JPH075304Y2 - Piston assembly for disc brake with parking brake mechanism - Google Patents

Description

TECHNICAL FIELD The present invention relates to a piston assembly used in a disc brake with a parking brake mechanism.

2. Description of the Related Art A piston body having a cylindrical shape with a bottom, an adjustment nut provided inside the piston body, and an outer peripheral side of the adjustment nut, which is inserted in a preload state between the adjustment nut and the piston body and has an annular shape. The adjust nut is moved to the bottom side of the piston body through a cage formed of a plate and having a plurality of through holes formed at predetermined intervals in the circumferential direction, and thrust bearings formed of rolling elements respectively arranged in the through holes. A disc brake piston assembly with a parking brake mechanism, which is provided with a spring member that urges the piston body to come into pressure contact with the piston body, is known, and an example thereof is disclosed in JP-A-60-53229.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in such a piston assembly, since a compression coil spring or a wave washer is usually used as the spring member, the rolling element is retained in the through hole of the annular and plate-shaped cage. Since it is necessary to insert a flat washer between the thrust bearing and the spring member, it is difficult to reduce the number of parts of the piston assembly and the number of assembling steps. It was a cause.

The present invention has been made in view of the above circumstances, and its purpose is to urge the adjusting nut toward the bottom side of the piston body through the thrust bearing as described above by the spring member. The object is to reduce the number of parts of the piston assembly and the man-hours for assembling.

Means for Solving the Problems In order to achieve such an object, the present invention provides an annular flat plate portion that is brought into contact with the thrust bearing in the disc brake piston assembly with a parking brake mechanism as described above, and The spring member is configured to have a plurality of elastic claw portions that are integrally provided on the flat plate portion and are brought into contact with the piston body in a preloaded state.

According to this structure, the spring member is provided with the annular flat plate portion that is brought into contact with the thrust bearing, and the plurality of elastic members that are integrally provided on the flat plate portion and are brought into contact with the piston body in a preloaded state. Since it has a claw part, the spring member not only performs the same function as a conventional compression coil spring or wave washer by its elastic claw part, but also functions as a conventional flat washer by the flat plate part. Will also be fulfilled. As a result, it is possible to reduce the number of parts of the piston assembly and the man-hours for assembling work, because a separate plain washer is not required.

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

FIG. 1 is a view showing a main part of a disc brake with a parking brake mechanism equipped with a piston assembly to which the present invention is applied. In the figure, a caliper 12 is laid across the outer peripheral portion of a disk rotor 10 that is rotatably provided with wheels, and the caliper 12 is not shown in a support member 14 fixed to a non-rotating member (not shown). It is movably supported in a direction parallel to the axis of the disk rotor 10 via a slide pin or the like. The curiper 12 has a first cylinder bore 16, and a piston body 18 having a cylindrical shape with a bottom as a whole is fitted in the first cylinder bore 16 so as to be capable of protruding in one direction in a state where the piston body 18 cannot rotate relative to its axis. Cylinder portion 20, a protruding portion 22 integrally provided on the cylinder portion 20 at an end of the cylinder portion 20 opposite to the protruding direction of the piston body 18, and an end portion of the cylinder portion 20 in the protruding direction of the piston body 18. And a bifurcated claw portion 24 opposed to the cylinder portion 20 with the disc rotor 10 interposed therebetween. Inside the caliper 12, namely the piston body 18
A pair of pads 26 and 28 are arranged between the claw portion 24 and the claw portion 24 with the disc rotor 10 sandwiched therebetween.
6, 28 are movably supported by the support member 14 in a direction parallel to the axis of the disk rotor 10.

A second cylinder bore 30 is formed inside the protrusion 22 so as to be adjacent to and substantially concentric with the first cylinder bore 16, and the second cylinder bore 30 has a male screw portion 32 and a head portion 34 having a larger diameter than that. The adjust bolt 36 having the above is fitted in the head portion 34 so that the male screw portion 32 is located inside the piston body 18 so as to be relatively movable in the axial direction and non-rotatable around the axial center. The adjust bolt 36 is a washer integrally provided on the head 34 and the inner peripheral surface of the first cylinder bore 16.
Piston body by spring 40 interposed between 38 and
It is always urged in the direction away from 18, and the external thread 32
An adjusting nut 42 is screwed into the shaft with a predetermined rattling in the axial direction. A flange portion 44 protruding in the outer peripheral direction is provided at an end portion of the adjustment nut 42 located on the tip side of the male screw portion 32.

A plate-shaped annular member 46 is integrally fixed by caulking to the inner peripheral surface located inside a predetermined distance from the opening end of the piston body 18, and also on the outer peripheral surface of the cylindrical portion of the adjust nut 42. Thrust bearing 48 is flange
It is fitted so that it is adjacent to 44. A spring member 50 is inserted between the thrust bearing 48 and the annular member 46 in a predetermined preload state, and the adjusting nut 42 is formed on the outer peripheral surface of the flange portion 44 thereof according to the biasing force of the spring member 50. On the tapered surface, the tapered inner wall of the piston body 18 and the protruding direction of the piston body 18 are pressed against each other. This prevents the adjustment nut 42 from being rotated due to vibration of the vehicle or the like during non-braking. In this embodiment, the piston assembly is composed of the piston body 18, the adjustment nut 42, the thrust bearing 48, the spring member 50, and the like. The biasing force of the spring member 50 is set to be smaller than the biasing force of the spring 40. In addition, 51
Is a piston seal that liquid-tightly seals between the piston body 18 and the first cylinder bore 16 and also serves to return the piston body 18.

The thrust bearing 48 is a retainer 52 that is annular and plate-shaped and has a number of through holes formed at predetermined intervals in the circumferential direction.
And a large number of balls 53 respectively arranged in the through holes of the retainer 52. The balls 53 form the rolling elements of this embodiment. Further, the spring member 50, as shown in FIGS. 1 and 2, has an annular flat plate portion 54.
And the plate portion 54 integrally extends from the inner peripheral edge of the plate portion 54.
The elastic claws 55 (three in this embodiment) are arranged to face one surface of the plate 54 at a predetermined distance. The elastic claws 55 are brought into contact with the thrust bearing 48 on the flat plate 54. Is brought into contact with an annular member 46 provided on the piston body 18 in a preloaded state.

Inside the protruding portion 22, the first cylinder bore 30 of the second cylinder bore 30 is further provided.
The second cylinder bore 30 on the side opposite to the cylinder bore 16 side
A mounting hole 56 is provided so as to communicate with the second cylinder bore 30 in a direction perpendicular to the axis center of the mounting hole.
Within 56, a cam shaft 58 is provided via a needle roller bearing 60 so as to be rotatable about its axis. A crank lever 62, to which the parking brake operating force is transmitted, is attached to one end of the cam shaft 58 and located outside the protruding portion 22 so as to be relatively unrotatable, and an intermediate portion in the longitudinal direction of the cam shaft 58. The engaging recess 64 is formed in the engaging recess 64.
A rod-shaped toggle 68 is provided between the engaging recess 66 formed on the tip surface of the head 34 of the adjusting bolt 36 and the needle roller bearing.
It is inserted with 60 inserted. The crank lever 62 is constantly urged in the parking brake non-operating direction (clockwise direction in FIG. 1) by a return spring (not shown).

In the disc brake configured as described above,
When the cam shaft 58 is rotated counterclockwise in FIG. 1 by the crank lever 62, a thrust is generated in the toggle 68, and the thrust is transmitted to the piston body 18 via the adjustment bolt 36 and the adjustment nut 42. Piston body 18
The pads 26, 28 are narrowed by the claw portion 24 of the caliper 12 and the parking brake is applied. on the other hand,
When hydraulic pressure is supplied into the first cylinder bore 16, the piston body 18 is pushed out, and braking is performed in the same manner as in the above case. At this time, when the wear amount of the pads 26, 28 exceeds a predetermined fixed limit, the piston body
The parking brake operation stroke is automatically adjusted based on the adjustment nut 42 being rotated in one direction when the forward movement of the 18 is performed. In addition,
The brake operation and the adjustment operation are not necessary for understanding the present invention, and thus detailed description thereof will be omitted.

As described above, according to this embodiment, the spring member 50 includes the flat plate portion 54.
And three elastic claws 55 are integrally provided,
Not only does the elastic claw 55 function like a conventional compression coil spring or wave washer, but also the flat plate 54
As a result, it also functions as a conventional flat washer.
As a result, it does not require a separate flat washer as in the past,
The number of parts of the piston assembly and the number of man-hours for assembling work are suitably reduced compared to the conventional one, and the weight of the elastic claw portion 55 can be made lighter than that of the compression coil spring or the wave washer, so that the weight of the piston assembly is reduced. Can be reduced to some extent.

Further, according to the present embodiment, after the intermediate molded product including the portion forming the elastic claw portion 55 and the flat plate portion 54 is punched out from the plate-shaped material by press working, the portion forming the elastic claw portion 55 is simply bent. Since the spring member 50 is formed only by raising it, there is an advantage that the spring member 50 that also functions as a flat washer can be easily manufactured.

In the above-described embodiment, the elastic claw portion 55 of the spring member 50 is integrally provided on the inner peripheral edge of the flat plate portion 54, but an elastic claw portion having a predetermined shape is integrally formed on the outer peripheral edge of the annular flat plate portion. It is also possible to provide.

In addition, in the above-described embodiment, the spring member 50 has three elastic claw portions.
Although it is configured to have 55, it may be configured to have two elastic claw portions, or may be configured to have four or more elastic claw portions.

Further, in the above-described embodiment, the thrust bearing 48 is configured to have the balls 53, but it is not always necessary, and the rolling elements may be configured by rollers.

In addition, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a disc brake with a parking brake mechanism equipped with a piston assembly according to an embodiment of the present invention. FIG. 2 is a perspective view of the spring member in FIG. 18: Piston body 42: Adjust nut 48: Thrust bearing 50: Spring member 52: Cage 53: Ball (rolling element) 54: Flat plate part 55: Elastic claw part

Claims (1)

[Scope of utility model registration request] 1. A piston body having a cylindrical shape with a bottom, an adjustment nut provided inside the piston body, and a preload state interposed between the adjustment nut and the piston body on the outer peripheral side of the adjustment nut. The adjust nut is inserted through a thrust bearing formed of a cage, which is annular and plate-shaped, and has a plurality of through holes formed at predetermined intervals in the circumferential direction, and thrust bearings each of which is a rolling element disposed in the through hole. In a piston assembly for a disc brake with a parking brake mechanism, comprising: a spring member that urges the piston body toward the bottom side to press the piston body, an annular flat plate portion that is brought into contact with the thrust bearing, and the flat plate portion. A plurality of elastic claw portions that are integrally provided on the piston body and are brought into contact with the piston body in a preloaded state. A piston assembly for a disc brake with a parking brake mechanism, which is configured as follows.