JP2002087238A - Relief valve and brake device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the number of parts of a relief valve, thereby reducing weight, assembling man-hours, and cost. SOLUTION: A valve body 3 housed in a housing 100 is provided.
2a is urged by a spring 32c, and the seat surface 10
In a relief valve which comes into contact with the valve body 2a and opens when a predetermined pressure is applied to the valve body 32a in the valve opening direction to release the pressure, the seat surface 102a is formed directly on the housing 100. And

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relief valve suitable for application to a brake device which automatically generates a braking force by supplying a brake fluid from a control hydraulic pressure source, and a brake using the relief valve. Related to the device.

[0002]

2. Description of the Related Art In recent years, there has been proposed a device for executing various automatic brake controls for automatically generating a braking force in a brake device. As the automatic brake control, for example, in a device that automatically controls the inter-vehicle distance to a preceding vehicle to an optimal distance according to the speed, an automatic braking control that automatically generates a braking force when the inter-vehicle distance is reduced, ,
When the vehicle attitude becomes unstable such as over-steer during turning, vehicle motion control that applies a braking force that generates a yaw moment in the direction that stabilizes the vehicle attitude, and acceleration slip occurs on the drive wheels A control to be executed when the driver is not performing a braking operation, such as a torque slip control for generating a braking force to suppress the acceleration slip when the vehicle attitude becomes unstable, or When a braking operation is performed, there is a by-wire control that generates a braking force according to the braking operation, a boost control that applies a braking force according to the braking operation, and the like.

[0003] As a brake device capable of executing such automatic brake control, for example, a brake device described in JP-A-8-53057 is known. This prior art is provided with a hydraulic pressure adjusting means provided with a pressure increasing source and a pressure reducing valve and capable of increasing / decreasing a wheel cylinder pressure in the middle of a brake circuit connecting the master cylinder and the wheel cylinder. And a pump for sucking brake fluid on the master cylinder side and discharging brake fluid between the out-side gate valve and the fluid pressure adjusting means. The configuration is such that an in-side gate valve is provided in the middle of the circuit. Therefore, while closing the out-side gate valve, the in-side gate valve is opened, the pump is operated to supply the brake fluid to the brake circuit, and the wheel cylinder pressure is arbitrarily adjusted by the fluid pressure adjusting means. By adjusting the pressure, the wheel cylinder pressure can be controlled to a desired pressure and a desired braking force can be generated.

A relief valve is provided in parallel with the out-side gate valve. When a brake fluid is supplied from the pump to the brake circuit and the pressure of the brake circuit exceeds a predetermined pressure, a relief valve is provided. The valve is opened to release the high pressure of the brake circuit to the master cylinder side to protect the circuit configuration.

[0005] As such a relief valve, for example, as described in Japanese Patent Application Laid-Open No. 4-262950, a seat plug is fitted to the inner periphery of a valve body.
A structure in which a valve member having a valve body that comes into contact with and separates from a seat surface formed on the seat plug is provided so as to be able to stroke the inner periphery of the valve body, and a spring that biases the valve member is provided. Those that have become common. Therefore, the pressure at which the relief operation is performed is determined by the spring force of the spring. The valve body is made of aluminum or the like in terms of workability and weight, but at least the portion of the seat plug that forms the seat surface has a hardness of steel or the like to prevent abrasion even if the valve body repeatedly collides. Use high metal as material.

[0006]

However, since the above-described relief valve has a configuration in which a seat plug is provided, the number of parts increases, which leads to an increase in weight, an increase in the number of assembly steps, and an increase in cost. Had.

The present invention has been made in view of this problem. The first object of the present invention is to reduce the number of parts of the relief valve, thereby reducing the weight, the number of assembly steps, and the cost. The purpose is. Further, the inventor of the present application
Knowing that the required hardness of the seat surface is determined by the opening / closing frequency of the relief valve, it is possible to reduce the opening / closing frequency of the relief valve in a brake device that performs automatic brake control. A second object is to make it easier to achieve the first object by reducing the requirement for hardness.

[0008]

In order to achieve the above-mentioned object, the present invention is directed to a valve element, wherein a valve element housed in a housing is urged by an urging means so as to abut against a seat surface. In a relief valve which opens when a predetermined pressure is applied in the valve opening direction to release the pressure, the seat surface is formed directly on the housing. According to a second aspect of the present invention, in the relief valve according to the first aspect, the housing is formed of aluminum.

According to a third aspect of the present invention, there is provided a control hydraulic pressure source capable of supplying a hydraulic pressure to a brake circuit connected to a wheel cylinder, the control hydraulic pressure source being provided in the brake circuit,
An out-side gate valve for releasing the hydraulic pressure supplied from the control hydraulic pressure source to the wheel cylinder to the low pressure side, and the brake circuit is provided between the out-side gate valve and the wheel cylinder in the brake circuit to communicate with the brake circuit. A hydraulic pressure adjusting means capable of forming an increased pressure state and a reduced pressure state in which the brake circuit is shut off and the wheel cylinder communicates with the lower pressure side, and a hydraulic pressure is supplied to the brake circuit by the control hydraulic pressure source. Brake control means capable of executing automatic braking control for arbitrarily controlling a braking force by adjusting a wheel cylinder pressure by operating an out-side gate valve and a hydraulic pressure adjusting means. During the automatic brake control, the control means causes the hydraulic pressure adjusting means to maintain the pressure increase state, and the pressure increase is controlled by the supply state of the brake fluid from the control hydraulic pressure source. 3. The control system according to claim 1, wherein the control is performed in accordance with an open state of the out-side gate valve, and in parallel with the out-side gate valve, when the pressure on the wheel cylinder side exceeds a predetermined pressure, the hydraulic pressure is released to the low pressure side. Is provided. According to a fourth aspect of the present invention, in the brake device according to the third aspect, the control hydraulic pressure source sucks the brake fluid from the brake fluid source via a suction circuit and supplies the brake fluid toward the brake circuit. An in-side gate valve for switching between communication and shutoff of the suction circuit is provided in the middle of the suction circuit, and the braking control means includes:
When increasing the pressure, the in-side gate valve is opened and the pump is operated with the out-side gate valve fully closed, and when reducing the pressure, the in-side gate valve is opened in addition to opening the out-side gate valve. The side gate valve is configured to be closed. According to a fifth aspect of the present invention, in the brake device according to the fourth aspect, the brake control means operates based on duty control in operating the pump during pressure increase during the automatic brake control, and operates during pressure decrease during the automatic brake control. The opening of the out-side gate valve is performed based on duty control. The invention according to claim 6 is a brake device according to claims 3 to 5, wherein the brake circuit is a circuit connecting a master cylinder and a wheel cylinder, and the brake fluid source connected to the suction circuit is a master cylinder. There is a feature.

[0010]

According to the relief valve of the present invention, since the seat surface is formed directly on the housing and a seat plug separate from the housing is not required, the number of parts can be reduced, thereby reducing the weight.・ Reduction of assembly time
The effect that the cost can be reduced can be obtained. According to the second aspect of the present invention, the housing is formed of aluminum, which is excellent in workability and lightweight.

Further, in the brake device according to the present invention, the brake fluid is supplied from the control hydraulic pressure source to the brake circuit to control the wheel cylinder pressure during the automatic brake control. The hydraulic pressure adjusting means provided between the out-side gate valve and the wheel cylinder in the brake circuit communicates the brake circuit to increase the pressure, and supplies the brake fluid from the control hydraulic pressure source. The pressure is increased, and the pressure is reduced by opening the out-side gate valve. Therefore, the brake circuit between the out-side gate valve and the wheel cylinder is controlled to the same pressure as the wheel cylinder pressure, so that it is difficult for the pressure to become abnormally high. Therefore, the operation frequency of the relief valve provided in parallel with the out-side gate valve is low, the frequency of contact between the seat surface and the valve body is reduced, the wear on the seat surface is suppressed, and the durability of the relief valve is improved. The effect that it can be achieved is obtained.

According to the fourth aspect of the present invention, during the automatic brake control, when the pressure is increased, the in-side gate valve is opened and the pump is operated with the out-side gate valve fully closed. Therefore, the pump sucks the brake fluid from the brake fluid source, discharges the brake fluid to the brake circuit, and supplies the brake fluid to the wheel cylinder. Therefore, a braking force corresponding to the supply amount of the brake fluid is generated. On the other hand, when the pressure is reduced, the in-side gate valve is closed and the out-side gate valve is opened.
Therefore, the pump cannot suck the brake fluid, the supply of the brake fluid to the brake circuit is stopped, and the out-side gate valve is opened in this state. To the low pressure side to reduce the wheel cylinder pressure.
As described above, when the pressure is increased, the out-side gate valve is fully closed, so that a high pressure increase response is obtained.In addition, when the pressure is reduced, the in-side gate valve is closed to supply the brake fluid from the pump. Is stopped, a high pressure reduction responsiveness is obtained.
Further, according to the fifth aspect of the invention, when the pressure is increased, the operation of the pump is controlled by the duty control, so that high controllability is obtained, and it is difficult for the pressure to exceed the target wheel cylinder pressure. In addition, when the pressure is reduced, the opening of the out-side gate valve is controlled by duty control, so that high controllability is obtained. Therefore, the brake circuit is less likely to become abnormally high pressure, and the frequency of contact between the valve body of the relief valve and the seat surface is further reduced, so that the durability of the relief valve can be further improved.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 2 is a brake circuit diagram showing a brake device according to a first embodiment. In the figure, MC is a master cylinder (brake fluid source), which is a well-known one that supplies brake fluid to a wheel cylinder WC via brake circuits 1 and 2 divided into two systems when a brake pedal BP is depressed. . In the present embodiment, the brake circuits 1 and 2 have a so-called X piping structure.
The brake circuit 1 connects the wheel cylinder WC of the left front wheel and the wheel cylinder WC of the right rear wheel, and the brake circuit 2
The wheel cylinder WC of the left front wheel and the wheel cylinder WC of the right rear wheel are configured to be connected. However, the wheel cylinder WC may be divided into a front wheel and a rear wheel.

An out-side gate valve 3 is provided in the middle of each of the brake circuits 1 and 2. The out-side gate valve 3 is a normally-open solenoid valve that switches between communication and shutoff of the brake circuits 1 and 2. Each out-side gate valve 3 has a master cylinder MC side (hereinafter referred to as upstream). A one-way valve 31 that allows only the flow of brake fluid from the vehicle to the wheel cylinder WC side (hereinafter, referred to as downstream) and a relief valve 32 described later are provided in parallel.

In the brake circuits 1 and 2,
Downstream of each out-side gate valve 3, a solenoid-driven O
A pressure increasing valve 5 comprising an N / OFF valve is provided, and a return circuit 1 connecting a position downstream of the pressure increasing valve 5 to the reservoir 7.
A pressure reducing valve 6 including an ON / OFF valve driven by a solenoid is provided in the middle of 0. A one-way valve 5a is provided in parallel with the pressure-intensifying valve 5 to allow only the flow returning from the wheel cylinder WC to the upstream, so that the brake fluid from the wheel cylinder WC can be smoothly returned. .

Further, a pump 4 is connected to the brake circuits 1 and 2 as a control hydraulic pressure source. That is, the pump 4 serves as a brake fluid pressure source during automatic brake control, and also serves as a return pump when performing ABS control. This pump 4 has a motor M
The plunger pump is operated by a reciprocating stroke of a plunger (not shown), and each pump function part is connected to the brake circuits 1 and 2 via branched suction circuits 4a and 4b. It is connected to a position upstream of each out-side gate valve 3 and to the reservoir 7. On the other hand, a discharge circuit 4c is connected to a position between each out side gate valve 3 and the pressure increasing valve 5 in the brake circuits 1 and 2. The suction circuits 4a and 4b are provided with check valves 4d and 4e for preventing the backflow of the brake fluid, respectively.
A check valve 4f for preventing backflow is also provided in c. The suction circuit 4a communicates with the suction circuit 4a.
An in-side gate valve 9 composed of a normally closed solenoid valve for switching off is provided. This in-side gate valve 9
Is opened at the time of pressure increase in automatic brake control described later.

Further, the brake device of the present embodiment
BS control and automatic brake control can be executed. A
The BS control is a control for preventing the wheels from locking when the driver performs a braking operation. When the wheels are likely to lock by performing the braking operation, the BS is connected to the wheel cylinder WC of the wheels. The pressure reducing valve 6 is opened and the pressure increasing valve 5 is closed, and the brake fluid in the wheel cylinder WC is returned to the reservoir 7. When the wheels recover from the locking tendency, the pressure increasing valve 5 is opened and the pressure reducing valve 6 is opened.
, And the operation of improving the braking force again is performed. At this time, the pump 4 performs an operation of returning the brake fluid released to the reservoir 7 to each of the circuits 1 and 2.

On the other hand, in the present embodiment, automatic braking control, boosting control and vehicle behavior control for automatically controlling the four wheel cylinders WC to the same pressure are executed as automatic brake control. The automatic braking control is a control that generates a braking force as necessary in accordance with the execution of the automatic driving control that keeps the inter-vehicle distance with the preceding vehicle at a predetermined distance, and determines a target deceleration based on the vehicle speed and the inter-vehicle distance. Then, the wheel cylinder pressure is increased, maintained, and reduced while feeding back the actual deceleration so that the determined target deceleration is obtained. In the case of this automatic braking control, while closing each out-side gate valve 3, opening the in-side gate valve 9, and further operating the pump 4, the brake fluid is discharged from the master cylinder MC via the suction circuit 4 a. The fluid is sucked and discharged from the discharge circuit 4c to each of the circuits 1 and 2, and the brake circuits 1 and 2 generate hydraulic pressure. The details of the pressure increase, holding, and pressure reduction at this time will be described later.

In the boost control, the target wheel cylinder pressure is determined based on the input from the means for detecting the braking operation performed by the driver, and the actual wheel cylinder pressure is determined so as to obtain the determined target wheel cylinder pressure. The wheel cylinder pressure is increased, maintained, and reduced while feeding back the cylinder pressure. In this boosting control, similarly to the automatic braking control described above, while closing the respective out-side gate valves 3, the in-side gate valves 9 are opened, and the pump 4 is operated to operate the wheel cylinders. The hydraulic pressure is supplied to the WC, and pressure increase, holding, and pressure reduction are executed by the same means as in the above-described automatic braking control.

In the vehicle behavior control, when the vehicle behavior is in an over-oversteer state or an over-understeer state during turning, a braking force for generating a yaw moment for returning the vehicle behavior to the neutral steer direction is generated at a desired wheel. Control. In this case, the target wheel cylinder pressure of the desired wheel is determined according to the vehicle behavior, and pressure increase, holding, and pressure reduction are performed so that the wheel cylinder pressure becomes the target wheel cylinder pressure.

Next, the structure of the out-side gate valve 3 and the relief valve 32 will be described with reference to FIG. In the figure, reference numeral 100 denotes an aluminum housing of a brake unit that accommodates the configuration of the brake circuits 1 and 2 except for the master cylinder MC and the wheel cylinder WC in FIG. In this housing 100, the first valve hole 101 is opened at each end face,
The second valve hole 10 having a smaller diameter than the first valve hole 101
2 are formed coaxially. The first valve hole 101
Is fitted with a cylindrical valve body 3a, and a seat plug 3b is fixed to the inner periphery of the valve body 3a.
A plunger 3c is slidably inserted into the seat surface formed on the seat plug 3b so as to be able to contact and separate therefrom. An amateur 3d is provided at the base end of the plunger 3c.
Are provided integrally or are in contact with each other. Further, a spring 3s for urging the plunger 3c in the valve opening direction is provided. In the first valve hole 101, the upstream of the seat plug 3b is connected to the master cylinder MC side of the brake circuits 1 and 2, and the downstream of the seat plug 3b is connected to the wheel cylinder WC side of the brake circuits 1 and 2. .

The bottom of the second valve hole 102 is connected to the bottom of the first valve hole 101 through a hole 103, and the side surface of the second valve hole 102 is connected to an oil passage 104 on the master cylinder MC side of the brake circuits 1 and 2. Connected through. A seat surface 102a is formed on the bottom surface of the second valve hole 102 on the outer periphery of the hole 103. The sheet surface 102 is formed by performing conical processing with a predetermined surface finish using a cutting tool, or performing indentation processing using a ball after performing conical processing.

The second valve hole 102 is provided with a valve body 32 made of a ball which can be in close contact with the seat surface 102a.
a in the second valve hole 102
A spring 32c is provided, one end of which is seated on a ball stopper 32b provided to close the opening of the valve body 32 and closes the valve body 32a with a predetermined urging force. This spring 32c
Determines the valve opening pressure for performing the relief operation.

Next, the operation of the embodiment will be described. B) When the driver performs the braking operation Normally, the valves 3, 5, 6, 9 and the motor M are not energized. Therefore, as shown in FIG. 1, the pressure increasing valve 5 is in a fully open state, the pressure reducing valve 6 is in a fully closed state, the in-side gate valve 9 is in a fully closed state, and the both out-side gate valves 3 are in a fully open state. The motor M is stopped.

In this state, when the driver performs the braking operation and the master cylinder pressure is generated, the brake fluid is supplied from the master cylinder MC to the wheel cylinder WC via the brake circuits 1 and 2 to generate a braking force. .

B) At the time of automatic braking control and boosting control At the time of automatic braking control, the motor M is driven to supply the brake fluid from the pump 4 to the brake circuits 1 and 2. In the automatic braking control, the automatic braking control and the boosting control control the braking force of the four wheels uniformly, whereas the vehicle behavior control generates the braking force only on the desired wheels, so that the control is slightly different. . Therefore, first, the case of the automatic braking control and the boosting control will be described.

At the time of pressure increase judgment, the two in-side gate valves 9 and 9 are fully opened, while the two out-side gate valves 3 and 3 are fully opened.
3 is closed, and in this state, the drive of the motor M is controlled by duty control to control the wheel cylinder pressure increase. As described above, since the pressure increase amount of the wheel cylinder WC is controlled by the duty control of the motor M, the pressure between the out-side gate valve 3 and the pressure increase valve 5 in the brake circuits 1 and 2 is higher than the target pressure. Therefore, the pressure does not become higher than the relief pressure of the relief valve 32. The above-described control of the pressure increase amount can also be performed by controlling the opening amount of the in-side gate valves 9 and 9 to control the supply amount of the brake fluid.

At the time of holding judgment, both the out-side gate valves 3 and 3 are closed, and both the in-side gate valves 9 and 3 are closed.
The valve 9 is closed, and the motor M is stopped or rotated at a very low speed (idling) where no discharge pressure is actually generated. In the case of idling rotation in this way, the responsiveness when shifting to pressure increase control is excellent.

At the time of pressure reduction judgment, both the in-side gate valves 9 and 9 are closed, and the motor M is stopped or idling and rotated.
Is controlled in accordance with the target deceleration or the target wheel cylinder pressure.

C) Vehicle behavior control Basically, even when the vehicle behavior is controlled, the two gate valves 3,
The control of the motor 9 and the motor M is common to the above-described automatic braking control and boosting control. However, during the vehicle behavior control, it is necessary to generate a braking force only on a desired wheel. The difference is that, for wheels without wheels, the pressure increasing valve 5 is closed and the pressure reducing valve 6 is opened so that the brake fluid is not supplied to the wheel cylinder WC.

As described above, in the present embodiment,
At the time of automatic brake control, the pressure increase amount is adjusted by the operation state of the pump 4 (motor M) and the open state of the in-side gate valves 9 and 9, and the pressure reduction amount is adjusted by the out-side gate valves 3 and 3.
In addition, during the holding, the in-side gate valves 9 and 9 are closed to stop the supply from the pump 4 and the out-side gate valves 3 and 3 are closed. Since the control is not performed by opening and closing the pressure increasing valve 5 and the pressure reducing valve 6 except during the control, the following effects can be obtained. a) In the brake circuits 1 and 2, the out side gate valve 3
It is difficult for the pressure between the pressure control valve 5 and the pressure increasing valve 5 to be higher than the target wheel cylinder pressure, and therefore it is difficult to reach the relief pressure of the relief valve 32. Therefore, the operation frequency of the relief valve 32 is extremely reduced as compared with the related art, and the seat surface 102a
Is prevented, the durability of the durable relief valve 32 can be improved, and in addition, generation of noise due to fluctuations in hydraulic pressure can be prevented. b) During the ABS control and the vehicle behavior control, the pressure increasing valve 5 and the pressure reducing valve 6 are operated to control the wheel cylinder pressure. During the automatic braking control and the boosting control, the out side gate valve 3 and the in side gate valve are controlled. 9 is operated to control the wheel cylinder pressure. Therefore, in all the controls, compared to the technique of operating the pressure increasing valve 5 and the pressure reducing valve 6,
It is possible to improve the durability by suppressing the operation frequency of each valve.

Further, in the present embodiment, in the relief valve 32, the seat surface 102a is formed directly at the bottom of the second valve hole 102 of the housing 100 for housing the brake unit, so that the valve body is formed. The valve body and the seat plug having the seat surface can be eliminated, and the effect of reducing the number of parts, reducing the weight, reducing the number of assembly steps, and reducing the cost can be obtained. In addition, in the present embodiment, since the operation frequency of the relief valve 32 is low as described above, even if the material of the housing 100 is aluminum,
There is no fear that the seat surface 102a will be worn, and high reliability can be obtained.

(Embodiment 2) FIG. 3 is a brake circuit diagram showing a brake device according to Embodiment 2. Hereinafter, in describing the second embodiment, the first embodiment
The same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted. Only the differences from the first embodiment will be described.

The second embodiment is an example in which a driver's braking operation is detected, and a by-wire control for generating a braking force corresponding to the braking operation is executed. The master cylinder MC is connected to a pedal simulator 202 via an oil passage 201.
And a configuration in which a change in the volume of the master cylinder MC can be achieved with a predetermined reaction force when a braking operation is performed, that is, a configuration in which the braking operation does not feel uncomfortable.

In the figure, SE is a control hydraulic pressure source, which is provided with a pump 4 and the discharge side of the pump 4 is a brake circuit 2.
11 are connected to four wheel cylinders WC. The suction circuit 205 of the pump 4 includes a master cylinder MC
Is connected to the reservoir 206. A pressure increasing valve 5 is provided in the middle of the brake circuit 211, and a return circuit 10 for releasing the brake fluid of the wheel cylinder WC is connected to the reservoir 206.
Is provided with a pressure reducing valve 6.

Therefore, in the brake device of the second embodiment, when the operation state of the brake pedal BP is detected, the in-side gate valve 9 is opened and the motor M
, And the motor M is duty-controlled to control the pressure increase amount. At the time of pressure reduction, the in-side gate valve 9 is closed as in the first embodiment, while the out-side gate valve 3 is opened. The wheel cylinder pressure is controlled to a target pressure by duty control of the state.

If wheel lock is likely to occur at the time of braking, AB is set based on the operation of the pressure increasing valve 5 and the pressure reducing valve 6.
Execute S control.

Although the embodiment has been described with reference to the drawings, the present invention is not limited to this embodiment. For example, in the embodiment, the housing 10 for the brake unit
Although 0 is shown, a valve body formed separately from the housing 100 may be used. Also in this case, a sheet plug compared with the same structure is not required, and a desired effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a relief valve according to an embodiment of the present invention used in a brake device according to a first embodiment.

FIG. 2 is a brake circuit diagram showing the brake device according to the first embodiment.

FIG. 3 is a brake circuit diagram showing the brake device according to the first embodiment.

[Explanation of symbols]

 Reference Signs List 1 brake circuit 2 brake circuit 3 out side gate valve 3a valve body 3b seat plug 3c plunger 3d amateur 3s spring 4 pump 4a suction circuit 4b suction circuit 4c discharge circuit 4d, 4e check valve 4f check valve 5 pressure increasing valve 5a one-way valve Reference Signs List 6 pressure reducing valve 7 reservoir 9 in-side gate valve 10 return circuit 31 one-way valve 32 relief valve 32a valve body 32b ball plug 32c spring 100 housing 101 valve hole 102 valve hole 102a seat surface 103 hole 104 oil passage 201 oil passage 202 pedal simulator 205 Suction circuit 206 Reservoir 211 Brake circuit M Motor MC Master cylinder WC Wheel cylinder

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D046 BB28 BB29 CC02 EE01 LL00 LL30 3H059 AA08 BB22 CB13 CB15 CD05 EE01 FF03

Claims (6)

[Claims] 1. A valve element housed in a housing is urged by an urging means to abut against a seat surface, and opens when a predetermined pressure is applied to the valve element in a valve opening direction. A relief valve for releasing pressure, wherein the seat surface is formed directly on a housing. 2. The relief valve according to claim 1, wherein the housing is formed of aluminum. 3. A control hydraulic pressure source capable of supplying a hydraulic pressure to a brake circuit connected to a wheel cylinder, and a liquid provided in the brake circuit and supplied from the control hydraulic pressure source to the wheel cylinder. An out-side gate valve for releasing pressure to the low-pressure side; a pressure-increasing state in which the brake circuit is connected to the out-side gate valve and the wheel cylinder in the brake circuit; A fluid pressure adjusting means capable of forming a reduced pressure state communicated with the low pressure side, and supplying fluid pressure toward a brake circuit by the control fluid pressure source to operate the out-side gate valve and the fluid pressure regulating means. Braking control means capable of executing automatic braking control for arbitrarily controlling the braking force by adjusting the wheel cylinder pressure by
In the brake device provided with, the brake control means, during automatic brake control, the hydraulic pressure adjustment means to maintain the pressure increase state, the pressure increase is controlled by the supply state of the brake fluid from the control hydraulic pressure source, The pressure reduction is configured to be controlled by an open state of an out side gate valve, and in parallel with the out side gate valve, when the pressure on the wheel cylinder side exceeds a predetermined pressure, the hydraulic pressure is released to the low pressure side. 3. A brake device provided with the relief valve according to 1 or 2. 4. The control hydraulic pressure source includes a pump that sucks brake fluid from a brake fluid source via a suction circuit and discharges the brake fluid toward the brake circuit. An in-side gate valve for switching between communication and cutoff of the circuit is provided. In the automatic brake control, when increasing the pressure, the in-side gate valve is opened with the out-side gate valve fully closed. The brake according to claim 3, wherein when the pressure is reduced by operating the pump and opening the outside gate valve, the inside gate valve is closed in addition to opening the outside gate valve. apparatus. 5. The brake control means operates based on duty control when operating the pump during pressure increase during the automatic brake control, and based on duty control when opening the out-side gate valve when operating pressure reduction during pressure reduction. The brake device according to claim 4, wherein the valve is opened by opening. 6. The brake circuit according to claim 3, wherein the brake circuit is a circuit connecting a master cylinder and a wheel cylinder, and a brake fluid source connected to the suction circuit is a master cylinder. Brake device.