JPH0536097Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a disc brake for a vehicle that performs a braking action by mechanically operating a pair of friction pads arranged on both sides of a disc rotor. This invention relates to a support structure for a camshaft disposed on a caliper orthogonally to a disk axis.

[Conventional technology]

A disc brake installed as a brake for the rear wheels of a vehicle is a hydraulic brake operated by hydraulic pressure generated in a hydraulic master cylinder when the brake pedal is pressed, as disclosed in, for example, Japanese Utility Model Application Publication No. 163335/1983. A so-called parking brake system is used, which combines a pressure-type actuation mechanism and a mechanical actuation mechanism that is activated by pulling the handbrake lever.

Among these, in the mechanical operating mechanism, bearing holes perpendicular to the disk shaft are provided penetrating both side walls of the caliper, and a camshaft for operation is inserted through the bearing holes.

A bearing that guides the rotation of the camshaft is inserted between the bearing hole and the insertion shaft of the camshaft disposed inside the bearing hole, and a bearing that guides the rotation of the camshaft is inserted between the bearing hole and the shaft of the camshaft that protrudes from one opening of the bearing hole. The cam lever rotates together with the camshaft by a brake wire pulled by the handbrake lever, and the camshaft and cam lever are rotated in opposite directions when the traction is released, returning to the non-operating position. A return spring is provided.

A circlip that prevents the camshaft from slipping out is fitted into the annular first engagement groove formed on the other end opening side of the bearing hole. On the other hand, at the tip of the insertion shaft of the camshaft, there is a tapered surface that engages with the inner peripheral edge of the circlip to enlarge the diameter of the circlip when the camshaft is inserted, and a circlip that extends over the tapered surface and is continuous with this tapered surface. A second annular engagement groove that engages is provided, and an inner surface of the second annular engagement groove that is located on the rear side in the camshaft insertion direction after the opposing inner surfaces engages with the inner circumferential edge of the circlip when the camshaft is removed. The camshaft is formed on a tapered surface that expands the diameter of the circlip, and the camshaft inserted into the bearing hole is prevented from coming out by the circlip that engages with both engagement grooves.

[The problem that the idea aims to solve]

However, in the above-mentioned retaining structure, both engagement grooves are formed to be slightly wider than the thickness of the circlip, which causes the camshaft to wobble in the axial direction when it rotates, causing power transmission loss. Further, the circlip acts as a rotational resistance of the camshaft, not only hindering smooth rotation of the camshaft but also causing wear and tear on the camshaft.

The present invention was developed against the background of the above-mentioned circumstances, and is designed to ensure smooth rotation of the camshaft, prevent the camshaft from slipping out, and prevent rattling during rotation. The purpose is to provide disc brakes.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a caliper disposed straddling the disc rotor with a bearing hole orthogonal to the disc axis opened in one side wall.
In a disc brake for a vehicle, in which a camshaft for pushing one of the friction pads disposed across the disc rotor is rotatably inserted through the bearing hole, A locking ring is fixed to the opening side of the bearing hole, and a locking ring is formed between the locking ring and the large diameter portion of the insertion shaft, and the tip of the insertion shaft and the bottom wall of the bearing hole. A bearing that allows rotation of the camshaft is interposed between the locking ring and the bottom wall of the bearing hole, and a resilient member that biases the camshaft in the axial direction is compressed between the locking ring and the bottom wall of the bearing hole. It is characterized by what it did.

As the above-mentioned bearing, a thrust bearing using balls or rollers as a rotor, an oil-less bearing, or a bearing plate formed of a plate material with a low coefficient of friction is used. Further, as the resilient member, a wave washer or a spring washer is suitable.

[Effect]

With this configuration, the camshaft inserted into the bearing hole is pressed toward the opening side or the bottom wall side of the bearing hole by the urging force of the resilient member, and is prevented from moving in the axial direction, and is also prevented from moving toward the opening side. is prevented from coming off. Further, while axial movement is suppressed, rotation of the camshaft is smoothly guided by both bearings.

〔Example〕

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

A rear wheel disc brake 1 is equipped with a parking brake including a hydraulic actuation mechanism 2 and a mechanical actuation mechanism 3, and is disposed on the side of a disc rotor 4, as shown in FIG.

A caliper 6 is supported by a bracket 5 fixed to the vehicle body on one side of the disc rotor 4 so as to be movable in the axial direction of the disc via a pair of sliding pins 7, 7.

A pair of friction pads 8, 8 are disposed facing each other on both sides of the disc rotor 4, and an action part 6a and a reaction part 6b of the caliper 6, which are arranged with both friction pads 8, 8 in between, are connected to the disc rotor 4 and the friction pads. 8, 8 are connected at a bridge portion 6c that straddles them.

Each friction pad 8 includes a lining 8a and a back plate 8b.
The pad spring 9 attached to the ceiling opening 6d of the bridge section 6c biases the disc toward its center, and prevents rattling during running and lifting of the disc toward its outer circumference during braking. is suppressed by this pad spring 9.

A cylinder hole 10 in which a large-diameter hole 10a and a small-diameter communication hole 10b are connected is formed in the action part 6a in the disk axial direction, and the large-diameter hole 10a that opens toward the disk rotor 4 side has a tip-shaped hole. Piston 11
is inserted in a fluid-tight and movable manner with the bottom wall 11a facing the disk rotor 4 side. Hydraulic pressure chamber 1 defined between the bottom of large diameter hole 10a and piston 11
2 includes an inlet port 13 into which hydraulic pressure generated by a known hydraulic master cylinder (not shown) is introduced.
is formed.

The above-mentioned hydraulic actuation mechanism 2 includes a piston 11,
The hydraulic master cylinder is composed of a hydraulic pressure chamber 12 formed in the large diameter hole 10a and an inlet port 13, and the hydraulic pressure of the hydraulic master cylinder supplied to the hydraulic pressure chamber 12 from the inlet port 13 is transferred to the piston of the large diameter hole 10a. 11
and an adjuster 14 of the mechanical actuation mechanism 3, which will be described later.
and the sleeve piston 15 are pushed together toward the disc rotor 4 side.

The piston 11 moving forward through the large diameter hole 10a with this supply fluid pressure presses one of the friction pads 8 against one side of the disc rotor 4, and then, due to this reaction, the caliper 6 moves toward the acting portion 6a. Reaction part 6b
However, the other friction pad 8 is pressed against the other side of the disc rotor 4, and the disc rotor 4 is pinched between the two friction pads 8, 8 to perform a braking action.

On the other hand, the mechanical actuation mechanism 3 is for a parking brake that performs a braking action by the driver's handbrake operation, and the actuation mechanism 3 is used for adjusting the adjusting bolt 1.
6 and an adjuster nut 17, a sleeve piston 15 disposed on the bottom side of the large diameter hole 10a, a camshaft 18 disposed orthogonally to the cylinder axis, and the camshaft 18 and the sleeve piston 15. and a push rod 19 interposed between the two.

The sleeve piston 15 has a large diameter shaft portion 15a disposed at the bottom of the large diameter hole 10a, which is prevented from rotating by a pin 20, and a rear small diameter shaft portion 15b connected to the communication hole 10b.
The large diameter shaft portion 15a has a tapered clutch surface 15c and a small diameter shaft hole 1.
5d are continuously formed.

In addition, the adjusting bolt 16 has a threaded portion 1 at the tip.
6a is screwed into the female threaded hole 17a of the adjusting nut 17 which prevents the piston 11 from rotating with the pin 21, and the rear end shaft 16b is inserted into the shaft hole 15d of the sleeve piston 15, and the outer circumference of the flange 16c is inserted into the shaft hole 15d. The clutch surface 16d is connected to the spring 2
It is attached by frictionally engaging with the clutch surface 15c of the sleeve piston 15 with an elastic force of 2.

At the rear of the communication hole 10b, a bearing hole 23 that is perpendicular to the disk axis is connected to the operating portion 6a, as shown in FIG.
The bearing hole 23 is provided with an opening in the lower wall of the bearing hole 23.
The camshaft 18 is inserted.

The camshaft 18 consists of an insertion shaft 18a disposed in the bearing hole 23 and a protruding shaft 18b protruding from the opening 23a to which the boot 25 is attached. The outer periphery of the large-diameter shaft 18c is rotatably supported by a bearing 24, and the upper and lower parts thereof are rotatably supported by bearings 26 and 27, which will be described later.

A cam lever 28 for rotation is provided on the protruding shaft portion 18b.
is fixed to the lever 28, and a coil-shaped return spring 29 is engaged with the lever 28.The camshaft 18 and the cam lever 28 are connected to a brake wire 30 pulled by a handbrake lever inside the vehicle.
When the traction is released, the restoring force of the return spring 29 returns to the non-braking position.

Among the bearings 24, 26, 27, the bearing 24 inserted between the large diameter shaft 18c of the insertion shaft portion 18a and the bearing hole 23 is attached to the camshaft 18.
The camshaft 1 is equipped with a radial bearing similar to the conventional example in which the rotation of the camshaft 1 is guided by roller-like rolling elements.
The rotor is partially omitted on the outer circumference of the cam groove 18d recessed in the large diameter shaft 18c of No. piston 1
A spherical recess 15e formed in the small diameter shaft portion 15b of No. 5
will be placed between the

The other bearings 26 and 27 are thrust bearings that use balls for their rotors and support the load in the axial direction of the camshaft 18 via the ball rotors. The other bearing 27 is interposed between the locking ring 31 engaged on the opening side of the shaft and the large-diameter shaft 18c of the insertion shaft 18a, and the other bearing 27 is connected between the tip of the insertion shaft 18a and the upper bottom wall of the bearing hole 23. 23b.
Both bearings 26 and 27 support the axial load of the camshaft 18 as described above, and also support the camshaft 1 along with the radial load bearing 24.
Smoothly guides the rotation of 8.

A wave washer 32 and a ring-shaped spacer 33 are provided between the lower bearing 26 and the locking ring 31 in an overlapping manner. this house,
The wave washer 32 corresponds to the resilient member of the present invention, and urges the large-diameter shaft 18c of the camshaft 18 toward the upper bottom wall 23b of the bearing hole 23 to fill unnecessary clearance in the axial direction due to manufacturing errors, etc. Movement of the camshaft 18 in the axial direction is restricted.

The mechanical actuation mechanism 3 of this embodiment is configured as described above, and when the brake wire 30 is pulled by the driver's handbrake operation, the camshaft 1
8 rotates together with the cam lever 28, and the rotational force of the camshaft 18 is converted into thrust by the push rod 19, thereby pushing the sleeve piston 15. When the sleeve piston 15 advances toward the disc rotor 4, the piston 11 moves forward together with the adjusting bolt 16 and the adjusting nut 17 toward the disc rotor 4, and both friction pads 8, 8 are moved in the same manner as in the hydraulic operation described above. It is pressed against the disc rotor 4 to perform a braking action.

When the lining 8a wears down due to repeated braking operations by the hydraulic and mechanical actuating mechanisms 2 and 3, the piston 11 to the sleeve piston 15 absorbs the wear of the lining 8a toward the disc rotor 4 during braking. The vehicle moves forward and performs a braking operation. When the pressure from these operating mechanisms 2 and 3 is released, the clutch engagement between the sleeve piston 15 and the adjusting bolt 16 is released, and the adjusting bolt 16 rotates to the bottom side of the large diameter hole 10a. It protrudes and engages the sleeve piston 15 again with the clutch, stopping the adjustment bolt 16 from being extended. This allows the adjustment nut 1
7, the retraction limit of the piston 11 is regulated, and an appropriate braking gap is set by compensating for the gap due to wear of the lining 8a.

The camshaft 18, which rotates together with the cam lever 28, is restricted from moving in the axial direction by the elastic force of the wave washer 32, as described above, so there is no power transmission loss due to backlash, and the rotational force of the camshaft 18 is reduced. can be effectively transmitted to the thrust force from the push rod 19 onwards, and a highly efficient braking operation can be performed. Furthermore, since wear and tear on the boot 25 attached to the opening 23a is suppressed, sealing performance can be maintained for a long time.

Further, since the bearings 26 and 27 placed on both sides of the large diameter shaft 18c support the axial load of the camshaft 18 while guiding the rotation, the camshaft 18 can be rotated smoothly and unlike the conventional one. There is no resistance or wear due to friction.

Moreover, the above-mentioned configuration reliably prevents the camshaft 18 arranged vertically in the bearing hole 23 from coming out, so the disc brake 1 can be mounted at any angle, and the layout around the wheels can be changed. You can do it freely.

FIG. 3 shows another embodiment of the present invention, in which bearings 40 and 41 that support an axial load are used.
It uses oil-less bearings and bearing plates made of plate material with a low coefficient of friction.

Further, the camshaft 18 is urged toward the upper bottom wall 23b of the bearing hole 23 by the wave washer 32 that is compressed between the lower bearing 40 and the locking ring 31, and as in the above embodiment, the camshaft 18 can be rotated smoothly, and can be prevented from rattling during rotation and from coming off toward the opening 23a side.

In both of the above embodiments, the large diameter portion formed in the insertion shaft portion was described as a large diameter shaft, but this large diameter portion has a shape that can support at least a bearing disposed on the opening side of the bearing hole. Any other shape such as a flange may be used.

Further, the resilient member may be compressed anywhere between the locking ring and the bottom wall of the bearing hole, and the spacer in the embodiment may be omitted.

[Effect of idea]

In the vehicle disc brake of the present invention, a camshaft is rotatably inserted through a bearing hole formed in the caliper perpendicular to the disc shaft, and a large-diameter portion is inserted into the shaft portion of the camshaft arranged in the bearing hole. a locking ring is fixed to the opening side of the bearing hole, and between the locking ring and the large diameter portion of the insertion shaft, and between the tip of the insertion shaft and the bottom wall of the bearing hole. ,
A bearing that allows the rotation of the camshaft is interposed, and a resilient member that biases the camshaft in the axial direction is provided between the locking ring and the bottom wall of the bearing hole, so that the rotation of the camshaft is prevented. The camshaft can smoothly guide the movement without axial play, frictional resistance, or wear and tear caused by these, and the power loss is extremely small, so the power of the camshaft can be effectively used as a braking force. .

Furthermore, since the above-mentioned structure also serves to prevent the camshaft from coming off, the camshaft can be arranged vertically, and the mounting angle of the disc brake is not limited, so the layout around the wheels can be freely designed.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a cross-sectional front view of the main part of a disc brake, FIG. 2 is a cross-sectional view of FIG. FIG. 2 is a cross-sectional view of main parts showing an example. DESCRIPTION OF SYMBOLS 1...Disc brake, 3...Mechanical operating mechanism, 4...Disc rotor for rear wheels, 6...Caliper, 6a...Action part, 8...Friction pad, 10
...Cylinder hole, 10a...Large diameter hole, 10b...
Communication hole, 11...Piston, 14...Adjuster, 15...Sleeve piston, 18...Camshaft, 18a...Insertion shaft part, 18b...Protruding shaft part, 18c...Large diameter shaft, 19...Push rod, 23...bearing hole, 23a...opening, 23b
...Top bottom wall, 24, 26, 27...Bearing,
28...Cam lever, 31...Latching ring, 32
...Wave washers, 33...Spacers.

Claims (1)

[Scope of utility model registration request] A caliper disposed straddling the disc rotor is provided with a bearing hole orthogonal to the disc axis in one side wall, and a camshaft is inserted into the bearing hole to push one side of the friction pads arranged across the disc rotor. In the disc brake for a vehicle in which a camshaft is rotatably inserted through the shaft, a large diameter portion is formed in the insertion shaft portion of the camshaft disposed in the bearing hole, and a locking ring is locked on the opening side of the bearing hole. , a bearing that allows rotation of the camshaft is interposed between the locking ring and the large diameter portion of the insertion shaft, and between the tip of the insertion shaft and the bottom wall of the bearing hole, and A disc brake for a vehicle, characterized in that a resilient member for biasing a camshaft in the axial direction is provided between the retaining ring and the bottom wall of the bearing hole.