JPH11189145A - Braking device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve boost responsiveness of a pump without causing enlargement and large cost increase in a braking device that can execute automatic brake control. SOLUTION: This braking device is provided with an inflow valve 5 and an outflow valve 6 optionally controlling fluid pressure of a wheel cylinder WC, a pump 4 for returning a brake fluid made to escape to a reservoir 7 at the time of decompression, to a braking circuit BR, a pressure-charging circuit 32 connecting the intake side of the pump 4 to the master cylinder MC side of the braking circuit BR, an inlet side gate valve 42 for opening/closing the pressure-charging circuit 32, and an outlet side gate valve 41 for opening/ closing the braking circuit BR. In this braking device executing automatic brake control for automatically generating braking force, a trap 90 is provided at an intermediate part of the braking circuit BR in a housing, and the upper reaches end of the pressure-charging circuit 32 is connected to the trap 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake device for performing automatic braking control for automatically generating a braking force.

[0002]

2. Description of the Related Art Conventionally, as a brake device capable of executing automatic braking control, a brake device described in Japanese Patent Application Laid-Open No. 8-58547 has been known. This conventional device consists of a brake circuit that connects the master cylinder and the wheel cylinder, a drain circuit that allows the brake fluid of the wheel cylinder to escape to the reservoir, and a wheel cylinder that is selectively connected to the master cylinder side and the reservoir side to reduce and maintain pressure. A hydraulic pressure control valve for increasing pressure,
A pump provided in the middle of a recirculation circuit connecting the drain circuit and the brake circuit to return the brake fluid in the reservoir to the brake circuit, a supply circuit connecting the suction side of the pump to the master cylinder, and a discharge position of the pump in the brake circuit An out-side gate valve provided upstream and downstream of the brake circuit for opening and closing the brake circuit, an in-side gate valve provided in the middle of the supply circuit for opening and closing the supply circuit, and operation of the pump, the hydraulic pressure control valve, and both gate valves. And a control unit for controlling. The above-described reservoir, drain circuit, hydraulic pressure control valve, recirculation circuit, supply circuit, in-side gate valve, and out-side gate valve are configured such that the pump is housed in one housing and configured as a brake unit. A brake unit is connected to the master cylinder and the wheel cylinder by a pipe.

According to this technique, the in-side gate valve is opened while the out-side gate valve is closed, and the pump is driven to supply the brake fluid of the master cylinder to the brake circuit via the supply circuit. At the same time, by controlling the hydraulic pressure of the wheel cylinder to a predetermined pressure by the hydraulic pressure control valve, it is possible to execute automatic braking control for generating a necessary braking force on a desired wheel.

[0004]

However, according to the above-mentioned prior art, the brake fluid is sucked from a master cylinder located at a distant position by the suction force of one pump during the automatic braking control. Due to the flow path resistance and the like, it takes time for the pump to actually suck in the brake fluid and discharge it to the brake circuit. In this case, control responsiveness is deteriorated. Therefore, to prevent the control response from deteriorating, increase the capacity of the pump or add a pump in series with the pump,
Alternatively, it is necessary to provide a feeding piston as described in JP-T-7-501506, and in this case,
There has been a problem that the size of the brake unit is increased, the in-vehicle performance is deteriorated, and the cost is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In a brake device capable of executing automatic braking control, it is possible to increase the pump pressure response without increasing the size and cost. It is an object of the present invention to be able to aim at the improvement of.

[0006]

According to a first aspect of the present invention, there is provided a brake unit for adjusting a hydraulic pressure of a wheel cylinder in a brake circuit connecting a master cylinder and a wheel cylinder. The brake unit is provided in the housing, a drain circuit for releasing the brake fluid of the wheel cylinder to a reservoir,
A pressure increasing state in which the wheel cylinder is connected to the master cylinder side, a pressure reducing state in which the wheel cylinder is connected to the reservoir side, and a holding state in which the wheel cylinder is shut off to both the master cylinder side and the reservoir side are formed. A possible hydraulic pressure control valve, a recirculation circuit connecting the drain circuit and a position upstream of the hydraulic pressure control valve of the brake circuit, and a brake fluid provided in the middle of the recirculation circuit for returning the brake fluid of the reservoir to the brake circuit. A pump, a supply circuit connecting a suction side of the pump to a master cylinder, an out-side gate valve provided between the discharge position of the pump and the master cylinder in the brake circuit to open and close a brake circuit, and An in-side gate valve that is provided in the middle of the circuit and opens and closes the feeding circuit, and the pump, the hydraulic pressure control valve,
A control unit that controls the operation of both gate valves
When a predetermined traveling state is detected, the in-side gate valve is opened while the out-side gate valve is closed, and the pump is driven to supply the brake fluid of the master cylinder to the brake circuit via the supply circuit. A brake device configured to execute automatic braking control for generating a braking force by controlling the hydraulic pressure of a wheel cylinder to a predetermined pressure by a hydraulic pressure control valve. Is provided, and a brake circuit and a supply circuit located closer to the master cylinder than the out-side gate valve and the in-side gate valve are directly or indirectly connected to the liquid reservoir. Features. According to a second aspect of the present invention, in the brake circuit of the first aspect, the hydraulic pressure control valve side is provided in parallel with the out-side gate valve when a differential pressure across the out-side gate valve exceeds a predetermined pressure. A relief valve for releasing brake fluid to the master cylinder side is provided, and the reservoir is disposed in the middle of the brake circuit, and the reservoir includes a portion of the brake circuit on the master cylinder side, and an out-side gate of the brake circuit. The valve and the relief valve side are connected, and the liquid reservoir is directly connected to the master cylinder side end of the feeding circuit.Each connection position is sequentially from the top when the brake unit is mounted on the vehicle, It is characterized by a brake circuit on the master cylinder side, a brake circuit on the out side gate valve side, and a feeding circuit. Claim 3
According to the present invention, in the brake device according to the first or second aspect, the volume of the liquid reservoir is formed to be larger than an amount necessary to operate the wheel cylinder to generate only a braking force. I do. The invention according to claim 4 is the brake device according to claim 3, wherein the volume of the liquid reservoir is 4.5 cc or more. According to a fifth aspect of the present invention, in the brake device according to the third aspect, a filter is provided in the liquid reservoir between a connection position of the brake circuit on the side of the out-side gate valve and a connection position of the supply circuit. It is characterized by being provided.

[0007]

In the automatic braking control, the out-side gate valve is closed to shut off the brake circuit, and the in-side gate valve is opened to connect the feeding circuit to operate the pump. Therefore, the pump sucks the brake fluid on the master cylinder side through the feeding circuit, and discharges the brake fluid from the recirculation circuit to the brake circuit. , A desired braking force can be generated at a desired wheel. In the automatic braking control, when the pump sucks the brake fluid on the master cylinder side, according to the present invention, at the start of operation, the brake fluid stored in the fluid reservoir can be sucked. Since this liquid reservoir is provided in the housing, the distance from the pump is short, the suction resistance is small, and high pressure response can be obtained. The amount corresponding to the sucked brake fluid in the reservoir is supplied from the master cylinder. In addition, since the reservoir is connected to the brake circuit, when the driver performs a brake operation and the master cylinder pressure is generated, the master cylinder pressure is also applied to the reservoir, and the brake fluid is reliably supplied to the reservoir. Can be secured.

According to the second aspect of the present invention, when the hydraulic pressure control valve is reduced or held during automatic braking control, the hydraulic pressure of the brake circuit is not supplied to the wheel cylinder. And the hydraulic pressure control valve becomes high pressure. When the hydraulic pressure exceeds a predetermined pressure, the relief valve opens to release the hydraulic pressure downstream of the out-side gate valve of the brake circuit to the upstream thereof, and the pump supplies the released brake fluid. Inhale through circuit. As described above, when the pressure between the out-side gate valve of the brake circuit and the hydraulic pressure control valve becomes high, the brake fluid is circulated through the relief valve.
In the liquid reservoir, the brake fluid released to the upstream of the brake circuit by the relief valve flows in from the connection end of the brake circuit with the out-side gate valve side, and is provided below the inflow position. The brake circuit located above the inflow position does not go from the connection end on the master cylinder side to the master cylinder side.

According to the third and fourth aspects of the present invention, the brake fluid can be supplied from the fluid reservoir in an amount necessary to reliably generate a braking force in the wheel cylinder.

According to the fifth aspect of the present invention, during the automatic braking control, when the brake fluid passes through the fluid reservoir, it is filtered by a filter to remove impurities such as dust and the like in the brake fluid.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First, the overall configuration of the brake device according to the first embodiment will be described with reference to the hydraulic circuit diagram of FIG. In the figure, WCFL is a wheel cylinder for the front left wheel,
WCRR is a wheel cylinder for the right rear wheel, WCFR is a wheel cylinder for the right front wheel, WCRL is a wheel cylinder for the left rear wheel, and MC is a master cylinder as a hydraulic pressure source to be supplied to each of the wheel cylinders WCFL to RL. The master cylinder MC is configured to supply a hydraulic pressure to the brake circuit BR in conjunction with the depression of the brake pedal BP, and a reservoir tank R for storing brake fluid is provided.
T is provided.

The brake circuit BR is connected to a first channel circuit 1 connected to the wheel cylinders WCFL, WCRR on the left front wheel and the right rear wheel, and to a wheel cylinder WCFR, WCRL on the right front wheel and the left rear wheel. And two channels of X piping with the second channel circuit 2. When the wheel cylinders WCFL to RL do not indicate a specific one, they are described as WC.

The wheel cylinders WC of each wheel and the master cylinder MC in the engine room are connected by the brake circuit BR with the X pipe, and a brake unit BU is provided in the middle of the pipe.

The brake unit BU has a housing in which a structure to be described later is housed, and the structure thereof will be described in detail below. However, since the structure of both channel circuits 1 and 2 is the same, Below is the first channel circuit 1
Only the configuration of the second channel circuit 2 will be described.

The first channel circuit 1 has a branch point 1d
, The vehicle is branched into a rear wheel branch circuit 1r reaching the wheel cylinder WCRR of the right rear wheel and a front wheel branch circuit 1f leading to the wheel cylinder WCFL of the left front wheel. Also, branch point 1
upstream (d is a side closer to the master cylinder MC in the first channel circuit 1, and downstream is a side closer to the wheel cylinder WC).
1 and a gate valve bypass circuit 1b and a relief circuit 1 that bypass the out-side gate valve 41.
m is provided. The out-side gate valve 41
Is constituted by a normally open 2-port 2-position solenoid-operated switching valve which brings the first channel circuit 1 into communication with a spring force when not in operation, and shuts off the first channel circuit 1 when in operation. In addition, the gate valve bypass circuit 1
b is configured such that only one flow from upstream to downstream can be performed by the one-way valve 1c provided in the middle. Also,
In the middle of the relief circuit 1m, there is provided a relief valve 1n for releasing the hydraulic pressure to the upstream when the downstream hydraulic pressure becomes equal to or higher than a predetermined pressure.

Each of the branch circuits 1r and 1f is provided with an inflow valve 5 and an outflow valve 6 which constitute a hydraulic pressure control valve for reducing, holding and increasing the brake fluid pressure of each wheel cylinder WC. That is, when the inflow valve 5 is not operated, the branch circuits 1r and 1f are brought into communication with each other by a spring force so that the wheel cylinder WC communicates with the master cylinder MC side. It is constituted by a normally open 2-port 2-position electromagnetic switching valve that shuts off the WC from the master cylinder MC side. The outflow valve 6 is connected to each of the branch circuits 1r and 1f.
Is provided in the middle of a drain circuit 10 branched from branch points 1e, 1e provided to the reservoir 7 downstream of the inflow valve 5 (toward the wheel cylinder WC side), and shuts off the drain circuit 10 when not operating. Wheel cylinder WC in reservoir 7
A normally closed 2 that connects the drain cylinder 10 and the wheel cylinder WC to the reservoir 7 during operation.
It is composed of an electromagnetic switching valve with two ports. In each of the branch circuits 1r and 1f, a check valve 1g that bypasses the inflow valve 5 and allows only the flow from downstream to upstream on the way.
Is provided.

The drain circuit 10 and a branch point 1d of the first channel circuit 1 are connected by a return circuit 40. In the return circuit 40, the brake fluid stored in the reservoir 7 is supplied to the first channel. Pump 4 returning to circuit 1
Are provided, a suction valve 4h and a discharge valve 4b having a one-valve structure are provided, and a damper 4d for absorbing discharge pulsation is provided. The pump 4
A plunger pump is used which expands and contracts the volume of a pump chamber (not shown) by reciprocating sliding movement of a plunger 4p, and thereby sucks and discharges a liquid. By the way, in the first channel circuit 1, a liquid reservoir 90 is provided in the middle of a portion closer to the master cylinder MC than the out-side gate valve 41 and the relief valve 1n. Is filled. The volume of the liquid reservoir 90 is set to a volume (for example, about 4.5 cc) capable of operating both the wheel cylinders WCFL and WCRR connected to the first channel circuit 1 as long as a braking force is generated. Have been.

The bottom of the liquid reservoir 90 and the position of the recirculation circuit 40 closer to the pump 4 than the suction valve 4h are connected by a charging circuit 32. In the middle of the charging circuit 32, an in-side gate valve 42 is provided. In addition, a check valve 4k is provided.

The in-side gate valve 42 is a normally closed 2-port 2-position electromagnetic switching valve that shuts off the supply circuit 32 by a spring force when not in operation and connects the supply circuit 32 when in operation.

In the liquid reservoir 90, the connection end 91a of the first channel circuit 1 on the master cylinder MC side is provided.
Is provided at the uppermost position of the liquid reservoir 90 when the brake unit BU is mounted on the vehicle, and a connection end 91b on the side of the out-side gate valve 41 of the first channel circuit 1 is provided on a side surface immediately below the reservoir. , The connection end 9 of the feeding circuit 32
1c is provided at the lowermost bottom. The filter 9 is located between the connection end 91b and the connection end 91c.
2 are provided. By the way, this filter 92
The value obtained by multiplying the mesh area by the number of meshes is the feeding circuit 32.
Is set to a value larger than the minimum flow path cross-sectional area.

As shown in FIG. 2, the operation of each of the valves 5, 6, 41, 42 of the electromagnetic valve structure and the motor M which is a drive source of the pump 4 is controlled by a control unit CU. That is, the control unit CU includes a wheel speed sensor S for detecting a rotational speed of a wheel (not shown), a yaw rate sensor YR for detecting a yaw rate of the vehicle body, a steering angle sensor HS for detecting a steering angle of the vehicle, and a brake operation state. A sensor group SG having a brake sensor BS for detecting whether or not the vehicle is moving, a G sensor GS for detecting the longitudinal and lateral acceleration of the vehicle, and the like is connected. The control unit CU operates based on signals input from these sensor groups SG. When the wheel speed falls below a pressure reduction value set based on the vehicle body speed during braking, the wheel speed is recovered by reducing the pressure, and the ABS control is performed to increase the wheel speed when the wheel speed recovers to near the vehicle speed. .

Further, the control unit CU executes automatic braking control for automatically generating a braking force as necessary, regardless of the driver's braking operation, in accordance with the running state. As the braking control, when the vehicle behavior is in a state in which stability is impaired, behavior stabilization control for controlling the vehicle in a direction to stabilize the behavior is executed. The behavior stabilization control includes a torque slip control that suppresses a drive wheel slip when it occurs, and a direction that stabilizes the vehicle by generating a braking force on predetermined wheels when the vehicle is likely to be disturbed. And a yaw rate control for generating a yaw rate. Note that the details of each control are not features of the present invention, and therefore detailed description is omitted.

Next, the operation of the first embodiment will be described. The operation of the first and second channel circuits 1 and 2 is the same in this operation, and therefore only the first channel circuit 1 will be described. a) During normal brake operation Normally, each of the valves 5, 6, 41, and 42 is in a non-operating state shown in the figure. When the brake pedal BP is depressed in this state, the brake fluid pressure generated in the master cylinder MC is generated. Is transmitted through the first channel circuit 1 to each wheel cylinder WC through each of the branch circuits 1f and 1r while passing through the out-side gate valve 41 and the inflow valve 5, and the wheels are braked according to the depression force of the brake pedal BP. Will be Since the reservoir 90 is filled with brake fluid, the master cylinder pressure is
It is transmitted to the wheel cylinder WC without delay.

B) At the time of ABS control When the wheels are locked or are about to be locked during the above-described brake operation, the control unit CU sets the wheel slip rate within a predetermined range and locks the wheels. ABS control is performed to prevent the above. That is, the ABS control reduces, maintains, and increases the brake fluid pressure so that the wheels do not lock during braking. First, the brake fluid pressure generated by the above-described brake operation is applied to either the left front wheel or the right rear wheel. When one or both of the slip ratios become equal to or more than a predetermined value, the drive of the motor M is started, and the inflow valve 5 of the branch circuits 1r and 1f connected to the wheel cylinder WC for braking the wheel which is likely to lock is closed. Then, the outflow valve 6 is opened. As a result of the closing of the inflow valve 5, the pressure in the wheel cylinder WC is not increased, and the brake fluid in the wheel cylinder WC is discharged to the reservoir 7 through the drain circuit 10 to be reduced in pressure, thereby weakening the braking force. The brake fluid stored in the reservoir 7 is returned to the first channel circuit 1 via the reflux circuit 40 by the operation of the pump 4.

When the wheel speed is restored as a result of the reduction of the braking force, the control unit CU sends the outflow valve 6
Is stopped, the outflow valve 6 is closed to maintain the hydraulic pressure of the wheel cylinder WC, and as a result of this holding operation, when the wheel speed returns to near the vehicle body speed, the inflow valve 5
As a result, the brake fluid in the first channel circuit 1, which is at a high pressure, is supplied to the wheel cylinder WC, and the braking force is increased again. By repeating the above operation, while the brake pedal BP is being depressed, the slip ratio of each wheel is maintained within a predetermined range, and the maximum braking force is obtained while preventing the wheels from being locked.
S control is performed. At the time of the above ABS control, the pump 4 does not suck the brake fluid from the supply circuit 32 because the in-side gate valve 42 maintains the closed state.

C) At the time of behavior stabilization control (at the time of automatic braking control) A torque slip control for keeping the slip ratio within a predetermined range in response to an increase in the slip ratio of the drive wheels due to sudden start and sudden acceleration, or a vehicle When performing the behavior stabilization control including the yaw rate control for generating the braking force for applying the yaw rate in the direction to stabilize the vehicle attitude in response to the attitude of the vehicle being disturbed, the control unit C
U drives the motor M and energizes the out-side gate valve 41 and the in-side gate valve 42 to close the out-side gate valve 41 and shut off the first channel circuit 1, and to control the in-side gate valve 42. Is opened to connect the feeding circuit 32. Therefore, the pump 4 sucks the brake fluid from the master cylinder MC via the supply circuit 32 and discharges the brake fluid to the first channel circuit 1 via the recirculation circuit 40 to operate the inflow valve 5 and the outflow valve 6. Based on this, the pressure of the wheel cylinder WC is increased, maintained, and reduced to generate a desired braking force.

In this behavior stabilization control, the pump 4 sucks the brake fluid filled in the reservoir 90 in the brake unit BU immediately after the start of the control. Can be sucked and discharged to the first channel circuit 1, and high boosting performance can be obtained. The amount of brake fluid corresponding to the amount sucked into the pump 4 from the reservoir 90 is supplied to the reservoir 90 from the master cylinder MC.

When the behavior stabilizing control is executed, when the inflow valve 5 is closed or the pressure is reduced, the brake fluid is discharged from the pump 4 toward the first channel circuit 1. This brake fluid is not supplied to the wheel cylinder WC. In such a case, in the first channel circuit 1, the out-side gate valve 41, the one-way valve 1
c, 1 g, the portion surrounded by the inflow valve 5 becomes high pressure. When the hydraulic pressure difference between this portion and the master cylinder MC side of the first channel circuit 1 exceeds a predetermined value, the relief valve 1n
Is opened and the relief valve 1n and the out side gate valve 41 are opened.
The high pressure downstream of is released upstream. Then, the brake fluid that has escaped against the inflow flows into the liquid reservoir 90 from the connection end 91b, is sucked into the pump 4 again from the connection end 91c via the feeding circuit 32, and is discharged to the first channel circuit 1. .

In circulating such brake fluid, in the reservoir 90, a connection end 91b for inflow is provided at an upper portion, and a connection end 91c for suction is provided at a bottom portion.
Moreover, since the connection end 91a on the master cylinder MC side is provided at a position higher than the connection end 91b, the brake fluid released from the relief valve 1n does not flow from the reservoir 90 to the master cylinder MC side. It is circulated.

As described above, in the brake device according to the first embodiment, the liquid reservoir 90 for storing an amount of brake fluid capable of operating the wheel cylinder WC is provided in the housing of the brake unit BU. When the behavior stabilization control (automatic braking control) is started, the pump 4
The brake fluid can be immediately sucked from the fluid reservoir 90 without receiving a resistance, and a high boosting property can be obtained. Thereby, the control response of the behavior stabilization control (automatic braking control) can be enhanced. As described above, a boosting pump is provided in series with the pump 4, or a means for supplying brake fluid using power applied to the pump 4 is provided.
As a result, high control responsiveness can be obtained without using a high-capacity device.

Further, in the first embodiment, the liquid reservoir 9
0, the brake circuit B
A connection end 91a of the R (each channel circuit 1, 2) on the master cylinder MC side, a connection end 91b of the brake circuit BR (each channel circuit 1, 2) on the out side gate valve 41 side, and a connection end 91c of the feeding circuit 32. Since the brake fluid is disposed, during the behavior stabilization control (automatic braking control), the brake fluid released from the relief valve 1n is sucked into the pump 4 via the feeding circuit 32 without being returned to the master cylinder MC side, and the behavior stabilization control is performed. There is no shortage of brake fluid when executing.

In the behavior stabilization control (automatic braking control), when the brake fluid passes through the fluid reservoir 90, particularly when the brake fluid is circulated as described above, the brake fluid is provided in the fluid reservoir 90. An effect is obtained that the particles are filtered by the filter 92 to remove contaminants and the like.

Next, a second embodiment will be described. Since the main configuration of the second embodiment is the same as that of the first embodiment, the description thereof will be omitted, and only the differences from the first embodiment will be described. FIG. 3 is a circuit diagram of the second embodiment. In the second embodiment, the liquid reservoir 290 is provided in each of the channel circuits 1 and 2 in the brake unit BU.
A communication circuit 21 is connected to a connection point 1p with the communication circuit 2, and a liquid reservoir 290 is provided at a tip of the communication circuit 21. Therefore, even in the second embodiment, when the pump 4 starts operating during the automatic braking control, the brake fluid is sucked from the fluid reservoir 290 provided in the brake unit BU. Even in the second embodiment, it is possible to obtain an effect that control responsiveness can be ensured without adding a feeding pump or a feeding means or expanding the capacity of the pump 4.

Although the embodiments have been described with reference to the drawings, the present invention is not limited to these embodiments, and the present invention is applicable even if there is a change in design without departing from the scope of the present invention. It is included in.

[0035]

According to the brake device of the present invention, a reservoir for storing a predetermined amount of brake fluid is provided in the housing of the brake unit. Since the brake circuit and the supply circuit located on the cylinder side are connected, the pump can suck the brake fluid from the fluid reservoir in the brake unit during automatic braking control. There is an effect that the boost response can be improved without using a means for increasing the size or increasing the cost, such as adding in series, providing a charging means, or increasing the capacity of the pump.

According to a second aspect of the present invention, in the liquid reservoir, the brake circuit on the master cylinder side, the brake circuit on the out gate valve side, and the supply circuit are connected in order from the top, so that the relief valve is automatically controlled during the automatic braking control. When the brake fluid is circulated by opening the valve, the brake fluid is circulated without returning to the master cylinder side, and there is no shortage of the brake fluid, so that the operation stability is excellent.

According to the third and fourth aspects of the present invention, since the volume of the liquid reservoir is set to an amount larger than the amount required for generating the braking force in the wheel cylinder, the amount of the liquid necessary for generating the braking force is reduced. The effect that the brake fluid can be supplied immediately without fail is obtained.

According to the fifth aspect of the present invention, since the filter is provided in the reservoir, when the brake fluid passes through the reservoir in the automatic braking control, particularly, the relief valve is opened and the brake fluid is circulated. Occasionally, the brake fluid is filtered to remove dust contained in the brake fluid.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing a brake device according to a first embodiment.

FIG. 2 is a block diagram of the first embodiment.

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

[Explanation of symbols]

 WCFL wheel cylinder WCRR wheel cylinder WCFR wheel cylinder WCRL wheel cylinder MC master cylinder BP brake pedal BR brake circuit RT reservoir tank CU control unit S wheel speed sensor YR yaw rate sensor HS steering angle sensor BS brake sensor GS G sensor SG sensor group 1st Channel circuit 1b Gate valve bypass circuit 1c One-way valve 1d, 1e Branch 1f Front wheel branch circuit 1g One-way valve 1h Inflow valve bypass circuit 1m Relief circuit 1r Rear wheel branch circuit 2 Second channel circuit 4 Pump 4b Discharge valve 4d Damper 4h Intake valve 5 Inflow valve (hydraulic pressure control valve) 6 Outflow valve (hydraulic pressure control valve) 7 Reservoir 10 Drain circuit 21 Communication circuit 32 Supply circuit 40 Reflux circuit 41 Out side gate valve 42 Out side gate valve 42 In side gate DOO valve 90 liquid receiver 91a connecting end 91b connecting end 91c connecting end 92 filters 290 sump

Claims (5)

[Claims] 1. A brake unit that regulates the hydraulic pressure of the wheel cylinder is provided in the middle of a brake circuit that connects a master cylinder and a wheel cylinder. The brake unit is configured to supply brake fluid of the wheel cylinder to a housing. A drain circuit for escaping to the reservoir, a pressure increasing state in which the wheel cylinder is connected to the master cylinder side, a pressure reducing state in which the wheel cylinder is connected to the reservoir side, and a state in which the wheel cylinder is connected to both the master cylinder side and the reservoir side. A fluid pressure control valve capable of forming a closed holding state, a recirculation circuit connecting the drain circuit and a position upstream of the fluid pressure control valve of the brake circuit, and a reservoir provided in the middle of the recirculation circuit. A pump for returning brake fluid to a brake circuit; a feeding circuit for connecting a suction side of the pump to a master cylinder; An out-side gate valve provided between the discharge position of the pump and the master cylinder in the brake circuit to open and close the brake circuit; and an in-side gate valve provided in the middle of the supply circuit to open and close the supply circuit. When the control unit that controls the operation of the pump, the hydraulic pressure control valve, and the two gate valves detects a predetermined traveling state, the control unit opens the in-side gate valve and opens the out-side gate valve. By closing the valve and driving the pump to supply the brake fluid of the master cylinder to the brake circuit via the supply circuit, the hydraulic pressure control valve controls the hydraulic pressure of the wheel cylinder to a predetermined pressure to generate a braking force. In a brake device configured to execute automatic braking control, a liquid reservoir that stores a predetermined amount of brake fluid is provided in the housing. The brake device is characterized in that a brake circuit and a supply circuit, which are located closer to the master cylinder than the out-side gate valve and the in-side gate valve, are directly or indirectly connected to the liquid reservoir. 2. In the brake circuit, a relief valve is provided in parallel with the out-side gate valve to release brake fluid on the hydraulic pressure control valve side to the master cylinder side when a differential pressure across the out-side gate valve exceeds a predetermined pressure. The liquid reservoir is disposed in the middle of the brake circuit, and the liquid reservoir includes a portion of the brake circuit on the master cylinder side,
The out-side gate valve and the relief valve-side portion of the brake circuit are connected, and the end of the feed circuit on the master cylinder side is directly connected to the liquid reservoir. 2. The brake device according to claim 1, wherein a brake circuit on the master cylinder side, a brake circuit on the out-side gate valve side, and a supply circuit are arranged in order from the top in time. 3. The brake device according to claim 1, wherein the volume of the liquid reservoir is formed to be larger than an amount necessary for operating the wheel cylinder to generate only a braking force. 4. The brake device according to claim 3, wherein the volume of the liquid reservoir is 4.5 cc or more. 5. The liquid reservoir is provided with a filter located between a connection position on the out-side gate valve side of the brake circuit and a connection position of the charging circuit. The brake device as described.