JP6763682B2 - Vehicle disc brakes - Google Patents

Description

The present invention relates to a vehicle disc brake provided with a pressurizing means for applying an axial driving force to a piston by using a rotational force around a central axis.

Patent Document 1 discloses a disc brake. A vehicle disc brake equipped with a mechanical parking brake mechanism has a configuration in which a shim is interposed between a friction pad and a piston in order to prevent brake squeal.

Jitsufuku 7-22502 Gazette

In a configuration provided with such a parking brake mechanism, the piston is normally locked to the pad by the claws at both ends in the radial direction of the disc of the shim to regulate the rotation of the piston. A convex portion is formed to engage with the shim, and the shim is provided with an insertion hole through which the convex portion of the pad can be inserted. However, the second friction pad arranged on the reaction force claw side has a piston rotation regulation mechanism. Therefore, if the second friction pad is erroneously assembled to the first friction pad side, the shim receives a force in the piston rotation direction due to the rotation force of the piston, and there is a risk that the durability may be lowered.

An object of the present invention is to provide a vehicle disc brake that can prevent the second friction pad from being erroneously assembled on the working portion and prevent the shim plate from being displaced from the friction pad even if it is erroneously assembled. ..

According to the first aspect of the present invention, the brake disc, the first friction pad and the second friction pad facing each other across the brake disc, and the back side of the first friction pad and the second friction pad, respectively, are arranged. A caliper body provided with a cylinder hole and a reaction force claw, a piston slidably fitted in the cylinder hole and capable of pressing the first friction pad, and a back plate of the first friction pad and the second friction pad. In a vehicle disc brake equipped with a shim plate mounted on the back plate and interposed between the piston or the reaction force claw and a pressurizing means capable of applying a pressing force based on a rotational force to the piston. The back plate of the second friction pad on the reaction force claw side is provided with a convex portion protruding toward the reaction force claw at a position other than the contact portion of the reaction force claw, and is attached to the back plate on the reaction force claw side. The shim plate is provided with an insertion hole through which the convex portion can be inserted , and the insertion hole is arranged along the contour of the projected image in the projected image of the piston projected on the shim plate on the reaction force claw side. the end face of the piston disc brake for a vehicle to which the engagement hole is opened in the outer peripheral surface of the piston Ru is formed is provided.

According to the second side surface, in addition to the configuration of the first side surface, the insertion hole is formed of a long elongated hole along a straight line connecting the convex portion and the central axis of the piston, and the minor axis of the elongated hole. The inner diameter in the direction is substantially the same as the outer diameter of the convex portion through which the elongated hole is inserted.

According to the first side surface, by providing a convex portion on the second friction pad side at a position other than the contact portion of the reaction force claw, even if the cylinder hole side is erroneously assembled, the provided convex portion allows the shim to be provided. Friction can be suppressed.

According to the second side surface, by making the insertion hole a long long hole along the straight line connecting the convex portion and the central axis of the piston, the dimensional tolerance between the friction pad and the shim plate cannot be made in the longitudinal direction of the long hole. Can be absorbed without.

It is a top view which shows typically the disc brake for a vehicle which concerns on one Embodiment of this invention. It is sectional drawing which cut in the plane which includes the central axis of a piston and is parallel to the tangential direction of a brake disc. It is sectional drawing which follows the 3-3 line of FIG. It is sectional drawing which follows the 4-4 line of FIG. It is an exploded perspective view of the 1st and 2nd friction pads and the 1st and 2nd shim plates. It is sectional drawing which follows the 6-6 line of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 schematically shows a vehicle disc brake 11 according to an embodiment of the present invention. The vehicle disc brake 11 includes a brake disc 12 that rotates around the axle center XL of the axle integrally with a wheel (not shown), a first friction pad 13a that faces the disc surface of the brake disc 12, respectively. A bracket 14 for supporting the second friction pad 13b is provided. The bracket 14 is fixed to the vehicle body side.

The caliper body 15 is connected to the bracket 14 via a pair of slide pins 16a and 16b extending parallel to the axle center XL of the axle via bolts. The bracket 14 is formed with pin holes 17 (only one of which is shown) that receives the slide pins 16a and 16b while guiding the axial movement of the slide pins 16a and 16b. The slide pins 16a and 16b are slidable, whereby the caliper body 15 is slidably fixed to the bracket 14 in parallel with the axle center XL of the axle.

The caliper body 15 includes an action portion 18 and a reaction force claw 19 arranged in a space between the slide pins 16a and 16b. The working portion 18 is separably fixed by the bolt 21 via the slide pins 16a and 16b. The acting portion 18 is arranged behind the first friction pad 13a. The reaction force claw 19 is arranged behind the second friction pad 13b. The reaction force claw 19 is connected to the action unit 18 by a bridge 22 straddling the edge of the brake disc 12 in a direction parallel to the axle center XL of the axle. An inspection window 23 is partitioned on the bridge 22. When inspecting the wear state of the first friction pad 13a and the second friction pad 13b, the first friction pad 13a and the second friction pad 13b can be visually inspected from the inspection window 23.

An electric actuator 41 that generates a pressing force of the first friction pad 13a and the second friction pad 13b is connected to the caliper body 15 against the brake disc 12. The piston 25 arranged behind the first friction pad 13a exerts a pressing force on the first friction pad 13a toward the disc surface of the brake disc 12.

As shown in FIG. 2, the first friction pad 13a includes a lining 27a that contacts the disc surface of the brake disc 12 and a metal back plate 28a that backs the lining 27a. Similarly, the second friction pad 13b includes a lining 27b that comes into contact with the disc surface of the brake disc 12, and a metal back plate 28b that backs the lining 27b. The first shim plate 29a and the second shim plate 29b are overlapped on the back plates 28a and 28b of the first friction pad 13a and the second friction pad 13b, respectively. As will be described later, the first shim plate 29a and the second shim plate 29b are elastically attached to the back plates 28a and 28b of the friction pads 13a and 13b.

The piston 25 is housed in a cylinder hole 31 formed in the action unit 18. When the piston 25 advances in the axial direction, the first friction pad 13a is pressed against the disc surface of the brake disc 12. The caliper body 15 is displaced by the reaction force, and the reaction force claw 19 of the caliper body 15 presses the second friction pad 13b against the disc surface of the brake disc 12. In this way, the brake disc 12 is sandwiched between the first friction pad 13a and the second friction pad 13b. The forward propulsive force of the piston 25 produces the braking force of the first friction pad 13a and the second friction pad 13b.

As shown in FIG. 3, support grooves 32 are partitioned in the brackets 14 on both sides of the back plates 28a and 28b in the circumferential direction of the brake disc 12. Both ends of the back plates 28a and 28b are fitted into the support groove 32 via the guide plate 33. The support groove 32 guides the movement of the back plates 28a and 28b in parallel with the axle center XL of the axle. The support groove 32 prevents the back plates 28a and 28b from being displaced in the circumferential direction of the brake disc 12.

As shown in FIG. 4, a hydraulic chamber 34 is partitioned between the inside of the piston 25 and the bottom wall of the cylinder hole 31. A hydraulic port 35 for guiding hydraulic pressure to the hydraulic chamber 34 is partitioned in the action unit 18. An output port of a master cylinder (not shown) is connected to the hydraulic port 35 via a hydraulic conduit 36. In this way, hydraulic pressure is introduced from the master cylinder into the hydraulic pressure chamber 34. The piston 25 moves forward by receiving hydraulic pressure from the master cylinder. An annular piston seal 37 that contacts the outer peripheral surface of the piston 25 is mounted on the inner surface of the cylinder hole 31. An annular dust boot 38 is mounted between the open end of the cylinder hole 31 and the piston 25.

The operating shaft 42 of the electric actuator 41 is connected to the piston 25. The electric actuator 41 rotates and drives the operating shaft 42 around the axis. An electric motor 43 is connected to the operating shaft 42 via a reduction mechanism (not shown). The electric motor 43 exerts a rotational driving force in response to energization. A motion conversion mechanism 44 is connected between the piston 25 and the operating shaft 42. The motion conversion mechanism 44 converts the rotational motion of the operating shaft 42 into a linear motion of the piston 25. When the switch for the parking brake lever is operated, the rotational driving force of the electric motor 43 is transmitted to the operating shaft 42, and the piston 25 advances in accordance with the rotation of the operating shaft 42.

The motion conversion mechanism 44 includes a male thread groove 45 carved on the outer peripheral surface of the operating shaft 42, a nut member 47 having a female thread 46 that meshes with the male thread groove 45, and a group of engagement grooves 48 that guide the axial movement of the nut member 47. And. The nut member 47 is abutted against the piston 25 from behind at the front end. The front end of the nut member 47 has an outer surface of a quadrangular prism coaxial with the piston 25. The ridgeline 47a of the quadrangular prism fits into the individual engagement grooves 48. Although the nut member 47 slides in the axial direction with respect to the piston 25 in response to such fitting, the relative rotation of the nut member 47 with respect to the piston 25 is prevented around the central axis. The electric motor 43, the operating shaft 42, and the motion conversion mechanism 44 establish a pressurizing means for applying an axial driving force to the piston 25 by using a rotational force around the central axis Px of the operating shaft 42. The central axis Px of the operating shaft 42 coincides with the central axis of the piston 25.

As shown in FIG. 5, the first shim plate 29a includes a plate-shaped main body 51 that is overlapped with the back plate 28a of the first friction pad 13a. An upper claw 52a is formed by bending on the upper edge of the main body 51. A pair of lower claws 52b are bent and formed on the lower edge of the main body 51. The back plate 28a is elastically sandwiched between the upper claw 52a and the lower claw 52b. In this way, the first shim plate 29a is supported by the back plate 28a. Similarly, the second shim plate 29b includes a plate-shaped main body 53, an upper claw 54a, and a lower claw 54b.

A first insertion hole 55a as an insertion hole is formed in the main body 51 of the first shim plate 29a. The first insertion hole 55a partitions a disk-shaped space having a central axis parallel to the central axis Px. The central axis of the first insertion hole 55a is set in a virtual plane including, for example, the central axis Px of the piston 25 and the axis XL of the axle. The first insertion hole 55a is arranged along the contour in the projected image 56 of the piston 25 projected on the first shim plate 29a. The projected image 56 may be drawn by the contour line of the piston 25 that moves in parallel with the central axis Px. In this way, the first insertion hole 55a is located at a position displaced from the central axis Px of the piston 25. The first shim plate 29a is punch-molded from, for example, one metal plate.

The main body 51 of the first shim plate 29a is further bored with a pair of second insertion holes 55b as insertion holes. The second insertion hole 55b is arranged at a position farthest from the central axis Px of the piston 25. The second insertion hole 55b may be located outside the acting portion 18 in the radial direction of the piston 25.

Similarly, the main body 53 of the second shim plate 29b is bored with a third insertion hole 57 as an insertion hole. In this embodiment the positional relationship between the contour of the back plate 28b of the third insertion hole 57 second friction pad 13b contour of the back plate 28a of the first insertion hole 55a and the first friction pad 13a of the first shim plate 29 a Reflects the positional relationship with. Therefore, the third insertion hole 57 is arranged along the contour in the projected image 58 of the piston 25 projected on the second shim plate 29b. The projected image 58 may be drawn by the contour line of the piston 25 that moves in parallel with the central axis Px. The third insertion hole 57 has a center line 59 in a virtual plane including the center axis Px of the piston 25, and is formed in a long elongated hole along the center line 59. Here, the virtual plane includes the central axis Px and the axle center XL of the axle. The elongated hole may be represented by the locus of the first insertion hole 55a that linearly moves in parallel with the virtual plane. The second shim plate 29b is punched and molded from, for example, one metal plate.

The first friction pad 13a includes a first convex portion 62a and an insertion protrusion 62b that project vertically from the back plate 28a. The first convex portion 62a is formed by a small shaft having an axial center parallel to the central axis Px of the piston 25. The first convex portion 62a is inserted into the first insertion hole 55a of the first shim plate 29a and penetrates the first shim plate 29a. In this way, the first convex portion 62a engages with the first shim plate 29a at an edge that resembles the contour of the first insertion hole 55a. The first convex portion 62a protrudes from the back surface of the first shim plate 29a.

The insertion protrusion 62b is formed by a small shaft having an axial center parallel to the central axis Px of the piston 25. The insertion protrusion 62b is inserted into the second insertion hole 55b of the first shim plate 29a. The positional relationship between the insertion protrusion 62b and the projected image 63 of the piston 25 projected on the back plate 28a of the first friction pad 13a reflects the positional relationship between the second insertion hole 55b and the projected image 56. The projected image 63 may be drawn by the contour line of the piston 25 that moves in parallel with the central axis Px.

The back plate 28b of the second friction pad 13b is provided with a second convex portion 64 protruding toward the reaction force claw 19 at a position other than the reaction force claw 19. The second convex portion 64 is formed by a small axis having an axial center parallel to the central axis Px of the piston 25. The second convex portion 64 is inserted into the third insertion hole 57 of the second shim plate 29b and penetrates the second shim plate 29b. In this way, the second convex portion 64 engages with the second shim plate 29b at an edge that resembles the contour of the third insertion hole 57. The second convex portion 64 projects from the back surface of the second shim plate 29b. The third insertion hole 57 is formed of a long elongated hole along a straight line connecting the second convex portion 64 and the central axis Px of the piston 25, and the dimension of the elongated hole in the minor axis direction is outside the second convex portion 64. It is about the same length as the diameter.

As shown in FIG. 6, an engaging hole 65 is formed on the end surface of the piston 25 corresponding to the first convex portion 62a. The first convex portion 62a is arranged at a position displaced from the central axis Px of the piston 25. The first convex portion 62a engages with the piston 25 when the piston 25 rotates around the central axis Px. Therefore, the first convex portion 62a prevents the piston 25 from rotating around the central axis Px. The engagement hole 65 is opened on the outer peripheral surface of the piston 25.

Next, the operation of this embodiment will be described. When the braking operation is performed while the vehicle is running, the braking hydraulic pressure is introduced from the master cylinder into the hydraulic chamber 34. When the oil pressure in the hydraulic chamber 34 increases, the piston 25 advances. When the piston 25 advances, the first friction pad 13a is pressed against the disc surface of the brake disc 12. The caliper body 15 is displaced by the reaction force, and the reaction force claw 19 of the caliper body 15 presses the second friction pad 13b against the disc surface of the brake disc 12. In this way, the brake disc 12 is sandwiched between the first friction pad 13a and the second friction pad 13b, and a braking force is generated.

Further, for example, when the switch for the parking brake lever is operated, electric power is supplied to the electric actuator 41. The electric motor 43 exerts a rotational driving force according to the electric power. The rotational force of the electric motor 43 is converted into a forward driving force with respect to the piston 25 by the action of the motion conversion mechanism 44. In this way, the piston 25 advances to perform the parking brake.

For example, it is removed from the bracket 14 when the first friction pad 13a and the second friction pad 13b are replaced. At this time, in the present embodiment, even if the second friction pad 13b is erroneously assembled to the action portion 18, the second convex portion 64 on the second friction pad 13b is the contour of the first friction pad 13a and the first convex portion 62a. Since the second convex portion 64 is formed to reflect the positional relationship with the piston 25, the second convex portion 64 can enter the engaging hole 65 of the piston 25. The second convex portion 64 is inserted into the third insertion hole 57 when entering the engagement hole 65. The second convex portion 64 engages with the edge of the second shim plate 29b around the central axis Px. Therefore, an unexpected relative displacement between the second friction pad 13b and the second shim plate 29b is prevented.

Moreover, the second friction pad 13b and the piston 25 are connected to each other around the central axis Px of the piston 25 by the action of the second convex portion 64. The rotation of the piston 25 is regulated by the action of the second convex portion 64. The rotation of the operating shaft 42 is reliably converted into an axial displacement of the nut member 47 via the male thread groove 45 and the female thread 46. Braking force is surely secured in the parking brake state.

When the convex portion is provided on the projected image in which the contact portion 63 of the piston in the first friction pad 13a is translated in parallel with the central axis Px of the piston 25, erroneous assembly can be prevented.

In the present embodiment, the third insertion hole 57 has a center line 59 in a virtual plane including the center axis Px of the piston 25, and is formed in a long elongated hole along the center line 59. The second shim plate 29b is a long hole and receives the second convex portion 64. Therefore, as the size of the elongated hole is reduced in the circumferential direction around the central axis Px of the piston 25, the relative displacement between the second shim plate 29b and the second friction pad 13b is suppressed to the minimum. On the other hand, the allowable range of positional deviation and dimensional deviation is expanded in the radial direction of the piston 25, which can contribute to the improvement of yield and the facilitation of assembly work.

11 ... Vehicle disc brake, 12 ... Brake disc, 13a ... 1st friction pad, 13b ... 2nd friction pad, 15 ... Caliper body, 19 ... Reaction force claw, 25 ... Piston, 28a ... Back plate, 28b ... Back plate , 29a ... 1st shim plate, 29b ... 2nd shim plate, 31 ... Cylinder hole, 43 ... Electric motor constituting the pressurizing means, 44 ... Motion conversion device constituting the pressurizing means, 57 ... Insertion hole, 64 ... Convex part, Px ... Central axis.

Claims (2)

The first friction pad (13a) and the second friction pad (13b) facing each other across the brake disc (12) and the brake disc (12), and the first friction pad (13a) and the second friction pad (13b). ) and a caliper body with a cylinder bore (31) and Hanchikaratsume (19) which is arranged on the rear side of (15), wherein is fitted slidably in said cylinder bore (31) a 1 The piston (25) capable of pressing the friction pad (13a) and the back plates (28a, 28b) of the first friction pad (13a) and the second friction pad (13b) are attached to the back plate (28a, A shim plate (29a, 29b) interposed between the 28b) and the piston (25) or the reaction force claw (19), and a pressurizing means (29a, 29b) capable of applying a pressing force based on a rotational force to the piston (25). In a vehicle disc brake provided with 43, 44), a reaction force is applied to the back plate (28b) of the second friction pad (13b) on the reaction force claw (19) side at a position other than the reaction force claw (19). The shim plate (29b) provided with the convex portion (64) protruding toward the claw side and attached to the back plate (28b) on the reaction force claw (19) side has an insertion hole (64) through which the convex portion (64) can be inserted. 57) , the insertion hole (57) is a projection image (58) of the piston (25) projected onto the shim plate (29b) on the reaction force claw (19) side. are arranged along the contour, the vehicular disc brake according to claim Rukoto engagement hole (65) is formed to be open at the outer peripheral surface of the piston (25) the piston (25) on the end face on the. In the vehicle disc brake according to claim 1, the insertion hole (57) is formed by a long elongated hole along a straight line connecting the convex portion (64) and the central axis (Px) of the piston (25). A disc brake for a vehicle, wherein the inner diameter of the elongated hole in the minor axis direction is substantially the same as the outer diameter of the convex portion (64) through which the elongated hole is inserted.

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