JPH0137241Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disc brake for a vehicle equipped with an automatic braking gap adjustment device.

[Conventional technology]

Traditionally, disc brakes installed on the rear wheels of vehicles have a hydraulic actuation mechanism operated by hydraulic pressure from a master cylinder, as well as those with a mechanical parking brake mechanism installed in parallel to the caliper cylinder. Some parking brake mechanisms are provided with an automatic braking gap adjustment device between the parking brake mechanism and the piston to compensate for displacement of the piston due to wear of the pads.

Figure 3 shows the Utility Development Act filed in 1986-
This shows the main parts of the automatic braking gap adjustment device disclosed in Publication No. 40835. A piston 3 that pushes a friction pad is inserted into a cylinder 2 formed in a caliper 1, and the piston 3 and the cylinder 2 are connected to each other. A hydraulic chamber 4 is defined between the bottom parts.

A pressure fluid introduction hole 5 communicating with the master cylinder is opened in the hydraulic chamber 4, and an automatic braking gap adjustment device 6 is disposed therein.

The adjustment device 6 includes an adjustment nut 7 whose rotation is regulated by the piston 3, an adjustment bolt 8 which is threaded into the nut 7 with a multi-thread screw, and a cylinder 2.
It consists of a sleeve piston 10 whose rotation is regulated by a pin 9 at the bottom and which clutch-engages with the outer periphery of the flange 8a of the adjusting bolt 8.
A bearing 11 is encircled at the stepped portion between the shaft portion 8b and the flange 8a of the adjustment bolt 8, and the adjustment bolt 8 is moved through a flat spring guide 12 mounted on the bearing surface of the bearing 11. cylinder 2
The coil spring 15 is always urged in the anti-piston direction by the elastic force of a tapered coil spring 15, which is compressed between the spring retainer 14 and the circlip 13 of the piston.

Further, a circumferential groove 10a is formed on the outer periphery of the sleeve piston 10, and a stopper portion 16a of a stopper member 16 that is engaged with the circumferential groove 10a regulates the moving distance of the adjustment bolt and the sleeve piston.

[Problem that the invention attempts to solve]

However, even when the braking gap is set wider than the set value in order to improve the workability of the disk ring during installation of the vehicle body, the adjustment bolt does not work properly during a test in which the brake is hydraulically operated. The purpose is to prevent leakage of hydraulic fluid and damage to the sealing member attached to the head of the adjuster bolt when it separates from the sleeve piston. The bearing that supports the coil spring could not be installed smoothly, making it impossible to improve the installation process.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic braking gap adjustment device that combines a sleeve piston, an adjusting bolt, and a bearing into a unit, thereby improving assembly work.

[Means for solving problems]

This invention was made in view of the above-mentioned purpose,
A piston is inserted into the cylinder of the caliper to define a hydraulic chamber at the bottom of the cylinder, an adjustment nut whose rotation is regulated by the piston within the hydraulic pressure chamber, and an adjustment bolt screwed into the adjustment nut.
It also incorporates an automatic braking gap adjustment device that includes a sleeve piston that engages with the clutch flange of the adjustment bolt, and a bearing supported on the flange of the adjustment bolt and a spring retainer that is hooked to the cylinder. In an automatic braking gap adjustment device for a vehicle disc brake that biases an adjuster bolt in the counter-piston direction by compressing a coil spring between the parts, a bearing retainer having a locking part and a pressing part is formed. The locking portion of the bearing holder is locked to the sleeve piston, and the pressing portion is hooked to the bearing to press the bearing against the flange of the adjustment bolt.

[Effect]

Therefore, the bearing is assembled integrally with the sleeve piston and the adjustment bolt, and can be easily installed in the cylinder.

〔Example〕

An embodiment of the invention will be described below with reference to FIGS. 1 and 2.

The caliper 17 of the disc brake 16 has an action part 17a and a reaction part 17b that push a pair of friction pads 19 and 20 that are arranged oppositely on both sides of the brake disc 18, and a bridge part that straddles the brake disc 18 and connects these parts. 17c, and is provided on a bracket 21 fixed to the vehicle body so as to be movable in the disk axial direction by being guided by a sliding pin.

The actuating portion 17a of the caliper 17 is formed with a cylinder 22 that is open on the brake disk 18 side, and a small cylinder 23 that is continuous with the cylinder 22. A rotating shaft 24 of a mechanical parking brake is attached to the rear of the small cylinder 23. A mounting hole 25 is provided in a direction perpendicular to the cylinder axis.

Inside the cylinder 22, there is a tip-shaped piston 26.
However, when the bottom portion 26a is directed toward the brake disc 18,
The piston 26 is fitted liquid-tightly and movably through the corner seal 22a, and the piston 2
6 and the bottom of the cylinder 22, a hydraulic chamber 27 is defined.

The hydraulic chamber 27 is provided with an introduction hole 28 for introducing pressure fluid from the master cylinder, and also has a braking gap that compensates for the amount of wear on the friction pads 19 and 20 and automatically sets a certain braking gap. An automatic adjustment device 29 is provided.

The adjusting device 29 includes an adjusting nut 31 whose rotation is regulated by the piston 26 and urged toward the bottom of the piston 26 by a spring 30, an adjusting bolt 32 which is threaded into the nut 31 with a multi-thread screw, and a cylinder 22. It consists of a sleeve piston 34 whose rotation is regulated by a pin 33 at the bottom and which engages with an adjuster bolt 32 as a clutch.

The head of the adjusting bolt 32 disposed on the bottom side of the cylinder 22 has a fitting shaft portion 32b fitted with a cup seal 32a, and a tapered surface 32c on the outer periphery.
A bearing 35 is mounted on the step between the flange 32d and the shaft portion 32e, a spring guide 36 is attached to the bearing surface of the bearing 35, and a circlip is fitted to the cylinder 22. Spring retainer 38 hooked to 37
A tapered coil spring 39 is compressed between the piston and the piston to constantly bias the adjustment bolt 32 in the counter-piston direction.

The sleeve piston 34 consists of a large diameter part 34a disposed within the cylinder 22 and a small diameter part 34b fitted into the small diameter cylinder 23 in a fluid-tight and movable manner.
A tapered hole 34c that engages with the clutch is formed on the tapered surface 32c of No. 2, and a fitting hole 34d continuous with the fitting hole 34c into which the fitting shaft portion 32b of the adjusting bolt 32 is fitted. is provided with a spherical recess 34e that engages with one end of the driven rod 40.

A cylindrical rotating shaft 24 is mounted in the mounting hole 25 at the rear of the small diameter cylinder 23 via a bearing 41, and a driven shaft is inserted between the cam groove 24a formed in the shaft 24 and the recess 34e of the sleeve piston 34. A rod 40 is interposed.

The bearing 35 is secured to the adjusting bolt 3 by a bearing retainer 42 that is locked to the sleeve piston 34.
The bearing retainer 42 is a disc with a circular hole 42a in the center, bent into steps, and has a pressing part 42b on the inner circumference and a retaining part on the outer circumference. 42c, and a plurality of locking pieces 42d are continuously formed on the outer periphery of the retaining portion 42c.

Each of these parts constituting the automatic braking gap adjustment device 29 is connected to the fitting shaft portion 32b of the adjuster bolt 32 in the fitting hole 34d of the sleeve piston 34.
The bearing 35 is fitted onto the shaft portion 32e of the bolt 32.
and the bearing holder 42, and the locking piece 42d of the bearing holder 42 is inserted into the large diameter portion 3 of the sleeve piston 34.
The sleeve piston 34, adjustment bolt 32, and bearing 35 are integrally combined by being engaged with the recess 34f formed on the outer periphery of the sleeve piston 4a.

The disc brake of this embodiment is constructed as described above, and when the brake is operated by the foot pedal, the pressure fluid introduced from the master cylinder into the hydraulic pressure chamber 27 through the introduction hole 28 pushes the piston 26 toward the brake disc. The caliper 17 moves to press one friction pad 19 against the brake disc 18, and further moves in the direction of the acting part 17a by this reaction force.
The reaction portion 17b presses the other friction pad 20 against the brake disc 18 to perform a braking action.

In addition, when the brake cable is pulled by operating the handbrake lever, the rotating shaft 24 attached to the rear end of the caliper 17 rotates and pushes the driven rod 40 toward the brake disc. do. The thrust caused by this pushing motion is transmitted to the piston 26 via the sleeve piston 34, the adjusting bolt 32, and the adjusting nut 31, and pushes the piston 26 toward the brake disc, thereby releasing both friction pads in the same way as in the hydraulic operation. 19,20 to brake disc 18
Pressure contact is applied to perform braking action.

When the braking gap between the brake disc 18 and both friction pads 19 and 20 is a predetermined amount, the piston 26 and the adjusting nut 31 disposed integrally with the piston 26 are operated by hydraulic fluid to compensate for the backlash of the adjusting bolt 32. A braking operation is performed by moving toward the brake disc.

Also, due to repeated braking, the friction pads 19, 2
0 wears out and the braking gap widens beyond a predetermined amount, the piston 26 and the adjusting nut 31 move forward, and the tapered surface 3 of the adjusting bolt 32
2c, and the tapered hole 34c of the sleeve piston 34.
The clutch engagement with is released, and the adjustment bolt 32 is moved by the biasing force of the coil spring 39.
The tapered surface 32c is extended until it engages with the tapered hole 34c of the sleeve piston 34, compensating for the amount of wear on the friction pads 19, 20, and when not braking, a predetermined braking gap is set by the restoring force of the square seal 22a. Ru.

In this embodiment, the bearing 35 is integrally assembled with the sleeve piston 34 and the adjusting bolt 32 by the bearing holder 42 to form a unit, so that it can be easily assembled into the cylinder 22 and removed during disassembly work. Furthermore, the pressing portion 42b of the bearing presser 42 can prevent the balls of the bearing 35 from falling off.

Furthermore, since the retaining portion 42c of the adjusting bolt 32 is provided on the bearing retainer 42, the fitting shaft portion 32b of the adjusting bolt 32 will not come out of the fitting hole 34d of the sleeve piston 34, and the fitting shaft portion 32b will not come out. Damage to the attached cup seal 32a and leakage of the hydraulic fluid can be prevented.

[Effect of idea]

As explained above, the automatic braking gap adjustment device for disc brakes of the present invention locks a bearing holder to the sleeve piston that engages with the clutch flange of the adjusting bolt, and the pressing part of the bearing holder
Since the coil spring for biasing the adjustment bolt is hooked onto the bearing that supports it and the bearing is pressed against the flange of the adjustment bolt, the bearing can be assembled together with the sleeve piston and adjustment bolt to form a unit. This makes it easy to assemble into the cylinder and remove during disassembly, improving work efficiency.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
Figure 1 is a cross-sectional front view of a disc brake equipped with a mechanical parking brake and an automatic braking gap adjustment device, Figure 2 is an enlarged view of the main part of Figure 1, and Figure 3 is a cross-sectional view of the main part showing a conventional example. be. 16... Disc brake, 17... Caliper, 18... Brake disc, 22... Cylinder, 22a... Square seal, 24... Rotating shaft, 25
... Mounting hole, 26 ... Piston, 27 ... Hydraulic pressure chamber, 28 ... Introduction hole, 29 ... Braking gap automatic adjustment device, 31 ... Adjustment nut, 32 ... Adjustment bolt, 32c ... Tapered surface, 32d...
Flange, 32e...Shaft portion, 34...Sleeve piston, 34c...Tapered hole, 35...Bearing, 3
8... Spring retainer, 39... Coil spring, 42... Bearing holder, 42b... Pressing part,
42c... Retaining part, 42d... Locking piece.

Claims (1)

[Scope of utility model registration request] A piston is inserted into the cylinder of the caliper to define a hydraulic pressure chamber at the bottom of the cylinder, and an adjustment nut whose rotation is regulated by the piston within the hydraulic pressure chamber;
A bearing supported by the flange of the adjusting bolt, which incorporates an automatic braking gap adjustment device including an adjusting bolt that is threadedly engaged with the adjusting nut, and a sleeve piston that engages with a clutch flange of the adjusting bolt; In an automatic braking gap adjustment device for vehicle disc brakes, a coil spring is compressed between a spring retainer that is latched to a cylinder, and the adjustment bolt is biased in the opposite direction to the piston. and a pressing part, and the locking part of the bearing holder is locked to the sleeve piston, and the pressing part is latched to the bearing to press the bearing against the flange of the adjusting bolt. An automatic braking gap adjustment device for vehicle disc brakes featuring: