JPH0247776Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field This invention is a disc brake device mainly used in vehicles such as automobiles and motorcycles, and in particular, a camshaft is mounted radially into a bearing hole of a brake caliper. A friction pad pressing member rotatably supported via a bearing and sliding in a direction crossing the axis of the camshaft is provided on the brake caliper, and one end engaging portion of the driven pin is connected to the outer peripheral surface of the camshaft. The camshaft is attached to an outer end of the camshaft protruding from the outer surface of the brake caliper, the other end engaging portion being engaged with the end face of the friction pad pressing member facing the cam groove, and protruding from the outer surface of the brake caliper. This invention relates to an improvement in which a return spring is connected to an operating lever to bias it toward a non-operating position.

(2) Prior Art Conventionally, in this type of device, in order to prevent the camshaft from slipping out of the bearing hole, the engagement part of the driven pin with the friction pad pushing member was closer to the operating lever than the engagement part of the driven pin with the cam groove. The driven pin is arranged at an angle with respect to the axis of the camshaft so that it approaches the camshaft.
It is known that the camshaft is brought into contact with the bottom surface of the bearing by the retracting force acting on the camshaft due to the inclination of the driven pin (see Japanese Utility Model Application No. 60-28640).

(3) Problems to be solved by the invention However, with the above configuration, the bottom surface of the bearing hole is worn by the camshaft due to the retraction force, and the frictional force between the camshaft and the bottom surface of the bearing hole is There is a problem in that it prevents smooth rotation.

An object of the present invention is to provide the disc brake device that can solve the above problems.

B. Structure of the Invention (1) Means for Solving Problems In the present invention, the engagement portion of the driven pin with the cam groove is closer to the operating lever than the engagement portion of the driven pin with the friction pad pushing member. The driven pin is arranged to be inclined with respect to the axis of the camshaft so that the driven pin approaches the axis of the camshaft. A spring member that biases the camshaft in a direction to retract the camshaft is connected to the camshaft, and the spring member is connected to the camshaft between an end surface opposite to the outer end of the camshaft and a bottom wall of the bearing hole facing thereto. It is characterized by having a thrust bearing installed in it.

(2) Effect With the above structure, the camshaft can be reliably prevented from coming out of the bearing hole by the retracting force based on the difference between the biasing force of the spring member and the pulling force of the driven pin.

Furthermore, the retraction force can be supported by the thrust shaft, allowing the camshaft to rotate smoothly. Moreover, since the retracting force is a small force based on the difference between the urging force and the pulling force, the load acting on the thrust bearing is small, thereby improving the durability of the thrust bearing.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 to 3, first and second friction pads 2 1 and 2 ₂ , which are arranged opposite to each other on both sides of the brake disc ₁ that rotates together with the wheels, are attached to guide rails of a bracket 3 fixed to the vehicle body. It is supported slidably in the axial direction of the brake disc 1. In addition, both friction pads 2 ₁ , 2 ₂ are attached to the bracket 3.
Brake caliper 4 that straddles the brake disc 1
are connected via a pair of sliding pins 5 so as to be slidable in the axial direction. Since such a structure is the same as the conventional one, a detailed structural diagram will be omitted.

The brake caliper 4 includes a first pinching arm 4a facing the back surface of the first friction pad ₂₁ , and a second pinching arm _4b contacting the back surface of the second friction pad 22. The first pinching arm 4a has a cylinder hole 6 that opens on its inner surface, and a first friction pad 2 ₁ is inserted therein.
The piston 7 that comes into contact with the back surface of the piston 7 is slid together. A hydraulic chamber 8 defined within the cylinder hole 6 by the piston 7 is communicated with an output port of a master cylinder (not shown) via a hydraulic conduit 9. Therefore,
Hydraulic chamber 8 is passed from the master cylinder to hydraulic conduit 9.
When hydraulic pressure is supplied to the piston 7, the piston 7 moves forward in response to the hydraulic pressure, presses the first friction pad ₂₁ against one side of the brake disc 1, and the reaction causes the brake caliper 4 to move through the sliding pin 5. The second pinching arm 4 moves in the opposite direction to the operation of the piston 7.
The second friction pad ₂₂ is brought into pressure contact with the other side surface of the brake disc 1 by b. In this way, braking force can be applied to the brake disc 1.

As clearly shown in FIGS. 2 and 4, a bearing hole 10 extending in a direction perpendicular to the axis of the piston 7 is formed at the outer end of the first pinching arm 4a of the brake caliper 4. A camshaft 11 is rotatably supported via a needle bearing 12 as a radial bearing.

Camshaft 1 protruding from the outer surface of brake caliper 4
A parking lever 14 as an operating lever is non-rotatably fitted to the outer end of the lever 1 and fixed with a nut 15. An operating wire 16 is connected to this parking lever 14. A rubber dustproof cap 17 is attached to the opening of the bearing hole 10 inside the parking lever 14 .

A stopper pin 18 that is arranged parallel to the camshaft 11 is protruded from the outer surface of the first pinching arm 4a. It is installed integrally with the Then, the parking lever 14 is rotated so that the stopper portion 19 is connected to the stopper pin 1.
A torsion coil type return spring 20 is tensioned between the parking lever 14 and the stopper pin 18 and biased to abut against the parking lever 14 . At that time, return spring 20
The coil portion 20a is arranged on the outer periphery of the nut 15 so as to surround it.

As clearly shown in FIG. 4, the camshaft 11 is connected to the piston 7 via a known brake gap automatic adjustment device 13 disposed in a cylinder hole 13 as described below. The device 13 and the piston 7 thus function as a friction pad pressing member.

The small diameter hole 6a of the cylinder hole 6 extends in a direction intersecting the center line of the bearing hole 10, and one opening thereof is located on the inner peripheral surface of the bearing hole 10.
The small-diameter portion 21a of the sleeve piston 21, which is a component of the device 13, is slid onto the portion a.

Sleeve piston 21 located on the bearing hole 10 side
A concave portion 22 having a concave spherical bottom surface opens at the end surface of the small diameter portion 21a. Also, a cam groove 2 having a concave spherical bottom surface is similarly formed on the outer peripheral surface of the camshaft 11.
3 opens toward the small diameter hole 6a.

The engaging portions 24a and 24b at both ends of the driven pin 24 are formed into convex spherical surfaces, and the engaging portion 24a at one end is connected to the bottom surface of the cam groove 23, and the engaging portion 24b at the other end is connected to the recessed portion 2.
2, respectively.

The bottom center O ₁ of the cam groove 23 is the concave portion 22
Parking lever 1 from bottom center O ₂ at
4, so that the driven pin 24 is disposed at an angle with respect to the axis of the camshaft 11. When the driven pin 24 is tilted in this way, the cam shaft 11 is caused to have a cam groove 2 as shown in FIG.
A vertical component force based on the pressing force F of the driven pin 24 with respect to the pin 3 acts as a pulling force f.

A small-diameter shaft portion 25 is provided protruding from the side opposite to the outer end of the camshaft 11 , and the small-diameter shaft portion 25 is surrounded by an annular bottom wall 26 of the bearing hole 10 .

A thrust bearing 27 is interposed between the inner surface of the bottom wall 26 and the end surface of the camshaft 11 facing thereto. Further, a circlip 28 is attached to the protruding end of the small diameter shaft portion 25 from the bottom wall 26, and a spring member shown in FIG. A corrugated washer 30 is installed. Thus, the wave washer 30 is connected to the camshaft 11 via the circlip 28 and the flat washer 29.

The elastic force f ₂ of the corrugated washer 30 is set larger than the pulling force f ₁ acting on the camshaft 11 (that is, f ₂ > f ₁ ),
This overcomes the pulling force _f1 and urges the camshaft 11 in the retracting direction. In the figure, 31 is the bearing hole 10
It is a rubber cap that closes the

Next, the operation of this embodiment will be explained.

When parking, if the parking lever 14 is rotated against the force of the return spring 20 by pulling the operation wire 16, the camshaft 11 moves counterclockwise in FIG. 1 (clockwise in FIG. 2). The piston 7 is rotated to move the piston 7 forward via the driven pin 24 and the automatic brake gap adjustment device 13. Therefore, braking force can be applied to the brake disc 1 in the same way as when hydraulic pressure is supplied to the hydraulic chamber 8.

During this time, the elastic force f ₂ of the wave washer 30 and the driven pin 2
Since the retracting force based on the difference between the pulling force f ₁ of 4 and the pulling force f 1 , that is, f ₂ - f ₁ is acting on the camshaft 11, the bearing hole 10
The camshaft 11 is reliably prevented from coming off. Further, since the retraction force is supported by the thrust bearing 27, the rotation of the camshaft 11 is performed smoothly.
Moreover, since the retraction force is a small force based on the difference, the load acting on the thrust bearing 27 is small.
This improves the durability of the thrust bearing 27.

C. Effects of the invention According to the invention, the camshaft can be reliably prevented from coming out of the bearing hole by the retraction force based on the difference between the biasing force of the spring member and the pullout force of the driven pin.

Further, the retraction force can be supported by a thrust bearing, so that the camshaft can rotate smoothly. Moreover, since the retracting force is a small force based on the difference between the urging force and the pulling force, the load acting on the thrust bearing is small, thereby improving the durability of the thrust bearing.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a front view, FIG. 2 is a cross-sectional view taken along the line taken from FIG. 1, FIG. 3 is a view taken along the arrow in FIG. FIG. 5 is an enlarged sectional view, FIG. 5 is an explanatory diagram of the function of the driven pin, and FIG. 6 is a perspective view of the corrugated washer. f ₁ ...Pull-out force, 4...Pulke caliper, 7,
13... Piston that functions as a friction pad pressing member, automatic brake gap adjustment device, 10... Bearing hole, 11... Camshaft, 12... Needle bearing as a radial bearing, 14... Parking lever as an operating lever, 20...Return spring, 2
3...Cam groove, 24...Followed pin, 24a, 24
b... Engaging portion, 26... Annular bottom wall, 27... Thrust bearing, 30... Corrugated washer as a spring member.

Claims (1)

[Scope of utility model registration request] The camshaft is rotatably supported in the bearing hole of the brake caliper via a radial bearing, and the brake caliper is provided with a friction pad pressing member that slides in a direction crossing the axis of the camshaft, and the driven pin is One end engaging portion is engaged with a cam groove on the outer circumferential surface of the camshaft, and the other end engaging portion is engaged with an end surface of the friction pad pressing member opposite to the cam groove, and protrudes from the outer surface of the brake caliper. In a disc brake device in which a return spring is connected to an operating lever attached to the outer end of the camshaft to urge it toward a non-operating position, the engagement portion of the driven pin with the cam groove is connected to the friction pad. The driven pin is arranged to be inclined with respect to the axis of the camshaft so as to be closer to the actuating lever than the engagement portion of the driven pin with respect to the pushing member, and connecting to the camshaft a spring member that biases the camshaft in a direction to retract the camshaft by overcoming a pulling force acting on the camshaft toward the operating lever;
A disc brake device characterized in that a thrust bearing is interposed between an end surface of the camshaft opposite to the outer end and a bottom wall of the bearing hole facing thereto.