JPH0225068B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic pressure sensing type check valve, and is particularly used in a brake control system for preventing skidding during braking and improving starting performance on a split road. This invention relates to a fluid pressure sensing type check valve.

[Conventional technology]

This type of brake control system has a first flow path that connects the master cylinder to the wheel cylinder via the solenoid valve, and a first flow path that connects the master cylinder to the wheel cylinder via the solenoid valve. and a third flow path connected between the electromagnetic shaft valve and the wheel cylinder and connected to the reservoir via the electromagnetic valve. The electromagnetic shut valve and the electromagnetic valves in the second and third flow paths are controlled by a controller based on signals from wheel lock sensors.

This system operates as an anti-skid device by closing the above-mentioned shuttle valve according to the deceleration state of the wheel rotation speed, opening the solenoid valve in the third flow path to reduce the brake pressure, and further reducing the brake pressure until the wheel rotation speed is sufficient. When the brake pressure is restored, the solenoid valve in the second flow path opens and the brake pressure is increased again.

[Problem that the invention seeks to solve]

The present invention provides a hydraulic pressure sensing type check valve which, in addition to the anti-skid function described above, is capable of performing so-called traction control in order to improve starting performance on a split road. When starting on a split road, this traction control detects the difference in rotational speed between the left and right driving wheels and prevents slipping on the side of the low-μ road.
It applies braking force to the driving wheels on the roadside to obtain the driving force for a smooth start. In this case, close the first flow path shut valve and close the second and third flow path valves.
The brake pressure is increased or decreased by opening and closing the solenoid valve in the flow path, and the rotational speed of the wheels is adjusted to an appropriate level.

[Means to solve the problem]

The check valve according to the present invention has a plunger slidably disposed in a chamber housing a valve body, the plunger having different pressure-receiving areas and having an internal passage communicating between the two pressure-receiving surfaces. A spring is provided between the large pressure receiving surface side and the valve body to seat the valve body on a seat, and the plunger is further urged toward the large pressure receiving surface side by a spring with a large spring force.
The valve body is pressed from the back. In the brake control system, this check valve is connected in parallel with the electromagnetic shut valve in the first flow path.

[Effect]

When the pressure in the room is high (above a predetermined value), the plunger moves and separates from the valve body, removing the force that presses the valve body and functions as a normal check valve.When the pressure is low, the plunger does not move and the valve body The pressure can be maintained while the flow path remains closed. Therefore, by using this check valve in a brake control system, anti-skid and traction control becomes possible.

[Embodiments of the invention]

The present invention will be explained below based on illustrated embodiments.
Fig. 1 shows an example of a hydraulic pressure sensing type check valve. The plug 2 is inserted into the large diameter hole 1a from the portion 1c and is screwed together. The part 2a of the plug 2 inserted into the main body 1 includes the main body 1.
A hole 2b having a smaller diameter than the large diameter hole 1a is formed in the large diameter hole 1a and the hole 2b of the plug 2.
Large diameter portion 3a with an outer diameter approximately equal to the inner diameter of each hole
A stepped plunger 3 having a small diameter portion 3b is slidably housed therein. Annular grooves 3 are formed in the large diameter portion 3a and the small diameter portion 3b of the plunger 3, respectively.
c, 3d are formed, and liquid tightness is maintained between the large diameter hole 1a and the hole 2b by seal members 4, 5 fitted in each annular groove.

Hole 3 formed on the large diameter portion 3a side of the plunger 3
One end of a holder 6 is slidably fitted into e, and a spherical valve body 7 is caulked to the other end of the holder 6. And plunger 3 is plug 2
The holder 6 is biased toward the large diameter portion 3a by a spring 8 provided between the end surface 2c of the plunger 3 and the stepped portion 3f of the plunger 3.
The plunger 3 is biased outward from the hole 3e of the plunger 3 by a spring 9 with a small spring force provided between the bottom surface 3g of the plunger 3 and the end surface 6a of the holder 3.
Therefore, the valve body 7 is held against the seat 1 by the spring 9.
0 and is pressed by a spring 8 via the plunger 3 and holder 7.

Passages 2d, 3h, and 1d are formed in the shaft core portions of the plug 2, plunger 3, and main body 1, respectively;
Further, the holder 6 is provided with an axial passage 6b and a radial passage 6c, and these passages 2d, the plug hole 2b, the passage 3h, the plunger hole 3e,
A brake oil flow path is formed by the passages 6b and 6c, the chamber 11 in the small diameter hole 1b of the main body, and the passage 1d, and this flow path is such that the valve body 7 is connected to the passage 1 of the main body 1.
d is normally closed by sitting on the seat 10 in the opening. Note that 1e is an air vent passage communicating with the chamber 9 of the main body 1.

The hydraulic pressure sensing check valve configured as described above is arranged in parallel with the electromagnetic shut valve provided between the master cylinder and the wheel cylinder in the brake control system.
The passage 2d of the plug 2 is connected to the master cylinder side, and the passage 1d of the main body 1 is connected to the wheel cylinder side.

This fluid pressure sensing type check valve attempts to move to the right when the pressure on the master cylinder side (right side in the figure) is higher than a predetermined pressure, that is, due to the difference in pressure receiving area between the large and small diameter portions 3a and 3b of the plunger 3. When the force exceeds the elastic force of the spring 8 that biases the plunger 3 to the left, the plunger 3 moves to the right and separates from the holder 6, so that the valve body 7 is held by the holder 6. The spring 9, which has a small spring force, functions as a normal check valve seated on the seat 10, allowing the hydraulic pressure in the wheel cylinder (left side in the drawing) to flow back to the master cylinder side. On the other hand, when the pressure on the master cylinder side is low, no force is exerted to move the plunger 3 to the right, so that the plunger 3 hits the back surface of the holder 6 and is stopped. Therefore, even if the hydraulic pressure on the wheel cylinder side increases, the valve body 7 does not separate from the seat 10, and the hydraulic pressure on the wheel cylinder side remains sealed and maintained at a high pressure. The fluid pressure sensing type check valve according to this embodiment operates as described above, and therefore, when used in a brake control system, it functions as a check valve in the case of anti-skid, and functions as a check valve in the case of traction control. , the pressure can be maintained while the flow path is closed.

FIG. 2 shows a second embodiment of the present invention, in which a stepped plunger 3 slides in a main body 1 and a plug 2 screwed into the main body 1 while maintaining liquid tightness, similar to the above embodiment. It is housed in a movable manner. The plunger 3 is connected to the end surface 2c of the plug 2.
is biased toward the large diameter portion 3a by a pressure sensing spring 8 provided between the main body 1 and the stepped portion 3f, and is stopped when the end surface 3i of the large diameter portion hits the stepped portion 1e of the main body 1. .

The plunger 3 has an opening 3j on the large diameter portion 3a side.
A concave portion 3k having a slightly small diameter is formed, and a holder 6 holding a valve body 7 is accommodated within this concave portion 3k. The holder 6 is urged toward the outside of the recess 3k by a low-pressure spring 9 provided between its end surface 6a and the bottom surface of the small diameter hole 3l of the axis of the recess 3k. The valve body is pressed in the same direction by the high-pressure spring 13 disposed between the retainer 12 that abuts the retainer 6b and the bottom surface 3m of the concave portion 3k, and the valve body is inserted into the seat 14 press-fitted into the end hole 1f of the main body 1. 7 is seated and stopped. At this time, a gap _l1 is formed between the retainer 12 and the inner surface of the opening 3j of the plunger 3, and this gap
l ₁ is smaller than the gap l 2 between the small diameter end face 3n of the plunger 3 and the bottom face 2e of the hole in the plug ₂ . The spring force of the high pressure spring 13 is set to be smaller than that of the hydraulic pressure sensing spring 8 and much larger than that of the low pressure spring 9.

In the check valve according to the second embodiment, when the pressure on the master cylinder side (right side in the figure) is higher than a predetermined value, the plunger 3 moves to the right, and when the amount of movement exceeds _l1 , the plunger 3 moves to the right. opening 3j
After the inner surface abuts the retainer 12, this retainer 1
2 is separated from the holder 6 to release the holder 6 and the valve body 7 from the spring force of the high pressure spring 13. As a result, the valve body 7 is opened by the hydraulic pressure on the wheel cylinder side, allowing pressure oil to flow back to the master cylinder side. In addition, if the plunger 3 does not move when the hydraulic pressure on the master cylinder side is below a predetermined value, the valve body 7 is pressed by the low pressure spring 9 and the high pressure spring 13, which has a larger spring force. The hydraulic pressure on the wheel cylinder side is sealed and maintained at high pressure without being released by the hydraulic pressure on the wheel cylinder side. In addition, in this check valve, the valve body 7 and the seat 1
Even if a slight liquid leak occurs from between 4 and the plunger 3 is slightly displaced by this generated liquid pressure,
Since the biasing force of the high-pressure spring 13 against the valve body 7 is not released, there is no risk of malfunction in which the check valve opens even though the pressure on the master cylinder side is low.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a hydraulic pressure sensing type check valve that can open or close the check valve depending on the level of hydraulic pressure on the outlet side of the check valve.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of the first invention;
FIG. 2 is a longitudinal sectional view showing an embodiment of the second invention. 3: plunger, 3a: large pressure receiving surface side (large diameter part) of plunger, 3b: small pressure receiving surface side (small diameter part) of plunger, 3e, 3h: internal passage of plunger,
7: Valve body, 8: Spring that biases the plunger, 9: Spring that seats the valve body.

Claims (1)

[Claims] 1. In a check valve that allows pressure fluid to flow in only one direction, both ends have different pressure receiving areas in a chamber in which a valve body is accommodated, and the two pressure receiving surfaces are in communication. A plunger having an internal passage formed therein is slidably disposed, and a spring for seating the valve body on the seat is provided between the large pressure receiving surface side of the plunger and the valve body, and a spring with a large spring force is provided to seat the plunger. A fluid pressure sensing type check valve characterized in that the large pressure receiving surface side is biased and brought into elastic contact with the valve body. 2. In a check valve that allows pressure fluid to flow in only one direction, an internal passage having different pressure receiving areas at both ends and communicating the two pressure receiving surfaces is formed in the chamber in which the valve body is housed. A first spring with a lower spring force and a second spring with a higher spring force are seated on the valve body and the seat between the large pressure receiving surface side of the plunger and the valve body. 2 springs, and a hydraulic pressure sensing spring with the largest spring force that biases the plunger toward its large pressure receiving surface.
A hydraulic pressure sensing type check valve characterized in that when the plunger is moved by hydraulic pressure, the second spring is deflected and the valve body is released from the spring force of the second spring.