JPH0248286Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an improvement in a hydraulic control valve, particularly a hydraulic control valve used in a vehicle brake system.

[Background of the idea]

FIG. 2 shows an example of a conventional hydraulic control valve of this type.

Reference numeral 1 denotes a valve body, which includes a liquid chamber 3 that accommodates a hydraulically actuated piston 2 so as to be able to move in the axial direction, an inlet port 4 that is connected to the master cylinder (not shown) of the vehicle, and a brake device (not shown) of the vehicle. An outlet port 5 connected to the side is provided, and the open end of the liquid chamber 3 is closed by a closing plug 6. A blind hole 6a formed in this plug 6
One end of the piston 2 is fitted into the. Reference numeral 7 denotes a one-way oil-tight seal ring disposed between the piston 2 and the fluid chamber 3, which prevents brake fluid from leaking from the fluid chamber 3 toward the plug 6, and prevents brake fluid from flowing in the opposite direction. is becoming more acceptable. Since the sealing performance of the seal ring 7 deteriorates due to wear etc., the brake fluid in the fluid chamber 3 leaks out to the plug 6 side during braking, albeit slightly, and the blind hole 6a of the plug 6 and this blind hole. The air in the shaft hole 2a of the piston 2 that communicates with the piston 6a is compressed and stored in the blind hole 6a. Then, when the hydraulic pressure on the master cylinder side is released, the leaked brake fluid in the blind hole 6a is passed between the inner peripheral surface of the seal ring 7 and the outer peripheral surface of the piston 2 by the air compressed by the leaked brake fluid. Returned to room 3.

By the way, in such a conventional hydraulic control valve, the blind hole 6a of the plug 6 also serves as a bearing for the piston 2, so the air chamber for returning leaked brake fluid to the fluid chamber 3 is The volume of the blind hole 6a
Since it is not enough, we added shaft hole 2 to piston 2.
It formed a.

Therefore, there was a problem that the number of man-hours required for machining the piston 2 increased.

[Purpose of the invention] The present invention was made in order to solve these conventional problems. The object of the present invention is to provide a hydraulic control valve that ensures the following.

[Summary of the idea]

A hydraulic control valve according to the present invention is a hydraulic control valve in which an opening of a cylinder housing a hydraulic control valve mechanism is oil-tightly closed by a cylinder closing plug, and the hydraulic control valve is disposed on the cylinder opening side of the valve mechanism. The end of the piston to be inserted is supported by a cylindrical member so as to be movable in the axial direction with respect to the cylinder, and furthermore, the tip of the cylindrical member and the end of the piston passing through the cylindrical member face the plug, and the surrounding area thereof is A recess forming a first air is formed in the plug, and a second air chamber is formed between the outer periphery of the plug and the cylinder through a gap formed between the tip of the plug and the cylindrical member. It is characterized by:

[Example of idea]

The present invention will be explained in detail below based on the embodiment shown in FIG.

This hydraulic control valve controls the vehicle's braking force as closely as possible to the ideal distribution ratio between the front and rear wheels, and is designed with two independent hydraulic systems in a double piping system to improve the reliability of the braking mechanism. Moreover, the overall simplification is achieved by standardizing the valve mechanism for controlling the front and rear wheel brake fluid pressures of each system.

In the figure, 11 is a cylinder body, and cylinders 12, 1 are concentric inside and gradually increase in diameter toward the opening.
3, 14, 15, 16, 17, 18 are formed,
Further, a threaded portion 19 is formed in the opening, and a cylinder closing plug 20 is screwed and fixed to this threaded portion 19 via a packing 21.
The valve mechanisms housed in each cylinder are similar to known ones, and are not directly related to the present invention, so a brief explanation will be provided for the cylinders 14,
5, 16, and 17, a corner spring 22 as a proportioning valve of the first hydraulic system, a control piston 25 and a valve forming a valve mechanism for opening and closing the communication state between the input oil chamber 23 and the output oil pressure 24. The seat 26 is accommodated, and the cylinders 12,1
3 accommodates a balance piston 27 and a valve seat 28, which constitute a proportioning valve of a second hydraulic system linked to the first hydraulic system. 29 is an input oil chamber of the second hydraulic system, and 30 is an output oil chamber of the same.

One end of the control piston 25 is slidably fitted through the inner cylinder 32 of the fixed inner cylinder member 31 and faces the air chamber A surrounded between the fixed inner cylinder member 31 and the cylinder closing plug 20. It is rare.

33 is a cup seal, and the control piston 25
The sliding surface of the inner cylinder 32 is oil-tightly sealed, and normally oil leakage from this sealing surface is sufficiently prevented, so oil leakage from the input oil chamber 23 to the air chamber A will not occur. do not have.

The plug 20 has a recess 20a that constitutes the air chamber A.
A notch 20c is formed on the outer peripheral surface of the peripheral wall 20b surrounding the recess 20a, and an air chamber B is formed between the notch 20c and the cylinder 18. Then, in a state where this plug 20 is screwed and fixed to the threaded portion 19, the plug 20
A gap 34 is formed between the tip of the peripheral wall 20b and the fixed inner cylinder member 31, and the air chamber A and the air chamber B are communicated through this gap 34.

On the other hand, in the event that oil leaks from the sealing surface of the cup seal 33, the leaked oil will accumulate in the air chamber A. However, this valve is installed on the vehicle with the plug 20 facing downward, and is attached to a fixed inner cylinder member. The tip 32a of the inner cylinder 32 of 31 is connected to the peripheral wall 20 of the plug 20.
Since it is located closer to the bottom of the recess 20a than the tip of the recess 20a, leaked oil cannot enter the air chamber B side through the gap 34.

Therefore, even if leaked oil accumulates in air chamber A, the leaked oil will not enter air chamber B, making it possible to return the leaked oil in air chamber A to the cylinder when the brake is released. .

[Effect of idea]

As explained above, according to the present invention, by providing an air chamber that communicates with the plug and the plug and the cylinder, it is possible to secure an air chamber with a volume sufficient to allow movement of the piston. The air chamber and the second air chamber communicate with each other through the gap formed between the end face of the plug and the cylindrical member, so even if leaked oil accumulates in the first air chamber, the leaked oil will be transferred to the second air chamber. It does not enter the air chamber, making it possible to return leaked oil when oil pressure fluctuates, eliminating the need for conventional machining such as providing a shaft hole in the piston to secure the volume of the air chamber. Effects can be obtained.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure shows a sectional view of a conventional hydraulic control valve. 11...Cylinder body, 12, 13, 1
4, 15, 16, 17, 18...Cylinder, 19
...Screw part, 20...Plug, 21...Puttle, 22...Spring, 23, 24, 29, 3
0... Oil chamber, 25, 27... Piston, 26, 2
8...Valve seat, 31...Fixed inner cylinder member, 3
2...Inner cylinder, 33...Cup seal, 3
4... Gap.

Claims (1)

[Scope of utility model registration request] In a hydraulic control valve in which the opening of a cylinder housing a hydraulic control valve mechanism is oil-tightly closed by a cylinder closing plug, the end of the piston disposed on the cylinder opening side of the valve mechanism is cylindrical. A recess that is supported through the cylinder so as to be movable in the axial direction by a member, and further includes a recess around which the tip of the cylindrical member and the end of the piston that penetrates the cylindrical member face the plug and form a first air chamber. and a second air chamber communicating between the outer periphery of the plug and the cylinder through a gap formed between the tip of the plug and the cylindrical member. .