JPH072087A - Hydraulic brake device - Google Patents

Abstract

PURPOSE:To obtain a brake device which supplies the hydraulic pressure of a hydraulic pressure source to a wheel cylinder through the control to the hydraulic pressure corresponding to the operation force of a brake operating member, electrically control the hydraulic pressure and provides high reliability. CONSTITUTION:The hydraulic pressure supplied from an accumulator 46 is adjusted to the nearly equal level to the hydraulic pressure of a master cylinder 12 by the first hydraulic pressure control valve 42. The piston which receives the master cylinder hydraulic pressure of the first hydraulic pressure control valve 42 is sealed by a sealing member, and the leak of the brake liquid is prevented. The hydraulic pressure adjusted by the first hydraulic pressure control valve 42 is supplied to the second hydraulic pressure control valve 44, and is used as the pilot hydraulic pressure for controlling the hydraulic pressure of the accumulator 46. Even if the brake liquid supplied from the first hydraulic pressure control valve 42 leaks into the second hydraulic pressure control valve 44, the liquid is supplied from the accumulator 46, no trouble is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the reliability of a hydraulic brake device.

[0002]

2. Description of the Related Art In a hydraulic brake device, a hydraulic pressure of a hydraulic pressure source is electrically controlled to a height corresponding to an operating force of a brake operating member such as a brake pedal and a brake operating lever, and a wheel cylinder of the brake is controlled. There is a supply device, and
An example is described in Japanese Patent Publication No. 69472.

However, in the hydraulic brake device described in the above publication, the operating force of the brake operating member is detected by the sensor,
The brake fluid pressure supplied to the wheel cylinders is controlled based on the detection signal. Therefore, if the sensor fails, the hydraulic pressure of the wheel cylinder becomes excessive or excessive with respect to the operating force of the brake operating member, and proper braking may not be performed. Therefore, the applicant
A hydraulic brake device that solves this problem has been developed and is being applied for as Japanese Patent Application No. 5-120686.

The hydraulic brake device in this application rotates a wheel by supplying a hydraulic pressure to a master cylinder for generating a hydraulic pressure in a pressurizing chamber according to an operating force of a brake operating member and a wheel cylinder. The brake, the reservoir, and the hydraulic pressure source other than the master cylinder are installed between the master cylinder, the wheel cylinder, the reservoir, and the hydraulic pressure source. It is supplied to the wheel cylinder by controlling the height according to (hereinafter referred to as mass cylinder pressure) and supplying it to the wheel cylinder, and by applying an electrically controlled force to the hydraulic pressure control valve. And an electric hydraulic pressure changing device for changing the hydraulic pressure.

The specifically disclosed hydraulic control valve includes a high pressure port connected to the hydraulic pressure source, a low pressure port connected to the reservoir, and a control pressure port connected to the wheel cylinder. A valve housing, a spool slidably and substantially fluid-tightly fitted in a valve hole in the valve housing, and a spool for selectively communicating the control pressure port with the high pressure port and the low pressure port; The control piston is slidably and substantially fluid-tightly fitted into the cylinder bore formed in the housing for forming a control pressure chamber on one side of the control piston and an atmospheric pressure chamber on the other side. By supplying the master cylinder pressure to the control pressure chamber, a control force proportional to the master cylinder pressure is applied to the spool so that the control pressure port communicates with the high pressure port. A control force generating device, and the control force based on the fluid pressure in the control pressure port to the spool is intended to include a reaction force means for applying a reaction force opposite.

When the brake operating member is operated in this hydraulic brake device, hydraulic pressure corresponding to the operating force is generated in the pressurizing chamber of the master cylinder, and the hydraulic pressure of the hydraulic pressure source is controlled by the hydraulic pressure control valve. Is the height according to the master cylinder pressure,
That is, the height is controlled according to the operating force of the brake operating member and is supplied to the wheel cylinder to suppress the rotation of the wheel. The height of the control pressure obtained by the hydraulic pressure control valve is basically determined by the master cylinder pressure, and the hydraulic pressure can be changed by the electric hydraulic pressure changing device. The control force can be controlled to a height that does not correspond one-to-one with the operating force, and antilock control, braking effect control, acceleration slip control, etc. can be performed. As described above, since the hydraulic pressure of the hydraulic pressure source is basically controlled without using the electric means, and the electric control is added to the control, the electric control means may be abnormal. Even if it occurs, its influence is small and a highly reliable hydraulic brake device can be obtained.

[0007]

However, in the above hydraulic control valve, it is inevitable that a small amount of brake fluid will leak out from the gap between the control force generating housing and the control piston, and the brake operating member is operated. When held in this state, the operating position of the brake operating member gradually changes.

This hydraulic pressure control valve adjusts the high pressure of the hydraulic pressure source by adjusting the spool position by the electric control force of the electric hydraulic pressure changing device and the hydraulic control force of the control force generating device. . Therefore, it is necessary to accurately transmit the master cylinder pressure to the spool via the control piston, and it is necessary to reduce the influence of friction between the control piston and the cylinder bore, which is a disturbance to the transmission. As means for reducing the influence of this friction, there are means for increasing the diameter of the control piston and means for reducing the friction between the control piston and the cylinder bore as much as possible.

With the means for increasing the diameter of the control piston, the master cylinder pressure is accurately transmitted to the spool even if the seal member for maintaining the liquid tightness between the control piston and the cylinder bore is provided. If a seal member is arranged between the control piston and the cylinder bore, a friction force due to the seal member is generated when the control piston operates, and the master cylinder pressure that is the input of the control piston and the hydraulic control force that is the output are generated. However, the ratio of the frictional force to the hydraulic control force can be reduced by increasing the diameter of the control piston. However, if the control piston diameter is increased to such an extent that the frictional force can be ignored compared to the hydraulic control force, an electric control force that adjusts the spool position in cooperation with the output of the control piston is obtained. The pressure changing device must be upsized, and the entire fluid pressure control valve is upsized, and power consumption is increased. Therefore, this means is not adopted in the hydraulic control valve of the above application, but a means for reducing the frictional force between the control piston and the cylinder bore is adopted.

Specifically, a seal member is not provided between the control piston and the valve housing, and a metal-to-metal seal for preventing leakage is formed by minimizing the gap. However, it is difficult to completely seal with a metal-metal seal, and if the pressure in the control pressure chamber is high, the brake fluid will leak from the control pressure chamber to the atmospheric pressure chamber, and if the brake operating member is held in an operated state, it will gradually The operating position of the brake operating member changes. Therefore, it is an object of the present invention to obtain a hydraulic brake device in which the brake fluid from the master cylinder does not leak while avoiding an increase in the size and power consumption of the device as much as possible.

[0011]

In order to solve the above-mentioned problems, a hydraulic brake device of the present invention comprises a master cylinder for generating a hydraulic pressure in a pressurizing chamber according to an operating force of a brake operating member, and a wheel cylinder. A brake that suppresses wheel rotation by supplying hydraulic pressure to the reservoir, a reservoir,
A hydraulic pressure source other than the master cylinder, a pressure receiving piston that receives the master cylinder pressure, a first housing in which the pressure receiving piston is slidably fitted, a pressure receiving piston and a first
A first hydraulic control valve having a seal member for maintaining liquid tightness with the housing, controlling the hydraulic pressure of the hydraulic pressure source to a height according to the master cylinder pressure, the wheel cylinder, the reservoir, and the liquid. Provided between the pressure source and the first hydraulic control valve,
By a spool that selectively switches communication between the hydraulic pressure source and the reservoir and the wheel cylinder, an electric control force applying device that applies an electrically controlled force to the spool, and a hydraulic pressure of the first hydraulic control valve. A control piston that applies a force to the spool and a second housing in which the control piston is fitted in a substantially liquid-tight manner and is slidable are provided.
The second hydraulic pressure control valve is configured to be transmitted to the wheel cylinder while being controlled based on the hydraulic pressure of the hydraulic pressure control valve and the electric control force.

[0012]

When the master cylinder pressure is applied to the pressure receiving piston of the first hydraulic pressure control valve, the hydraulic pressure of the hydraulic pressure source is adjusted to a height corresponding to the master cylinder pressure applied to the pressure receiving piston.
At that time, since the seal member is provided between the pressure receiving piston and the first housing, the brake fluid from the master cylinder does not leak. When the master cylinder pressure is applied to the pressure receiving piston, a frictional force due to the seal member is generated with the operation of the pressure receiving piston, but it can be ignored compared to the force generated in the pressure receiving piston by increasing the diameter of the pressure receiving piston. It can be made as small as possible.
Therefore, good correlation (input / output characteristic) between the master cylinder pressure input to the first hydraulic pressure control valve and the hydraulic pressure output from the first hydraulic pressure control valve is maintained.

The hydraulic pressure adjusted by the first hydraulic control valve is the second hydraulic pressure.
When applied to the control piston of the hydraulic pressure control valve, the hydraulic control force generated in the control piston causes the spool to move in a direction in which the hydraulic pressure source and the wheel cylinder communicate with each other, so that the hydraulic pressure of the hydraulic pressure source becomes the first pressure. The height is adjusted to correspond to the hydraulic pressure of the hydraulic control valve. Here, when the fitting between the control piston and the second housing is substantially liquid-tight, that is, when the seal member is not provided between the control piston and the second housing and the metal-metal seal is formed. The frictional force between the control piston and the second housing becomes extremely small. In such a state where the frictional force is extremely small, the hydraulic pressure of the first hydraulic pressure control valve is accurately transmitted to the spool even if the control piston has a small diameter. At this time, a small amount of brake fluid leaks from between the control piston and the second housing, but this brake fluid is replenished from the hydraulic pressure source via the first hydraulic pressure control valve, which is not a problem. The hydraulic pressure of the second hydraulic pressure control valve is indirectly controlled by the master cylinder pressure via the first hydraulic pressure control valve. When the electric control force is applied to the spool, the position of the spool is determined by the cooperation of the electric control force and the hydraulic control force generated in the control piston based on the master cylinder pressure, and the spool is supplied to the wheel cylinder. The hydraulic pressure of the brake fluid is adjusted. In such a case, in general, it is necessary to increase the electric control force as the hydraulic control force increases, and particularly when the electric control force and the hydraulic control force are in opposite directions. The electric control force must move the spool against the hydraulic control force, and the greater the hydraulic control force, the greater the required electric control force. If the control piston diameter is small, the hydraulic control force is small, and the electric control force is small. Therefore, a small electric control force applying device can be used.

[0014]

As described above, according to the present invention, the brake fluid in the master cylinder can be prevented from leaking, and the bottom cylinder of the master cylinder can be bottomed to increase the hydraulic pressure in the pressurizing chamber of the master cylinder. It is possible to avoid the occurrence of a situation in which it becomes impossible to obtain a highly reliable hydraulic brake device. Further, by providing the first hydraulic pressure control valve, it is possible to avoid an increase in the size of the electrical control force application device, so that the first and second spaces are provided in a space smaller than the space occupied by the second hydraulic pressure control valve having the same effect. The hydraulic pressure control valve can be installed, and the hydraulic brake device can be prevented from increasing in size and power consumption.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, 10 is a brake pedal as a brake operating member. By depressing the brake pedal 10, hydraulic pressure is generated in each of the two pressurizing chambers of the master cylinder 12. The master cylinder 12 is connected to a proportioning and bypass valve (P & B valve) 16 so that the hydraulic pressure generated in each pressurizing chamber is P
Front wheel braking unit 18 and rear wheel braking unit 20 via the & B valve
Is being supplied to.

In the front wheel braking portion 18, a solenoid valve 28 is provided in the middle of a main passage 27 for supplying hydraulic pressure from the P & B valve 16 to the front wheel cylinders 26 of the left and right front wheels 22, 24.
Is normally provided, and the P & B valve 16 and the front wheel cylinders 26 of the left and right front wheels 22, 24 are normally communicated with each other. A sub passage 29 is provided between the main passage 27 between the solenoid valve 28 and the front wheel cylinder 26 and the main passage 27 between the P & B valve 16 and the solenoid valve 28. A solenoid valve 30 and a motor 32 are provided in the sub passage 29.
And a pump 33 for recirculating the brake fluid, which is driven by. Check valves 34 are provided on the inlet side and the outlet side of the pump 33, respectively, to allow only one-way flow of the brake fluid. In addition, the pump 3 is installed in the reservoir 35 provided between the solenoid valve 30 and the pump 33.
The brake fluid that cannot be delivered in time by 3 is temporarily stored. When the brake pedal 10 is depressed, hydraulic pressure is generated in the pressurizing chamber of the master cylinder 12, and the hydraulic pressure P &
It is supplied to the front wheel cylinder 26 via the B valve 16 and the solenoid valve 28, and the left and right front wheels 22, 24 are braked. When the depression force of the brake pedal 10 is excessive with respect to the friction coefficient of the road surface and the slip ratio of the wheels exceeds the appropriate range, antilock control is performed. When an antilock control command is issued from a control device (not shown), the motor 32 is started and the solenoid valves 28 and 30 are opened / closed in accordance with the command of the control device to perform the antilock control.

In the rear wheel braking unit 20, the P & B valve 16 and the rear wheel cylinder 40 of the left and right rear wheels 36, 38.
Between the first hydraulic pressure control valve 42 and the second hydraulic pressure control valve 44.
The first hydraulic pressure control valve 42 and the second hydraulic pressure control valve 44 are connected to an accumulator 46, which is a hydraulic pressure source for supplying hydraulic pressure to each. Accumulator 46
A pump 50 driven by a motor 48 is connected to the pump 50, and a brake fluid is supplied from the reservoir 52 connected to the pump 50 to the accumulator 46 and stored therein. The pump 50 is provided with a discharge pressure detection device and a relief valve, which are not shown, so that the hydraulic pressure of the stored brake fluid is maintained within a certain range. Brake pedal 1
When the hydraulic pressure generated in the pressurizing chamber of the master cylinder 16 becomes a certain value or more due to the depression of 0, the P & B valve 16 reduces the hydraulic pressure at a constant ratio and supplies it to the first hydraulic pressure control valve 42. In the first hydraulic pressure control valve 42, the hydraulic pressure supplied from the accumulator 46 is adjusted to almost the same height as the master cylinder hydraulic pressure supplied via the P & B valve 16, and the adjusted hydraulic pressure is adjusted to the second hydraulic pressure. It is supplied to the control valve 44. The hydraulic pressure supplied from the first hydraulic pressure control valve 42 is a pilot hydraulic pressure for adjusting the hydraulic pressure of the accumulator 46 supplied to the second hydraulic pressure control valve 44 to the hydraulic pressure supplied to the rear wheel cylinder 40. Used as. Accumulator 46
The hydraulic pressure is adjusted to a height corresponding to the pilot hydraulic pressure and supplied to the wheel cylinders 40 for braking. When the depression force of the brake pedal 10 is excessive with respect to the friction coefficient of the road surface and the slip ratio of the wheels exceeds the appropriate range, antilock control is performed. When an antilock control command is issued from a control device (not shown), the second hydraulic pressure control valve 44 adjusts the hydraulic pressure supplied to the rear wheel cylinder 40 in accordance with the command to perform antilock control.

Next, the structure and operation of the first hydraulic pressure control valve 42 will be described. As shown in FIG. 2, the first hydraulic pressure control valve 42 includes a first housing 60. A cylinder bore 62 and a valve chamber 64 are formed inside the first housing 60, and are partitioned by a partition wall 66 that is formed so as to project inside the first housing 60. Partition wall 66
Of the valve chamber 64 is tapered to form a valve seat 67, and the through hole 6 having a circular cross section is formed in the center of the valve seat 67.
8 is formed.

A pressure receiving piston 70 that receives the master cylinder hydraulic pressure is slidably fitted in the cylinder bore 62, and a master cylinder pressure chamber 72 and a control pressure chamber 74 are formed in the cylinder bore 62. The pressure receiving piston 70 is biased by a spring 76 in the direction of the through hole 68, and the seal between the pressure receiving piston 70 and the first housing 60 is maintained by a seal member 78. On the other hand, in the valve chamber 64,
A ball 82 biased by a spring 80 toward the through hole 68 is provided. The tip of the small diameter portion 83 of the pressure receiving piston 70 is formed along the spherical shape of the ball 82, and a liquid passage 86 is formed from the center portion thereof to the annular groove 84 formed on the outer peripheral portion of the pressure receiving piston 70. ing.

A port 8 for connecting the P & B valve 16 and the master cylinder pressure chamber 72 is provided on the bottom wall of the cylinder bore 62.
8 is provided, and the reservoir 52 and the annular groove 8 are provided on the side wall.
4 is provided with a port 90 and a port 92 for communicating the second hydraulic pressure control valve 44 with the control pressure chamber 74. The valve chamber 64 has a port for communicating the accumulator 46 with the valve chamber 64. 94 is provided.

Next, the operation will be described. When the brake pedal 10 is not depressed and the hydraulic pressure from the accumulator 46 is not supplied, the pressure receiving piston 70 is biased by the spring 76 and the shoulder portion 96 of the partition wall 66 as shown in FIG.
Forward (moves to the right in the figure) until it comes into contact with the spring 80
The ball 82 is pushed away from the valve seat 67 against the urging force of.
However, since hydraulic pressure is normally supplied from the accumulator 46, as shown in FIG. 3, the pressure receiving piston 70 retracts, the ball 82 contacts the valve seat 67, and the brake pedal 1
This state is maintained until 0 is depressed. When the brake pedal 10 is depressed, the master cylinder pressure chamber 72
When the master cylinder hydraulic pressure is supplied to the pressure receiving piston 7
0 advances and the ball 82 is separated from the valve seat 67 against the biasing force of the spring 80. As a result, as shown in FIG. 2, the valve chamber 64 and the control pressure chamber 74 are communicated with each other, and the hydraulic pressure of the control pressure chamber 74 increased by the hydraulic pressure of the accumulator 46 is supplied to the second hydraulic pressure control valve 44. To be done. When the hydraulic pressure in the control pressure chamber 74 and the hydraulic pressure in the master cylinder pressure chamber 72 become equal, the holding state shown in FIG. 3 is established and the hydraulic pressure supplied from the control pressure chamber 74 to the second hydraulic pressure control valve 44 is increased. It will not change. In the holding state, the ball 82 moves the pressure receiving piston 7
Since it abuts both 0 and the valve seat 67, the communication between the valve chamber 64 and the control pressure chamber 74 and the communication between the control pressure chamber 74 and the reservoir 52 are both blocked.

When the hydraulic pressure in the master cylinder pressure chamber 72 decreases, the pressure receiving piston 70 moves backward as shown in FIG.
4 and the reservoir 52 are communicated with each other. Therefore, the hydraulic pressure in the control pressure chamber 74 decreases until it becomes the same as the hydraulic pressure in the master cylinder pressure chamber 72, and when the control pressure chamber 74 and the master cylinder pressure chamber 72 have the same hydraulic pressure, the holding state of FIG. Become.
In this way, the hydraulic pressure in the control pressure chamber 74 is adjusted to the same height as the hydraulic pressure in the master cylinder pressure chamber 72 and supplied to the second hydraulic pressure control valve 44.

Next, the structure and operation of the second hydraulic pressure control valve 44 will be described. As shown in FIG. 5, the second hydraulic pressure control valve 44 includes a second housing 100. Inside the second housing 100, a bottomed valve hole 102 having a circular cross-sectional shape, a large space 84 located on the opening end side of the valve hole 102, and a side of the space 84 where the valve hole 102 opens. Has a bottomed cylinder bore 106 that opens to the opposite side. The valve hole 102, the space 84 and the cylinder bore 106 are formed concentrically with each other. A spool 108 is slidably fitted in the valve hole 102. The spool 108 has a stepped shape, a small diameter portion 114 is formed between the first large diameter portion 110 and the second large diameter portion 112, and the small diameter portion 114 is formed in the valve hole 102 in the first and second large diameter portions 110 and 112. It is fitted. The clearance between the outer peripheral surfaces of the first and second large-diameter portions 110 and 112 and the inner peripheral surface of the valve hole 102 is extremely small at a diameter of 10 μm or less. A space seal is formed.

Also inside the second housing 100 is the valve hole 1
A cylinder bore 116 having a diameter smaller than 02 and a bottom is formed. A reaction force piston 118 is slidably fitted in the cylinder bore 116. An intermetallic seal is formed between the cylinder bore 116 and the reaction force piston 118, and the reaction force piston 118 is urged by the spring 120 in a direction to abut the spool 108. Valve hole 10
The space between the bottom surface of 2 and the spool 108 is connected to the reservoir 52 via the first low pressure port 122. Second
The housing 100 is further provided with a high pressure port 124 to which the accumulator 46, which is a hydraulic pressure source, is connected, a second low pressure port 126 to be connected to the reservoir 52, and a control pressure port 128 to be connected to the rear wheel cylinder 40. .

The control pressure port 128 is connected to the spool 10
8 is connected to an annular chamber 130 formed by the small diameter portion 114 and the inner peripheral surface of the valve hole 102, and the high pressure port 1
24 communicates with an annular groove 132 formed in a portion of the valve hole 102 on the bottom side of the control pressure port 128. Further, the second low pressure port 126 is an annular groove 13 formed on the opening side of the valve hole 102 with respect to the control pressure port 128 of the valve hole 102.
It is connected to 4. Further, the cylinder bore 1
A liquid passage 136 branched from the control pressure port 128 is connected between the bottom surface of 16 and the reaction force piston 118, and the reaction force piston 118 receives the fluid pressure of the control pressure port 128 and becomes the fluid pressure. Generates a reaction force based on the spool 10
8 is provided in a direction in which communication between the high pressure port 124 and the control pressure port 128 is blocked.

In the space 84, the force motor 13
8 are provided. The force motor 138 has a permanent magnet 140 and a moving coil 142. Space 8
An annular groove 146 is provided in the yoke 144 fixed in the inner circumference of the circular groove 146, and a cylindrical portion 148 is formed in the center of the yoke 144. ing. The moving coil 142 is formed by winding a coil 152 around a holding member 150 made of a non-magnetic material. The holding member 150 has a bottomed cylindrical shape, a coil 152 is wound around the outer peripheral side of the cylindrical portion 154, and is slidably fitted to the cylindrical portion 148 via a bush 156 fixed to the inner peripheral surface. The bush 156 is made of a material having a small coefficient of friction, and the movement of the moving coil 142 is guided by the cylindrical portion 148. Further, the protrusion 160 is provided on the bottom wall portion 158 of the holding member 150.
It is projected toward 8. A diaphragm 162 is provided between the protrusion 160 and the second housing 100, and brake fluid leaking from a metal-to-metal seal between the outer peripheral surface of the spool 108 and the inner peripheral surface of the valve hole 102 is protruded from the protrusion 16.
0, the second housing 100, and the diaphragm 162 hold the first drain space 164. This first
The drain space 164 is connected to the reservoir 52 via a first drain port 166 provided in the second housing 100.

A control piston 168 is slidably fitted in the cylinder bore 106 so that the cylinder bore 1
An intermetallic seal is formed between 06 and the control piston 168. Control piston 168 and cylinder bore 10
A control pressure chamber 170 is formed between the bottom surface of 6 and the first hydraulic pressure control valve 42 via a port 172.
A spring 174 is arranged in the control pressure chamber 170, and the control piston 168 is biased by the spring 174.
A protrusion 178 protruding from the front end surface of the control piston 168 is brought into contact with the bottom wall 158 of the holding member 150. A diaphragm 180 is provided between the control piston 168 and the yoke 144.
The brake fluid leaking from the metal-to-metal seal is held in the second drain space 182 formed by the control piston 168, the second housing 100, the yoke 144, and the diaphragm 180. The second drain space 182 is connected to the reservoir 52 via a second drain port 184 provided in the second housing 100.

The spool 108, the reaction force piston 118, the moving coil 142 and the control piston 168 are integrally moved by being biased by springs 120 and 174 having biasing forces opposite to each other. When the pilot hydraulic pressure is not supplied to the control pressure chamber 170 from the first hydraulic pressure control valve 42 and the exciting current is not supplied to the coil 152, the protrusion 186 provided on the control piston 168 has the cylinder bore 106 as shown in FIG. Abutting the bottom surface of the spool 108, the spool 108 is in an original position communicating the control pressure port 128 with the second low pressure port 126.

By supplying the pilot hydraulic pressure to the control pressure chamber 170, the control piston 168 moves forward to apply a hydraulic control force to the spool 108 via the moving coil 142. This hydraulic control force is applied to the control pressure port 12
8 is connected to the high pressure port 124.

Further, from the electronic control unit 190 (hereinafter referred to as ECU) shown in FIG.
When an exciting current is supplied to the coil 152 of No. 38, the moving coil 142 moves. At this time, the moving direction of the moving coil 142 can be changed by changing the direction of the exciting current. An electric control force in the same direction as the hydraulic control force applied to the spool 108 by the control piston 168 is applied to the spool 108 to move the spool 108 forward, or an electric control force in the opposite direction to the hydraulic control force is applied. In addition to the control piston 168, the control piston 168 is retracted to allow the spool 108 to retract.

With the control piston 168 exerting a hydraulic control force on the spool 108 to control the hydraulic pressure supplied to the rear wheel cylinder 40, the force motor 1
38 by the spool 108 or control piston 168
When a force is applied to the rear wheel cylinder 40, the hydraulic pressure supplied to the rear wheel cylinder 40 is changed. Force motor 1
38 constitutes an electric control force applying device.
Further, when the exciting current is supplied to the coil 152 and the force in the same direction as the control force is applied to the spool 108 while the control piston 168 does not apply the hydraulic control force to the spool 108, the second hydraulic pressure control is performed. The valve 44 functions similarly to a conventional spool-type electromagnetic hydraulic pressure control valve, and can control the hydraulic pressure of the accumulator 46 to a height proportional to the exciting current of the coil 152 and supply the hydraulic pressure to the rear wheel cylinder 40.
By controlling the exciting current to an appropriate value, the wheel cylinder hydraulic pressure can be changed and controlled to a desired height.

Next, the operation will be described. During non-braking, spool 108, reaction force piston 118, moving coil 1
42 and control piston 168 are in the home position shown in FIG. 5, with spool 108 communicating control pressure port 128 with second low pressure port 126.

When the brake pedal 10 is depressed and hydraulic pressure is generated in the pressurizing chamber of the master cylinder 12, the hydraulic pressure is the same as the hydraulic pressure in the pressurizing chamber (at a certain value or more, the P & B valve 16).
The pilot hydraulic pressure (although the hydraulic pressure reduced in step 1) is adjusted by the first hydraulic pressure control valve 42. When the pilot hydraulic pressure is supplied to the control pressure chamber 170, the control piston 168 moves forward, the spool 108 moves forward via the moving coil 142, and the communication between the control pressure port 128 and the second low pressure port 126 is cut off. . Further, as the spool 108 is advanced, the control pressure port 128 is changed to the high pressure port 124.
The brake fluid of the accumulator 46 is supplied to the rear wheel cylinder 40. At the same time, the reaction force piston 118 receives the hydraulic pressure from the control pressure port 128, and the reaction force acts on the spool 108 to control the wheel cylinder hydraulic pressure.

When the pilot hydraulic pressure is supplied to the control pressure chamber 170, the brake fluid slightly leaks from the metal-metal seal between the control piston 168 and the second housing 100.
The pilot hydraulic pressure decreases by that amount. However, as soon as the pilot hydraulic pressure decreases, brake fluid is replenished by the first hydraulic pressure control valve 42 to adjust the pilot hydraulic pressure, so that the rear wheel cylinder 40 is substantially used. There is no change in the hydraulic pressure supplied to. The leaked brake fluid is
The second drain port 184 is stored in the drain space 182.
It is collected in the reservoir 52 via the.

When the depression force of the brake pedal 10 is excessive with respect to the friction coefficient of the road surface and the slip ratio of the wheels exceeds the proper range, antilock control is performed. In this case, the force motor 1 is controlled by the ECU 190.
The coil 152 of 38 is supplied with an exciting current in a direction in which an electric control force opposite to the hydraulic control force is applied to the control piston 168. As a result, the control piston 168 is retracted, the spool 108 is retracted, the control pressure port 128 is communicated with the second low pressure port 126, and the wheel cylinder hydraulic pressure is reduced. If the wheel slip is reduced, the exciting current of the coil 152 is reduced and the control piston 16
8 advances the spool 108 so that the control pressure port 128 does not communicate with either the second low pressure port 126 or the high pressure port 124, or the control pressure port 1
28 is brought into communication with the high pressure port 124, and the wheel cylinder hydraulic pressure is held or increased. By controlling the electric control force, the wheel cylinder hydraulic pressure is controlled, and the slip ratio of the wheel is kept within an appropriate range. For acceleration slip control, accumulator 46
The hydraulic pressure of the rear wheel cylinder 40 is controlled only electrically by the force motor 132.

As described above, according to this embodiment, it is possible to eliminate the leakage of the brake fluid in the master cylinder, to obtain a highly reliable hydraulic brake device, and to prevent the leakage. (2) An increase in the space occupied by the hydraulic brake device and an increase in power consumption that accompany the increase in size of the hydraulic control valve can be avoided.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this embodiment. For example, the boosting factor of the master cylinder hydraulic pressure in the first hydraulic control valve 42 does not need to be 1, and the pressure receiving area ratio of the pressure receiving piston 70 (the master cylinder pressure chamber side pressure receiving area and the control pressure chamber side pressure receiving area). You may adjust by changing (ratio) etc. Therefore, it is not necessary to change the master cylinder and the brake pedal in order to obtain different wheel cylinder hydraulic pressures depending on the type of automobile, and it is possible to reduce costs by sharing parts such as the master cylinder. In addition, the control piston 1 of the second hydraulic pressure control valve 44
Similar effects can be obtained by changing the ratio of the cross-sectional areas of 68 and the reaction force piston 118.

Although the present invention is applied to the rear brake in the above-mentioned embodiments, the present invention is not limited to the rear brake and may be applied to the front brake, or may be applied to both the rear and front brakes. Further, in the hydraulic brake device of the above embodiment, the electric hydraulic pressure changing device is not operated during normal braking, and the rotation of the wheels is suppressed only by the hydraulic pressure mechanically controlled by the hydraulic control valve. However, the hydraulic pressure may be controlled by both the hydraulic pressure control valve and the electric hydraulic pressure changing device during normal braking. For example, the depression force of the brake pedal 10 and the deceleration of the vehicle may be detected, and the electric control force may be controlled so that the deceleration corresponding to the depression force is obtained.

Further, the electric control force applying device is not limited to the force motor 138, and a solenoid for generating a force in only one direction by supplying an exciting current to the coil can be used. In that case, if the electric control force in both the forward and reverse directions is required, two solenoids may be provided so as to oppose each other. Spool 1 by control piston 168 with one solenoid
The hydraulic control force applied to 08 is applied in the same direction as the hydraulic control force, and the other solenoid is applied with the opposite electric control force. At the time of anti-skid control, the other solenoid is operated. At the time of acceleration slip control, one of the solenoids is operated.

In addition to the force motor and the solenoid, the electric control force applying device may be any device that can apply an electrically controllable force to the hydraulic pressure control valve. In addition, without departing from the scope of claims,
The present invention can be carried out in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a system diagram showing the hydraulic brake device.

FIG. 2 is a front cross-sectional view of a first hydraulic pressure control valve provided in the hydraulic brake device.

FIG. 3 is a diagram showing another operating state of the first hydraulic control valve.

FIG. 4 is a view showing still another operating state of the first hydraulic pressure control valve.

FIG. 5 is a front sectional view of a second hydraulic pressure control valve provided in the hydraulic brake device according to the embodiment of the present invention.

[Explanation of symbols]

 10 brake pedal 12 master cylinder 40 rear wheel cylinder 42 first hydraulic pressure control valve 44 second hydraulic pressure control valve 46 accumulator 50 pump 52 reservoir 60 first housing 70 pressure receiving piston 78 seal member 80 second housing 88 spool 118 force motor 148 Control piston

Claims (1)

[Claims] 1. A master cylinder for generating a hydraulic pressure in a pressurizing chamber according to an operating force of a brake operating member, a brake for suppressing rotation of wheels by supplying hydraulic pressure to a wheel cylinder, and a reservoir. A hydraulic pressure source different from the master cylinder, a pressure receiving piston that receives the hydraulic pressure of the master cylinder, a first housing in which the pressure receiving piston is slidably fitted, and a space between the pressure receiving piston and the first housing. A first hydraulic control valve for controlling the hydraulic pressure of the hydraulic pressure source to a height corresponding to the hydraulic pressure of the master cylinder, a wheel cylinder, a reservoir, and a hydraulic fluid. A spool provided between the pressure source and the first hydraulic pressure control valve for selectively switching the communication between the hydraulic pressure source and the reservoir and the wheel cylinder, and a spool for applying an electrically controlled force to the spool. Control force applying device, a control piston that applies a force by the hydraulic pressure of the first hydraulic pressure control valve to the spool, and a second housing in which the control piston is fitted in a substantially liquid-tight and slidable manner. And a second hydraulic pressure control valve which transmits the hydraulic pressure of the hydraulic pressure source to the wheel cylinder while controlling the hydraulic pressure of the hydraulic pressure source based on the hydraulic pressure of the first hydraulic pressure control valve and the electric control force. Brake device.