JPS6032053B2 - Automatic adjustment device for disc brakes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic adjustment device for adjusting a constant gap between a brake disc and a friction pad in a disc brake. To automatically obtain a large amount of vibration, to eliminate a dragging phenomenon of a friction pad against a brake disk even when the lateral vibration of a rotating brake disk is large, and to prevent wear of the friction pad due to the phenomenon.

It is an object of the present invention to provide the device which is simple in structure and compact in the axial direction. Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The illustrated example is a bicycle disc brake device, where F is a bicycle body supporting a rear wheel A, and D is a rear wheel (not shown) on a rear axle A. A bracket 1 adjacent to one side of the brake disc D is fixed to the vehicle body F.

The bracket 1 has a pair of upper and lower channel-shaped support parts la, l.
b, into which the pair of upper and lower ears 3, 3' of the brake caliper 2 are inserted with some play, and the two support shafts 4, 4' attached to the supports la, lb are inserted. The brake caliper 2 is slidably passed through the ears 3 and 3'.
support.

Both support shafts 4, 4' are arranged parallel to the axis of rotation of the brake disc D, and are guided by them so that the brake caliper 2 can be moved in the direction of the axis of rotation of the brake disc D. Brake gear IJ pa 2 is brake disc D
It has a pair of arm parts 2a and 2b that straddle the part from the left and right,
A hydraulic cylinder 6 connected to the left arm 2a is connected via a hydraulic conduit 5 to a well-known brake master cylinder (not shown).
is formed, and the piston 7 slides thereon via an annular seal ring 8.

Inside the hydraulic cylinder 6 is a fixing pin 1 extending in the axial direction.
3 is arranged without penetrating the piston 7, and the base end of this fixing pin 13 is fixed to the trim of the hydraulic cylinder 6.
A movable friction pad 9 facing the left side of the brake disc ○ is removably connected to the outer end surface of the piston 7 by a screw 10, and at this time, a rotation stopper plate 11 is held between the piston 7 and the friction pad 9. Ru.

A fixed friction pad 9' facing the right side surface of the brake disc D is removably fixed to the right arm 2b of the brake cap IJ pad 2 by suitable fixing means. The rotation stopper plate 11 has a stopper claw 11a protruding from its outer peripheral edge.
The movable friction pad 9 and the piston 7 are thereby prevented from rotating.

A large diameter recessed hole 17 is provided at the center of the inner end surface of the piston 7, and a small diameter recessed hole 18 is provided at the center of the bottom of the recessed hole 17. be accommodated.

The regulating plate 14 is made of synthetic resin and is formed into an annular shape as a whole, and is loosely inserted into the fixing pin 13, and has an inner circumferential end.
A plurality of elastic chuck claws 14a are integrally provided, which protrude substantially in the axial direction toward the trimming of the hydraulic cylinder 6, and whose protruding ends e cooperate with each other to perform a clamping action. Further, a cylindrical reinforcing flange 14b is integrally provided on the outer peripheral edge of the regulating plate 14. Therefore, a plurality of elastic chuck jaws 1
4a has each protruding end portion e in frictional contact with the fixing pin 13 to hold the pin 13 in place. Therefore, the regulating plate 14 is frictionally coupled to the fixing pin 13 via its elastic chuck claw 14a. The tip of the fixing pin 13 is received in the small diameter concave hole 18 so as not to interfere with the operation of the piston 7. A stop plate 19 that can engage with the reinforcing flange 14b and limit the axial displacement of the regulating plate 14 to a certain amount s is fixed to the inner surface of the recessed hole 17. Between 19 and 19, there is installed a coil type tuft 20 that forces the regulating plate 14 toward the bottom of the recessed hole 17.

A through hole 19a is bored in the center of the contact plate 19, into which the elastic chuck claw 14a enters. Thus, the displacement amount s of the regulating plate 14 becomes the specified deformation amount of the return spool 20. In the above, the chuck claw 14a of the regulating plate 14 and the fixing pin 13
If the frictional resistance between the piston 7 and the hydraulic cylinder 6 is F, the spring force of the return spring 20 is F2, and the frictional resistance between the piston 7 and the hydraulic cylinder 6 is F3, then
They are set so that the following relationship holds.

F,>F2>F3 Next, to explain the operation of this embodiment, if oil is supplied to the hydraulic cylinder 6 by operating the brake master cylinder (not shown), the piston 7 moves to the right in Fig. 2 due to the oil pressure. Press the movable friction pad 9 onto the left side of the brake disc ○.

Then, the reaction force causes the brake caliper 2 to move against the support shaft 4.
, 4' to the left to press the fixed friction pad 9' onto the right side surface of the brake disc ○. In this way, the brake disc D is braked by equally receiving the frictional braking force from both friction pads 9, 9'. In this case, the relative displacement between the piston 7 and the hydraulic cylinder 6 in the hoe direction causes a relative displacement between the contact plate 19 and the fixing pin 13, and as a result, the relationship of F and > F2 in the previous equation does not initially return. 20 is compressed and deformed,
After the deformation reaches the specified amount s, that is, after the regulation plate 14 comes into contact with the support plate 19, as the relative displacement between the piston 7 and the hydraulic cylinder 6 progresses, the chuck claw 14a,
Therefore, slippage occurs between the regulating plate 14 and the fixing pin 13 in all axial directions.

Therefore, it is necessary to release the braking of the brake disc D. If the master cylinder is deactivated and the hydraulic pressure in the hydraulic cylinder 6 is released, there is The piston 7 is moved through the twill plate 19 by the spring force of the return spring 20 without causing any slippage.
is retracted, and the amount of retraction does not exceed the amount of restoration of the return 20, that is, the specified amount of deformation s.

As a result, a gap corresponding to the specified amount of deformation s of the return spring 20 is obtained between the brake disc ◯ and the friction pads 9, 9'. Incidentally, in the above operation, the frictional resistance between the chuck claw 14a and the fixed pin 13 is different when the piston 7 moves forward and when it retreats. That is, the elastic chuck claws 14
a extends from the inner circumferential end of the regulating plate 14 loosely inserted into the fixed pin 13 toward the end wall of the hydraulic cylinder 6 in the substantially axial direction thereof, and the elevating device part e is exposed to friction against the fixed pin 13. Since they are engaged, when the piston 7 moves forward, the fixed pin 13
The sliding resistance that is applied to the protruding end e of the chuck jaw 14a creates a moment in the extending direction to the chuck jaw 14a, and conversely, when the piston 7 retreats, the sliding resistance applies a moment to the chuck jaw 14a in the continuing direction. Therefore, when the piston 7 is retracting, the chuck jaw 1 is stronger than when it is moving forward.
The frictional resistance F between the fixing pin 4a and the fixing pin 13 tends to increase. As described above, according to the present invention, the brake disc D and the friction pad 9 are provided on the side surface of the brake disc ○.
In a disc brake comprising a brake cap IJ pad 2 having a piston 7 capable of pressing the piston 7 and a hydraulic cylinder 6 with which the piston 7 slides, a fixing pin 13 is arranged in the hydraulic cylinder 6 in all directions of its axis. A recessed hole 17 that is fixed to the end of the hydraulic cylinder 6 and receives the tip of the fixing pin 13 is provided in the inner end surface of the piston 7, and in the recessed hole 17 is formed an annular ring. Synthetic resin regulation plate 1
4, and a plurality of elastic chuck claws 14a that extend toward the end wall of the hydraulic cylinder 6 and cooperate with each other to frictionally engage the fixing pin 13 are integrally provided at the inner peripheral end of the regulating plate 14. A contact plate 19 is provided protrudingly and fixed to the inner surface of the concave hole 17, and is capable of engaging with the regulating plate 14 to limit the displacement of the plate 14 in the vertical direction to a certain amount s. The regulation plate 14
A return counter 20 is installed vertically in between, and the spring force F2 of the return counter 20 is greater than the frictional resistance F3 between the hydraulic cylinder 6 and the piston 7, and the friction between the fixed pin 13 and the chuck claw 14a is increased. Since the resistance F is set to be larger than the spring force F2 of the return imitation 20, the fixing pin 13,
Due to the cooperative action of the regulating plate 14, the support plate 19, the return copy 20, etc., the piston 7 can be automatically and reliably retreated by a certain amount s whenever the brake is released, and the amount of retreat is equal to the return amount. This can be achieved by selecting the prescribed deformation allowance of the imitation 20, and as a result, the gap between the brake disc D and the friction pad 9 can be made sufficiently large, and even when the lateral vibration of the brake disc D is large, the gap between the friction pad 9 and the brake disc D can be sufficiently large. The friction phenomenon can be eliminated and the friction wear can be prevented, and the piston 7 can be operated with a constant operating stroke of the brake operating member regardless of the wear of the friction pad 9, so that braking can always be performed appropriately. can.

In particular, although the synthetic resin regulation plate 14 is itself a single component, it functions as a friction member that frictionally engages with the fixing pin 13 and as a spring receiving part on which the return ring 20 is seated. Since it is possible to simultaneously achieve the functions of a spring deformation limit regulating member that cooperates with the bale board 19 to determine the prescribed deformation distance of the return imitation 20, the number of parts is small, the structure is simple, and the manufacturing and roughness are reduced. It is easy to attach and can reduce manufacturing costs.

Furthermore, the elastic chuck claws 14a are inserted into the through holes 19a formed in the contact plate 19 to prevent the claws 14a from interfering with the bale board 19, so that the chuck claws 14a
Even if it is extended long in the direction of the cylinder 6, the axial thickness of the movement space of the regulating plate 14 in the concave hole 17, that is, the distance between the bale board 19 and the bottom surface of the concave hole 17, is determined by the total length of the regulating plate 14 in the vertical direction. Therefore, even though the regulating plate 14 and the like are built into the piston 7, the piston 7 will not become too long in the axial direction, which can contribute to making the disc brake device more compact. It is something.

In particular, the plurality of elastic chuck claws 14a are
Hydraulic cylinder 6 from the inner peripheral machine of regulating plate 14 loosely inserted into
They protrude toward the machine wall approximately in the axial direction, and the protruding ends e frictionally engage with the fixed pin 13, so that when the piston 7 moves forward and backwards, the chuck pawl 14a and the fixed pin 13 is different, that is, when the piston 7 moves forward, the fixed pin 13 touches the protruding end e of the chuck claw 14a.
When the piston 7 retreats, the sliding resistance exerted on the chuck jaws 14a generates a moment in the tightening direction. There is a head direction in which the frictional resistance F between the chuck claw 14a and the fixing pin 13 is greater than when moving forward, and as a result, the piston 7
The forward movement of the piston 7 is carried out smoothly without being hindered by the frictional resistance F, and when the piston 7 is retracted, the chuck claw 14a is securely frictionally engaged with the fixed pin 13, and the piston 7 is moved forward.
can be reliably moved back by a predetermined amount s using the restoring force of the return imitation 20.

Moreover, since only the protruding ends e of the elastic chuck claws 14a come into frictional contact with the fixing pin 13, the length of the frictional contact portion in the direction of the molding direction can be shortened.
Even if the friction pads 9, 9' are used, there is no fear that the protruding end e will slip out of the fixing pin 13 as the friction pads 9, 9' wear out and the frictional contact area between the two will decrease. The resistance F can always be applied stably.

Due to the shortening effect of the fixing pin 13, the hydraulic cylinder 6
Of course, it is possible to reduce the size of the piston 7, and there is no need for the fixed pin 13 to penetrate the piston 7, and accordingly, there is no need to provide a special sealing means between the fixed pin 13 and the piston 7. The structure is that much simpler and can contribute to cost reduction.

[Brief explanation of drawings]

FIG. 1 is a side view of one embodiment of the device of the present invention, FIG. 2 is a cross-sectional view of the device along the 0-Ro line, and FIG. 3 is a plan view of a regulating plate. 2... Brake gear IJ pa, 6... Hydraulic cylinder, 7.
...Piston, 9...Movable friction pad,
13...Fixing pin, 14...Regulation plate, 14
a...Elastic chuck claw, 19...Abutting plate, 19
a...Through hole, 20...Return imitation, D...Brake disc, e...Extruded end. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A disc brake consisting of a brake disc D, a brake caliper 2 equipped with a piston 7 capable of pressing a friction pad 9 against the side surface of the brake disc D, and a hydraulic cylinder 6 with which the piston 7 slides, in which the hydraulic cylinder a fixing pin 13 arranged in its axial direction within 6;
is fixed to the end wall of the hydraulic cylinder 6, and its fixing pin 1
3 does not pass through the piston 7.
A recessed hole 17 for receiving the tip of the piston 7 is provided in the inner end surface of the piston 7, and a synthetic resin regulating plate 14 formed in an annular shape and loosely inserted into the fixing pin 13 is inserted into the recessed hole 17. The hydraulic cylinder 6 is housed at the inner peripheral end of the regulating plate 14.
A plurality of elastic chuck pawls 14a are integrally protruded from each other in the substantially axial direction toward the end wall of the chuck, the respective protruding ends e of which cooperate with each other and frictionally engage with the fixing pin 13,
A contact plate 19 that can engage with the restriction plate 14 to limit the axial displacement of the plate 14 to a certain amount s is fixed to the inner surface of the recessed hole 17, and this contact plate 19 and the restriction plate 14 A return spring 20 is compressed in between, and the chuck pawl 14a is attached to the abutting plate 19.
The spring force F_2 of the return spring 20 is made larger than the frictional resistance F_3 between the hydraulic cylinder 6 and the piston 7, and the frictional resistance between the fixing pin 13 and the chuck pawl 14a is made. An automatic adjustment device for a disc brake in which F_1 is set larger than spring force F_2 of the return spring 20.