JPH0536098Y2 - - 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]

The disc brake installed as a brake for the rear wheels of a vehicle is a hydraulic type that is 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 No. 61-58744. A so-called parking brake system is used, which combines an actuation mechanism and a mechanical actuation mechanism that is actuated by pulling a handbrake lever.

Among these, the mechanical actuation mechanism is provided with a bearing hole that is perpendicular to the disk axis and opened in one side wall of the caliper, and a camshaft for actuation is inserted through this bearing hole.

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 protruding shaft of the camshaft that protrudes from the opening of the bearing hole has a bearing that guides the rotation of the camshaft. A cam lever that rotates together with the camshaft by a brake wire pulled by the handbrake lever, and a coiled return spring that rotates the camshaft and cam lever in the opposite direction after the traction is released and returns them to the non-operating position. will be provided.

[The problem that the idea attempts to solve]

However, in the above structure, since the camshaft does not have a means to restrict the movement in the axial direction, the operation of the return spring, cam lever, etc. acts on the camshaft, causing the camshaft to wobble in the axial direction, and the smoothness of operation is reduced. This causes a lack of power transmission and power transmission loss.

SUMMARY OF THE INVENTION An object of the present invention is to provide a disc brake for a vehicle that prevents the camshaft inserted into the bearing hole from moving in the axial direction and at the same time improves the sealing performance of the bearing hole.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a caliper disposed astride the disc rotor with a bearing hole perpendicular to the disc axis, and a friction pad disposed in the bearing hole with the disc rotor sandwiched therebetween. In the vehicle disc brake, the camshaft is rotatably inserted through the camshaft, and the bearing hole is a step-like through hole with a large diameter hole and a small diameter hole connected, and the camshaft has a bearing hole. A flange portion is formed at the tip of the insertion shaft portion placed in the small diameter hole, and this flange portion is placed at the bottom of the large diameter hole, and an elastic boot is fitted into each opening of the large diameter hole and the small diameter hole. At the same time, the inner part of the elastic boot on the large diameter hole side is pressed against the outer end surface of the flange part, and grooves are formed in the outer periphery of the flange part and the inner periphery of the large diameter hole, respectively. It is characterized in that an annular sealing material is fitted across both grooves.

It is preferable to interpose a bearing for supporting the thrust load of the camshaft between the bottom of the large-diameter hole and the flange, so that the camshaft can rotate smoothly.

[Effect]

The camshaft is inserted from the insertion shaft side of the large diameter hole of the bearing hole, and the flange part is pressed against the bottom side of the large diameter hole by the elastic force of the elastic boot on the large diameter hole side, and the flange part and Movement in the axial direction is restricted by an annular sealing material fitted into the groove of the large diameter hole.

The bearing hole through which the camshaft was inserted is fluid-tightly closed with elastic boots fitted into the large-diameter and small-diameter openings, and the large-diameter hole side is double sealed with the above-mentioned annular sealing material. It will be sealed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

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 bracket 5 fixed to the vehicle body on one side of the disc rotor 4 supports a caliber 6 via sliding pins 7, 7 so as to be movable in the axial direction of the disc.

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.

The action part 6a has a large diameter hole 10a and a medium diameter hole 10b.
and a small-diameter communication hole 10c.
0 is formed in the disk axial direction, and a small-tip piston 11 is fluid-tightly and movably inserted into a large diameter hole 10a that opens toward the disk rotor 4 side, with the bottom wall 11a facing the disk rotor 4 side. has been done.

A hydraulic chamber 12 is defined between the piston 11 and the bottom of the medium-diameter hole 10b, and the medium-diameter hole 10b includes:
An inlet port 13 is formed to introduce hydraulic pressure generated by a known hydraulic master cylinder (not shown) into the hydraulic pressure chamber 12.

The above-mentioned hydraulic actuation mechanism 2 includes the above-mentioned piston 11
The hydraulic master cylinder is composed of a hydraulic pressure chamber 12 and an inlet port 13, and the hydraulic pressure of the hydraulic master cylinder supplied from the inlet port 13 to the hydraulic pressure chamber 12 is transferred to the piston 11 of the large diameter hole 10a and the mechanical cylinder to be described later. Adjuster 14 and sleeve piston 15 of actuation mechanism 3
and are pushed together toward the disk 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 across the medium diameter hole 10b and the communication hole 10c, and a camshaft 18 disposed perpendicular to the cylinder axis.
It has a push rod 19 interposed between the camshaft 18 and the sleeve piston 15.

The sleeve piston 15 has a large diameter shaft 15a disposed in a medium diameter hole 10b, which is prevented from rotating by a pin 20, and a rear small diameter shaft 15b inserted into a communication hole 10c. A tapered clutch surface 15c and a small diameter shaft hole 15d are continuously formed in the portion 15a.

Also, the adjustment bolt 16 is connected to the spring 2
1, the threaded portion 16a at the tip is screwed into the female threaded hole 17a of the adjuster nut 17 which engages the piston 11 unevenly to prevent rotation, and the rear end shaft 16b
The sleeve piston 15 is inserted into the shaft hole 15d of the sleeve piston 15, and the clutch surface 16d on the outer periphery of the flange 16c is compressed by the elastic force of the spring 22, which is compressed between the sleeve piston 15 and the large diameter hole 10a.
It is attached to the clutch surface 15c in frictional engagement.

At the rear of the communication hole 10c, 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 openings in the upper and lower walls of the bearing hole 23.
The camshaft 18 is inserted therethrough.

The bearing hole 23 includes a large diameter hole 23a and a small diameter hole 23.
The camshaft 18 is formed into a stepped shape in which the camshafts 18b and 18b are vertically connected, and the camshaft 18 is composed of an insertion shaft portion 18b having a flange portion 18a at its tip, and a protruding shaft portion 18c continuous thereto.

The camshaft 18 is inserted into the large diameter hole 23a from the protruding shaft part 18c, and the protruding shaft part 18c is inserted into the small diameter hole 2.
3b, the insertion shaft portion 18b is inserted into the small diameter hole 2.
3b, the flange portion 18a also has a large diameter hole 23a.
The insertion shaft portion 18b
and the small diameter hole 23b.
4 and is rotatably supported by a bearing 25 disposed 23 between the bottom of the large diameter hole 23a and the flange portion 18a.

Concave grooves 18d and 23c are provided facing each other on the outer circumferential surface of the flange portion 18a and the inner circumferential surface of the large diameter hole 23a, and an O-ring 26 is fitted into both the concave grooves 18d and 23c. , camshaft 18
Elastic boots 27 and 28 are fitted into the openings of the large-diameter hole 23a and the small-diameter hole 23b, respectively, to seal the inside of the bearing hole 23 liquid-tightly.

The protruding shaft portion 18c protruding from the bearing hole 23 has a
A cam lever 29 for rotation is fixed, and the lever 2
A coil-shaped return spring 30 is engaged with the camshaft 18 and the cam lever 29, and the camshaft 18 and cam lever 29 are rotated together in the braking direction by a brake wire 31 pulled by a handbrake lever inside the vehicle. When the traction is released, the restoring force of the return spring 30 returns to the non-braking position.

Of the two bearings 24 and 25, the bearing 24 fitted on the outer periphery of the insertion shaft portion 18b is a radial bearing similar to the conventional example in which the rotation of the camshaft 18 is guided by roller-shaped rolling elements.
The above-mentioned rotor is partially omitted on the outer circumference of the cam groove 18e recessed in the insertion shaft portion 18b of the camshaft 18, and the push rod 19 penetrates the bearing 24 inwardly and outwardly, and is connected to the above-mentioned cam groove 18e. ,
It is disposed between the sleeve piston 15 and a spherical recess 15e formed in the small diameter shaft portion 15b.

The bearing 25 is a thrust bearing that supports the load in the axial direction of the camshaft 18 via roller-like rolling elements, and is provided with a washer 32 that also serves as a spacer between the bottom of the large diameter hole 23a and the flange portion 18a. It is sandwiched between the bearings 18 and 18 to support the axial load of the camshaft 18 as described above, while also smoothly guiding the rotation of the camshaft 18 together with the bearing 24 for the radial load.

Small-diameter protrusions 18f and 27a are provided on the outer end surface of the flange portion 18a and on the inner side of the elastic boot 27 on the large-diameter hole 23a side, respectively, so that the elastic boot 27 can be fitted into the opening of the large-diameter hole 23a. When you arrive,
The protrusion 27a is pressed against the protrusion 18f of the flange portion 18a. The camshaft 18 is urged toward the small diameter hole 23b by the pressing force of the elastic boot 27, and the flange portion 18a is supported by the bottom of the large diameter hole 23a via the bearing 25 and washer 32. As a result, unnecessary clearance in the axial direction due to manufacturing errors or the like is filled in the camshaft 18, and movement in the axial direction is restricted.

Further, an O-ring 26 fitted across the grooves 18d and 23c restricts the axial movement of the camshaft 18, similar to the elastic boot 27 described above.
Furthermore, together with the elastic boot 27, the large diameter hole 23a side is double sealed.

The mechanical actuation mechanism 3 of this embodiment is configured as described above, and when the brake wire 31 is pulled by the driver's handbrake operation, the camshaft 1
8 rotates together with the cam lever 29, 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 the friction pads 8, 8
Similar to the hydraulic pressure operation described above, the disc rotor 4 is pressed to perform a braking operation.

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. The adjusting bolt 16 is then protruded, and the sleeve piston 15 is again engaged with the clutch, and the adjustment bolt 16 is stopped from being extended. This allows the adjustment nut 17
At the same time, 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.

As described above, the camshaft 18, which rotates together with the cam lever 29, has its flange portion 18a pressed against the bottom of the large diameter hole 23a by the elastic force of the elastic boot 27 on the large diameter hole 23a side. 18b,2
Since the movement in the axial direction is restricted together with the O-ring 26 fitted to 3c, there is no looseness during operation, and rotation can be performed smoothly and without power transmission loss.

In particular, when the camshaft 18 is arranged in the vertical direction as in this embodiment, the flange portion 18a supported at the bottom of the large diameter hole 23a is attached to the camshaft 1.
An elastic boot 27 and an O-ring 26 are used to prevent the bearing hole 23 from coming out, and the upper side of the bearing hole 23, which is prone to rainwater, is
This is suitable because it is double sealed with a double seal to ensure waterproofing.

Furthermore, by using an O-ring, the camshaft can be securely prevented from coming out in any axial direction.
The disc brake can be installed at any angle, which has the effect of allowing you to freely arrange the layout around the wheels.

[Effect of idea]

In the vehicle disc brake of the present invention, the bearing hole provided perpendicularly to the disc shaft in the caliper is a step-like through hole in which a large diameter hole and a small diameter hole are connected, and the camshaft inserted through the bearing hole is In this method, a flange is formed at the tip of the insertion shaft that is placed in the small diameter hole of the bearing hole, and this flange is placed at the bottom of the large diameter hole, and a In addition to fitting an elastic boot to close the bearing hole,
The inner side of the elastic boot on the large-diameter hole side is pressed against the outer end surface of the flange portion, and grooves are formed on the outer periphery of the flange portion and the inner periphery of the large-diameter hole, respectively, so that the annular sealing material is attached to both sides. By fitting across the groove,
Since the movement of the camshaft in the axial direction is restricted, there is no play during operation of the camshaft, and rotational operation can be performed smoothly and without loss of power transmission.

In addition, when the camshaft is arranged vertically, the flange supported at the bottom of the large diameter hole prevents the camshaft from coming out, and the upper side of the bearing hole, where rain water is likely to get wet, is protected by an elastic boot and an O-ring. Double sealing is suitable for ensuring waterproofing.

Furthermore, by using an O-ring, the camshaft can be securely secured in any axial direction, allowing the disc brake to be installed at any angle, allowing for free layout around the wheels. .

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a cross-sectional view taken from FIG. 2, FIG. 2 is a front view of the disc brake, and FIG. 3 is a cross-sectional view taken from FIG. 2. 1... Disc brake, 3... Mechanical operating mechanism, 4... Disc rotor, 6... Caliper, 6
a...Action part, 8...Friction pad, 10...Cylinder hole, 18...Camshaft, 18a...Flange part, 18b...Insertion shaft part, 18c...Protruding shaft part, 18d...Concave groove, 23 ...Bearing hole, 23a...
...Large diameter hole, 23b...Small diameter hole, 23c...Concave groove,
24, 25... Bearing, 27, 28... Elastic boot, 29... Cam lever.

Claims (1)

[Scope of utility model registration request] A bearing hole is provided perpendicularly to the disk shaft in a caliper placed across the disk rotor, and a camshaft that pushes one of the friction pads placed across the disk rotor can be rotated in the bearing hole. In vehicle disc brakes that are inserted through the
The bearing hole is a step-shaped through hole in which a large diameter hole and a small diameter hole are connected, and the camshaft has a flange portion formed at the tip of an insertion shaft portion disposed in the small diameter hole of the bearing hole. The flange portion is placed at the bottom of the large diameter hole, and an elastic boot is fitted into each opening of the large diameter hole and the small diameter hole to close the bearing hole, and the inner part of the elastic boot on the large diameter hole side is It is characterized by being pressed into contact with the outer end surface of the flange portion, further forming grooves on the outer periphery of the flange portion and on the inner periphery of the large diameter hole, and fitting the annular sealing material across both grooves. Disc brakes for vehicles.