JPH0289826A - Disc brake device - Google Patents

Abstract

PURPOSE:To enable reliable recognition of wear of a friction lining when the friction lining is worn to a state in which the thickness thereof exceeds a limit value by a method wherein an arm extending toward the brake disc side is mounted in a protruding manner to a shim, and the protrusion on the tip thereof is inserted into an opening formed in a bridge part located astride the brake disc of a caliper. CONSTITUTION:When a friction lining 22 between brake pads 16 and 18 is worn to a state in which wear exceeds a limit value, a protrusion 32 at the tip of an arm 30 of a shim 28 is brought into contact with the side edge of an opening 36 of a bridge part 34 of a caliper 12 is resiliently bend the protrusion 32 or (and) the arm 30. When, during release of a brake, the bent protrusion 32 or (and) the arm 30 are restored to its original shape, a piston 26 of a hydraulically responding device is forcibly moved back to a position located further away from a brake disc 10 than a usual brake release position, i.e. a rest position. Thereby, a brake step-on amount by a driver is increased, and even a careless or an insensitive drive is apt to notice abnormality of a bake pedal stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a disc brake, particularly a disc brake for vehicles such as automobiles.

(Prior Art) Disc brakes, which have been widely used in vehicles such as automobiles, include a brake disc that is fixed to a wheel and rotates together with the wheel, and a fixed member such as a torque plate that is fixed to the vehicle body. A caliper is mounted to be slidable in the axial direction but substantially non-rotatable around the disk axis, and a caliper is housed in the same caliper plane and is disposed opposite to both sides of the outer circumferential portion of the brake disc. The brake pad includes a pair of brake pads that are pressed against the side surfaces of the brake disc by a hydraulic response device installed in the brake pad, and the brake pads have a back plate and suitable fixing means such as rivets on the back plate. It consists of a friction lining fitted with a Furthermore, between the hydraulic response device and the brake pad adjacent to the device,
Usually, shims are installed mainly to prevent brake squeal.

The friction lining is pressed against the surface of the brake disc each time the brake is applied and wears out, so when it wears down to a certain limit thickness, it is necessary to accurately detect this and replace it with a new one. If the friction lining becomes excessively worn and the back plate comes into direct sliding contact with the side of the brake disc, not only will it not be possible to secure the required braking performance, but problems will occur that will cause damage to the expensive brake disc. do.

Therefore, various means have been proposed to alert the driver when the wear of the friction lining of the brake pad reaches a preset wear limit. A system has already been put into practical use in which a diaphragm is attached to the brake 9, and when the friction lining wears down to its wear limit, the diaphragm slides into contact with the side of the brake disc and generates an alarm sound. I am forced to do so.

(Problem to be Solved by the Invention) The above-mentioned diaphragm type brake/tire wear warning device has a sufficient warning effect for drivers who are paying considerable attention to the driving condition of the vehicle, but In the case of a distracted or insensitive driver, or a driver with extremely poor knowledge of vehicle structure, the driver may not recognize the warning generated by the activation of the diaphragm and continue driving, resulting in excessive wear of the brake pads and eventually There are problems that lead to situations where expensive brake discs have to be replaced.

The present invention provides a disc brake device equipped with a novel warning means that can surely make the driver aware of the fact when the friction lining of a play brake or RAD wears beyond a preset limit thickness. The purpose is to provide the following.

(Means for Solving the Problems) The disc brake device according to the present invention has been devised to achieve the above-mentioned object, and is provided with a disc brake that is slidable in the axial direction of the brake disc and that is slidable in the axial direction of the disc. A carrier/branch is installed to straddle the axis so as not to rotate substantially, and is housed in the carrier 9 and is placed opposite both sides of the outer circumferential portion of the brake disc, and a liquid provided in the caliper. A pair of brake pads that are pressed against the side surface of the disk by the pressure response device, and the brake pad adjacent to the hydraulic response device! The shim is equipped with a shim interposed between the brake disc and the brake disc, and the shim is provided with an arm extending toward the brake disc, and the protrusion at the tip of the shim is connected to the brake disc of the above-mentioned Kya IJ t4. When the friction lining of the brake pad is worn beyond a preset wear limit when the protrusion is inserted into the opening provided in the spanning bridge, the protrusion abuts against the opening side edge of the bridge by applying the brake. The present invention is characterized in that the protrusion and/or the arm are configured to be elastically deformable.

(Function) According to the present invention, when the friction lining of the brake pad is worn beyond the wear limit, when the brake is applied, the protrusion at the tip of the arm of the seam comes into contact with the opening side RK of the bridge portion of the carrier and flat. The protrusion or (and) arm is elastically bent, and the protrusion or (and) is bent when the brake is released.
When the arm returns to its original shape, the piston of the hydraulic response device is pushed back to a position farther from the brake disc than the normal brake release or rest position. This is no good,
The amount of brake pedal depression by the driver increases, and even inattentive or insensitive drivers use brakes that are frequently used on a daily basis (modulation of dull stroke is easy to notice, so excessive wear on the brake pedal can be effectively prevented). will be recognized.

(Example) An example of the present invention will be specifically described below with reference to the accompanying drawings. In the figure, the reference numeral 10 is a brake disc that is fixed to the wheel knob of the automobile and rotates integrally with the hub, and the reference numeral 12 is a caliper that is installed over the outer circumference of the brake disk 10 and is fixed to the vehicle body. It is mounted on the tricycle plate 14 so that it can freely slide in the direction of the disk axis, but not substantially rotate around the disk axis. A pair of inner brake pads 16 and outer brake pads 18 are housed in the caliper 12, and each brake disc 16 and 18 is connected to a back plate 20 and a brake disc 1 of the same back plate.
The friction lining 22 is fixed to the side surface facing 0 by any means such as riveting.

The caliper 12 is provided with a hydraulic response device 24, whose piston 26 is in contact with two back plates of the inner brake pad 16 via a shim 28 made of a thin stainless steel plate. Brake disc 1 from the upper edge of shim 28
An arm 30 extending substantially in the disk axial direction toward the zero side.
The arm 30 is provided with a protrusion 32 extending outward in the radial direction of the disk at the tip thereof.

The protrusion 32 corresponds to the brake disc 10 of the caliper 12.
It is inserted into an opening 36 provided in a bridge section 34 that spans the bridge. The cylinder 38 of the hydraulic response device 24 communicates with a hydraulic fluid chamber of a known brake fluid pressure source, ie, a brake master cylinder, which is linked to a brake pedal operated by the driver.

A rubber seal ring 40 that surrounds the outer periphery of the piston 26 is interposed on the inner periphery of the cylinder 38, and the seal ring 40 functions as a brake fluid sealing member, as is well known in the art. and the above friction lining 2
It functions as an automatic gap correction device that automatically adjusts the gap between the brake pads 16 and 18 and the friction surface of the brake disc 10 as the brake pads 16 and 18 wear out.

In the above configuration, when the brake is applied, the hydraulic response device 24
When brake fluid pressure is supplied into the cylinder 38 of
The outer brake pad 18 is pressed against the side surface, and then the outer brake pad 18 is pressed against the brake disc 1 via the caliper 12 due to the reaction force.
It is pressed against the other side of the outer circumferential portion of 0. At this time, if the friction lining 22 of the plate flats 16 and 18 has little wear and its thickness is thicker than the wear limit thickness, the piston 2
The shim 2 advances toward the brake disc 10 together with the shim 6
The protrusion 32 provided on the arm 30 of the carrier 12 is in an idle state by simply moving idly within the opening 36 provided in the bridge portion 34 of the carrier 12.

Therefore, when the brake fluid pressure in the multi-cylinder 38 disappears due to brake release, the piston 26 is retracted to the rest position by the restoring action of the rubber seal ring 40, which is well known in the art, and as the brake non-rad 16 and A minute gap is formed between 18 and the friction surface of brake disc 10.

Next, due to the use of the brake many times, the brake disc 1
When the friction linings 22 of Nos. 6 and 18 wear out and exceed the wear limit, as shown in FIG. 32 is the front side edge 3 of the opening 36
6' and elastically bends from the free state shown by the dotted line in the figure as shown by the solid line. Next, when the brake is released and the piston 26 retreats, not only the retreat force based on the elastic restoration of the conventional seal ring 40 but also the protrusion 32
Since a retraction force based on zero elastic restoration acts on the piston 26, the piston is separated from the friction surface of the brake disc 10 in the disc axial direction to a greater extent than usual, and this increased separation distance causes the brake to have a large stroke. increases to That is, the cross-sectional area of the hydraulic fluid chamber of the mask cylinder that generates brake hydraulic pressure when the driver depresses the brake pedal is much smaller than the cross-sectional area of the cylinder 38, and moreover, the hydraulic fluid chamber of one mask cylinder Since normally two disc brake cylinders 38 are connected to the chamber, if the above-mentioned separation distance increases even slightly compared to the conventional case, the corresponding stroke of the mask cylinder and therefore the amount of depression of the brake pedal will increase significantly. be. Therefore, even a driver who is extremely inattentive or insensitive to changes in conditions, or even a driver who lacks knowledge of vehicle structure, can reliably detect an abnormal increase in the amount of brake pedal depression. As a result, it is effectively avoided that the friction lining 22 is used to the point of complete wear, leading to a reduction in braking performance and damage to expensive brake discs.

In addition, in the above embodiment, the brake/hoods 16 and 18
The protrusion 32 at the tip of the arm 30 provided on the shim 28 is configured to elastically bend or deform when the arm wears beyond the wear limit. It is also possible to configure the arm 30 itself to bend or deform together with the protrusion 32 to store elastic energy.
Furthermore, the protrusion 32 may be designed to be relatively rigid so that the piston 26 is retracted by bending or deforming the arm 30 without deforming the protrusion. In addition, the above brake
In order to make the driver more reliably aware of the large increase in stroke of the brake pedal caused by excessive wear of the brake pedal, a switch etc. that detects the position of the brake pedal is installed and a buzzer and alarm lamp are activated. Auxiliary alarm means such as the above can be installed in parallel, and furthermore, the present invention can be used in combination with conventional diaphragm type acoustic alarm means.

('Effects of the Invention) As described above, the disc brake device according to the present invention has a structure on the outer periphery of the brake disc that is slidable in the disc axial direction but not substantially rotated around the disc axis. a pair of calipers housed in the caliper and placed opposite to each other on both sides of the outer circumferential portion of the brake disc, and pressed against the side surfaces of the disc by a hydraulic response device provided in the caliper; brake pads,
and a shim interposed between the hydraulic response device and a brake disc adjacent to the device, wherein the shim is provided with an arm extending toward the brake disc, Insert the protrusion at the tip into the opening provided in the bridge section spanning the brake disc of the caliper,
When the above friction lining wears beyond a preset wear limit, the protrusion comes into contact with the opening side edge of the bridge section due to the application of the brake, causing the protrusion or (and) the arm to become elastic. It is characterized by a structure that can be deformed, and has a simple structure in which an arm with a protrusion is attached to a shim that is conventionally provided mainly to prevent brake squeal.
This has the advantage of being able to effectively warn of excessive wear on the joints.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part showing an embodiment of the present invention, FIG. 2 is a front view of the shim 28 in FIG. 1, and FIG. 3 is a front view of the shim 28 in FIG. FIG. 3 is a longitudinal cross-sectional view showing a state in which the brake is applied when the brake is worn. 10... Brake disc, 12... Caliper 1
6 and 18...Brake pad, 20...Back grate, 22...Friction lining, 24...Hydraulic pressure response device, 26...Piston, 28...Shim, 30...
...Arm, 32...Protrusion, 34...Bridge part, 36
...Opening, 38...Cylinder. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] a caliper disposed astride the outer circumferential portion of the brake disk so as to be slidable in the disk axis direction but not substantially rotated around the disk axis; an outer circumferential portion of the brake disk housed within the caliper; a pair of brake pads arranged oppositely on both sides and pressed against the side surfaces of the disc by a hydraulic response device provided in the caliper;
and a shim interposed between the hydraulic response device and a brake pad adjacent to the device, wherein the shim is provided with an arm extending toward the brake disc, The protrusion at its tip is inserted into the opening provided in the bridge section spanning the brake disc of the caliper, and when the friction lining of the brake pad is worn beyond a preset wear limit, the protrusion is removed by the application of the brake. A disc brake device characterized in that the protrusion or (and) the arm are elastically deformed by coming into contact with the opening side edge of the bridge portion.