JPS6221148Y2 - - Google Patents

Description

[Detailed description of the invention] This invention has a multi-thread threaded part facing the piston and rotates in accordance with the hydraulic pressure within a hydraulic pressure chamber defined by a piston fitted in a cylinder with restricted rotation. Alternatively, a clutch part whose rotation is regulated is placed on the cylinder side, and an adjusting mechanism is built in, and a rod that is engaged with the camshaft to restrict its rotation is attached to the head of an adjusting bolt that rotates when the clutch operates. This invention relates to an automatic braking gap adjustment device for a vehicle brake that is capable of mechanical braking operation by rotating a camshaft.

The feature of this invention is that it is an automatic braking gap adjustment device for vehicle brakes that has this kind of adjuster mechanism and can be operated hydraulically by hydraulic pressure from the master cylinder and mechanically by mechanical force from the handbrake lever. A coil spring that urges the adjustment bolt toward the rear of the cylinder is wound around the adjustment bolt, and a retainer is provided that includes the coil spring, and the retainer includes:
The adjusting bolt has a flange which is shaped like a slit and has an opening at one end that can be folded back radially outward and compressively deformed radially inward by the slit, and a straight shaft of the adjusting bolt that holds a bearing at the bottom of the other end. The flange portion of the retainer is fitted into a groove formed in the small diameter portion of the cylinder, and the head of the adjusting bolt hits the flange portion and advances. The purpose of the present invention is to provide an abutment stopper for regulating the amount, and one end of the coil spring is brought into contact with the head of the adjusting bolt, and the other end is brought into contact with the bottom of the retainer via the bearing. The reason for this is that the coil spring rotates together with the adjustment bolt without galling or damaging the bearings, preventing adjustment defects, and preventing the adjustment bolt from moving further than necessary, and preventing it from falling out of the cylinder. To provide an automatic braking gap adjustment device for vehicle brakes that is free from the risk of damage.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a disc brake will be described below with reference to the drawings.

The caliper 1 consists of an actuating part 1a, a counter-actuating part 1b, and a bridge part 1c connecting these parts.The caliper 1 straddles the disk 2 by the bridge part 1c, and is provided on a bracket 3 so as to be movable in the disk axial direction. A cylinder 4 which is open on the disk 2 side is formed in the actuating part 1a, and a pot-shaped piston 5 is tightly and slidably fitted into the large diameter part 4a of the cylinder 4 by means of a piston seal 6. As a result, a hydraulic pressure chamber 7 is defined within the cylinder 4, and the hydraulic pressure chamber 7 is defined by a fluid communication hole 8 communicating with a master cylinder (not shown).
Pressure fluid is supplied inside. Friction pads 9, 9' are arranged on both sides of the disk 2. The cylinder-side friction pad 9 is supported by the bracket 3 so that it can move in the disk axial direction, but its rotation is restricted, and the other friction pad 9' is engaged with the reaction portion 1b.

The piston 5 has a recess 5 formed in the head 5a.
b fits into a corresponding convex portion 9b formed on the back plate 9a of the friction pad 9 and abuts against the back plate 9a. As a result, the piston 5 pushes the friction pad 9 in the disk axial direction, but its rotation is restricted by the friction pad 9.

An adjuster 12 consisting of an adjuster bolt 10 and a nut member 11 is built in the hydraulic pressure chamber 7, and the nut member 11 has a multi-thread internal thread 11a, and the small diameter shaft of the adjuster bolt 10 has a multi-thread internal thread 11a. A multi-thread male thread 10a is formed respectively, and both 11a and 10a are threaded together with a multi-thread thread with a small threading gap.

A protrusion 11c formed in the radial direction on the lower side of the head 11b of the nut member 11 is connected to the piston 5.
The head 11b of the nut member 11 abuts the inner surface of the piston 5, and the head 11b of the nut member 11 contacts the inner surface of the piston 5. The tip of the bolt 10 is fitted into the hole 5c with some play so as not to interfere with the piston 5. From this, nut member 1
The rotation of the piston 1 is restricted by the piston 5, and an upper groove portion in which the protrusion 11c formed on the inner surface of the piston 5 is not fitted serves as an air vent passage 13.

One end of the first coil spring 14 wound around the shaft of the nut member 11 is attached to the head 11 of the nut member 11.
b, the other end is brought into contact with a seat stopper 15 fitted to the inner periphery of the cylindrical portion 5e of the piston 5 via a spring seat 16, whereby the nut member 11 is urged toward the disk, and its The front surface of the head 11b is in contact with the inner surface of the piston 5. An air exhaust groove 17 is formed in the inner surface of the cylindrical portion 5e of the piston 5 in the axial direction of the piston to be deeper than the seat stopper 15 and to straddle this.

The head 10b of the adjusting bolt 10 is tightly fitted into the small diameter portion 4b of the cylinder 4 by a cup 18 so as to be slidable and rotatable. At the rear of this cylinder small diameter part 4b, a cylindrical rear wall 1d is formed perpendicularly to the small diameter part 4b, integrally with the actuating part 1a, and communicating with the small diameter part 4b. 19 are rotatably fitted through two bearings 20, large and small.

A rod 23 is interposed between a recess 21 formed in the head 10b of the adjusting bolt 10 and a cam groove 22 formed in the axial direction of the camshaft 19. This rod 23 has a spherical shape on the adjuster bolt side and a wedge shape on the camshaft side.
The adjustment bolt 10 is allowed to rotate at a, but
The rotation of the rod 23 itself is restricted by the wedge-shaped portion 23b, and is pushed by the rotation of the camshaft 19 to push the adjustment bolt 10, thereby converting the rotation of the camshaft 19 into a propulsion force in the braking direction.
A grease discharge passage 21a is formed in the recess 21 of the adjusting bolt head 10b in the shape of a groove and communicating with the rear chamber 24 from the bottom to prevent grease from adversely affecting the clutch action of the adjusting bolt 10. There is.

The spring retainer 25 has a slit-like shape, and has a flange portion 25b that can be folded radially outward at an opening 25a at one end and compressively deformed radially inward by the slit, and a bottom portion 25 at the other end.
c has a guide portion 25d folded back inward in the axial direction, and a bearing 2 is provided on the bottom portion 25c.
Holds 7. The spring retainer 25 is inserted into the small diameter straight shaft portion 10c of the adjusting bolt 10, and is attached by fitting the flange portion 25b into the groove 4c formed in the small diameter portion 4b of the cylinder 4, and the guide portion 25d is attached to the small diameter straight shaft portion 10c. The adjustment bolt 10 is rotatably and slidably guided by the portion 10c to prevent vibration of the adjustment bolt 10 that occurs during operation.

Small diameter straight shaft part 1 of adjusting bolt 10
A second coil spring 26 is wound around 0c,
One end thereof directly contacts the head 10b of the adjusting bolt 10, and the other end contacts the bottom 25c of the spring retainer 25 via a bearing 27. As a result, the adjusting bolt 10 is biased toward the rear of the cylinder by the second coil spring 26, and when the adjusting bolt 10 is pushed out and moves forward by compressing the second coil spring 26, its head 10b The head 10b abuts against the flange portion 25b, restricts its advancement amount to a predetermined set value, and prevents the head 10b from falling off from the small diameter portion 4b of the cylinder 4.

A lever 28 is fixed to the base 19a of the camshaft 19 by a nut 29, and when this lever 28 is rotated in the direction A in FIG. 3, the camshaft 19 is rotated counterclockwise in FIG. 2, and the handbrake is activated. When the brake is applied and the brake is released, the return spring 30 rotates in the direction B and returns to the original position.

Next, the operation of this embodiment will be explained.

When the pressure fluid from the master cylinder is introduced into the hydraulic chamber 7 through the fluid passage hole 8, the piston 5 moves to the left in FIG. 2 and presses one friction pad 9 against one side of the disk 2. As a result, the caliper 1 moves in the opposite direction to the right, and the reaction part 1b presses the other friction pad 9' toward the other side of the disk 2, thereby producing a braking action.

Assuming that the hydraulic pressure at this time is _P1 , as the piston 5 moves forward, the nut member 11 also moves forward together with the first coil spring 14, but this amount of movement is due to the multi-thread internal thread 11a of the nut member 11. This is the amount to fill the gap between the adjustment bolt 10 and the multi-thread male thread 10a, and since no axial force is generated that acts on the multi-thread threaded part, no rotational torque is generated, and therefore the adjustment bolt 10, the braking action is performed without rotation.

Then, when a hydraulic pressure P ₂ higher than the hydraulic pressure P ₁ is supplied into the hydraulic pressure chamber 7, the nut member 11 advances together while maintaining the engaged state with the piston 5, and the nut member 11 and the adjuster The clearance for threading the multi-thread screw with the bolt 10 disappears, and a hydraulic pressure higher than the hydraulic pressure _P1 is generated to the right, generating a force that moves the adjusting bolt 10 to the right, and the multi-thread screw is tightened. Axial force is generated at the joint, and this axial force generates rotational torque. This rotational torque becomes a force that tends to rotate the adjustment bolt 10 because the nut member 11 is engaged with the piston 5 and its rotation is restricted.

The force that tries to restrict the rotation of the adjustment bolt 10 at this time, that is, the frictional resistance between the cylinder small diameter portion 4b and the head 10b and cup 18 of the adjustment bolt 10, The frictional resistance between the adjusting bolt and the spherical portion 23a of the second coil spring 23 is extremely small, and the rotational torque generated by the hydraulic pressure _P2 is set to be larger than this frictional resistance. They rotate together, the screwing state of the nut member 11 and the adjuster bolt 10 changes, and the adjuster 12 extends. Then, when the supply of pressure fluid is released, the piston 5 attempts to return to its original position by the piston seal 6, but is restricted by the extended adjuster 12, and the braking gap between the disc 2 and the friction pads 9, 9' is automatically adjusted to remain constant.

Next, when a hydraulic pressure P ₃ higher than the hydraulic pressure P ₂ is supplied into the hydraulic pressure chamber 7, the axial force acting on the multi-thread threaded joint between the nut member 11 and the adjusting bolt 10 Therefore, the generation of rotational torque is caused by the hydraulic pressure
Same as P ₂ , but adjusting bolt 10
The force pushing the rearward part of the cylinder, that is, to the right in Fig. 2, increases, and the adjusting bolt head 1
The concave portion 21 of the rod 23 is strongly pressed against the spherical portion 23a of the rod 23 to increase frictional resistance. As a result, the frictional resistance that attempts to restrict the rotation of the adjuster bolt 10 becomes greater than the rotational torque, and the adjuster bolt 10 no longer rotates.

Since the nut member 11 is engaged with the piston 5 in a concave and convex manner, even if the high hydraulic pressure P ₃ occurs or the caliper 1 etc. is deformed at this time, the nut member 11
does not rotate, and only the piston 5 compresses the first coil spring 14 and moves forward. This creates a gap between the inner surface of the piston 5 and the head 11b of the nut member 11, but the protruding strip 11c of the head 11b is set so as not to disengage from the groove 5d of the piston 5. , the nut member 11 does not rotate and adjust.

In this way, high hydraulic pressure _P3 is supplied into the hydraulic pressure chamber 7, and the piston 5 is also deformed by the caliper 1 etc.
Even if P2 advances excessively from inside the cylinder 4, the adjuster 12 will not extend at any pressure other than the set hydraulic pressure _P2 . Adjustment is prevented.

Next, the handbrake action will be explained.

When you pull the handbrake lever (not shown),
The lever 28 receives this mechanical force and rotates in the direction A in FIG. 3. As a result, the camshaft 19 rotates counterclockwise in FIG.
The rod 23 is pushed to the left, which causes the piston 5 to be pushed by the adjuster 12 and move forward to the left, pressing one of the friction pads 9 against one side of the disk 2, and this reaction causes the caliper to move forward. 1 moves to the right in the opposite direction and presses the other friction pad 9' against the other side of the disc 2, applying the handbrake.

At this time, the spherical portion 23a of the rod 23 presses against the recess 21 of the adjusting bolt head 10b, and the frictional resistance between them increases, so that the adjusting bolt 10 does not rotate. Therefore, the state of the multi-thread screw engagement between the nut member 11 and the adjuster bolt 10 does not change, and the adjuster 12 does not shrink.

The amount of advance of the adjuster bolt 10 at this time is within a range in which the head 10b does not hit the flange portion 25b of the spring retainer 25, and when an excessive advance force is applied from the camshaft 19, the head 10b does not reach the flange portion 25b. It abuts against the portion 25b and restricts its advance, thereby preventing it from falling off from the cylinder small diameter portion 4b and from adversely affecting the operating mechanism of the adjusting bolt 10.

As described above, the present invention is a spring retainer in which one end of the coil spring that urges the adjusting bolt toward the rear of the cylinder is in contact with the head of the adjusting bolt, and the other end is locked by fitting the flange part into the cylinder. The bearing is in contact with other components through the bearing, and the advance amount of the adjustment bolt is regulated by the abutment stopper provided on the cylinder, so the bearing will not come into contact with or interfere with other components.
Since the bearings are not galled or damaged, the coil spring rotates smoothly together with the adjustment bolt, preventing adjustment defects, and preventing the adjustment bolt from advancing more than necessary. There is no risk of it falling off the cylinder. Further, as mentioned above, the unique single retainer has the function of guiding the adjustment bolt and the function of holding the bearing.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a front view, Fig. 2 is a cross-sectional side view taken from Fig. 1,
3 is a side view of the camshaft mounting portion, FIG. 4 is a partially cutaway perspective view of the camshaft mounting portion, and FIG. 5 is a sectional side view of the main parts of the present invention. 1 is the caliper, 4 is the cylinder, 4b is the small diameter part,
4c is a groove, 10 is an adjustment bolt, 10b is a head, 10c is a small diameter straight shaft portion, 25 is a spring retainer, 25b is a flange portion, 25c is a bottom portion, 25d is a guide portion, 26 is a second coil spring, 27 is a It's a bearing.

Claims (1)

[Scope of utility model registration request] An adjuster mechanism having an adjuster bolt and a nut member screwed into the adjuster bolt with a multi-thread screw is built into the hydraulic pressure chamber defined by a piston fitted in a cylinder with restricted rotation. The joint part is placed on the piston side, and the clutch part, which rotates or whose rotation is regulated according to the hydraulic pressure, is placed on the cylinder side, and the head of this rotatable and slidable adjustment bolt is placed on the camshaft to restrict its rotation. In a vehicle brake cylinder device that is capable of mechanical braking action by rotation of a camshaft by abutting an engaged rod, a coil spring is wound around the adjustment bolt to bias the adjustment bolt toward the rear of the cylinder. and a flange portion which is folded radially outward at one end opening and can be compressed and deformed radially inwardly by the slit; The other end has a guide part that holds a bearing at the bottom part and rotatably and slidably guides the straight shaft part of the adjusting bolt, and the flange part of the retainer fits into a groove formed in the small diameter part of the cylinder. The flange portion is used as an abutment stopper against which the head of the adjustment bolt abuts and limits the amount of advancement thereof, and one end of the coil spring is brought into contact with the head of the adjustment bolt, and the other end is connected via the bearing. An automatic braking gap adjustment device for a vehicle brake, characterized in that the device is brought into contact with the bottom portion of the retainer.