JPH01103562A - Pressure control valve for vehicle hydraulic braking device - Google Patents

Abstract

PURPOSE:To make normal control and antilock control both performable with a changeover of electromagnetic force by installing a braking pressure feed control valve part in a plunger intermediate part free of slide motion through the changeover electromagnetic force, while installing a braking pressure quick discharge valve part in the said end. CONSTITUTION:A plunger 307 is made free of slide motion with the changeover electromagnetic force of a magnet coil 301, while a braking pressure control valve part 501 is installed in the intermediate part, and control over the feed of generating braking pressure by a hydraulic booster 20 to a wheel cylinder takes place. A discharge valve part 502 consisting of the same constitution is installed in an end of the plunger 307, and thereby quick discharge of braking pressure in the wheel cylinder 40 is made possible. When a supply of electromagnetic force to the magnet coil 301 is little, the specified braking pressure control is carried out by the control valve part 501, and at the time of slip occurrence, the magnetic force supply is made larger, quickly eliminating the braking pressure in the wheel cylinder 40, thus antilock control is made performable in a simple structure.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a pressure control valve for a hydraulic brake system for a vehicle, and more specifically, it continuously controls the brake pressure during normal braking and reduces the pressure associated with the braking. When wheel slip occurs,
This invention relates to a pressure control valve that can reduce, maintain, and increase brake pressure.

[Prior Art] Conventionally, a vehicle brake system equipped with an anti-skid control device has a switching valve that increases or decreases brake pressure for anti-skid control, and a proportion that adjusts brake pressure distribution between front wheels and rear wheels. Since each closing valve is required separately, the number of parts increases and there is also a problem in terms of cost. Furthermore, since the conventional proportioning valve has fixed braking force distribution characteristics, there is a problem in that it is not possible to realize an appropriate braking force distribution depending on the driving condition.

Therefore, between the front and rear wheel cylinders, there is a
A device has been proposed that includes a pressure regulator consisting of a two-position control valve and controls energization in a pulse manner depending on the front wheel slip state (for example, Japanese Patent Laid-Open No. 199352/1983).

[Problem that the invention seeks to solve]

However, since the above device operates the two-position control valve in a pulsed manner, that is, intermittently, there is a problem in that large pulsations occur in the braking pressure and the braking feeling is undesirable.

The present invention has been made in view of the above problems, and is a vehicle capable of continuously adjusting braking force distribution during normal braking, and rapidly reducing brake pressure when wheel slip occurs due to sudden braking. The object of the present invention is to provide a pressure control valve for a hydraulic brake device for use in a vehicle.

[Means for solving problems]

Therefore, the present invention provides a pressure control valve (30) for a vehicle hydraulic brake system that controls brake pressure supplied from a hydraulic pressure generating means (20) that generates brake hydraulic pressure to a wheel cylinder (40), the pressure control valve (30) comprising: a plunger (307) that slides due to the differential pressure between a first hydraulic chamber (203) communicating with the hydraulic pressure generating means (20) and a second hydraulic chamber (204) communicating with the wheel cylinder (40); A control valve section (501) that controls the wheel cylinder (40) and the hydraulic pressure generating means (20) from a normal communication state to a cutoff state as the plunger (307) moves within a first movement range; a switching valve section (502) that opens and closes the wheel cylinder (40) and the reservoir (50) to communicate with each other and to cut off communication with the reservoir (50) as the wheel cylinder (307) moves to a second movement range outside the first movement range; The control valve section (501) is connected to the plunger (307'').
A control spring (4) biases the
02), a switching device that separates when the plunger (307) is within the first movement range, and contacts and biases the switching valve in the direction in which it should close when switched to the second movement range; The spring (401) and the plunger (3 (
1), and in order to open the switching valve section (502), the plunger (307) is moved from the first movement range to the second movement range.
) for applying a relatively large switching electromagnetic force to the coil means (30
1).

[Effect]

According to the above configuration, when the coil means (301) generates a relatively small control electromagnetic force, the plunger (301) generates a relatively small control electromagnetic force.
07) is a wheel cylinder (40) and a hydraulic pressure generating means (
20), the control valve part (Sol) moves within the first movement range due to the balance with this control electromagnetic force, and
from the normal communication state to the cutoff state. This causes the oil pressure generating means (20) to move from the wheel cylinder (40) to the wheel cylinder (40).
) is continuously controlled to be reduced by the control electromagnetic force of the coil (301).

On the other hand, when a relatively large switching electromagnetic force is generated in the coil means (301), the plunger (307) moves from the first movement range to the second movement range and opens the switching valve section (502). As a result, the brake fluid in the wheel cylinder (40) is released to the reservoir (50).
Wheel cylinder pressure can be rapidly reduced.

[Effects of the Invention] As described above, the pressure control valve can continuously or rapidly increase the brake pressure of the wheel cylinder by continuously or greatly changing the magnitude of the electromagnetic force generated in the coil means. Can be depressurized. Therefore, during normal control, the braking force can be appropriately distributed by continuously controlling the brake pressure. Further, when a slip occurs, the brake pressure can be reduced quickly by generating a large switching electromagnetic force, so that it is possible to appropriately adjust the pressure while suppressing excessive brake pressure.

〔Example〕

Next, the configuration of an embodiment of the present invention will be described based on the drawings.

Inside a casing 300 that forms the outer shape of the pressure control valve 30, first to sixth cylinders 511 to 516 are formed, and a plunger 307 is slidably disposed.

The plunger 307 is connected to the second, third, and fourth cylinders 512
, 513, 514, E oil chamber 201 from the left side of the oil chamber,
An A oil chamber 203, a B oil chamber 204, and a C oil chamber 205 are formed. Further, an annular groove 202 is provided in the second cylinder 512 between the E oil chamber 201 and the A oil chamber 203.

The plunger 307 has an armature 308 which is a magnetic material.
are integrally attached, and by applying current to the coil 301, it receives electromagnetic force in the left direction in the figure.

The E oil chamber 201 on the left side communicates with the reservoir 50, and the C oil chamber on the right side communicates with the reservoir 50.
The oil chamber 205 also communicates with the reservoir 50 via the passage 602 and the E oil chamber 201. Both the B (second) oil chamber 204 and the annular groove 202 communicate with the wheel cylinder 40 via passages 605.60.4. Further, the A (first) oil chamber 203 communicates with the hydraulic booster 20 via a passage 603.

Built inside the plunger 307 are a first check (control) valve 501 on the right side and a second check (switch) valve 502 on the left end. The internal oil chamber 207 on the right side of the first check valve 501 is
It communicates with the wheel cylinder 40 via a plurality of radially bored passages 606. The internal oil chamber 208 on the left side of the first check valve 501 is connected to the hydraulic booster 20 through a passage 607 communicating with the outer periphery of the plunger 307, an oil chamber A 203, etc.
is connected to.

The internal oil chamber 209 on the right side of the second check valve 502 communicates with the wheel cylinder 40 via a passage 608 communicating with the outer periphery of the plunger 307, an annular groove 202, and the like.

A stopper 505 that protrudes into the C oil chamber 205 on the right side is integrated into the housing 300, and abuts the right end surface of the plunger 307 in FIG. Also,
As shown in FIG. 2, a through rod 306 is integrally inserted into the housing 300 near the right side of the first check valve 501, and crosses the internal oil chamber 207 inside the plunger 307. In FIG. 1, the penetrating rod 306 is in contact with the bushing rod 305, and the first check valve 501 is in an open state. Furthermore, a rod 504 that protrudes into the E oil chamber 201 on the left side is integrated into the housing 300.

The diameters of the second cylinder 512 and the fourth cylinder 514 are set to be equal to A, and the diameter of the third cylinder 513 is set to B.
(>A).

A weak control spring 402 that applies a rightward biasing force to the plunger 307 is provided in the A oil chamber 203. In addition, a strong switching spring 401 is installed in the E oil chamber 201.
A predetermined set load is applied by a stopper 503 integrated with the housing 30'0. Furthermore, in the state within the first movement range where the plunger 307 in FIG. 1 is in contact with the stopper 505 at the right end, the gap between the above-mentioned strong switching spring 401 and the plunger 307 is! , set to .

Then, from this position, the plunger 307 moves to the left! , the first movement range is until the plunger 30 moves.
After the pressure end of 7 contacts the switching spring 401, the leftward direction becomes the second movement range. Also, the gap until the bushing rod 504 is about to open the second check valve 502 is l! And 2□ is! , is set larger.

Therefore, when the plunger 307 moves leftward within the first movement range from the state shown in FIG. 1, the first check valve 501 shifts from the open (communicating) state to the blocking state. Further, from the position where the first check valve 501 is completely closed, the plunger 307 moves to an initial range (f) to the left of the first movement range.
! , z j! +) when moving within the first check valve 5.
01, the second check valves 502 are both in the closed state. This range is called the intermediate movement range. Further, when the plunger 501 moves leftward within a second movement range on the left side of the intermediate movement range, the second check valve 502 changes from a closed state to an open state.

The operation will be explained based on FIG.

When the coil 301 is not energized and the brake pedal 1 is not depressed, that is, when the output pressure of the hydraulic booster 20 is zero, the plunger 307 is moved by the weak biasing force of the control spring 402, as shown in FIG. Therefore, it is at the position where it abuts against the stopper 505 at the right end, that is, at the right end position of the first movement range. In this state, the penetrating rod 30
6 pushes the bushing rod 305 to open the first check valve 501. At this time, the lift amount of the first check valve 501 from the ball seating position is 2 degrees.

At this time, the second check valve 303 is in a closed state. Therefore, the wheel cylinder 40 includes the pipe 103, the passage 605,
Internal oil chamber 207, first check valve 501, passages 607, 60
3 to the hydraulic booster 2o, and its hydraulic pressure is zero.

Next, consider when the driver depresses the brake pedal 1 and starts braking. The hydraulic booster 2o multiplies the hydraulic pressure generated in the mask cylinder 0 by a certain ratio and outputs the multiplied hydraulic pressure. The oil (pressure=P,) in the hydraulic booster 20 is led to the A oil chamber 203, and the rightward force ((B"A") x Ps in FIG.
) is applied to the plunger 307. wheel cylinder 40
The oil (pressure - P.) is led to the B oil chamber 204,
A leftward force (-(B"-A")xPw) in FIG. 1 is applied to the plunger 307. Here, when the coil 301 is energized in a control range below a medium current value, which will be described later, and a control electromagnetic force is applied to the plunger 307 to the left in FIG.
. Before reaching P, the leftward force in FIG. 1 is overcome, the plunger 307 moves to the left within the first movement range, and the first check valve 501 is closed. Since the plunger 307 moves within the first movement range so that the forces acting on the left and right sides are balanced, the first check valve 501 opens and closes, restricting the flow of oil from the hydraulic booster 20 to the wheel cylinder 40. The pressure in the wheel cylinder 40 is regulated. Since the weak spring 402 can be ignored, this balance of forces is expressed as +Fs, where F is the electromagnetic force. This is P. Expressed as P, = P,
--F.

becomes. However, S=-(BZ-A'').

By allocating one pressure control valve to each wheel cylinder, by controlling the electromagnetic force F, it is possible to achieve ideal braking force distribution for the four wheels independently during normal braking.

FIG. 3 shows an example of the relationship between the wheel cylinder oil pressure waveform of the rear right wheel, the oil pressure booster output oil pressure, and the coil current value during braking force distribution. As shown in Figure 3, coil 3
As the current value applied to 01 increases, the wheel cylinder pressure P. It can be seen that the pressure is continuously reduced from the hydraulic booster pressure P++.

Next, anti-skid control when the wheels lock due to excessive braking force, that is, when slipping occurs, will be explained. When a slip occurs, a large current is applied to the coil 301 to generate a switching electromagnetic force to move the plunger 307 to the left within the second movement range, and the first check valve 501
At the same time, the switching spring 401 with a larger set load is also compressed, and the second check valve 50 is closed.
2 with the bushing rod 504 to open it.

As a result, the wheel cylinder 40 includes the pipe 103, the passages 605, 604, the annular groove 202, the passage 608, the oil chamber 209 of the second check valve 502, the E oil pressure 201, the passage 601,
The reservoir 50 is communicated with the pipe 102, and the wheel cylinder pressure is reduced.

Furthermore, when the current value is set close to the set load of the switching spring 401, the plunger 307 is at a position within the intermediate movement range that hardly compresses the spring 401, and in this state, the first check valve 501 is in a closed state. Further, the second check valve 502 is also in a closed state because the bushing rod 504 and the ball are not in contact with each other, and the wheel cylinder pressure is maintained. On the other hand, when the current value is set to zero, the plunger 307 returns to the state shown in FIG. It becomes a pressure state.

As mentioned above, the current value given to the coil can be set to three values: large, medium, and no.
Reducing the wheel cylinder pressure by giving a stage,
Three-position action for holding and increasing pressure is achieved and anti-skid control is possible.

FIG. 4 shows an example of the relationship between the wheel cylinder hydraulic pressure waveform, the hydraulic booster output pressure waveform, and the coil current value during anti-skid control. As shown in Figure 4, 16A to the coil.
When a large current value of 8A is applied, the wheel cylinder pressure P is reduced, and when a medium current value of 8A is applied, the wheel cylinder pressure P is reduced. is maintained, and when the current is not applied, the wheel cylinder pressure P.

It can be seen that the pressure is reduced.

The hydraulic booster shown in Fig. 1 is configured separately from the mask cylinder 10, receives the hydraulic pressure generated by the mask cylinder 10 as pilot pressure, multiplies it by a certain ratio, and outputs it, but the hydraulic booster is directly connected to the brake pedal. It may also be a boost plate.

Furthermore, although the pressure control valve is configured to supply the brake pressure from the hydraulic booster to the wheel cylinder, it may be configured to control the brake pressure of the mask cylinder and supply it to the wheel cylinder.

In the above embodiment, one pressure control valve is provided for one wheel cylinder, but one pressure control valve may be provided for each of the front and rear systems.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional configuration diagram showing one embodiment of the present invention, Fig. 2 is a partial cross-sectional view taken along the line X-X in Fig. 1, and Fig. 3 is a current value and wheel cylinder pressure during braking force distribution. FIG. 4 is a characteristic diagram showing the relationship between current value and wheel cylinder pressure during anti-skid control. ■...Brake pedal, 2...Hydraulic pressure source, 20...
Hydraulic booster, 30... Pressure control valve, 40... Wheel cylinder, 50... Reservoir, 203... A (
1st) oil chamber, 204...B (2nd) oil chamber, 301...
·coil. 307... Plunger, 401... Switching spring. 402... Control spring, 501... First check valve (control valve part), 502... Second check valve (switching valve part). Representative Patent Attorney Takashi Okabe

Claims (1)

[Scope of Claims] A pressure control valve for a vehicle hydraulic brake system that controls brake pressure supplied to a wheel cylinder from a hydraulic pressure generating means for generating brake hydraulic pressure, the pressure control valve comprising a first valve communicating with the hydraulic pressure generating means. a plunger that slides due to a pressure difference between a hydraulic chamber and a second hydraulic chamber that communicates with the wheel cylinder; and as the plunger moves within a first movement range, the wheel cylinder and the hydraulic pressure generating means are normally communicated with each other. a control valve section that controls the state to the cutoff state, and as the plunger moves to a second movement range outside the first movement range,
a switching valve part that opens and closes to communicate and cut off communication between the wheel cylinder and the reservoir; a control spring that biases the plunger in a direction to bring the control valve part into communication; a switching spring that separates when within the movement range and contacts and biases the switching valve in the direction in which it should close when switched to the second movement range; Applying a relatively small control electromagnetic force to the plunger within the first movement range, and applying a relatively large control electromagnetic force to the plunger from the first movement range to the second movement range in order to open the switching valve section. A pressure control valve for a vehicle hydraulic brake system, comprising coil means for applying a switching electromagnetic force.