JP2002274351A - Rear wheel brake fluid pressure control device for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and the number of components of a rear wheel brake fluid pressure control device for a motorcycle. SOLUTION: A valve piston part 12c forming an output chamber 13 communicated with a rear wheel brake side connection passage 6 in a space with a housing 7 is coaxially, integrally, and connectively provided so as to be seatable from an output chamber 13 side on the entire inner circumferential part of a seat member 11 at one end of a first piston 12 inserted inside a housing hole 9. A second piston 14 forming an input chamber 17 communicated with a master cylinder side connection passage 5 in a space with the seat member 11 and allowing fluid-tight and relatively slidable fitting of another end of the first piston 12 is fluid-tightly and slidably fit in the housing hole 9. The first piston 12 is energized by a first spring 19 to a side separating the valve piston part 12c from the seat member 11. A second spring 24 with a spring load larger than that of the first spring 19 is contractedly provided between the housing 7 and a receiving member 20 provided connectively to the second piston 14 in a side opposite to the input chamber 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a housing provided with a master cylinder side connection path connected to a master cylinder and a rear wheel brake side connection path connected to a rear wheel brake, and a liquid in the master cylinder side connection path. As the pressure becomes equal to or higher than the first set pressure, the connection between the master cylinder side connection path and the rear wheel brake side connection path is shut off, and the hydraulic pressure of the master cylinder side connection path is higher than the first set pressure. The present invention relates to a motorcycle rear-wheel brake fluid pressure control device configured to increase the volume of the rear-wheel brake-side connection path as the pressure becomes equal to or higher than a second set pressure.

[0002]

2. Description of the Related Art Conventionally, such a brake fluid pressure control device has
For example, it is already known in Japanese Patent Application Laid-Open No. 8-133040, etc., and increases the brake fluid pressure of the rear wheel brake in proportion to the output pressure of the master cylinder until the output pressure of the master cylinder reaches the first set pressure. The brake fluid pressure of the rear wheel brake is maintained substantially constant as the output pressure of the master cylinder becomes equal to or higher than the first set pressure, and further, as the output pressure of the master cylinder becomes equal to or higher than the second set pressure. When the brake fluid pressure of the rear wheel brake is reduced and the front wheel and the rear wheel brake are operated in conjunction, the distribution ratio of the braking force of the front and rear wheels approaches the ideal distribution ratio.

[0003]

However, in the prior art described above, a pair of storage holes are provided in the housing in parallel, and one of the storage holes has a hydraulic pressure of the master cylinder side connection passage equal to or higher than the first set pressure. As a result, the components of the hydraulic pressure cut-off means for shutting off the connection between the master cylinder side connection path and the rear wheel brake side connection path are accommodated, and the other storage hole is provided with the fluid of the master cylinder side connection path. Components of pressure reducing means for reducing the brake fluid pressure of the rear wheel brake by increasing the volume of the rear wheel brake side connection path in accordance with the pressure becoming equal to or higher than the second predetermined pressure which is higher than the first predetermined pressure. Is stored. That is, the hydraulic pressure cutoff means and the pressure reducing means are configured independently of each other, and the number of parts is large, which causes an increase in the size of the housing, that is, the entire rear wheel brake hydraulic pressure control device.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rear wheel brake fluid pressure control device for a motorcycle, which can reduce the number of parts and reduce the size.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a housing provided with a master cylinder side connection path connected to a master cylinder and a rear wheel brake side connection path connected to a rear wheel brake. And shuts off the connection between the master cylinder-side connection path and the rear wheel brake-side connection path when the hydraulic pressure of the master cylinder-side connection path becomes equal to or higher than the first set pressure. The rear wheel brake hydraulic pressure control device for a motorcycle, which is configured to increase the volume of the rear wheel brake-side connection path in accordance with the second set pressure which is higher than the first set pressure, A communication hole having one end communicating with the rear-wheel brake-side connection passage, and a housing in which one end is coaxially connected to the other end of the communication hole and a master cylinder-side connection passage is opened in an intermediate portion. Is provided in the housing so as to form an annular step between the other end of the communication hole and one end of the storage hole, and when in close contact with the step, the inner peripheral portion is directed inward from the step. An annular sheet member having an annular plate portion that protrudes is fitted in the storage hole in a liquid-tight and slidable manner, and comes into contact with a plurality of circumferential positions of the sheet member from the side opposite to the step portion into the storage hole. An output chamber communicating with the rear-wheel brake-side connection passage is formed at one end of the first piston coaxially and axially movably inserted between the housing and the first piston. A valve piston portion that can be seated from the output chamber side is coaxially and integrally connected to the entire circumference of the inner peripheral portion of the member, and has an annular shape surrounding the axially intermediate portion of the first piston through the master cylinder side connection passage. An input chamber is formed between the input chamber and the sheet member. A bottomed cylindrical second piston for fitting the other end of the first piston in a liquid-tight and relatively slidable manner is liquid-tightly and slidably fitted to the other end of the storage hole, Between the second piston and the first piston, a first spring that biases the first piston toward the side that separates the valve piston from the seat member that is in contact with the step is contracted, and is opposed to the input chamber. The first member is connected to the second piston on the side and movement of the housing toward the input chamber is regulated by the housing.
A second spring for urging the receiving member toward the input chamber with a spring load greater than that of the spring is contracted.

According to such a configuration, the first piston contacts the step portion of the housing by the spring force of the first spring until the hydraulic pressure in the connection passage on the master cylinder side, that is, the input chamber reaches the first set pressure. In this state, the input chamber and the output chamber are in communication with each other, and the connection passage on the rear wheel brake side, that is, the hydraulic pressure of the rear wheel brake is proportional to the output of the master cylinder. The pressure is increased. However, when the hydraulic pressure in the master cylinder side connection path, that is, the input chamber pressure is equal to or higher than the first set pressure, the first pressure is applied from the output chamber side to the direction in which the valve piston portion is seated on the seat member.
The hydraulic pressure acting on the piston overcomes the spring force of the first spring, and the space between the input chamber and the output chamber is shut off by the seating of the valve piston on the seat member. Further, when the hydraulic pressure in the master cylinder side connection path, that is, the input pressure is equal to or higher than the second set pressure which is higher than the first set pressure, the hydraulic pressure acting on the side for moving the second piston away from the step portion is increased by the spring of the second spring. The force overcomes the force and the second piston moves away from the step. As a result, the first piston moves toward the side where the seat member on which the valve piston portion is seated is separated from the step portion, so that the volume of the output chamber communicating with the master cylinder side connection passage increases, and the brake fluid pressure of the rear wheel brake increases. Is decompressed. Thus, the respective components are concentrated and arranged in the communication hole and the storage hole provided coaxially in the housing, and the seat member, the first piston, the second piston, the receiving member, the first spring, and the second spring Since the parts are shared by constituting the hydraulic pressure cutoff means and the pressure reducing means, the number of parts can be reduced, and the housing, that is, the entire rear wheel brake hydraulic pressure control device for a motorcycle can be reduced in size.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on one embodiment of the present invention shown in the attached drawings.

FIGS. 1 to 4 show an embodiment of the present invention. FIG. 1 is a simplified plan view of a motorcycle provided with a braking device, and FIG. 2 is a hydraulic circuit diagram of the braking device. 3 is a longitudinal sectional view of the rear wheel brake fluid pressure control device, and FIG. 4 is a brake fluid pressure characteristic diagram by the rear wheel brake fluid pressure control device.

1 and 2, a front wheel WF of a motorcycle V is provided with a front wheel brake BF and a rear wheel WR.
Is equipped with a rear wheel brake BR. At the right end of the steering handle 1, there is provided a first master cylinder M1 for outputting a hydraulic pressure in accordance with the operation of the brake lever 2. At the left end of the steering handle 1, there is provided a first master cylinder M1 in accordance with the operation of the brake lever 3. A second master cylinder M2 for outputting the hydraulic pressure is provided. When the brake lever 2 is operated alone without operating the brake lever 3, the first master cylinder M1
The front wheel brake BF and the rear wheel brake BR operate in conjunction with each other if the front wheel brake BF is braked by the hydraulic pressure output from the vehicle and the brake lever 3 is operated alone without operating the brake lever 2.

[0010] The first master cylinder M1 is directly connected to the front wheel brake BF. Also, the second master cylinder M2
Is connected directly to the front wheel brake BF and to the rear wheel brake BR via the rear wheel brake fluid pressure control device 4.

In FIG. 3, the rear wheel brake fluid pressure control device 4 includes a master cylinder side connection path 5 to which the second master cylinder M2 is connected and a rear wheel brake side connection path 6 to which the rear wheel brake BR is connected. A housing 7 is provided.

The housing 7 includes a communication hole 8 having one end closed, and a storage hole 9 formed to have a larger diameter than the communication hole 8 and having one end coaxially connected to the other end of the communication hole 8. Communication hole 8
Is formed so as to form an annular step portion 10 between the other end of the storage hole 9 and one end of the storage hole 9. Further, a rear wheel brake side connection path 6 is opened at one end of the communication hole 8, and a master cylinder side connection path 5 is opened at an intermediate part of the storage hole 9.

An annular sheet member 11 is fitted to one end of the storage hole 9 in a liquid-tight and slidable manner. The sheet member 11 has an annular plate portion 11a that is brought into contact with the step portion 10 so that the inner peripheral portion protrudes inward from the step portion 10.
A lip portion 11b which is connected to the outer periphery of the annular plate portion 11a and resiliently contacts the inner surface of the storage hole 9; Are formed in an approximately L-shaped vertical section by an elastic material.

A first piston 12 is inserted into the storage hole 9 coaxially and movably in the axial direction. This first piston 1
2 has a flange 12a projecting radially outward from one end of the first piston 12 so as to come into contact with the protrusions 11c of the sheet member 11, and one end at the center of the flange 12a. A connecting shaft portion 12b having a small diameter and coaxially penetrating the sheet member 11 and a valve piston portion 12c coaxially connected to the other end of the connecting shaft portion 12b are integrally provided. An output chamber 13 communicating with the wheel brake-side connection path 6 is formed between the output chamber 13 and the housing 7 and is loosely inserted into the communication hole 9. Moreover, the valve piston portion 12c is
a at the end of the seat member 11 side, and the valve portion 12d
Is formed in an annular shape so that it can be seated from the output chamber 13 side all around the inner peripheral portion of the annular plate portion 11a in the seat member 11.

A second cylindrical piston 14 having a bottom and an open inner end is slidably fitted to the other end of the storage hole 9. An annular sealing member 15 that is in sliding contact is mounted. The second piston 1
4 is fitted with the other end of the first piston 12 so as to be relatively slidable.
An annular seal member 16 that is in sliding contact with the outer surface of is mounted.
That is, the second piston 14 is liquid-tightly and slidably fitted to the other end of the housing hole 9, and the other end of the first piston 12 is slidably and liquid-tight relative to the second piston 14. Will be fitted. Moreover, an annular input chamber 17 is formed in the housing 7 between the seat member 11 and the second piston 14 so as to communicate with the master cylinder side connection passage 5 and surround the axially intermediate portion of the first piston 12.

Between the spring receiving member 18 mounted on the end of the second piston 14 on the input chamber 17 side and the first piston 12, the valve piston portion 12 c is separated from the seat member 11 in contact with the step portion 10 to open the valve. A first spring 19 for urging the first piston 12 is contracted on a side where the portion 12d is separated from the annular plate portion 11a of the seat member 11.

A receiving member 20 formed separately from the second piston 14 is disposed outside the housing 7, and the receiving member 20 has a disk portion 20a provided on one end side.
However, it is coaxially connected to the second piston 14 on the side opposite to the input chamber 17. Moreover, the disk portion 20a can abut on a ring-shaped regulating surface 21 provided on the housing 7 so as to surround the opening at the other end of the storage hole 9, and the movement of the receiving member 20 toward the input chamber 17 is circular. The plate portion 20a is regulated by contacting the regulation surface 21.

A cover 22 is provided on the housing 7 so as to cover the receiving member 20.
23, and a second spring 24 for urging the receiving member 20 toward the input chamber 17 with a spring load greater than that of the first spring 19 between the cover 22 and the receiving member 20.
Is contracted.

In the meantime, the atmospheric pressure chamber 25 formed between the second piston 14 and the first piston 12 does not undergo pressure increase or decrease due to the relative movement of the first and second pistons 12, 14 in the axial direction. Thus, it is open to the outside through the opening 26 provided in the second piston 14.

Next, the operation of this embodiment will be described with reference to FIG. 4. In the first piston 12, the spring force W1 of the first spring 19 separates the valve portion 12d of the valve piston portion 12c from the seat member 11. While acting in the seating direction, that is, in the valve opening direction, the hydraulic pressure P in the output chamber 13 and the input chamber 17 is applied to the first piston 1 at the contact portion of the seal member 16.
The liquid pressure (P × S1) obtained by multiplying the cross-sectional area S1 of FIG. 2 acts on the direction in which the valve portion 12d of the valve piston portion 12c is seated on the seat member 11, that is, the valve closing direction. Therefore, when the output hydraulic pressure of the second master cylinder M2 (brake hydraulic pressure of the front wheel brake BF) is relatively low, the first piston 12 is actuated by the spring force of the first spring 19 so that the valve piston 1
2c has been moved to a position where it is separated from the sheet member 11, and the input chamber 17 and the output chamber 13 are in communication. Therefore, the brake fluid pressure of the rear wheel brake BR also increases as the brake fluid pressure of the front wheel brake BF increases.

The output hydraulic pressure of the second master cylinder M2 increases, and the spring force W1 in the valve opening direction and the hydraulic pressure (P
× S1) balances the first set pressure P1 (= W1 / S)
1) When the above is reached, the first piston 12 moves toward the side where the valve portion 12d of the valve piston 12c is seated on the seat member 11 against the spring force of the first spring 19, and between the input chamber 17 and the output chamber 13, that is, The state in which the connection between the master cylinder side connection path 5 and the rear wheel brake side connection path 6 is cut off, and the brake hydraulic pressure of the rear wheel brake BR is maintained substantially constant even if the output hydraulic pressure of the second master cylinder M2 further increases. You.

In the state where the connection between the master cylinder side connection path 5 and the rear wheel brake side connection path 6 is interrupted, the second piston 14 outputs the output to the cross-sectional area S2 of the storage hole 9 at the contact portion of the seat member 11. The hydraulic pressure (P1 × S2) obtained by multiplying the hydraulic pressure P1 of the chamber 13 acts via the first spring 19, and the sectional area S3 of the storage hole 9 at the contact portion of the sealing member 15 is calculated from the sectional area S1. (S3-S1)
Multiplied by the hydraulic pressure P of the input chamber 17 に P ×
(S3-S1)} is acting, and the second piston 14 is biased in a direction away from the step portion 10 by the sum of the liquid pressures {P1 × S2 + P × (S3-S1)}. On the other hand, the spring force W2 of the second spring 24 that urges the second piston 14 toward the step portion 10 is applied to the second piston 14.
It acts via a receiving member 20 connected to the second piston 14.

Thus, the output hydraulic pressure of the second master cylinder M2, that is, the hydraulic pressure of the input chamber 17, becomes higher than the first set pressure P1, and the sum of the hydraulic pressures acting on the second piston 14, ΔP1
× S2 + P × (S3-S1)} and the second set pressure P2 ｛= (W2) at which the spring force W2 of the second spring 24 is balanced.
When the hydraulic pressure increases more than (−P1 × S4) / (S3−S1)}, the second piston 14 moves to the side away from the step portion 10. As a result, the first piston 12 moves to the side where the seat member 11 on which the valve portion 12d of the valve piston portion 12c is seated is separated from the step portion 10, so that the volume of the output chamber 13 communicating with the master cylinder side connection passage 6 is reduced. As a result, the brake fluid pressure of the rear wheel brake BR is reduced.

That is, according to the rear wheel brake hydraulic pressure control device 4, as shown by the point 0-ABC in FIG. 4, the rear wheel brake BR which approximates the ideal distribution characteristic of the front wheel brake BF to the hydraulic pressure is obtained. It is possible to obtain a hydraulic pressure.

Further, in the rear wheel brake fluid pressure control device 4,
Each component is centrally disposed in a communication hole 8 and a storage hole 9 provided coaxially in a housing 7, and the seat member 1
1, first piston 12, second piston 14, receiving member 2
0, the first spring 19 and the second spring 24 share the parts so as to constitute the hydraulic pressure cut-off means and the pressure reducing means. Therefore, the number of parts is reduced, and the housing 7, that is, the rear wheel brake hydraulic pressure control device is reduced. 4 can be reduced in size.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, in the above embodiment, the second piston 14
And the receiving member 20 connected to the second piston 14 are formed separately, but the second piston 14 and the receiving member 20 may be formed integrally.

[0028]

As described above, according to the present invention, the parts commonly used to constitute the hydraulic pressure interrupting means and the pressure reducing means are concentrated in the communication hole and the accommodation hole provided coaxially in the housing. With this arrangement, the number of components can be reduced, and the size of the housing, that is, the entire rear wheel brake hydraulic pressure control device can be reduced.

[Brief description of the drawings]

FIG. 1 is a simplified plan view of a motorcycle including a braking device.

FIG. 2 is a hydraulic circuit diagram of the braking device.

FIG. 3 is a longitudinal sectional view of a rear wheel brake fluid pressure control device.

FIG. 4 is a brake fluid pressure characteristic diagram by a rear wheel brake fluid pressure control device.

[Explanation of symbols]

 4 ... Rear wheel brake fluid pressure control device 5 ... Master cylinder side connection path 6 ... Rear wheel brake side connection path 7 ... Housing 8 ... Communication hole 9 ... Storage hole 10 ... Step 11: Seat member 11a: Annular plate 12: First piston 12c: Valve piston 13: Output chamber 14: Second piston 17: Input chamber 19 ... 1st spring 20 ... receiving member 24 ... 2nd spring BR ... rear wheel brake M2 ... master cylinder

Claims (1)

[Claims] 1. A master cylinder side connection path (5) connected to a master cylinder (M2) and a rear wheel brake (B).
R) is provided with a housing (7) provided with a rear wheel brake-side connection path (6) connected to the master cylinder-side connection path (5). The connection between the side connection path (5) and the rear wheel brake side connection path (6) is cut off, and the hydraulic pressure of the master cylinder side connection path (5) is equal to or higher than a second set pressure which is higher than the first set pressure. A rear wheel brake hydraulic pressure control device for a motorcycle configured to increase the volume of the rear wheel brake-side connection path (6) in accordance with the rear wheel brake-side connection path (6). Communication hole (8)
And a storage hole (9) for connecting one end coaxially to the other end of the communication hole (8) and opening a master cylinder side connection path (5) at an intermediate portion, in addition to the communication hole (8). An annular step (10) is formed between the end and one end of the storage hole (9) in the housing (7). An annular sheet member (11) having an annular plate portion (11a) protruding inward from the portion (10) is fitted in the storage hole (9) in a liquid-tight and slidable manner, and the step portion (10) is provided. ) Is coaxially and axially movably inserted into the storage hole (9) while contacting a plurality of circumferential positions of the sheet member (11) from the side opposite to the first side.
An output chamber (13) communicating with the rear wheel brake side connection path (6) is formed at one end of the piston (12) between the piston (12) and the housing (7), and is loosely inserted into the communication hole (8). A valve piston portion (12c) that can be seated from the output chamber (13) side is coaxially and integrally connected to the entire periphery of the inner peripheral portion of the seat member (11), and is connected to the master cylinder side connection passage (5). The annular input chamber (17) surrounding the axially intermediate portion of the first piston (12) through the seat member (11)
And a bottomed cylindrical second piston (14) that fits the other end of the first piston (12) in a liquid-tight and relatively slidable manner. The second piston (14) is fitted to the end side in a liquid-tight and slidable manner.
Between the first piston (12) and the step (10)
A first spring (19) for urging the first piston (12) is contracted to the side that separates the valve piston (12c) from the seat member (11) that has come into contact with the input chamber (17).
The first member (20) is connected to the second piston (14) on the opposite side and is restricted from moving toward the input chamber (17) by the housing (7). A rear wheel brake fluid for a motorcycle, wherein a second spring (24) for urging the receiving member (20) toward the input chamber (17) with a spring load greater than that of the spring (19) is contracted. Pressure control device.