JPS6117703B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic pressure control valve for anti-skid.

Hydraulic brakes are used in automobiles and other vehicles, but if the rising hydraulic pressure from the master cylinder, which is activated by the brake pedal pressed by the driver, is directly applied to the brake cylinder to perform braking, it is difficult to brake the wheels. Since the brake cylinder may lock up, which is dangerous, an anti-skid device is used to prevent this danger by interposing a hydraulic pressure control valve in the communication fluid path between the master cylinder and the brake cylinder to appropriately intermittent fluid pressure. It will be done.

To explain the conventional anti-skid device for an automobile with reference to FIG. 1, 1 is a brake pedal, 2 is a master cylinder connected to the brake pedal 1, and is connected to a master cylinder via a pipe 3, a hydraulic control valve body 4, and a pipe 5. It is connected to a brake cylinder 7 provided on the wheel 6, and when the brake pedal 1 is depressed, hydraulic pressure that increases is applied to the brake cylinder 7 to apply braking to the wheel 6. The fluid pressure control valve main body 4 interrupts the fluid in this system to supply the wheels 6.
This is to prevent locking.

A gear plate 8 is integrally attached to the wheel 6, and a wheel angular velocity detector 9 is provided opposite the teeth of the gear plate 8. The output signal of the wheel angular velocity detector 9 is applied to a control circuit 10, and the solenoid valve 11 is switched to position a or position b based on the brake release signal or brake signal output from the control circuit 10.

A pump 12 and a drain tank 13, which serve as a hydraulic pressure source, are connected to the solenoid valve 11.
As will be described later, the liquid supply/drainage port 24 of the hydraulic control valve main body 4
These can be switched against each other.
14 is an accumulator, and 15 and 16 are conduits.

Next, the hydraulic control valve main body 4 will be explained. A stepped cylinder having a large diameter hole 17, a medium diameter hole 18, and a small diameter hole 19 is formed in the hydraulic pressure control valve main body 4. A stepped piston 20 having a portion that fits into the large-diameter hole 17 and a portion that fits into the medium-diameter hole 18 is fitted into the cylinder so as to tightly slide therein. 21 is a seal ring.

On the right side of the large diameter portion of the stepped piston 20, there is a stepped portion 22 having a slight depth, and a first pressure chamber 23 is formed in the large diameter hole 17 on the stepped portion 22 side of the stepped piston 20. has been done.

The hydraulic control valve main body 4 has a liquid supply/drainage port 24 opened to the large diameter hole 17 and a liquid supply/drainage port 25 opened to the medium diameter hole 18.
In addition, a liquid supply/drainage port 26 opened at the tip side of the small diameter hole 19 is provided, and each of the above-mentioned pipe lines 1
6, 5, and 3 are connected.

The right tip 27 of the stepped piston 20 has a small diameter hole 1
9 and is in contact with a ball 29 that is urged leftward by a spring 28.
A spring 30 stronger than the spring 28 is installed between the left end of the stepped piston 20 and the bottom surface of the large diameter hole 17.
Since the stepped piston 20 is always urged to the right by interposing the stepped piston 20, the ball 29 is pushed rightward by the tip 27 of the stepped piston 20,
The valve seat 31 is moved away from the valve seat 31 against the pressure. The ball 29 and the valve seat 31 constitute a valve mechanism. 32 is a second pressure chamber formed within the medium diameter hole 18.

Next, the operation of this conventional device will be explained.

First, when the signal from the control circuit 10 is a braking signal, the solenoid valve 11 is normally located on the position b side as shown in the figure.
is connected to the drain tank 13, and when a brake release signal is received, the position is switched to the side a and the first pressure chamber 23 is connected to the pump 12 side. When the driver depresses the brake pedal 1 when the solenoid valve 11 is in position b as shown in the figure, the hydraulic pressure from the master cylinder 2 increases, and this hydraulic pressure is applied to the pipe line 3 and the hydraulic control valve main body 4. The liquid is applied to the brake cylinder 7 via the liquid drain port 26, the second pressure chamber 32, the liquid supply/drain port 25, and the pipe line 5, and brakes the wheels 6.

During this braking, a control circuit 10 receives an output signal from a wheel angular velocity detector 9 provided opposite to the teeth of a gear plate 8 that rotates the wheel 6 integrally.
When it is detected that the rotation of the solenoid valve 11 is close to being locked, a side movement loosening signal is given to the solenoid valve 11, and it is switched to the position a side so that the hydraulic pressure from the pump 12 is supplied to the first pressure chamber 23. do.

When hydraulic pressure is supplied to the first pressure chamber 23, the stepped piston 20 moves to the left against the spring 30 until it is separated from the valve seat 31 by the tip 27 of the stepped piston 20. The ball 29 that was sitting is now seated on the valve seat 31, cutting off communication between the master cylinder 2 and the brake cylinder 7.

By cutting off the communication of this system, the volumes of the second pressure chamber 32, liquid supply/drainage port 25, pipe line 5, and brake cylinder 7 become closed to the outside, and then When the stepped piston 20 moves to the left due to the hydraulic pressure in the pressure chamber 23,
The pressure in the second pressure chamber 32 decreases and the wheel 6 is released from its near-lock condition.

When the wheel 6 is released from the nearly locked state and the rotational speed is restored and there is no danger of the wheel being locked, a brake signal from the control circuit 10 causes the solenoid valve 11 to return to its original state, that is, position b.
Returning to the side, the first pressure chamber 23 is connected to the drain tank 13.
The stepped piston 20 is pushed back to the right by the elastic force of the spring 30. As a result, the brake cylinder 7 is pressurized again to apply braking to the wheels 6.

This device prevents the wheels 6 from locking by repeating the operation described above, and the braking signal c of the solenoid valve 11 and the pressure fluctuation d of the brake cylinder 7 shown in FIG. 2 are as follows. It is a relationship. As is clear from FIG. 2, there is a delay due to the mechanically operating parts from the time when the control circuit 10 issues a signal to operate the solenoid valve 11 until the start of pressure reduction or pressure increase, and a state where the pressure is excessively increased or decreased may occur. It was happening. Therefore, there is a drawback that the operation lacks smoothness, and an excessive increase in hydraulic pressure may cause the wheels 6 to lock.

This invention eliminates these drawbacks,
One embodiment of this will be described with reference to FIG. 3. The hydraulic control valve main body 33 has a liquid drain port 34 and a liquid supply port 35 in the medium diameter hole 18 instead of the liquid supply and drain port 24 of the conventional device described above. The stepped piston 36 is provided independently at a predetermined interval in the operating direction, while the stepped piston 3
A small diameter hole 37 of an appropriate length is formed on the outer circumferential surface of the portion that fits into the medium diameter hole 18 of 6, and this small diameter hole 37 communicates and blocks communication between the liquid supply port 35 and the liquid drain port 34. It begins to form a valve. The stepped piston 36 has two passages 38 in the diametrical direction.
39 is provided, and these two passages 38 and 39 are communicated through a passage 40 provided at the center of the stepped piston 36. One passage 38 has a small diameter hole 37
the other passage 39 is connected to the first pressure chamber 23
There are openings in each part.

The above-mentioned liquid supply port 35 and liquid drain port 34 and pipe line 1
6, two check valves 41 and 42 having different directions are interposed. That is, between the pipe line 16 and the liquid supply port 35, there is a check valve 42 that opens against the flow from the pipe line 16 toward the liquid supply port 35 and restricts the flow in the opposite direction. A check valve 41 that opens against the flow in the direction from the drain port 34 toward the pipe line 16 is interposed between the channel 16 and the drain port 34 . Other parts are the same as those in Figure 1, so
The same parts as in FIG. 1 are given the same reference numerals.

In the device shown in FIG. 3, as well as in the device shown in FIG.
0 switches the solenoid valve 11 to position a and moves the stepped piston 36 to the left. That is, the hydraulic pressure from the pump 12, which is a hydraulic pressure source, is transmitted from the solenoid valve 11 to the pipe line 16,
It enters the liquid supply port 35 through the check valve 42, and enters the passage 38,
acts on the first pressure chamber 23 through 40, 39,
This will move the stepped piston 36 to the left.

In this case, when the stepped piston 36 moves to the left by a certain distance and the small diameter hole 37 communicates the liquid supply port 35 with the liquid drain port 34, the hydraulic pressure from the pump 12 is transferred from the liquid supply port 35 to the liquid drain port 34. Go back to the side and pump 12
Hydraulic pressure supply from is limited. Therefore, the moving speed of the stepped piston 36 to the left becomes slow from this point on.

When the wheel 6 is released from the nearly locked state and the solenoid valve 11 returns to the original position b, the stepped piston 36 will move to the right in the same way as in FIG. In this case, the small diameter hole 37 moves rapidly while first communicating with the liquid drain port 34, and then when the small diameter hole 37 communicates only with the liquid supply port 35, the flow from the first pressure chamber 23 increases. Liquid discharge is restricted and the stepped piston 36 moves slowly. These operating states are the fourth
The result will be as shown in the figure.

As is clear from FIG. 4, the stepped piston 36
In the reciprocating stroke, the liquid supply port 35, the liquid drain port 3
4 and a small diameter hole 37, the speed becomes slow after the spool valve has moved a certain amount.
Since there is no excessive increase or drop in hydraulic pressure, it is possible to effectively brake the wheels 6 without locking them.

As described above, in this invention, the inner periphery of the hole of the hydraulic control valve body into which the small diameter portion of the stepped piston fits is provided with a liquid supply port 35 for guiding the working liquid and a liquid drain port 34 for discharging the working liquid. and are opened at intervals in the operating direction of the stepped piston, and the stepped piston has each liquid port 3.
4, 35 and the first pressure chamber 23
8 is provided, and the peripheral surface of the stepped piston where this passage faces the inner periphery of the hole in the hydraulic control valve main body is reduced in diameter to form a small diameter portion 37, and this small diameter hole 37 serves as a liquid supply port 35 and a liquid drain port 34. Since it is configured to act as a spool valve that opens and closes, when the stepped piston 36 moves more than a certain amount, its operation slows down, so delay in the operation of the valve mechanism does not become a problem and prevents an excessive rise in hydraulic pressure. It is possible to obtain an anti-skid hydraulic control valve that operates safely without causing any drop or drop.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional system diagram showing a conventional anti-skid device for automobiles, Fig. 2 is a characteristic diagram showing the operating state of the device shown in Fig. 1, and Fig. 3 is a longitudinal cross-section of an embodiment of the present invention. 4 are characteristic diagrams showing the operating state of the device shown in FIG. 3. 2... Master cylinder, 6... Wheel, 7... Brake cylinder, 9... Wheel angular velocity detector, 11
...Solenoid valve, 12...Pump, 13...
...Drain tank, 17...Large diameter hole, 18...Medium diameter hole, 22...Step part, 23...First pressure chamber, 29
... Ball, 31 ... Valve seat, 32 ... Second pressure chamber, 33 ... Hydraulic pressure control valve body, 34 ... Drain port,
35...Liquid supply port, 36...Stepped piston, 37...
...Small diameter section, 38... passage.

Claims (1)

[Scope of Claims] 1. A stepped piston is fitted inside the hydraulic control valve main body having a stepped hole to define a first pressure chamber on the large diameter stepped portion side, and A second pressure chamber is defined between the small-diameter end of the piston and the hydraulic pressure control valve main body, and the first pressure chamber is selectively connectable to a hydraulic pressure source or a drain tank, and the The second pressure chamber has one end connected to the master cylinder and the other end connected to the brake cylinder, and the second pressure chamber is provided with a valve mechanism that communicates with and shuts off the master cylinder and the brake cylinder. Hydraulic pressure for anti-skid switching the connection of the first pressure chamber to the hydraulic pressure source or the drain tank by determining the rotational state, and operating or returning the stepped piston to open and close the valve mechanism. In the control valve, a liquid supply port and a liquid drain port are provided at a predetermined interval in the operating direction of the stepped piston on the inner periphery of the hole of the hydraulic control valve body into which the small diameter portion of the stepped piston fits. The stepped piston is provided with a passage that communicates each liquid port with the first pressure chamber, and the circumferential surface facing the inner circumference of the hole of the passage is reduced in diameter, and the outer circumference of the fitting part is reduced. 1. A hydraulic pressure control valve for anti-skid, characterized in that the valve is configured to act as a spool valve for opening and closing a liquid supply port or a liquid drain port.