JPS6144016Y2 - - Google Patents

Description

[Detailed description of the invention] This invention incorporates an adjuster consisting of an adjuster bolt and a nut member screwed onto the adjuster bolt with a multi-thread screw, in a hydraulic pressure chamber defined by a piston fitted in a cylinder. Regulates the rotation of the nut member,
On the other hand, the present invention relates to an automatic braking gap adjustment device for a vehicle brake that rotates an adjuster bolt using hydraulic pressure, thereby extending an adjuster.

The feature of the present invention is that in this type of automatic braking gap adjustment device, a flange formed at the opening of a spring retainer is engaged with the cylinder, and a guide portion is folded back inward in the axial direction at the bottom of the spring retainer. The purpose of this is to hold the coil spring, which has one end in contact with the bottom and urges the adjuster bolt toward the rear of the cylinder, and also to guide the adjuster bolt. This prevents the coil spring from coming off or interfering with the adjustment bolt, and also suppresses the vibration of the adjustment bolt as much as possible, ensuring smooth and reliable operation of the adjustment bolt without adversely affecting the cylinder. The braking gap can be adjusted. An object of the present invention is to provide an automatic braking gap adjustment device for a vehicle brake.

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 part 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 screw 10a is formed respectively, and both 11a, 11a are screwed together with a multi-thread screw with a small screwing 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.
Engages with a lower groove portion of groove portions 5d formed above and below the hole portion 5c in the radial direction, which is bored at the center of the hole portion 5c;
The head 11b of the nut member 11 is in contact with the inner surface of the piston 5, and the tip of the adjusting bolt 10 is fitted into the hole 5c with some play so as not to interfere with the piston 5. As a result, the rotation of the nut member 11 is restricted by the piston 5, and the 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, thereby urging the nut member 11 in the direction of the piston. and its head 11
The front surface of b 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, deeper than the seat stopper 15 in the axial direction of the piston, and extending over the seat stopper 15.

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. ing.

The spring retainer 25 has a cup-like shape, and a guide portion 25b that is folded back inward in the axial direction is formed at the bottom portion 25a, while a flange portion 25d that is folded back in the radial direction is formed at the other end opening 25c. is formed, and a plurality of slits 25 are formed in the axial direction from this flange portion 25d.
e is formed.

The spring retainer 25 has its guide portion 25b inserted into the small diameter straight shaft portion 10c of the adjusting bolt 10, and the small diameter straight shaft portion 10c is slidable on the guide portion 25b.
On the other hand, the flange portion 25d is secured to the groove 26 formed inside the mouth end of the cylinder small diameter portion 4b. One end of the second coil spring 27 wound around the small diameter straight shaft portion 10c is in contact with the head of the adjusting bolt 10 via a bearing 28, and the other end is in contact with the bottom portion 25a of the spring retainer 25. Therefore, the adjuster bolt 10 is always urged toward the rear of the cylinder.

A lever 29 is fixed to the base 19a of the camshaft 19 by a nut 30. When the lever 29 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 31 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 disc 2, thereby applying a braking action.

Assuming that the hydraulic pressure at this time is _P1 , the nut member 11 also moves forward together with the first coil spring 14 as the piston 5 moves forward. 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 adjuster bolt 10 at this time, that is, the cylinder small diameter portion 4b
This is the frictional resistance between the head 10b of the adjusting bolt 10 and the cup 18, and the frictional resistance between the concave portion 21 of the head 10b and the spherical portion 23a of the rod ₂₃ is extremely small. Since the resulting rotational torque is set to be larger than these frictional resistances, the adjuster bolt 10 rotates, 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 tries 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 1 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 moves forward against the first coil spring 14. This allows piston 5
Although a gap is created between the inner surface of the nut member 11 and the head portion 11b of the nut member 11, since the protruding line 11c of the head portion 11b is set so as not to disengage from the groove portion 5d of the piston 5, the nut member 11 will not rotate and adjust.

In this way, a high hydraulic pressure _P3 is supplied to the hydraulic chamber 7, and the piston 5 is deformed by the deformation of the caliper 1, etc.
Even if the adjuster 12 extends excessively from within the cylinder 4, the adjuster 12 will not extend unless the hydraulic pressure _P2 is set to a certain pressure, so that excessive adjustment, including deformation of brake components such as deformation of the caliper 1, is prevented.

Next, the handbrake action will be explained.

When you pull the handbrake lever (not shown),
The lever 29 receives these mechanical forces and rotates in the direction A in FIG. As a result, the camshaft 19 rotates counterclockwise in FIG. 9 is pressed against one side of the disk 2, and this reaction causes the caliper 1 to move in the opposite direction to the right, pressing the other friction pad 9' against the other side of the disk 2 to apply 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.

In the present invention, as described above, the flange portion is engaged with the groove of the cylinder to attach the spring retainer, and the guide portion formed at the bottom of the spring retainer holds one end of the coil spring that biases the adjuster bolt toward the rear of the cylinder. The end of the coil spring is regulated by this guide part, so there is no risk of it coming off the bottom of the spring retainer or interfering with the adjustment bolt. In addition, since the guide part guides the adjustment bolt so that it can slide, the vibration of the adjustment bolt that occurs during operation is suppressed as much as possible by this guide part, and the cylinder is not damaged. It has the following effects: the surface pressure on the adjustment bolt is reduced, the adjustment bolt is not damaged, the operation of the adjustment bolt is smooth, there is no negative effect on the adjustment operation, and the braking gap can be adjusted reliably. There is.

[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,
Figure 3 is a side view of the camshaft attachment part, Figure 4 is a partially cutaway perspective view of the camshaft attachment part, Figure 5 is a cross-sectional side view of the main part showing how the spring retainer is attached, and Figure 6 is the spring retainer. FIG. 1 is the caliper, 4 is the cylinder, 5 is the piston,
10 is an adjuster bolt, 11 is a nut member, 2
5 is a spring retainer, 25a is a bottom, 25b
25c is an opening, 25d is a flange, 25e is a slit, 26 is a groove, and 27 is a second coil spring.

Claims (1)

[Scope of utility model registration request] An adjuster consisting of an adjuster bolt and a nut member threaded with a multi-thread screw is built into the hydraulic pressure chamber defined by the piston fitted in the cylinder, and this nut member engages with the piston in a concave and convex manner. Rotation is restricted and the adjusting bolt is urged in the piston direction by a first coil spring, while the adjusting bolt is rotatable in the cylinder and is compressed by a second coil spring compressed between the adjusting bolt and the spring retainer. Therefore, in an automatic braking gap adjustment device for a vehicle brake in which the cylinder is biased toward the rear side and the adjuster bolt rotates in response to hydraulic pressure and the adjuster extends, the spring retainer has a tip shape, and an axis line is formed at the bottom of the spring retainer. forming a guide portion folded back inward in one direction, forming a flange portion folded back in one direction at the other end opening, and locking this flange portion in a groove formed in the cylinder;
An automatic braking gap adjustment device for a vehicle brake, characterized in that the guide portion holds a second coil spring whose one end is in contact with the bottom portion, and guides the adjuster bolt by allowing it to slide.