JPS6033160A - Antiskid braking device for vehicle - Google Patents

Abstract

PURPOSE:To simplify a brake structure, by using only one solenoid both as a solenoid performing the selection of a directional selector valve and a solenoid for an on-off valve cutting off the interconnection between the selector valve and a master cylinder, in time of skid controlling. CONSTITUTION:An on-off valve 14 interconnecting or intercepting a master cylinder to or from a directional selector valve 18 consists of a ball 130 and a valve seat 128 formed in a piston 48, and both the ball 130 and the piston 48 are produced with a magnetic material. Therefore, in time of antiskid controlling, a solenoid 66 is excited by a microcomputer, while the directional selector valve 18 is selected to a position closing a wheel cylinder or to a position interconnected it to a reservoir. Along with this selection, the ball 130 is accurately seated on a valve seat 128 by excitation of the solenoid 66 whereby the on-off valve 14 closes and the master cylinder and the selector valve 18 are intercepted from each other. With this constitution, when brake pressure is repressurized, the piston 48 operates with certainly by hydraulic pressure out of the master cylinder and the on-off valve 46 opens.

Description

Detailed Description of the Invention Technical Field The present invention relates to a hydraulic brake system for a vehicle, and in particular to a hydraulic brake system for a vehicle that monitors the skid state of a wheel and suppresses the rotation of the wheel. The present invention relates to an anti-skid brake device for a vehicle that is capable of efficiently braking a vehicle while controlling pressure and preventing the occurrence of skids.

In conventional hydraulic brake systems for vehicles, hydraulic pressure generated in a mask cylinder based on the driver's brake operation is transmitted to the brake cylinder via a liquid passage, and the brake cylinder suppresses the rotation of the wheel by the hydraulic pressure. The brake is configured to actuate the brake. In recent years, an electromagnetic directional switching valve that selectively communicates the brake cylinder with the mask cylinder and the reservoir has been provided in the fluid passage of this hydraulic brake device, and this electromagnetic directional switching valve is automatically controlled by a control device. It became so. The controller is configured to detect a wheel skid condition and control the electromagnetic directional valve based on the presence or absence of a skid condition.

This device connects the brake cylinder to the reservoir and discharges the brake fluid in the brake cylinder to the reservoir when the wheels tend to skid. In order to increase this, it is necessary to supply new brake fluid from the mask cylinder to the brake cylinder. Therefore, as the electromagnetic directional switching valve is repeatedly switched, the brake fluid in the mask cylinder decreases, and the amount of depression of the brake pedal increases.

Therefore, it was devised to use a pump to pump up the brake fluid once discharged into the reservoir and return it to the mask cylinder. For example, the one described in Japanese Patent Publication No. 49-32494 is one example of this.In this way, the decrease in brake fluid in the mask cylinder is compensated for by the pump, so as mentioned above, the electromagnetic directional control valve is This solves the problem of the brake pedal being pressed deeper each time switching is repeated. However, when the brake cylinder is once connected to the reservoir and then connected to the mask cylinder again, a considerable amount of brake fluid is required, but the pump's discharge capacity can be used to instantly supply the required brake fluid. It is not practical to select a size large enough to do so. It is rare for the brakes to be applied to the extent that the wheels skid, and it would be wasteful to have a relatively large pump in preparation for such a situation, and the pump would only be effective momentarily. This is because it is difficult to make them work.

Therefore, in the past, the pump was relatively small, the brake fluid was momentarily supplied to the brake cylinder from the mask cylinder, and then the brake fluid was returned to the mask cylinder in small amounts by the pump. As a result, each time the electromagnetic directional control valve was repeatedly switched, the brake pedal was forced into a deeper depression position and then pushed back to its original position, resulting in a situation where the brake pedal could not be said to have a good feel. .

OBJECTS OF THE INVENTION The present invention provides an anti-skid brake device that prevents deterioration of the brake feeling and prevents the brake pedal from becoming too deep to be depressed, and which has a simple and compact structure. It was created for the purpose of providing something.

Structure of the Invention As described above, the present invention comprises Ta) a master cylinder that generates hydraulic pressure based on a brake operation by a vehicle driver; and (b)
l A reservoir for storing brake fluid, and a brake cylinder that operates the brake to suppress the rotation of the fcl wheel.
(d+ An electromagnetic directional switching valve connected to the brake cylinder, the mask cylinder, and the reservoir, which selectively communicates the brake cylinder with the mask cylinder and the reservoir; t
a control device that detects the skid state of the el wheels and controls an electromagnetic directional control valve based on the presence or absence of the skid state;
1. A vehicle anti-skin braking device comprising: a pump that pumps up brake fluid from a reservoir or a fluid passage that is always in communication with the reservoir and supplies the brake fluid to the brake cylinder via the electromagnetic directional switching valve, wherein the electromagnetic directional switching valve The mask cylinder and the electromagnetic directional control valve are always connected to the part of the valve that is connected to the mask cylinder and the pump, but when current is supplied to the solenoid, the mask cylinder and the electromagnetic directional control valve communicate with each other. The control valve is integrated to cut off the communication between the pump and connect the pump to the electromagnetic directional control valve instead, reduce the liquid pressure supplied from the pump to a liquid pressure equal to the liquid pressure of the mask cylinder, and supply it to the electromagnetic directional control valve. The present invention is characterized in that the control valve is provided in a compact manner. That is, the control valve includes (a) a piston chamber that is integrally formed with the housing of the electromagnetic directional switching valve, and a mask cylinder passage that extends from the first end of the piston chamber and connects to the mask cylinder;
A housing having a pump passage and a switching valve passage extending from the second end of the piston chamber and connected to the pump and the electromagnetic directional switching valve, respectively; (c) a piston made of a magnetic material that is fitted into the piston and has a through hole at the bottom and a valve seat provided at the inner opening of the through hole; The hydraulic pressure chambers on both sides of the piston are arranged in a manner that does not prevent them from communicating with each other through the through hole, and when the solenoid of the electromagnetic directional control valve is energized, it is attracted to the valve seat by the magnetic force based on the solenoid, and the piston is attracted to the valve seat on both sides of the piston. (d) a biasing means for biasing the valve to a position away from the valve seat; and (iii) a piston chamber in the pump passage. The opening to the second end is provided in such a manner that the pump passage is always blocked, and the hydraulic pressure difference between the hydraulic pressure chambers on both sides of the piston is generated by blocking communication between the hydraulic pressure chambers on both sides of the piston. - an on-off valve that is opened by the piston or a member that moves integrally therewith when the piston is moved toward the second end of the piston chamber, and closed when the piston is moved toward the first end of the piston chamber; It is configured to include the following.

Effects of the Invention In the vehicle anti-skin braking device configured as described above, once the electromagnetic directional switching valve is switched and the brake cylinder is brought into communication with the reservoir, the mask cylinder is disconnected from the brake cylinder by the control valve. After the brake cylinder is disconnected, the next time it is necessary to supply brake fluid to the brake cylinder, this brake fluid is supplied from the pump. Therefore, the brake fluid in the mask cylinder does not decrease or increase, thereby preventing the brake pedal from becoming deeper or shallower, thereby improving the brake feeling. Moreover, the hydraulic pressure supplied from the pump is reduced by the control valve to a hydraulic pressure equal to the hydraulic pressure of the mask cylinder and then supplied to the brake cylinder, so high hydraulic pressure is supplied to the brake cylinder regardless of the driver's will. It will never happen.

Furthermore, in the anti-skinned brake device according to the present invention, a liquid passage connecting the mask cylinder and the electromagnetic directional control valve is formed through the piston, and a valve element provided inside the piston is magnetized by a solenoid. By sitting on the valve seat and blocking this liquid passage, communication between the mask cylinder and the electromagnetic directional switching valve is cut off, and a liquid pressure difference is created before and after the piston, and the piston is moved forward by this liquid pressure difference. In addition, the closed on-off valve is opened to connect the pump to the electromagnetic directional control valve, and the solenoid for seating the valve element on the valve seat also serves as the switching solenoid for the electromagnetic directional control valve. Because of this, the structure is simple and compact.

Embodiment Fig. 1 shows that four wheels of a vehicle are each equipped with a brake, and the hydraulic pressure from the mask cylinder is applied to the wheel cylinder, which is the brake cylinder for operating each brake, in two independent liquid passages at the front and rear. 1 is a diagram illustrating an embodiment in which the present invention is applied to a so-called front and rear two-system hydraulic brake device in which transmission is transmitted by a hydraulic brake device. In reality, the hydraulic pressure of the two front wheels is controlled independently by a dedicated control valve and an electromagnetic directional control valve, and the hydraulic pressure of the two rear wheels is controlled by a common valve. However, since the configuration of each system is the same, only the portion that controls the hydraulic pressure of the wheel cylinder provided in the front left wheel is representatively shown in FIG.

The mask cylinder 10 has two independent pressurizing chambers, and when the pedal 11 is depressed, liquid pressure of the same height is generated in the two pressurizing chambers, but one of the pressurizing chambers has no liquid pressure. Passage 12. Solenoid on-off valve 14° liquid passage 16. It is connected to a wheel cylinder 22 via an electromagnetic directional control valve 18 and a liquid passage 20.

That is, the main liquid passage is constituted by the liquid passages 12, 16 and 20, and the electromagnetic on-off valve 14 and the electromagnetic directional switching valve 18 are connected in series to the main liquid passage to constitute a main circuit. It is.

A check valve 24 is connected in parallel to the electromagnetic directional control valve 18.
A bypass passage 26 is provided, so that the brake fluid returning from the wheel cylinder 22 to the mask cylinder 1O can quickly return to the mask cylinder 10 through this bypass passage 26.

The wheel cylinder 22 is selectively communicated with the mask cylinder 10 and the reservoir 28 by the electromagnetic directional control valve 18.
The return passage 30 leading to the wheel cylinder 8 is provided with a throttle 32 for suppressing sudden outflow of brake fluid from the wheel cylinder 22.

A pump 38 is connected to the middle of this return passage 30 by a liquid passage 36 which is provided with a check valve 34, and this pump 38 is further connected to an on-off valve 46 by a liquid passage 44 having check valves 40 and 42. has been done. Open/close valve 4
6 is normally closed, but is opened when the piston 48 moves forward, and supplies brake fluid supplied from the pump 38 to the main circuit through the fluid passage 50. An accumulator 52 is connected in the middle of the liquid passage 44, and the liquid pressure in the accumulator 52 is detected by a pressure swifter 54, and the pump 38 is activated when the liquid pressure in the accumulator 52 decreases to the lower limit set value, and It is stopped when the value is reached. Therefore, even if the pump 38 has a small discharge capacity, a sufficient amount of high-pressure brake fluid is always stored in the accumulator 52, and whenever the on-off valve 46 is opened, the required amount of brake fluid is supplied to the main circuit. Supplied. However, the fluid passage 44 is provided with a throttle 56 to suppress the rapid flow of brake fluid.
The piston 48 receives hydraulic pressure on the downstream side of the on-off valve 46 on one pressure-receiving surface, and receives hydraulic pressure from the mask cylinder 10 on the other pressure-receiving surface, and operates.By opening and closing the on-off valve 46, piston 48 operates. It plays the role of reducing the hydraulic pressure of the supplied brake fluid to a value equal to the hydraulic pressure of the mask cylinder 10 and supplying it to the main circuit.

The rotational speed of the left front wheel 58 equipped with a brake operated by the wheel cylinder 22 is detected by a sensor 60, and based on this detection signal, the computer 6
2 calculates the rotational deceleration or acceleration of the front wheel 58,
If the deceleration becomes larger than a predetermined value, it is determined that the wheels 58 are about to skid, and the electromagnetic on-off valve 14, the electromagnetic direction switch, the solenoid 64 of the valve 18,
66 (actually, the solenoid 66 also serves as the solenoid 64 as will be detailed later), closes the electromagnetic on-off valve 14, and moves the electromagnetic directional control valve 18 from the first position shown in FIG. Switch to second or third position. That is, the electromagnetic directional control valve 18 is a 3-boat, 3-position electromagnetic directional control valve, and when no current is supplied to the solenoid 66, it is in the first position and the wheel cylinder 22 is in the first position.
is connected to master cylinder ■0, but when a small current is supplied to the solenoid 66, it switches to the second position and cuts off all three boats, and when a large current is supplied to the solenoid 66, the third The configuration is such that the wheel cylinder 22 and the mask cylinder 10 communicate with the reservoir 28 by switching the position. Further, when the rotational deceleration of the wheels 58 becomes less than a certain value, or when the rotational acceleration becomes more than a certain value, the computer 62 determines that the wheels 58 are coming out of the skid state, and controls the solenoid 66. The current supply is cut off and the electromagnetic directional control valve 18 is switched to the first position. However, in this state, the electromagnetic on-off valve 14 is kept closed for reasons that will be detailed later, so the 7-cumulator 52, not the mask cylinder 10,
The brake fluid is communicated with the wheel cylinder 22 via the pump 8, and the brake fluid that has been pressurized from the pump 38 and stored in the accumulator 52 is supplied to the wheel cylinder 22.

As is clear from the above description, in this embodiment, the electromagnetic on-off valve 14. A control valve 70 is constituted by an on-off valve 46, a piston 48, etc., and a more specific structure of this control valve 70 is shown in FIG. As is clear from the figure, in this embodiment, the housing of the control valve 70 and the housing of the electromagnetic directional control valve 18 are integrally constructed. For manufacturing reasons, this housing 72 is
Although the housing 72 is divided into many parts including 4, 75, 76, 78, 80, 82, 84, and 86, when assembled, it functions as an integral housing 72.

The members 75, 76 and 80 of each section I are made of magnetic material, and the section 1fA' 78.

82, 84 and 86 are made of non-magnetic material. The housing 72 also includes a mask cylinder lO and a pump 3.
8. A mask cylinder passage 88 communicating with wheel cylinder 22 and reservoir 28, respectively. Pump passage 90.
A wheel cylinder passage 92 and a reservoir passage 93 are formed.

The upper part of the housing 72 constitutes the housing of the electromagnetic directional control valve I8, and the lower part constitutes the housing of the control valve 70.

First, the electromagnetic directional control valve 18 will be explained in detail. A cylindrical member 94 made of a magnetic material is disposed in a hollow space formed in the center of the housing 72, and a ball hair ring 96 is provided.
and 98, and is held by the housing 72 so as to be movable in a direction parallel to the center line. That is, the housing 72 includes the cylindrical members 10 disposed coaxially and facing each other.
0 and 102, and the cylindrical portion 44' 100 and 102 hold the cylindrical member 94 via ball bearings 96 and 98. Valve seats 104 and 106 are provided at mutually opposing ends of the cylindrical members 100 and 102, respectively, and valve pieces 108 and 110 are provided opposite to these valve seats 104 and 106. Valve members 108 and 110 each have a cylindrical member 94
It consists of a valve body slidably fitted inside the valve body and a ball fixed thereto, and the valve body 10B and 110 are separated from each other by a compression coil spring 112, that is, the valve body 10B and 110 are connected to the valve seat 104 and 106 in the direction of seating. The cylindrical member 94 is urged toward the valve seat 104 by a plurality of compression coil springs 114 so that the sum of elastic forces is greater than the elastic force of the spring 112.
It is kept seated in 04. In this state, the cylindrical member 94 is connected to the valve element 10 through the outer ring of the ball bearing 98 and the spacers 116, 118 and 120.
B and is prevented from moving further towards the valve seat 104. When the solenoid 66 fixed to the housing 72 is excited, the cylindrical member 9
4 is moved toward the valve seat 106, the valve element 110 is seated on the valve seat 106, and when the cylindrical member 94 is moved toward the valve seat 106 with an even greater force, the valve element 108 is seated on the valve seat 106.
is pushed back against the elastic force of the spring 112 via the outer ring of the ball bearing 96 and the spacer 122, and is moved away from the valve seat 104. That is,
In order to seat the valve element 110 on the valve seat 106, the cylindrical member 94 is pressed against the spring 112 by the elastic force of the spring 114.
It would be good if the valve element 108 could be moved toward the valve seat 106 with a force equal to the elastic force of the valve seat 104.
In order to separate the valve seat 10 from the valve seat 10, a force equal to the elastic force of the spring 114 plus the elastic force of the spring 112 is applied.
Therefore, in order to apply such force, the current supplied to the solenoid 66 can be changed in two levels, large and small.

In the state shown in FIG. 2, the reservoir passage 93 is blocked by the valve element 108 being seated on the valve seat 104, and the wheel cylinder passage 92 is separated from the space within the cylindrical member 94 by the valve element 110 being separated from the valve seat 106. Cylindrical member 10
It is communicated with a control valve 70 via a liquid passage in 2 and a liquid passage 16. In other words, this is the first position. If the valve element 110 is seated on the valve seat 106 while the valve element 108 remains seated on the valve seat 104, the wheel cylinder passage 92. Both the reservoir passage 93 and the liquid passage 16 are in a blocked state.

This is the second position. Furthermore, the valve element 110 is connected to the valve seat 10.
6, the valve 108 is placed on the valve seat 10.
4, the wheel cylinder passage 92 is communicated with the reservoir passage 93 via the liquid passage in the cylindrical member 100 while the liquid passage 16 remains blocked. This is the third position.

A piston 48 is fitted in a piston chamber 124 formed in the lower part of the housing 72 in a liquid-tight and slidable manner. The piston 48 has a cylindrical shape with a bottom and is fitted with the open end facing the first end of the piston chamber 124. The piston 48 has a through hole 126 at the bottom, and a valve seat is placed in the inner opening of the through hole 126. 12B is formed. Inside the piston 48, a ball 1.30 made of a magnetic material and serving as a valve element C is movably disposed so as to be received by a cup portion 1tA131 made of a non-magnetic material. The ball 130 can sit on the valve seat 12B and block the through hole 126, but is always urged away from the valve seat 128 by a compression coil spring 132 as a protection means. A liquid passage 134 is formed in the cup portion +A131, and when the ball 130 is separated from the valve seat 128, the liquid pressure chambers 136' and 13B on both sides of the piston 48 are in communication with each other. The piston 48 is biased toward the hydraulic pressure chamber 136, that is, toward the first end of the piston chamber 124 by a compression coil spring 140. A mask cylinder passageway 88 extends from this first end of the piston chamber 124, while
The pump passage 90 and the liquid passage 16 as a switching valve passage connected to the electromagnetic directional switching valve 18 extend from the second end side of the piston chamber 124 .

An on-off valve 46 is provided in a portion of the pump passage 90 that opens into the piston chamber 124 . The on-off valve 46 includes a valve seat 142 formed in the housing 72, a ball I44 as a valve disposed opposite to the valve seat 142, and a compression coil spring 14 that urges the ball 144 toward the valve seat 142.
It consists of 6. Ball 144 is the valve seat 1 for wealth.
When the piston 48 moves forward, a protrusion 150 formed thereon contacts the ball 144 and pushes it away from the valve seat 142. Let go. The piston 48 is the hydraulic chamber 13
This hydraulic pressure difference is generated by the ball 130 sitting on the valve seat 128 and cutting off communication between the hydraulic pressure chambers 136 and 138. The solenoid 64 for bringing the ball 130 into close contact with the valve seat 128 also serves as the solenoid 66 for switching the electromagnetic directional switching valve 18 .

A bypass passage 26. further provided within the housing 72 includes a check valve 24. A diaphragm 32, 56, etc. is provided.

Next, the operation will be explained.

When the vehicle is running, brake fluid is pumped up from the reservoir 28 by the pump 38 and stored in the accumulator 52, and this fluid pressure is applied to the pressure switch 54.
The pump 38 is stopped with the temperature increased to the upper limit setting of °C. When the brake pedal 11 is not depressed, the electromagnetic on-off valve 14 and the electromagnetic directional control valve 18 are in the state shown in FIGS. They are communicated by a main liquid passageway of road area.

Therefore, when the brake pedal 11 is depressed, the brake fluid discharged from the mask cylinder 10 is immediately supplied to the wheel cylinder 22.
The brake clearance of the brake operated by the brake is eliminated, and the hydraulic pressure within the wheel cylinder 22 is increased. As a result, the rotation of the wheels 58 is suppressed and the vehicle is braked, but the brake pedal 11
During normal braking operation where the pedaling force is not high, the wheels 58
computer 6 will not go into a skid state.
2 does not supply current to the solenoid 66, and the solenoid valve 14
and the electromagnetic directional valve 18 are maintained in the state shown in FIG. Then, when the vehicle is decelerated to a speed desired by the driver or stopped and the brake pedal 11 is released, the brake fluid is quickly returned from the wheel cylinder 22 to the mask cylinder 10 via the pipe passage 26. Note that even if the hydraulic pressure in the mask cylinder IO is increased, the piston 48 will not move forward because the hydraulic pressure chambers 136 and 138 are communicated with each other and maintained at the same hydraulic pressure. Therefore, the on-off valve 46 is never opened, and brake fluid is not supplied from the accumulator 52 to the main fluid passage.

On the other hand, the depression force of the brake pedal 11 is large, and the wheel 58
If the engine falls into a skinned state, the computer 62 detects this fact based on the rotational speed signal from the sensor 60,
A small current is supplied to the solenoid 66 (64). As a result, the electromagnetic on-off valve 14 is closed, the mask cylinder lO is disconnected from the wheel cylinder 22, and the electromagnetic directional control valve 18 is switched to the second position, so that the mask cylinder 10, the wheel cylinder 22. Accumulator 52
(pump 38) and reservoir 28 are completely isolated from each other.
f+ state, and the hydraulic pressure in the wheel cylinder 22 is kept constant.

Even if the hydraulic pressure in the wheel cylinder 22 is kept constant as described above, if the hydraulic pressure in the wheel cylinder 22 is still so high that the wheel 58 cannot escape from the skid state, the computer 62 supplies a large current to the solenoid 66. do. As a result, the electromagnetic directional control valve 1B is switched to the third position, and the wheel cylinder 22 returns through the throttle 32 to the return passage 1i830.
from the wheel cylinder 22 to the reservoir 2.
Brake fluid is caused to flow out to 8. As a result, the hydraulic pressure in the wheel cylinder 22 decreases and the wheel 58 begins to come out of the skid state, so the computer 62 detects this fact and switches the current supplied to the solenoid 66 to a small current to control the electromagnetic directional valve 18. Switch to third position.

If the rotational speed of the wheel still increases, the computer 62 cuts off the current supply to the solenoid 66 and connects the wheel cylinder 22 to the fluid passageway 16. Even if the power supply to the solenoid 66 is cut off, the once closed electromagnetic on-off valve 14 closes the hydraulic pressure chambers 136 and 1 on both sides of the piston 48.
Because it is kept closed by the l & pressure difference with 38,
The brake fluid of the mask cylinder 10 is not supplied to the wheel cylinder 22, but instead is supplied from the accumulator 52. That is, if the liquid passage 16 is brought into communication with the wheel cylinder 22 by switching the electromagnetic directional control valve 18 to the first position, the liquid pressure in the liquid pressure chamber 138 of the control valve 70 becomes equal to the liquid pressure in the wheel cylinder 22, Hydraulic pressure chamber 13
6, the piston 48 moves forward and opens the on-off valve 46.
The wheel cylinder 22 is communicated with the accumulator 52. As a result, brake fluid is supplied from the accumulator 52 to the wheel cylinder 22.
Since the flow of the brake fluid is given a throttling effect by the throttle 56, the brake fluid is not supplied to the wheel cylinders 22 at an excessive flow rate. Furthermore, when the hydraulic pressure in the hydraulic chamber 138 becomes equal to the hydraulic pressure in the hydraulic chamber 136 (more precisely, the hydraulic pressure in the hydraulic chamber 138 becomes lower by the hydraulic pressure corresponding to the biasing force of the springs 140 and 146, This fluid pressure difference keeps the ball 130 seated on the valve seat 128), and the piston 48 moves back to close the on-off valve 46, so the wheel cylinder 22 has a height that is approximately equal to the fluid pressure in the mask cylinder 1o. Therefore, high hydraulic pressure will not be supplied to the wheel cylinder 22 regardless of the driver's intention.

If the wheel 58 begins to skid again as a result of increasing the hydraulic pressure in the wheel cylinder 22 as described above, the computer 62 resumes supplying current to the solenoid 66. By repeating the above operations, the wheels 58 can brake the vehicle most efficiently without skidding. While the electromagnetic directional control valve 18 is being repeatedly switched, the piston 48 of the control valve 70 repeats small strokes forward and backward in order to open and close the on-off valve 46.
2 to the mask cylinder 10 and appears as a minute rocking of the brake pedal 11, the driver can know that the anti-skid device is in operation without feeling uncomfortable. Furthermore, as a result of the brake fluid being supplied from the accumulator 52 to the wheel cylinder 22 as a result of the repetition of the above-mentioned operation, if the hydraulic pressure in the accumulator 52 becomes lower than the lower limit set value of the pressure switch 54, this The pump 38 is activated based on the detection signal from the pressure switch 54, and the accumulator 52 is replenished with brake fluid.

If the vehicle is accelerated to the fourth speed desired by the driver and the brake pedal 11 is not depressed enough, the hydraulic pressure supplied from the accumulator 52 to the wheel cylinder 22 is also reduced. When the depression is released, the hydraulic pressure in the mask cylinder 10 disappears, so the piston 48 of the control valve 7o immediately retreats to the hydraulic pressure chamber 136 side, closing the on-off valve 46. Therefore, the pressure is removed from the accumulator 52. The brake fluid will no longer flow out. Also, the computer 62 detects that the rotational acceleration of the wheels 58 exceeds a predetermined value, so that it is no longer necessary to perform skid prevention control. , the supply of current to the solenoid 66 is stopped.

The above is the operation when the circuit that supplies brake fluid to the wheel cylinders 22 is normal, but if the hydraulic pressure in the system to which the wheel cylinders 22 belong cannot rise due to a cause such as a pipe rupture, the on-off valve 46 remains closed, automatically preventing the brake fluid stored in the accumulator 52 from flowing out of the damaged line. In the normal system, the same operation as described above is performed, and the vehicle is efficiently braked. Further, the accumulator 52. If pump 38 fails, check valve 42 prevents brake fluid from flowing out of the main circuit.

Although one embodiment of the present invention has been described above, this is literally an illustration, and the present invention is not limited to this embodiment. For example, in the above embodiment, the on-off valve 46 is opened and closed by a part of the piston 48 itself, but it can also be opened and closed by another member that moves integrally with the piston 48. The structure of is also not limited to that of the above embodiment. Furthermore, brakes whose hydraulic pressure is to be controlled are not necessarily limited to those installed on wheels; for example, a hydraulic brake system that indirectly suppresses the rotation of wheels by suppressing the rotation of a propeller shaft, etc. The present invention can be similarly applied to

Although not illustrated individually, it is of course possible to implement the present invention in various modifications and improvements based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an anti-skid brake device which is an embodiment of the present invention, and FIG. 2 shows an example of a specific structure of the control valve and electromagnetic directional control valve shown in FIG. FIG. 10: Mask cylinder 14: Solenoid on-off valve 16: Liquid passage (switching valve passage) 18: Solenoid directional switching valve 22: Wheel cylinder 24:
Check valve 26: Bypass passage 28: Reservoir 38: Pump 46: Open/close valve 48: Piston 52: Accumulator 58: Left front wheel 60: Sensor
62: Microcomputer 70: Control valve 72: Housing 88: Mask cylinder passage 90: Pump passage 92: Wheel cylinder passage 93: Reservoir passage 124: Piston chamber 126: Through hole 128.142: Valve seat 130.144: Pole (valve 132.146: Compression coil spring Applicant Toyota Motor Corporation Nippon Denso Co., Ltd. Figure 1

Claims (1)

[Scope of Claims] A mask cylinder that generates hydraulic pressure based on a brake operation by a vehicle driver; a reservoir that stores brake fluid; a brake cylinder that operates a brake that suppresses rotation of a wheel; an electromagnetic directional switching valve that is connected to a mask cylinder and a reservoir and selectively communicates the brake cylinder with the mask cylinder and the reservoir; a control device that controls the electromagnetic directional control valve based on the above, and a pump that pumps up brake fluid from the reservoir or a fluid passage constantly communicating therewith and supplies the brake fluid to the brake cylinder via the electromagnetic directional control valve. A vehicle anti-skid brake device comprising: a piston chamber formed integrally with a housing of the electromagnetic directional control valve at a portion connected to the mask cylinder and the pump of the electromagnetic directional control valve; a master cylinder passage extending from a first end of the piston chamber and communicating with the mask cylinder; and a pump passage and a switching valve passage extending from a second end of the piston chamber and communicating with the pump and the electromagnetic directional switching valve, respectively. , made of a magnetic material, which has a cylindrical shape with a bottom, is fitted liquid-tightly and slidably into the piston chamber, and has a through hole at the bottom and a valve seat provided at the inner opening of the through hole. a piston, and is disposed at iπ so as to be movable inside the piston and in a state that does not prevent fluid pressure chambers on both sides of the piston from communicating with each other through a through hole in the bottom of the piston, and is arranged so as to be movable inside the piston so as not to prevent fluid pressure chambers on both sides of the piston from communicating with each other through a through hole in the bottom of the piston. A valve element made of a magnetic material that is attracted to the valve seat by the magnetic force generated by the solenoid when the solenoid is energized and blocks communication between the hydraulic pressure chambers on both sides of the piston, and the valve element is always kept at a position away from the valve seat. energizing means for energizing; and an energizing means provided at an opening of the pump passage to the second end of the piston chamber, preferably in a state that blocks the pump passage; opened by the piston or a member that moves integrally therewith when the piston is moved toward the second end of the piston chamber due to a hydraulic pressure difference between the two hydraulic pressure chambers caused by the communication being cut off; A control valve including an on-off valve that closes when the piston is moved toward the first end of the piston chamber is provided, and communication between the mask cylinder and the electromagnetic directional switching valve is cut off by excitation of the solenoid. , the pump, which had been disconnected until then, is brought into communication with the electromagnetic directional switching valve, and the electromagnetic directional switching valve is controlled so that the hydraulic pressure supplied from the pump is equal to the hydraulic pressure of the mask cylinder. An anti-skid brake device characterized by being supplied to.