JPH0526360Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disc brake for vehicles that performs braking action by mechanically operating friction pads, and more specifically relates to a camshaft inserted into a bearing hole of a caliper. Regarding the support structure of

[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, the mechanical actuation mechanism has bearing holes perpendicular to the disk shaft penetrating both side walls of the caliper, and a camshaft that presses the friction pad against the disk rotor is inserted through this bearing hole. There is.

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 is provided with a cam lever that rotates together with the camshaft by a brake wire pulled by the handbrake lever, and a coil-shaped return spring that returns the camshaft and cam lever to a non-operating position after the traction is released.

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 to be engaged is provided, and an inner surface of the opposing inner surfaces of the second annular engagement groove that is located on the rear side in the camshaft insertion direction is engaged with the inner peripheral edge of the circlip when the camshaft is removed. The camshaft is formed into a tapered surface that expands the diameter of the circlip, and the camshaft that is 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 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 during rotation, 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 for Solving the Problems] In order to achieve the above-mentioned object, the first means of the present invention is to provide a caliper disposed astride the disc rotor with a bearing hole penetrating therein, and to provide a bearing hole in the bearing hole. In a disc brake for a vehicle, a camshaft that presses a friction pad against a disc rotor is rotatably inserted through the disc brake, and a cam lever for rotational operation is pivotally attached to the protruding shaft of the camshaft that protrudes from the bearing hole. , the camshaft is formed in a stepped shape with a large-diameter hole and a small-diameter hole connected, and the camshaft has a flange portion formed at the tip of the insertion shaft portion disposed in the small-diameter hole of the bearing hole, and the flange portion is formed with a large-diameter hole. A first bearing is interposed between the flange portion and the bottom of the large diameter hole, and a lid body is fitted into the opening of the large diameter hole, so that a first bearing is inserted between the lid body and the flange portion. A spring is compressed to urge the camshaft toward the cam lever, and a second bearing is interposed to allow the camshaft to rotate together with the first bearing.

In the second method, a bearing hole is provided in a caliper disposed straddling the disc rotor, and a camshaft that presses a friction pad against the disc rotor is rotatably inserted into the bearing hole. In a vehicle disc brake in which a cam lever for rotational operation is mounted on a protruding shaft portion of a camshaft protruding from the hole, the bearing hole is formed in a stepped shape with a large diameter hole and a small diameter hole connected, and the camshaft for,
A flange part is formed at the tip of the insertion shaft part arranged in the small diameter hole of the bearing hole, this flange part is arranged in the large diameter hole, and a first
A bearing is interposed between the cam lever and the caliper, and a spring for biasing the camshaft toward the cam lever is compressed between the cam lever and the caliper.
A second bearing is interposed to allow rotation of the camshaft together with the bearing.

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.

[Effect]

With this configuration, the camshaft inserted into the bearing hole is prevented from moving in the axial direction and from coming off. Further, while axial movement is suppressed, rotation of the camshaft is smoothly guided by both bearings.

[Example] Hereinafter, a first example using the first means of the present invention will be described based on FIGS. 1 to 3.

A rear wheel disc brake 1 includes 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 through a pair of sliding pins 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 for introducing 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 from 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 machine described later. The adjuster 14 and sleeve piston 15 of the actuating mechanism 3 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 clamped 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
It is inserted into the shaft hole 15d of the sleeve piston 15, and the clutch surface 1 on the outer periphery of the flange 16c
6d is attached to the clutch surface 15c of the sleeve piston 15 in frictional engagement by the elastic force of the spring 22 compressed between the sleeve piston 15 and the large diameter hole 10a.

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 18 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 with the insertion shaft portion 18b.

The camshaft 18 is inserted into the large diameter hole 23a from the protruding shaft part 18c side, and the protruding shaft part 18c is made to protrude from the small diameter hole 23b, so that the insertion shaft part 18b is inserted into the small diameter hole 23b, and the flange part 18a is inserted into the large diameter hole 23b. Hole 23
a, and the flange portion 1
The first and second bearings 24 and 25 arranged above and below with 8a in between, the insertion shaft portion 18b and the small diameter hole 23
At the third bearing 26 inserted between
Rotatably supported.

The bearing hole 23 into which the camshaft 18 is inserted and arranged as described above has an opening 23c of the large diameter hole 23a.
The fitting protrusion 27a of the plug 27 is fitted into the opening 23d of the small diameter hole 23b, and the dustproof boot 28 is fitted into the opening 23d of the small diameter hole 23b.
is deposited.

A cam lever 29 for rotation is provided on the protruding shaft portion 18c.
A coil-shaped return spring 30 is engaged with the lever 29, and the camshaft 18 and the cam lever 29 are connected to 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.

Among the bearings 24 to 26, the first and second bearings 24 and 25 use balls as rolling elements,
A thrust bearing that supports the axial load of the camshaft 18 via this ball roller,
The first bearing 24 is interposed between the flange portion 18a and the bottom of the large diameter hole 23a together with the washer 32, and the second bearing 25 is interposed between the flange portion 18a and the bottom of the large diameter hole 23a.
A ring-shaped retainer 33 is interposed between the plug 27 and the fitting protrusion 27a of the plug 27.

Further, a third
The bearing 26 is a radial bearing similar to the conventional example in which the rotation of the camshaft 18 is guided by roller-like rolling elements.
Part of the rotor is omitted, and the push rod 19 passes through the bearing 26 inside and out.
It is arranged between the cam groove 18d and a spherical recess 15e formed in the small diameter shaft portion 15b of the sleeve piston 15.

The camshaft 18 inserted into the bearing hole 23 is
The axial thrust load is applied to the first and second bearings 2.
4, 25, the radial load perpendicular to the axis is
Each is supported by a bearing 26 and rotation is smoothly guided.

The plug 27 corresponds to the lid of the present invention, and the fitting protrusion 27a is inserted into the large diameter hole 2 of the bearing hole 23 as described above.
3a, and screw the cover 27b onto the action part 6a with bolts 34, and then open the opening 2 of the large diameter hole 23a.
A coiled spring 35 is compressed between the retainer 33 and a spring hole 27c which is provided by closing the retainer 3c and is recessed in the fitting protrusion 27a.

The spring 35 uses its elastic force to urge the camshaft 18 toward the cam lever 29, supporting the flange portion 18a at the bottom of the large diameter hole 23a,
It fills in unnecessary clearances in the axial direction due to manufacturing errors, etc., and restricts the movement of the camshaft 18 in the axial direction.

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 moves forward toward the disk rotor 4, the piston 11 moves forward toward the disk rotor 4 together with the adjusting bolt 16 and adjusting nut 17, thereby causing both friction pads 8, 8 to move forward.
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. 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 29, engages the cam lever 29 at the bottom of the large diameter hole 23a.
Axial movement is prevented by a flange portion 18a that is prevented from coming off to the side, and a spring 35 that presses the flange portion 18a toward the bottom side of the large diameter hole 23a to prevent it from coming off toward the large diameter hole 23a side. Because it is regulated,
Power transmission loss due to rattling of the camshaft 18 is eliminated, and the rotational force of the camshaft 18 can be effectively used as thrust from the push rod 19 onwards, allowing for highly efficient braking.

Furthermore, wear and tear on the boot 28 attached to the opening 23d of the small diameter hole 23b is suppressed, so that sealing performance can be maintained for a long time.

In addition, the first and second bearings 24, 25, which are arranged above and below the flange portion 18a, support the axial load of the camshaft 18 and guide its rotation together with the third bearing 26, so that the camshaft 18 can rotate smoothly and there is no resistance or wear due to friction.

Furthermore, the above-mentioned configuration reliably prevents the camshaft 18 arranged in the vertical direction from coming off, so the disc brake 1 can be mounted at any angle, and the layout around the wheels can be freely arranged. effective.

FIG. 4 shows a second embodiment using the second means of the present invention, in which together with the first bearing 24,
A second bearing 40 that supports the thrust load in the axial direction of the camshaft 18, and a spring 41 that prevents the camshaft 18 from coming off toward the large diameter hole 23a side.
is arranged between the cam lever 29 and the caliper 6, and the construction is similar to that of the first embodiment except that a dust boot 42 is provided on the large diameter hole 23a side to cover the opening 23c.

The second bearing 40 is inserted into an annular groove 43 formed concentrically with the bearing hole 23 on the side surface of the cam lever of the action part 6a, and the spring 41 is disposed outside the cam lever 29 and the second bearing 40. The camshaft 18 is compressed between the camshaft 18 and the retainer 44, and this structure prevents the camshaft 18 from moving in the axial direction and from coming off.

Note that the second bearing and the spring that biases the camshaft in both of the above embodiments may be arranged in opposite directions.

In addition to the above-mentioned plug and dust boot, a metal plate or the like is used for the lid constituting the first means.

[Effect of idea]

In the vehicle disc brake of the present invention, the bearing hole formed through the caliper is formed in a stepped shape with a large-diameter hole and a small-diameter hole connected, and the camshaft has an insertion shaft arranged in the small-diameter hole of the bearing hole. A flange portion is formed at the tip of the large diameter hole, the flange portion is placed in the large diameter hole, a first bearing is interposed between the flange portion and the bottom of the large diameter hole, and a first bearing is further disposed at the opening of the large diameter hole. The lid is fitted, and a spring is compressed between the lid and the flange to bias the camshaft toward the cam lever, and a second bearing is provided to allow the camshaft to rotate together with the first bearing. Alternatively, by arranging the above-mentioned spring and second bearing between the caliper around the protruding shaft and the cam lever, the rotation of the camshaft can be prevented from rattling, sliding resistance, and the like. Since the camshaft can be guided smoothly without any wear and tear and has little power loss, 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 to 3 show the first embodiment, FIG. 1 is a sectional view taken from FIG. 2, FIG. 2 is a front view of the disc brake, and FIG. 3 is a sectional view taken from FIG.
FIG. 4 is a sectional view of a main part of the second embodiment. 1... Disc brake, 3... Mechanical operating mechanism, 4... Disc rotor, 6... Caliper, 6
a...Action part, 8...Friction pad, 10...Cylinder hole, 10a...Large diameter hole, 10b...Medium diameter hole,
10c...Communication hole, 11...Piston, 15...
Sleeve piston, 18...Camshaft, 18
a...flange part, 18b...insertion shaft part, 18c
...Protruding shaft portion, 19...Push rod, 23...
...Bearing hole, 23a...Large diameter hole, 23b...Small diameter hole, 23c, 23d...Opening, 24...First bearing, 25...Second bearing, 26...Third bearing, 27...Plug , 27a...fitting protrusion, 27c...spring hole, 29...cam lever, 33...retainer, 35...spring.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A caliper disposed straddling the disc rotor is provided with a bearing hole passing through it, and a camshaft that presses a friction pad against the disc rotor is rotatably inserted into the bearing hole. , in a vehicle disc brake in which a cam lever for rotational operation is pivotally attached to a protruding shaft portion of a camshaft protruding from a bearing hole, the bearing hole is formed in a stepped shape with a large diameter hole and a small diameter hole connected, The camshaft has a flange formed at the tip of the insertion shaft disposed in the small diameter hole of the bearing hole, and this flange is disposed in the large diameter hole, and between the flange and the bottom of the large diameter hole. interposing a first bearing, further fitting a lid into the opening of the large diameter hole, and compressing a spring that biases the camshaft toward the cam lever between the lid and the flange; a second bearing that allows rotation of the camshaft together with the first bearing;
A disc brake for vehicles characterized by a bearing. 2. A bearing hole is provided in a caliper disposed straddling the disc rotor, and a camshaft that presses a friction pad against the disc rotor is rotatably inserted into the bearing hole, and the camshaft protruding from the bearing hole is In a disc brake for a vehicle in which a cam lever for rotational operation is mounted on a protruding shaft portion, the bearing hole is formed in a stepped shape with a large diameter hole and a small diameter hole connected, and the camshaft has a cam lever for rotation operation. forming a flange at the tip of the insertion shaft disposed in the small diameter hole, disposing the flange in the large diameter hole, and interposing a first bearing between the flange and the bottom of the large diameter hole; Furthermore, a spring is compressed between the cam lever and the caliper, and the spring biases the camshaft toward the cam lever.
A disc brake for a vehicle, characterized in that a second bearing is interposed to allow rotation of a camshaft together with the first bearing.