JPH10238568A - Disc brake for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a caliper compact, simplify a device, reduce a hydraulic fluid amount, facilitate an air bleeding work, and improve initial slide efficiency. SOLUTION: A first cylinder hole 6d boosted by a hydraulic pressure from a first master cylinder 9 coupled through a brake hose 13 is formed in a caliper 6 supported pivotally in the rotation direction of a disc rotor 3 at a bracket 4 fixed at a car body. A second master cylinder 10 boosted by brake torque exerted on the caliper 6 is formed on the inner peripheral side of the disc rotor of the caliper 6. A second master cylinder hole 6e boosted by a hydraulic pressure from the second master cylinder 10 is formed. The cylinder hole 10a of the second master cylinder 10 and the first cylinder hole 6d are intercommunicated and the hydraulic pressure chamber 10c of the second master cylinder 10 and the second cylinder hole 6e are intercommunicated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake for a vehicle in which a braking effect is enhanced by utilizing a braking torque acting on a caliper during a braking operation.

[0002]

2. Description of the Related Art For example, in a vehicle disk brake disclosed in Japanese Utility Model Publication No. 5-29386, a caliper rotatable in the rotation direction of a disk rotor is pivotally supported on a bracket fixed to a vehicle body. A first cylinder hole is formed on the disk rotor inlet side and a second cylinder hole is formed on the outlet side, and a second master cylinder is further formed on the disk rotor outlet side than the second cylinder hole.
A first master cylinder and a first cylinder integrated with a reservoir, wherein a base end of a piston push rod of the master cylinder is rotatably supported by a bracket, and a hydraulic pressure is generated by rotation of a brake lever provided on a bar handle. The second master cylinder is connected to the second master cylinder via a brake hose, and a reservoir separate from the first master cylinder is connected to the second master cylinder via a brake hose.
It communicates with the cylinder hole.

When the brake lever is operated to generate hydraulic pressure in the first master cylinder, the pressure in the first cylinder hole is increased, and the piston in the first cylinder hole performs a braking operation. The braking torque causes the caliper to rotate toward the disk rotor outlet side, to generate hydraulic pressure in the hydraulic chamber of the second master cylinder, the pressure in the second cylinder hole is increased, and the piston in the second cylinder hole performs a braking action. Enhance the braking effect.

[0004]

However, in the above construction, the first cylinder hole and the second cylinder hole are provided on a caliper provided continuously in the circumferential direction of the disk rotor, and the second cylinder hole is further provided on the outlet side.
Since the master cylinder is formed, the caliper becomes longer. In addition, since the first master cylinder and the second master cylinder hole are supplied with hydraulic fluid from separate reservoirs, the amount of hydraulic fluid increases and the device becomes complicated. Further, the air bleeding of the first cylinder hole and the second cylinder hole is a separate operation, and the air bleeding of the second cylinder hole requires rotating the caliper. In addition, in the initial stage of braking, only the first cylinder hole is pressurized, so that the initial braking efficiency is low.

Accordingly, an object of the present invention is to provide a disc brake for a vehicle in which the caliper can be made compact, the apparatus can be simplified, the amount of hydraulic fluid can be reduced, the air bleeding operation can be facilitated, and the initial braking efficiency can be increased. I have.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention pivotally supports a caliper rotatable in a rotation direction of a disk rotor on a bracket fixed to a vehicle body.
A first caliper connected to the caliper via a brake hose;
A first cylinder hole for increasing pressure by hydraulic pressure from the master cylinder, a second master cylinder for increasing pressure by braking torque acting on the caliper, and a second cylinder hole for increasing pressure by hydraulic pressure from the second master cylinder are formed. In the vehicle disk brake, in the means of claim 1, the second master cylinder is formed on the inner peripheral side of the disk rotor of the caliper, and the cylinder hole of the second master cylinder communicates with the first cylinder hole. A hydraulic chamber of the second master cylinder communicates with the second cylinder hole, and when the braking torque is equal to or less than a predetermined value, the first cylinder hole communicates with the second cylinder hole. The communication between the first cylinder hole and the second cylinder hole is interrupted when is greater than or equal to a predetermined value. The static cylinder, formed in the disc rotor peripheral side of the caliper, the second cylinder bore, and characterized in that formed on the entry side of the disc rotor times than the first cylinder bore.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail based on embodiments shown in the drawings. 1 to 3 show a first embodiment in which the present invention is applied to a piston-facing disc brake. A disc brake 1 for a vehicle is supported by a lower end of a front fork 2 and rotates integrally with a wheel. A rotor 3, a caliper 6 pivotally supported on a bracket 4 formed on the front fork 2 by a support shaft 5, and a reservoir-integrated second type operated by an operation lever 8 provided at one end of a handlebar 7. And one master cylinder 9.

The caliper 6 is formed by joining a caliper half 6a arranged on one side of the disk rotor 1 and a caliper half 6b arranged on the other side to a bridge portion on the outer peripheral side of the disk rotor 1. The two caliper halves 6a and 6b are connected to each other by bolts 6c. The caliper halves 6a and 6b have a first cylinder hole 6d on the outlet side of the disk rotor 1 and a second cylinder hole 6e on the inlet side of the disk rotor 1. Each formed,
A communication passage 6f is provided between the first cylinder holes 6d, 6d,
A communication passage 6g is opened between the cylinder holes 6e, 6e,
The piston 6h is inserted into the cylinder hole 6d,
Each of the pistons 6i is liquid-tightly and movably fitted into the e.

The caliper half 6a forms a pivotal support 6j connected to the bracket 4 on the outflow side of the disk rotor 1 and on the outer peripheral side of the disk rotor 1. The two master cylinders 10 are formed integrally. The second master cylinder 10 has a center valve type piston 10b inserted into a cylinder hole 10a to define a hydraulic chamber 10c between the center valve type piston 10b and the bottom of the cylinder hole 10a. A push rod 10d pivotally supported by the bracket 4 is in contact with the rear end of the piston 10b.

A first hydraulic fluid flow path 11 is formed between the first cylinder hole 6d of the caliper half 6a and the cylinder hole 10a of the second master cylinder 10, and the first hydraulic fluid passage 11 is formed in the cylinder hole 10a of the second master cylinder 10. A second hydraulic fluid channel 12 is formed between the bottom and the second cylinder hole 6e of the caliper half 6a, and the brake hose 13 connected from the first master cylinder 9 to the caliper 6 is connected to the second It is connected to a communication passage 6f between the one cylinder holes 6d.

As a result, the first cylinder holes 6d, 6d are provided from the first master cylinder 9 via the brake hose 13.
Communicate with the cylinder hole 10a of the second master cylinder 10 from the first cylinder hole 6d of the caliper half 6a via the first hydraulic fluid flow path 11, and further from the cylinder hole 10a of the second master cylinder 10. The second cylinder holes 6e, 6e communicate with each other via the second hydraulic fluid channel 12.

Therefore, the hydraulic fluid from the reservoir of the first master cylinder 9 can be supplied to the second cylinder holes 6e, 6e, so that only one reservoir is required to simplify the apparatus and reduce the amount of hydraulic fluid. Can be. further,
The first cylinder holes 6d, 6d and the second cylinder holes 6e, 6e
Can be performed by repeating the light gripping operation of the operation lever 8, so that the air bleeding operation can be easily performed.

Further, when a hydraulic pressure is generated in the first master cylinder 9 by the gripping operation of the operation lever 8 during the braking operation, the first cylinder holes 6d, 6d rise in pressure and the piston 6
h and 6h are in sliding contact with the disk rotor 3 and the second
The cylinder holes 6e, 6e are also pressurized, and the pistons 6i, 6i slide on the disk rotor 3 to perform a braking action, thereby generating a braking torque.

The braking torque causes the caliper 6 to rotate toward the inner periphery of the disk rotor 3, and the second master cylinder 10
When the center valve type piston 10b of the second master cylinder 10 closes the relief port, hydraulic pressure is generated in the hydraulic chamber 10c of the second master cylinder 10. The hydraulic pressure further increases the pressure in the second cylinder holes 6e, 6e, and the pistons 6i, 6i slide on the disk rotor 3 to perform a braking action, thereby enhancing the braking effect.

As described above, when the braking torque until the center valve type piston 10b of the second master cylinder 10 closes the relief port is equal to or less than a predetermined value, the first cylinder holes 6d, 6d and the second cylinder holes 6e, 6e, 6e, the first cylinder holes 6d, 6d and the second cylinder holes 6e,
6e, the pressure is increased by the hydraulic pressure generated in the first master cylinder 9, but when the braking torque after the center valve type piston 10b closes the relief port is equal to or more than a predetermined value,
The first cylinder holes 6d, 6d and the second cylinder holes 6e, 6e
Communication between the first master cylinder 9 and the first cylinder bores 6d, 6d
The pressure in the cylinder holes 6e, 6e is increased by the hydraulic pressure generated in the hydraulic pressure chamber 10c of the second master cylinder 10.

Therefore, as shown in FIG. 3, the braking efficiency A of the vehicle disk brake 1 is greater than the braking efficiency B of the vehicle disk brake utilizing the hydraulic pressure of the second master cylinder generated by the conventional braking torque. Also, the first cylinder hole 6 can be used even in the initial stage of braking when the braking torque is equal to or less than the predetermined value C.
Since d and 6d and the second cylinder holes 6e and 6e are pressurized,
The efficiency is good from the beginning of the braking, and the efficiency of the braking torque is equal to or higher than the predetermined value C. Therefore, the input of the operation lever 8 can be small, and the supply amount of the working fluid can be small, so that the body diameter of the first master cylinder 9 can be reduced and the stroke of the piston can be reduced. Can be downsized. Furthermore, since the efficiency is good from the beginning of braking, the operation feeling of the operation lever 8 is good.

Moreover, the second master cylinder 10 is formed on the inner peripheral side of the disk rotor of the caliper 6, and the second cylinder holes 6e, 6e are formed closer to the reciprocating side of the disk rotor 3 than the first cylinder holes 6d, 6d. As a result, the second master cylinder 10 does not protrude in the circumferential direction of the disk rotor 3, the caliper 6 as a whole is made compact, and the space required for mounting the vehicle body can be reduced.

FIG. 4 shows a second embodiment of the present invention in which the second master cylinder 20 is of a side port type, a piston 20b is inserted into a cylinder hole 20a, and a space between the piston 20b and the bottom of the cylinder hole 20a. Hydraulic chamber 20
c, and a push rod 20d pivotally supported by the bracket 4 is in contact with the rear end of the piston 20b. When the relief port 20e is closed by the braking torque, the second cylinder holes 6e, 6e are formed. The pressure is increased by the hydraulic pressure generated in the hydraulic pressure chamber 20c of the second master cylinder 20, and the same operation and effect as those of the first embodiment are exerted.

[0019]

As described above, the disc brake for a vehicle according to the present invention is provided on a bracket fixed to a vehicle body, on a caliper pivotally supported in a rotational direction of a disc rotor, via a brake hose. A first cylinder hole that is boosted by the hydraulic pressure from the connected first master cylinder, a second master cylinder that is boosted by the braking torque acting on the caliper, and a second cylinder that is boosted by the hydraulic pressure from the second master cylinder. In the means according to the first aspect, the second master cylinder is formed on the inner peripheral side of the disk rotor of the caliper, and the second master cylinder communicates with the cylinder hole of the second master cylinder and the first cylinder hole. 2 When the hydraulic pressure chamber of the master cylinder communicates with the second cylinder hole, and when the braking torque is equal to or less than a predetermined value, the first cylinder hole and the second cylinder hole communicate with each other. When the torque is equal to or more than a predetermined value, the communication between the first cylinder hole and the second cylinder hole is cut off. Therefore, when the braking torque is equal to or less than the predetermined value, the first cylinder hole and the second cylinder hole are connected to the first master cylinder. When the braking torque is equal to or more than a predetermined value, the first cylinder hole is increased by the hydraulic pressure generated in the first master cylinder, and the second cylinder hole is increased by the second master cylinder. The pressure is increased by the hydraulic pressure generated in the hydraulic chamber.

Therefore, even in the initial stage of braking where the braking torque is less than the predetermined value, the pressure in the first cylinder hole and the second cylinder hole increases, so that the efficiency is good from the beginning of braking and the efficiency of the braking torque is more than the predetermined value. Further, since the hydraulic fluid from the reservoir of the first master cylinder can be supplied to the second cylinder hole, the device can be simplified by using only one reservoir, and the amount of hydraulic fluid can be reduced. For this reason, the body diameter of the first master cylinder can be reduced and the stroke of the piston can be reduced, and the first master cylinder can be reduced in size. Furthermore, the first
Workability is good because the air bleeding operation of the cylinder hole and the second cylinder hole can be performed together.

According to the second aspect of the present invention, the second master cylinder is formed on the inner peripheral side of the disc rotor of the caliper, and the second cylinder hole is formed on the reciprocating side of the disc rotor with respect to the first cylinder hole. The second master cylinder does not protrude in the circumferential direction of the disk rotor, so that the caliper as a whole is compact, and the vehicle body can be mounted in a small space.

[Brief description of the drawings]

FIG. 1 is a partially sectional front view showing a first embodiment of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a graph showing a comparison of braking efficiency.

FIG. 4 is a partially sectional front view showing a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc brake for vehicles, 3 ... Disc rotor, 4
... Bracket, 6 ... Caliper, 6d ... First cylinder hole,
6e: second cylinder hole, 9: first master cylinder, 1
0, 20 ... second master cylinder, 10a, 20a ... second
Cylinder holes of the master cylinder 10, 10c, 20c: hydraulic chamber of the second master cylinder 10, 11: first hydraulic fluid flow path, 12: second hydraulic fluid flow path, 13: brake hose

Claims (2)

[Claims] A caliper rotatable in a rotation direction of a disk rotor is pivotally supported on a bracket fixed to a vehicle body, and a hydraulic pressure from a first master cylinder connected to the caliper via a brake hose is provided. A first cylinder hole for increasing pressure by a brake torque applied to the caliper, a second master cylinder for increasing pressure by a braking torque acting on the caliper, and a disk brake for a vehicle having a second cylinder hole for increasing pressure by hydraulic pressure from the second master cylinder. The second master cylinder is formed on the inner peripheral side of the disc rotor of the caliper, communicates the cylinder hole of the second master cylinder with the first cylinder hole, and is connected to the hydraulic chamber of the second master cylinder. When the braking torque is equal to or less than a predetermined value, the first cylinder hole and the second cylinder hole are communicated with each other. When the torque is equal to or more than a predetermined value, the communication between the first cylinder hole and the second cylinder hole is interrupted. 2. A caliper rotatable in a rotation direction of a disk rotor is pivotally supported on a bracket fixed to a vehicle body, and a hydraulic pressure from a first master cylinder connected to the caliper via a brake hose is provided. A first cylinder hole for increasing pressure by a brake torque applied to the caliper, a second master cylinder for increasing pressure by a braking torque acting on the caliper, and a disk brake for a vehicle having a second cylinder hole for increasing pressure by hydraulic pressure from the second master cylinder. The disk for a vehicle according to claim 1, wherein the second master cylinder is formed on the inner peripheral side of the disk rotor of the caliper, and the second cylinder hole is formed closer to a recirculation side of the disk rotor than the first cylinder hole. brake.