulky.

  Therefore, the present invention can prevent wear of the piston and reduce the weight of the friction pad even if the piston is in contact with the friction pad in a tilted state due to the deformation of the caliper body due to the braking reaction force. An object of the present invention is to provide a vehicle disc brake having a resin piston.

  In order to achieve the above object, a vehicle disc brake according to the present invention is disposed on both sides of a disc rotor, and is inserted into a pair of friction pads having a lining and a back plate, and a cylinder hole formed in a caliper body. In the vehicle disc brake including the resin piston that presses the friction pad, the friction pad pressed against the piston is formed so that the length in the disc radial direction is shorter than the diameter of the piston. Further, a linear portion formed linearly is provided at an outer end portion in the disk radial direction of the surface where the back plate abuts on the piston.

  Further, it is preferable that the linear portion is orthogonal to an imaginary line passing through the center of the disk rotor and the center of the piston. Furthermore, the piston is formed in a bottomed cylindrical shape, and the opening is inserted into the cylinder hole with the opening facing the friction pad, and the center of the linear portion is disposed in the opening end surface of the piston. It is preferable. Further, it is preferable that the back plate is provided with chamfered portions at corners on both sides of the linear portion in the disk rotation direction. Furthermore, the friction pad on the working side is formed on the piston side surface of the back plate, on the main body portion along the shape of the back plate, and on the piston protruding outward in the disk radial direction from the outer end surface in the disk radial direction of the back plate. It is preferable that a shim plate provided with a protruding portion along the shape is provided.

  According to the vehicle disc brake of the present invention, since the length of the friction pad in the radial direction of the disc is shorter than the diameter of the piston, the weight of the friction pad can be reduced. Further, by providing a linear portion formed linearly at the outer end of the disk radial direction on the surface where the back plate abuts the piston, the caliper body is moved around the bridge that straddles the disk rotor by the braking reaction force. When the piston is deformed into a letter shape, the piston strongly hits the linear portion, and therefore, it is possible to suppress the wear of the piston as compared with the conventional case where the piston and the back plate are strongly hit at two points or one point.

  In addition, by forming the straight portion so as to be orthogonal to the imaginary line passing through the center of the disk rotor and the center of the piston, when the caliper body is deformed by the braking reaction force, the piston is in a good condition in the straight portion. It can be made to contact.

  Furthermore, the piston is formed in a bottomed cylindrical shape, the opening is inserted into the cylinder hole with the friction pad side facing, and the center portion of the linear portion is disposed in the opening end surface of the piston, thereby providing a braking reaction force. Thus, when the caliper body is deformed, the piston can be reliably brought into contact with the linear portion.

  In addition, by providing chamfered portions at the corners on both sides of the disk rotation direction of the linear portion of the back plate, the friction pad can be prevented from interfering with the caliper body, and the weight of the friction pad can be reduced.

  Further, the friction pad on the working part side is formed on the piston side surface of the back plate along the shape of the main body portion along the shape of the back plate, and the shape of the piston protruding outward in the disk radial direction from the disk radial direction outer end surface of the back plate. By providing a shim plate with a protrusion, it is possible to widen the pressing surface on which the piston presses the friction pad, and to suppress the application of high surface pressure locally, thus preventing piston wear. can do.

It is II sectional drawing of FIG. It is a partial cross-sectional exploded perspective view of the friction pad, shim plate, and piston showing the first embodiment of the present invention. FIG. 3 is a sectional view taken along line III-III in FIG. 1. 1 is a plan view of a vehicle disc brake showing a first embodiment of the present invention. It is a partial cross-section exploded perspective view of a friction pad, a shim plate, and a piston showing a second embodiment of the present invention. It is a sectional view of a disk brake for vehicles similarly.

  FIG. 1 to FIG. 4 are views showing a first embodiment of the vehicle disc brake of the present invention, and an arrow A indicates the rotation direction of the disc rotor that rotates integrally with the wheel when the vehicle moves forward.

  The vehicle disc brake 1 includes a disc rotor 2 that rotates integrally with a wheel, a caliper bracket 3 that is fixed to the vehicle body at one side of the disc rotor 2, and caliper support arms 3a and 3a of the caliper bracket 3. Further, the caliper body 5 supported so as to be movable in the disc axial direction via a pair of slide pins 4 and 4 and the disc rotor 2 is sandwiched between the action portion 5a and the reaction portion 5b of the caliper body 5. A pair of friction pads 6, 7 arranged opposite to each other is provided, and shim plates 8, 9 are attached to the friction pads 6, 7.

  The caliper body 5 includes the action portion 5a and the reaction portion 5b disposed on both sides of the disk rotor 2, and a bridge portion 5c that connects these across the outer periphery of the disk rotor 2, and the action portion 5a includes: A cylinder hole 5d opened on the disk rotor 2 side is provided. In the cylinder hole 5d, a bottomed cylindrical piston 10 is inserted into the cylinder hole 5d with the opening directed toward the friction pad, and the piston 10 is supplied with hydraulic pressure supplied to the hydraulic chamber 11 at the bottom of the cylinder hole. Thus, the cylinder hole 5d is moved in the direction of the disk rotor. Further, slide pin mounting arms 5e and 5e are provided on both sides of the action portion 5a, and the slide pins 4 are mounted on the tips of the slide pin mounting arms 5e with mounting bolts 12, respectively. ing.

  On the inner peripheral surface of the cylinder hole 5d, a piston seal mounting groove 5f is provided in the middle in the axial direction, and a dust seal mounting groove 5g is provided on the cylinder hole opening side, and the piston 10 is rolled back in the piston seal mounting groove 5f. The dust seal 14 for preventing the intrusion of dust into the cylinder hole is fitted into the dust seal mounting groove 5g of the piston seal 13 to be made.

  The caliper support arms 3a and 3a straddle the outer periphery of the disc rotor 2 in the disc axial direction from both sides of the caliper bracket 3 while sandwiching both sides of the bridge portion 5c. Each caliper support arm 3a is formed with a guide hole 3b for receiving the slide pin 4, and each of the caliper support arms 3a has a pair of pad guide portions 3c facing each other on the side surface of the disc rotor 2. Provided, each pad guide portion 3c is provided with a torque receiving surface 3d facing each other. Further, a pad retainer mounting portion 3e for mounting the pad retainer 15 is provided outside the pad guide portion 3c in the disk radial direction.

  Each friction pad 6, 7 is formed of a back plate 6 a, 7 a and a lining 6 b, 7 b attached to the side of the disc rotor of the back plate 6 a, 7 a, and the length L 1 in the disc radial direction is the piston 10. It is shorter than the diameter L2. The back plate 6a of the friction pad 6 on the working portion side pressed by the piston 10 is formed with a flat surface portion 6d on the outer end surface 6c in the radial direction of the disk, and a straight line contacting the piston 10 at the piston side end portion of the flat surface portion 6d. A portion 6e is formed, and the straight portion 6e is formed to be orthogonal to a virtual line CL1 passing through the center P1 of the disk rotor 2 and the center P2 of the piston 10. Further, chamfered portions 6f and 6f are formed at the corners on both sides of the disc rotating direction of the straight portion 6e of the back plate 6a. Further, ear pieces 6g and 6g protrude from both sides of the back plate 6a in the disk rotation direction, and a binding hole 6h of the lining 6b is formed at the center. Further, on the piston side surface of the back plate 6a, protrusions 6i and 6i for attaching the shim plate 8 are provided on both inner sides in the disk radial direction.

  The back plate 7a of the friction pad 7 on the reaction portion side is formed such that the disk radial direction outer end surface 7c is curved substantially along the outer periphery of the disk rotor, and the shim plate 9 is formed at the center of the disk radial direction outer end surface 7c. A mounting groove 7d is formed. Further, like the back plate 6a on the action side, a binding hole 7e of the lining 7b is formed in the center, and ear pieces (not shown) are projected on both sides of the disk rotation direction. Further, a chamfered portion 7f is formed on the outer side in the disk rotor radial direction on the side of the back plate 7a opposite to the disk rotor.

  The shim plate 8 on the working portion side is formed of a thin metal plate, and the main body portion 8a along the shape of the back plate 6a and a piston projecting outward in the disc radial direction from the outer end surface of the back plate 6a in the disc radial direction outside. The main body portion 8a is formed with insertion holes 8c and 8c through which the protrusions 6i and 6i of the back plate 6a are inserted. The shim plate 9 on the reaction portion side includes a main body portion 9a that follows the shape of the back plate 7a, and a claw piece 9b that is inserted into the mounting groove 7d.

Both friction pads 6 and 7 are supported by the respective pad pieces 3c and 3c on the disk insertion side and the extraction side via pad retainers 15 with the shim plates 8 and 9 assembled. Is done. On the action part side, a part of the piston 10 is disposed on the outer side in the disk radial direction from the outer end surface of the friction pad 6 in the disk radial direction, and the linear part 6e is
The central portion P3 of the straight portion 6e is disposed in the opening end surface 10a of the piston 10, and the shim plate 8 is disposed at a position corresponding to the outer side in the disk radial direction of the piston 10 where the protruding portion 8b protrudes from the back plate 6b. .

  In the vehicular disc brake 1 formed as described above, when the pressurized hydraulic fluid is supplied to the hydraulic chamber 11 by the driver's braking operation, the piston 10 moves forward through the cylinder hole 5d, and the shim plate 8 Then, the friction pad 6 on the action portion 5a side is pressed to the disk rotor 2 side. In the friction pad 6 on the action side, each of the ear pieces 6g, 6g moves the pad guide portions 3c, 3c to the disk rotor 2 side via the pad retainers 15, 15, and the lining 6b on one side of the disk rotor 2. Make sliding contact. Next, due to this reaction force, the caliper body 5 moves in the direction of the action part 5a via the slide pins 4 and 4, and the reaction force claw 5h provided on the reaction part 5b side becomes the reaction part via the shim plate 9. The friction pad 7 on the 5b side is pressed against the other side surface of the disk rotor 2. In the friction pad 7 on the reaction portion side, each ear piece moves the pad guide portions 3c and 3c to the disk rotor 2 side via the pad retainers 15 and 15, and the lining 7b is brought into sliding contact with the other side surface of the disk rotor 2. .

  During braking as described above, when the caliper body 5 is deformed in a direction in which the action part 5a and the reaction part 5b are opened in the shape of a letter with the braking reaction force as the center, the piston 10 is tilted. To contact the friction pad 6. As a result, the outer side of the disk 10 in the radial direction of the piston 10 strongly abuts against the straight portion 6e formed on the back plate 6a of the friction pad 6, but can receive a pressing force at the straight portion 6e. The wear of the piston 10 can be suppressed as compared with the conventional case where the point or one point is strongly hit. Further, since the straight portion 6e has the central portion P3 of the straight portion 6e disposed in the opening end face 10a of the piston 10, the piston 10 can surely press the friction pad 6 and the shim plate 8 Since the protruding portion 8b is in contact with the outer side in the disk radial direction of the piston 10 protruding from the back plate 6a, the pressing surface on which the piston 10 presses the friction pad 6 can be widened, and the locally high surface pressure is obtained. Can be suppressed.

  Further, the friction pads 6 and 7 are formed such that the length L1 in the disk radial direction is shorter than the diameter L2 of the piston 10 and the chamfered portions 6f and 7f are formed. The chamfered portions 6f and 7f can prevent the friction pads 6 and 7 from interfering with the caliper body 5.

  5 and 6 show a second embodiment of the present invention. Components that are the same as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. .

  In this embodiment, the back plate 6a of the friction pad 6 on the working side has a chamfered portion 6j formed on the piston side of the flat surface portion 6d, and a linear portion 6k formed on the piston side end portion of the chamfered portion 6j. Yes.

  In this embodiment, as in the first embodiment, when the piston 10 is in contact with the friction pad 6 in a tilted state during braking, the outer side in the disk radial direction of the piston 10 is formed on the back plate 6a of the friction pad 6. The linear portion 6k can receive the pressing force, and the chamfered portion 6j can also receive the pressing force, and the wear of the piston 10 can be suppressed.

  The present invention is not limited to the above-described embodiments, and the friction pad may not include a shim plate. Moreover, the linear part provided in the back plate does not need to be orthogonal to the imaginary line CL1, and the linear part may protrude to the outer peripheral side of the opening end face of the piston. Furthermore, the central part of the straight part may not be in the opening end face of the piston. It can also be applied to a piston-facing disc brake.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle disc brake, 2 ... Disc rotor, 3 ... Caliper bracket, 3a ... Caliper support arm, 3b ... Guide hole, 3c ... Pad guide part, 3d ... Torque receiving surface, 3e ... Pad retainer attaching part, 4 ... Slide Pin, 5 ... caliper body, 5a ... action part, 5b ... reaction part, 5c ... bridge part, 5d ... cylinder hole, 5e ... slide pin mounting arm, 5f ... piston seal mounting groove, 5g ... dust seal mounting groove, 5h ... anti Force claws, 6 ... friction pads, 6a ... back plate, 6b ... lining, 6c ... outer end surface in the radial direction of the disk, 6d ... flat portion, 6e ... straight portion, 6f ... chamfered portion, 6g ... ear piece, 6h ... binding hole , 6i: Projection, 6j: Chamfered part, 6k ... Linear part, 7 ... Friction pad, 7a ... Back plate, 7b ... Lining, 7c ... Disk radial outer end surface, 7d ... Mounting groove, 7e ... Binding 7f ... Chamfered portion, 8 ... Shim plate, 8a ... Main body portion, 8b ... Projection portion, 8c ... Insertion hole, 9 ... Shim plate, 9a ... Main body portion, 9b ... Claw piece, 10 ... Piston, 11 ... Hydraulic chamber 12 ... Mounting bolt, 13 ... Piston seal, 14 ... Dust seal, 15 ... Pad retainer

Claims (5)

A pair of friction pads arranged on both sides of the disk rotor and provided with a lining and a back plate, and a resin piston inserted into a cylinder hole formed in the caliper body and pressing the friction pad. In the vehicle disc brake, the friction pad pressed against the piston is formed such that the length in the disc radial direction is shorter than the diameter of the piston, and the back plate is in the disc radial direction of the surface in contact with the piston. A vehicular disc brake, characterized in that a linear portion formed linearly is provided at an outer end portion. 2. The vehicle disc brake according to claim 1, wherein the straight portion is orthogonal to an imaginary line passing through the center of the disc rotor and the center of the piston. The piston is formed in a bottomed cylindrical shape, and is inserted into the cylinder hole with the opening directed toward the friction pad, and the center of the linear portion is disposed in the opening end surface of the piston. The disc brake for a vehicle according to claim 1 or 2, characterized in that The vehicular disc brake according to any one of claims 1 and 3, wherein the back plate is provided with chamfered portions at corners on both sides of the linear portion in the disc rotation direction. The friction pad on the working side is formed in a shape of a piston projecting outwardly in the disk radial direction from the disk radial outer end surface of the main body along the shape of the backplate on the piston side surface of the backplate. The vehicle disc brake according to any one of claims 1 to 4, further comprising a shim plate provided with a protruding portion along the same.

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