JPH0260866A - Anti-lock hydraulic control device - Google Patents

Abstract

PURPOSE:To secure the braking force even with the blinding of an orifice and the like by enlarging the flow area of a fixed orifice part when the differential pressure of the fixed orifice reaches the specific value exceeding the constant value at the pressure reapplying time of an anti-lock. CONSTITUTION:When an electromagnetic valve 5 is disconnected at the pressure reapplying time of an anti-lock, a variable orifice is formed between the metering edge 32d of a spool 32 and a passage 31f, and a small passage is formed starting with an entrance 31a, onto a passage 31d, a fixed orifice 33, a spring chamber 36, passages 31f, 31e, the peripheral groove part 32a of the spool 32 and an exit so that a wheel brake 4 is moderately boosted by the balance between the differential pressure at the fixed orifice 33 and a spring 34. When the spool 32 is adhered, the adjusting action of the variable orifice is stopped so that the differential pressure becomes large, the fixed orifice 33 is alienated from the spool 32, a passage to the spring chamber 36 through the periphery of the fixed orifice 33, and the flow is increased. The braking force can be thus secured even with the blinding of the orifice and the adhesion of the spool.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an anti-lock hydraulic pressure control device equipped with a flow control valve that can ensure a minimum normal braking force even in an emergency.

[Conventional technology]

Vehicle anti-lock devices are becoming popular, and costs are being reduced.
Application to small cars is an urgent need. One solution to this problem is to use one solenoid valve per wheel, for example, instead of the hydraulic pressure control using two solenoid valves per wheel as shown in Japanese Patent Publication No. 49-283071, to reduce pressure and slowly increase the pressure. The GB851 control method uses two control modes.
2.610.

As shown in Figure 4, this is
The solenoid valve that controls pressure increase in Publication No. 1 is replaced with a flow control valve B 3, and this flow control valve 3 has an inlet 31a that communicates with the master cylinder 2, an outlet 31b that communicates with the wheel brakes 4, and a solenoid valve. A housing 31 has three ports, including a discharge port 31C communicating with the casing 5, and a spool 32 which is slidable and which switches the communication state between these ports is housed inside the housing 31 and biased by a spring 34τ.

When the anti-lock is not activated, it remains at the original position shown in the figure, and the inlet 31a, the outer circumferential groove 32a of the spool 32, and the outlet 31b
A completely large flow path is formed, and when the anti-lock pressure is reduced, the solenoid valve 5 is supplied with power and opened, and the flow is discharged from the discharge port 31c to the reservoir 6.
3, the hydraulic fluid is discharged to the spool 32, a pressure difference is generated at both ends of the spool 32, and the spool 32 moves to the state shown in FIG. 4A. Then, the large flow path is first closed by the edge 32b of the spool 32, and the spool 32 further moves to the state shown in FIG.
A, a passage 31e, and a discharge port 31c are formed in the discharge path, and the hydraulic fluid for the wheel brakes 4 is discharged to the reservoir 63 via the solenoid valve 5 and is depressurized.

Then, this working fluid is sucked and pressurized by a pump 61 driven by a motor 62, and returned between the master cylinder 2 and the inlet 31a.

Furthermore, when the electromagnetic valve 5 is de-energized when repressurizing the anti-lock, the spool 32 performs a metering action between the edge 32d and the inner peripheral end of the passage 31f in the state shown in FIG. 4B, and the inlet 31
a, passage 31d, orifice 33, spring chamber 36,
Passage 31f, passage 31e, outer circumferential groove 32a, outlet 31b
A small flow path is formed to slowly increase the pressure of the wheel brake 4. When the differential pressure between the outlet 31a and the outlet 31b becomes smaller, the spool returns to its original position, resulting in the state shown in FIG. 4.

In this case, only one solenoid valve is required per wheel, which is advantageous in terms of cost, and the flow rate when repressurizing the antilock in the state shown in FIG. 4B is equal to the effective cross-sectional area of the spool 32 and the spring
The metering edge 3 is adjusted so that the flow rate is such that the differential pressure determined by the biasing force of
Since the opening degree of the variable orifice consisting of 2d and the inner peripheral end of the passage 31r is adjusted, it remains constant regardless of the differential pressure between the inlet 31a and the outlet 31b, and the differential pressure before and after the orifice can be reduced. It is possible to secure a small flow rate with a relatively large orifice diameter, and it can be easily applied to small cars with small brakes that consume a small amount of fluid.

[Problems to be Solved by the Invention] In the anti-lock hydraulic pressure control device having the flow control valve of the prior art method, the spool 32 is located in the position where the small flow path is secured, as shown in FIG. 4B. If rust or foreign matter in the brake fluid sticks to the body 31, the opening degree of the variable orifice will not be adjusted and the wheel brake 4 will be pressurized through the small flow path even during normal braking when anti-lock is not activated. Excessive throttling will cause a boost delay.

Also, if the fixed orifice were to become clogged at this position, the small flow path would be blocked, so the wheel brake 4
A problem arises in that the pressure cannot be applied at all. This invention was made with the aim of solving such problems.

[Means to solve the problem]

Therefore, as a means for solving the above problems, the present invention provides a housing having at least two ports, an inlet and an outlet, and a fixed orifice that is slidably fitted into the housing and changes the relative position between the housing and the fixed orifice. It has a spool with a variable orifice that can change the flow path area by changing the flow path area, and a spring that biases the spool in one direction. constitute a series flow path, and the flow rate of this flow path is independent of the pressure difference between the inlet and the outlet, and a constant pressure difference determined by the effective cross-sectional area of the spool and the biasing force of the spring is maintained before and after the fixed orifice. The variable orifice has a flow control valve configured such that the flow path area of the variable orifice is adjusted to provide a constant flow rate when the variable orifice operates, and when the differential pressure acting before and after the fixed orifice exceeds the constant differential pressure, A configuration is adopted in which the flow path area of the fixed orifice section is expanded when the fixed orifice reaches .

[Effect]

When the anti-lock hydraulic pressure control device having the flow control valve of the prior art type is normal, the variable orifice is opened so that the differential pressure acting before and after the fixed orifice is equal to the value based on the biasing force of the spring. The degree is adjusted,
Since the flow rate is controlled, the differential pressure acting across the fixed orifice does not exceed a value based on the biasing force of the spring.

However, if the spool is fixed at the position where the small flow passages communicate with each other as shown in FIG. 4B, the variable orifice is fixed and the entire flow from the inlet to the outlet passes through the fixed orifice.
The differential pressure generated before and after the fixed orifice becomes larger than during normal operation.

Therefore, by expanding the flow path area of the fixed orifice when the differential pressure reaches a specific value, a large flow rate can be secured, and the problem of delayed effectiveness during normal braking can be solved.

Furthermore, even if the fixed orifice should become clogged, the differential pressure across the fixed orifice will similarly increase, so when a specific value is reached, a flow path will be secured in the fixed orifice portion, making it possible to increase the pressure.

Note that the probability that the spool will stick to the housing is thought to be highest in the non-operating position shown in Figure 4, but even if it sticks in this position, the large flow path is secured, so normally there will be no problem with the brake. Does not occur.

[Embodiments] Examples of the present invention will be described below with reference to the attached drawings.

1 1A IB, 1IU- Fig. 1 is a schematic system diagram of the anti-lock hydraulic pressure control device according to the present invention.
Only the ring system is shown. The hydraulic pressure control system itself is exactly the same as the conventional one, and the braking pressure P generated in the master cylinder 2 when the brake pedal 1 is depressed is sent to the wheel brakes 4 via the flow control valve 3, and the pressure is reduced. At times, the hydraulic pressure of the wheel brakes 4 is discharged from the discharge port of the flow control valve 3 by opening the electromagnetic valve 5 and returned to the pressurization source 6. Pressure R
6 consists of a pump 61, a motor 62, and a reservoir 63.

Only the flow control valve 3 is different from the prior art shown in FIG. That is, in the prior art shown in FIG. 4, the fixed orifice 33 is machined directly into the spool 32, but in the embodiment shown in FIG. It is being held,
This point differs from the prior art.

When the anti-lock is not activated, it remains at the original position shown in the figure, and the inlet 31a, the outer circumferential groove 32a of the spool 32, and the outlet 31
A large flow path leading to b is formed, and when the electromagnetic valve 5 is supplied with power and opened when the anti-lock pressure is reduced, the hydraulic fluid is discharged from the discharge port 31c to the reservoir 63, and a differential pressure is generated at both ends of the spool 32, causing the spool 32 to move. Then, the state shown in FIG. 1A is reached.

First, the large flow path is closed at the edge 32b of the spool 32, and the spool 32 further moves to the state shown in FIG. 1B, opening at the edge 32C to the outlet 31b.
, a discharge path connecting the groove 32a, the passage 31e, and the discharge port 31c is formed, and the hydraulic fluid of the wheel brake 4 is discharged to the reservoir 63 via the electromagnetic valve 5 and is depressurized. Then, the hydraulic fluid is sucked and pressurized by a pump 61 driven by a motor 62, and returned between the master cylinder 2 and the pump 31a.

Further, when the electromagnetic valve 5 is de-energized when repressurizing the anti-lock, a variable orifice is formed between the metering edge 32d of the spool 32 and the inner peripheral end of the passage 31f in the state shown in FIG. 1B, and the inlet 31a1 passage 31d, a fixed orifice 33, a spring chamber 36, passages 31f and 31e of the variable orifice portion, an outer circumferential groove 32a of the spool 32, and a small flow path leading to the outlet 31b. The differential pressure between the front and rear is adjusted to a value that balances the biasing force of the spring 34, and the pressure of the wheel brake 4 is increased.

When the pressure difference between the inlet 31a and the outlet 31b becomes smaller than the pressure difference based on the biasing force of the spring, the spool 3
2 returns to the position shown in FIG. Furthermore, if the spool 32 is stuck while the small channels shown in FIG. 4B are connected, the adjustment action of the variable orifice will stop, and the differential pressure acting before and after the fixed orifice 33 will increase as the fluid pressure in the port 31a increases. As the fixed orifice becomes larger, the fixed orifice separates from the spool 32 as shown in Fig. 1C, and a passage is created passing through the outer circumference of the fixed orifice 33 to the spring chamber 36, increasing the flow rate, resulting in a delay in pressure increase during normal braking and clogging of the orifice. This solves the problem of voltage boost stop caused by

In this embodiment, a rubber ring member 33a is provided between the fixed orifice 33 and the spool 32, and the fixed orifice 3
The only difference from the embodiment shown in FIG. 1 is that the seal between the fixed orifice 33 and the spool 32 is ensured, and the flow of the working fluid other than the orifice hole of the fixed orifice 33 is prevented during normal operation. The rest is completely the same as the first embodiment, and the explanation will be omitted.

3 3A This example shows a different type of 21! A quantity control valve is used. That is, the flow control valve 3 has an orifice 3 in the housing 31.
3 and a spring 34 provided as an elastic member. During non-anti-lock control, the braking pressure P is applied to the inlet 37a of the housing 31, the first port P of the spool 32, the karari apply chamber 35, the second port P2, and the -
It is sent to the wheel brake 4 through the outlet port 31b.

When the anti-lock control B is started and the electromagnetic valve 5 is opened, the pressure inside the spring chamber 36 decreases, and therefore a hydraulic pressure difference is generated between the spring chamber 36 and the rear braking chamber 35.

Therefore, the spool 32 is pushed down against the elastic force of the spring 34, and 31a and 31P are in a slightly open state, and two branch paths R, , R2 that merge into the second port Pt and the first outlet port 31b are formed. The upper R+ is cut off and the large flow rate is closed, and when the spool 32 is further lowered, it reaches the position shown in FIG. 36 and is returned to the second outlet port 31C where it is hydraulically pressurized.

When the solenoid valve 5 is de-energized and closed when repressurizing the anti-lock, a variable orifice is formed by the metering edge portion 32a above the first port P of the spool 32 and the inner peripheral end of the population 31a, and the fixed orifice 33 The inlet 31a, the first port Pl, the rear brary chamber 35, and the fixed The flow rate of the small flow path leading to the orifice 33, the third port P3, the passage R2, and the first outlet bow h31b is adjusted.

If the spool 32 were to become stuck at this position, the hydraulic fluid would flow through the fixed orifice 33 even during normal braking, resulting in an excessive pressure difference across the orifice 33.

Therefore, in this embodiment, the wall thickness of the orifice part is made thinner than before, and although it does not break during normal brake control or anti-lock control, when the above-mentioned sticking occurs, the wall thickness of the orifice part is large enough to break due to the excessive differential pressure when the brake is depressed. It is formed as thick. Therefore, in such an emergency, if the brake is strongly depressed, the orifice 33 is destroyed as shown in FIG. 3A, the flow path is enlarged and the flow rate is increased, and the problem of pressure increase delay is also solved.

〔effect〕

As explained in detail above, in the present invention, the configuration of the flow control valve of the hydraulic pressure control device is such that the flow path area is expanded at a specific value higher than the differential pressure that can act on the fixed orifice part under normal conditions. Since the flow rate at the orifice increases in the event of an emergency, at least normal braking force can be secured even in the extremely rare event of the orifice becoming clogged or the spool becoming stuck, ensuring safety. It is extremely beneficial.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a first embodiment of the anti-lock hydraulic pressure control device according to the present invention, FIGS. 1A and 1B are explanatory diagrams of its operation, FIG. 1C is a partially detailed diagram, and FIG. A schematic configuration diagram of the second embodiment, FIGS. 2A and 2B are operation explanatory diagrams, FIG. 2C is a partial detailed diagram, FIG. 3 is a schematic configuration diagram of the third embodiment, and FIG. 3A is an operation explanatory diagram. , FIG. 4 is a schematic diagram of a conventional example, and FIGS. 4A and 4B are explanatory diagrams of its operation. 1... Brake pedal, 2... Master cylinder, 3... Flow control valve, 4...
...Wheel brake, 5...Solenoid valve,
6... Pressure source, 31... Housing, 33... Orifice, 35... Re-ply chamber, 32... Spool, 34・・・・・・Spring, 36・・・Spring chamber.

Claims (4)

[Claims] (1) A housing having at least two ports, an inlet and an outlet, and a variable orifice that is slidably fitted into the housing and can change the flow path area by changing the relative position between the fixed orifice and the housing. and a spring biasing the spool in one direction, the inlet, the variable orifice, and a spring biasing the spool in one direction.
The fixed orifice and the outlet constitute a series flow path, and the flow rate of this flow path is independent of the pressure difference between the inlet and the outlet, and the constant pressure difference determined by the effective cross-sectional area of the spool and the biasing force of the spring is An anti-lock hydraulic pressure control device having a flow control valve configured such that the flow path area of the variable orifice is adjusted to provide a constant flow rate when acting before and after the fixed orifice, wherein the variable orifice acts before and after the fixed orifice. An anti-lock hydraulic pressure control device, characterized in that when the differential pressure exceeds the certain pressure differential and reaches a specific value, the flow path area of the fixed orifice portion is expanded. (2) The fixed orifice is made of a different member from the spool body and is locked to the spool body, and when the differential pressure before and after the fixed orifice reaches the specific value, the fixed orifice moves relative to the spool. 2. The anti-lock hydraulic pressure control device according to claim 1, wherein the flow path is expanded. (3) A member having the fixed orifice is held between the spring and the spool in a fluid-tight manner with respect to the spool, and the differential pressure acting before and after the fixed orifice causes the member to adjust the biasing force of the spring to the specific value. 3. The anti-lock hydraulic pressure control device according to claim 2, wherein the anti-lock hydraulic pressure control device separates from the spool against the force, thereby disabling the liquid tightness and enlarging the flow path. (4) When the differential pressure before and after the fixed orifice exceeds the specific value, the fixed orifice is destroyed, thereby enlarging the flow path.
The anti-lock hydraulic pressure control device described above.