JPH08159184A - Disc brake for vehicle - Google Patents

Abstract

PURPOSE: To provide a means capable of easily performing exchanging work of a friction pad as well as to preventing drag in not-braking by providing a retainer for energizing a piston with the friction pad when braking is released, so that the behavior of the piston and the friction pad are integrally moved in a disc brake for a vehicle. CONSTITUTION: A plate-like retainer 11 is fixed on a line traversing near the central part of a piston of a back plate on the contact side of the back plate 8 of a friction pad with a piston 4, and a ring-like groove 4a is provided on the outer periphery on the piston contact end, so as to be freely engaged with and disengaged from the elastic gripping releasing end of the retainer. Moreover, exchanging work of the friction pad 8 can be performed only by disengaging the retainer 11 from the piston 4 after moving it in parallel with the disc rotor surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a means for causing a friction pad to follow the behavior of a piston in order to prevent the friction pad from being dragged when the disc brake is not braked while the vehicle is traveling.

[0002]

2. Description of the Related Art Conventionally, as a technique of this type of disc brake, for example, a technique disclosed in Japanese Utility Model Laid-Open No. 61-24545 is known. In this embodiment, as shown in FIG. 4, the inner wall surface of the piston 4 inserted in the cylinder 3 formed in the caliper 2 and the retainer 11 fixed to the back metal 8a of the friction pad are elastically engaged to form the piston. The behavior of the friction pad is integrated. (Hereafter, this technology will be referred to as (a) example)

As another example, the one disclosed in Japanese Utility Model Laid-Open No. 5-45264 is known. Its embodiment is shown in FIGS. FIG. 5 shows the arrangement of the caliper 2, the piston 4, the back metal 8a of the friction pad and the retainer 11 in the caliper assembly, and FIG. 6 shows the engagement relationship between the piston 4 and the retainer 11. Is.
More specifically, a piston 4 inserted into a cylinder 3 formed in the caliper 2 is provided with a ring-shaped groove 4a on the outer periphery of the end portion side of the friction pad which comes into contact with the back metal 8a, and the retainer 1
1 is engaged with the lower tongue 11a of the retainer so as to hold the lower edge of the backing metal 8a of the friction pad so that the behaviors of the piston and the friction pad are integrated. (Hereafter, this technology is referred to as (b) example)

[0004]

However, in the above-mentioned prior art (a), the tip of the retainer fixed to the back metal of the friction pad is simply elastically engaged with the inner wall surface of the piston. Since it is not possible to completely follow the behavior of the piston, the friction pad is consumed by a distance 1 from the contact surface of the friction pad of the piston 4 to the back metal 8a shown in FIG. 4 to the open end of the piston inner wall surface contact portion of the retainer shown in FIG. There was a problem that there was no space to replace the friction pad with a new one unless it was done.

Further, in the above-mentioned prior art (b),
If the pad pin 10 shown in FIG. 5 is removed, the friction pad can be replaced from above. However, the engagement between the piston 4 and the back metal 8a of the friction pad is caused by the tongue piece 11 of the retainer 11.
Since it is engaged so as to hold the lower edge of the backing plate 8a of the friction pad at a, when the braking is released, the piston slightly retracts to the bottom side of the sillinder 3 due to the elastic restoring force of the piston seal 5. The retraction function causes the lower part of the friction pad to follow the behavior of the piston, but the upper part of the friction pad cannot follow sufficiently and the drag tends to remain on the outer peripheral side of the disk rotor.

In the conventional disc brake, when the brake is released, the piston retracts into the cylinder due to the retraction function of the piston seal, but if there is no engaging means at the contact portion of the friction pad backing, the friction pad The light contact with the disk rotor causes the knock back action to be separated from the disk rotor side surface. However, due to uneven sliding resistance such as the braking torque receiving surface of the friction pad and the pad pin hole, if there is a drag that causes the disk rotor and the friction pad to come into light contact even after braking is released, uneven wear of the friction pad and disk rotor will occur. Also, it causes judder caused by wear of the disk rotor and fluctuating thickness of the disk rotor, resulting in energy loss, life loss, and unpleasant squeal. Therefore, in order to solve the above problems, the present invention aims to separate the friction pad accurately from the disk rotor integrally with the retraction behavior of the piston at the time of releasing the brake, and to facilitate the replacement work of the friction pad. This is a technical issue.

[0007]

Means for Solving the Problems The means for solving the above technical problem is a piston inserted in a cylinder having a caliper formed with a friction pad for sandwiching and braking a disk rotor rotating integrally with a wheel. In the disc brake that is pressed by, the friction pad is suspended by a pad pin that is inserted into a pad pin support hole that is formed in a direction perpendicular to the braking torque receiving surface on the caliper side and a pad pin hole that is formed in the back metal of the friction pad. At the contact point between the back metal of the friction pad and the piston, a retainer having a plate-shaped elastic grip open end is provided on the back metal at one or two points on a line that crosses the center of the piston, and a protrusion riveted or embossed is provided. It is fixed by caulking, etc., and is elastically engaged and disengaged with a ring-shaped groove provided on the outer circumference of the piston end that contacts the back metal. Characterized in that was.

[0008]

With this structure, the elastic gripping open end of the retainer fixed to the back metal of the friction pad on the line crossing the center of the piston engages with the ring-shaped groove of the piston to release the braking. When this is done, the friction pad also separates from the disk rotor surface substantially in parallel with the behavior of the piston retracting to the cylinder bottom side due to the relaxation function. In other words, the friction pad has a ring-shaped groove on the piston and the retainer engaged at the center of the piston even if there is some deviation in sliding resistance, such as the braking torque receiving surface of the caliper or the pad pin hole. Along with the behavior, the friction pad also separates from the disc rotor.

Further, when the friction pad is worn out and the pad is removed or a new pad is mounted for replacement, the pad pin supported by the caliper is pulled out and the pad pin is moved upward or downward along the braking torque surface. If the pad is moved, the elastic grip open end of the retainer can be easily disengaged from the engagement with the ring-shaped groove of the piston, and the replacement work can be easily performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a vehicle disc brake having an opposed piston type caliper will be described with reference to the drawings.

FIG. 1 shows an assembly of a vehicle disc brake 1. The caliper 2 liquid-seals a piston 4 in a cylinder 3 with a piston seal 5, and hydraulic fluid is supplied to each cylinder from a hydraulic pressure introduction hole 6 via a communication hole (not shown). A pair of friction pads 8 arranged opposite to each other on both sides of the disc rotor 7 rotating integrally with the wheels generate a braking torque by being pressed against the disc rotor 7 by the braking pressure acting on the piston 4 and slidingly contacting the disc rotor 7. It is transmitted from the receiving surface 9 to the vehicle body mounting portion (not shown) of the caliper assembly 1. On the other hand, the friction pad 8 is suspended by a pad pin 10 that passes through a pad pin hole 8b formed in the back metal 8a and a pad pin support hole formed in the caliper side.

2a, 2b and 3 show the features of the present invention. Friction pad backing 8a with which piston 4 contacts
Then, the retainer 11 having a plate-like elastic grip open end on a line that crosses the center of the piston is fixed by a fixing means such as caulking or a screw using a projection riveted or embossed. The elastic grip open end of the retainer 11 is elastically engageable and disengageable in a direction parallel to the disk rotor 7 with a ring-shaped groove 4a provided on the outer circumference of the end of the piston 4 that abuts the back metal 8a. Therefore, the friction pad 8 behaves integrally with the piston 4, and the friction pad can be easily replaced.

[0013]

As described above, according to the present invention, the plate-shaped retainer is fixed to the back metal of the friction pad on a line that traverses the center of the piston, and the retainer is provided with a ring-shaped groove provided on the outer periphery of the end of the piston. Since it is elastically engageable and disengageable, when the braking is released, the friction pad follows the behavior of the piston and is accurately separated from the disc rotor surface, so that dragging can be prevented. Therefore, it is possible to prevent judder caused by uneven wear of the friction pad or the disc rotor and fluctuating wear of the disc rotor, and prevent unnecessary energy loss, life loss, and squeal. Further, since the replacement work of the friction pad can be carried out only by moving the retainer from the piston by moving it in parallel with the disk rotor surface, it can be more easily carried out.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of an assembly of a disc brake of an embodiment.

FIG. 2 a. The engagement side view of the piston and friction pad which are the characteristics of an example. b. The enlarged view of A part of a.

3 is a sectional view taken along line XX of FIG. 2a.

FIG. 4 is a side view of engagement between a piston and a friction pad according to a conventional example (a).

FIG. 5 is a side view of engagement between a piston and a friction pad according to a conventional example (b).

6 is an engagement state diagram of the retainer and piston of FIG.

[Explanation of symbols]

 1: Vehicle disc brake 2: Caliper 3: Cylinder 4: Piston 4a: Piston ring groove 5: Piston seal 6: Hydraulic pressure introduction hole 7: Disc rotor 8: Friction pad 8a: Friction pad backing 9: Braking Torque receiving surface 10: Pad pin 11: Retina

Claims (1)

[Claims] 1. In a disc brake in which a friction pad for sandwiching and braking a disc rotor that rotates integrally with a wheel is pressed by a piston inserted in a cylinder formed in a caliper, a back plate of the friction pad is provided with the piston contact side. And fixing a retainer having a plate-like elastic grip open end on a line that traverses the center of the piston, and the elastic grip open end becomes a ring-shaped groove provided on the outer circumference of the piston end that contacts the back metal. A disc brake for a vehicle, which is elastically engaged and disengaged.