JPS5849546A - Hydraulic pressure control valve for brake of vehicle - Google Patents

Abstract

PURPOSE:To reduce the size of the device by facing both ends of a piston to an input cylinder and an output cylinder, respectively and by disposing one seal between them for division so as to have the travel of the piston susceptible to the differential liquid pressure and the force of a spring. CONSTITUTION:A housing 4 for an inertia ball 3 is formed at the deep position of an input cylinder 2 which is placed inside a valve body 1 and a plug 5 is inserted in the liquid-tight manner at the open end of the input cylinder 2. A port 8 which communicates with an input port 7 is connected to the input cylinder 2. An output cylinder 9 is put inside the plug 5 and communicated with an output port 11 by a passage 10. At the border of both the cylinders 2 and 9 a seal member 12 is fit to the inner periphery of the output cylinder 9 in the frictional conjunction with the periphery of a small-diameter part 14 of the piston 13. A coiled spring 19 which is inserted into the input cylinder 2 is engaged on the periphery of the piston 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake fluid pressure control valve for a vehicle, and particularly to a deceleration sensing type brake fluid pressure control valve.

Conventional deceleration-sensing brake fluid pressure control valves have a deceleration sensing section using an inertial body and a proportional pressure reducing section inside the valve body, resulting in a complex valve structure and large size. It had to become something. Therefore, it is possible to consider a simple and compact control valve in which the inertial body and the differential piston are arranged on the same axis (for example,
4-'137684). A control valve with such a configuration performs proportional pressure reduction control based on the area ratio of the input side and output side of the differential piston, and is suitable for applications where the load difference between empty and loaded is relatively small. In order to create a difference in area between the input side and the output side of the piston, it is necessary to provide a step part in the middle of the cylinder, and it is necessary to fit seal rings to the piston before and after the step. Therefore, two sliding parts are required, which poses problems in terms of sliding resistance and durability.

Therefore, this invention is designed to reduce the pressure proportionally by the spring constant of the spring in contact with the piston, without relying on the principle of a differential piston, and to create a simple and compact deceleration-sensing brake fluid with only one sliding part. The purpose is to provide a pressure control valve. Hereinafter, the present invention will be explained based on the accompanying drawings.

A housing chamber 4 for an inertial ball 3 is formed at the actual location of an input cylinder 2 provided in the valve body 1, and a plug 5 is inserted into the open end of the input cylinder 2 in a liquid-tight manner. The storage chamber 4 is formed to have a diameter one step smaller than that of the cylinder 2, and has an appropriate number of grooves 6 in the peripheral wall.
This is provided. Further, the input cylinder 2 is provided with a passage 8 that communicates with the input port door.

An output cylinder 9 having a smaller diameter than the input cylinder 2 is provided at the other end of the input cylinder 2, that is, the plug 5, and communicates with the output port 11 through a passage 10 provided in the plug 5. Further, a seal member 12 is attached to the inner periphery of the output cylinder 9 at the boundary between the input cylinder 2 and the output cylinder 9, and is adapted to slide around the small diameter portion 14 of the piston 13. .

Most of the piston 13 is inserted into the input cylinder 2, and the small diameter part 14 at the tip is inserted into the output cylinder 9 from the stepped part 15 provided in the middle.
A collar 17 is formed at the rear end of the piston 13, and is engaged with the stepped portion of the cylinder to prevent the piston 13 from retreating beyond a certain level. In addition, the flange 17
As shown in Fig. 2, the outer periphery of the
'8 are formed in an appropriate number, thereby communicating the input side cylinder 2 and the ball storage chamber 4.

A coil spring 19 inserted into the input cylinder 2 is fitted around the piston 13, and one end of the coil spring 19 is fitted into the flange 17, and the other end is fitted into the inner surface of the plug 5.
0, thereby moving the piston 13 into the housing chamber 4.
It is biased in the direction of . A communication passage 21 is formed in the axis of the piston 13, and a valve seat 22 made of an elastic body is provided at one end of the passage concentrically with the ball 3 together with its holder 23. It communicates with the output cylinder 9.

In addition, 24 in the figure is a bleeder for air removal.

FIG. 3 shows the piping system of the above-mentioned control valve. Like the conventional deceleration sensing type, this control valve is installed at a predetermined angle of inclination (θ), and the input port door is connected to the master cylinder 25. It is used by connecting the output port 11 to the rear wheel brake system 26.

Note that the front wheel brake system 27 is directly connected to the output port 25a of the other chamber of the mask cylinder 25.

Next, the operation of the control valve will be explained. When not braking, the ball 3 hits the end wall of the storage chamber 4 due to the inclination angle (θ), and the ball 3 is separated from the valve seat 22. pedal 28
When braking is started by pressing the button, the hydraulic pressure from the mask cylinder 25 is applied to the input port door, the input side cylinder 2,
It acts on the rear wheel brake system 26 through the ball storage chamber 4, the communication path 21, the output cylinder 9, and the output port 11. Until the input hydraulic pressure exceeds a certain value, the input hydraulic pressure and the output hydraulic pressure Pr appear equal, as shown by O-Pl or 0-P2 in FIG. When this input hydraulic pressure rises and exceeds a certain value P1, the deceleration of the vehicle increases to a certain value υ, and the inertial ball 3 starts to move due to inertial force and comes into contact with the valve seat 22. The condition for the inertial ball 3 to start moving is when the deceleration of the vehicle becomes equal to tanθ. When the ball 3 comes into contact with the valve seat 22, a constant brake fluid pressure is sealed in the rear wheel brake system 25. The brake fluid pressure is proportional to the vehicle weight, so the fluid pressure when the vehicle is empty is
As shown in the figure, the hydraulic pressure during loading can be expressed by P2, which is larger than Pl.

When the ball 3 comes into contact with the valve seat 22, the output hydraulic pressure P
Since the increase in r stops and the input hydraulic pressure continues to increase, a hydraulic pressure difference occurs between the input side and the output side. Thus, the force of the hydraulic pressure difference in the cross-sectional area Ax of the small diameter portion of the piston 13 moves the piston to the left, and when this force becomes larger than the set load of the spring 19, the piston 13 moves together with the ball 3, compressing the spring 19, and Increase the output hydraulic pressure Pr. In this case, if the rate of increase in the output hydraulic pressure Pr, that is, the pressure reduction ratio is 6P, then it is expressed as △Pm.

Here, β is the hydraulic rigidity value of the hydraulic pressure absorber (wheel cylinder, etc.) connected to the output port door, that is, the hydraulic pressure I K9/
The rate of increase in volume per cTR, K is the spring constant of the spring 19, and A is the cross-sectional area of the piston small diameter portion 14.

The above β is a value that can be determined depending on the vehicle, and A is a constant value. Therefore, the pressure reduction ratio of the output hydraulic pressure is I(,
That is, it can be determined by the spring constant of the spring 19, and by selecting the spring 19, the pressure reduction ratio can be set to 1 or less.

As described above, the present invention allows both ends of the piston to face the input side cylinder and the output side cylinder, and separates them with one seal, so that the movement of the piston is controlled by the hydraulic pressure difference without depending on the area difference. Since the movement is made in relation to the magnitude of the elasticity of the spring, the degree of proportional reduction of the output hydraulic pressure can be appropriately determined depending on the spring constant of the spring, and characteristics close to ideal braking force distribution can be obtained. In addition, it is possible to reduce the size of the mechanism, and since only one sliding point is required, the durability is also excellent.

[Brief explanation of drawings]

FIG. 1 is a sectional view, FIG. 2 is a sectional view along line II-II, FIG. 3 is a piping system diagram, and FIG. 4 is a characteristic diagram. ' 1...Valve body 2...Input side cylinder 3...Inertial body ball 4...Ball storage chamber 5...
・Plug 7...Input boat 9...Output side cylinder 11...Output port 12...Seal member 13...Piston 14...Small diameter part
19...Coil spring Z...Communication path 2
2... Benza patent applicant Sumitomo Electric Industries Co., Ltd. Agent Kama 1) Text 2 Procedural amendment (spontaneous) January 20, 1981 1, Indication of case 1982 Patent Application No. 150108 2, Title of the invention: Brake fluid pressure control valve for vehicles 3; Relationship with the case of the person making the amendment Patent applicant address: 5-15 Kitahama, Higashi-ku, Osaka Name (F, Kan)
213) Sumitomo Electric Industries, Ltd. 4, as per the agent's attached document, page 6 of the detailed statement of amendment, second line from the bottom, the symbol rBJ in formula (1) has been changed to "
Corrected to "β".

Claims (1)

[Claims] A housing chamber for the inertial ball is formed at one end of the input cylinder provided in the valve body, and an output cylinder is formed at the other end of the input cylinder, and a seal is provided at the boundary between the two cylinders. The seal is brought into sliding contact around the inserted piston, the valve seat of the inertia ball is provided at one end of the communication path formed at the axis of the piston, and the piston is inertized by a spring inserted into the input cylinder. A brake fluid pressure control valve for a vehicle, characterized in that the valve is biased toward a body ball storage chamber.