JP2001001878A - Brake control device - Google Patents

Abstract

(57) [Problem] To provide a brake control device configured to be able to supply brake fluid from a sub-pump to a hydraulic pressure control valve during execution of automatic braking control, without increasing the discharge capacity of the sub-pump. It is possible to increase supply responsiveness to a valve so that initial responsiveness can be ensured while having a compact and low-cost configuration. SOLUTION: Even when a non-brake operation is performed, an automatic braking control for arbitrarily increasing or decreasing the brake fluid pressure of a wheel cylinder b by supplying a control fluid pressure to a fluid pressure control valve e by a sub-pump h can be executed. In the brake control device,
A circulation circuit k is provided in parallel with the sub-pump h, and a relief valve n and a circulation switching valve m are provided in the circulation circuit k. During automatic braking control, the circulation switching valve m is closed for a predetermined time from the start of the control. A circulation switching valve control means j1 for opening the valve m is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device, and more particularly, to a brake control device even if a driver does not perform a braking operation.
Automatically generates braking force according to vehicle behavior and running conditions,
The present invention relates to a brake control device configured to be able to execute automatic braking control such as control for suppressing deceleration or driving force, or control for generating a yaw moment in a vehicle to stabilize the vehicle attitude.

[0002]

2. Description of the Related Art Conventionally, so-called ABS control for preventing wheels from locking during braking, and automatic generation of braking force in accordance with vehicle behavior and running conditions even when a driver does not perform a braking operation. A brake control device capable of executing automatic braking control is known.

[0003] As such a conventional technique, for example, an apparatus described in Japanese Patent Publication No. 7-501506 is known. In this prior art, as a brake circuit connecting a master cylinder and a four-wheel wheel cylinder, two brake circuits connected to two-wheel wheel cylinders are provided, and each wheel cylinder is provided in the middle of each brake circuit. A hydraulic control valve capable of independently increasing and decreasing the pressure is provided.
Each of the brake circuits of the system is provided with a main pump that returns the brake fluid drained from the hydraulic pressure control valve to an upstream side of the hydraulic pressure control valve, and a supply circuit is connected to a suction side of the main pump. Further, a charging piston is provided upstream of the brake circuit. This charging piston is
When the sub-pump is driven, a predetermined amount of brake fluid is supplied to the supply circuit.

Therefore, in this prior art, even when the driver does not perform the braking operation, when the sub pump and the main pump are driven, a predetermined amount of brake fluid is supplied to the brake circuit, and the hydraulic pressure control valve is operated. By actuating, the required amount of brake fluid is supplied to the wheel cylinders of the required wheels, and an arbitrary braking force can be generated. Further, according to this conventional technique, the discharge pressure of the sub-pump is prevented from being higher than a predetermined pressure, and the oil supplied to the charging piston is quickly returned to the reservoir side when the operation of the charging piston is stopped. To return, a low-pressure relief valve is provided in parallel with the sub-pump, and a return circuit having an orifice is provided.The flow rate that can be supplied to the charging piston is changed from the sub-pump flow rate to the low-pressure relief valve and the return path. This is the amount obtained by subtracting the return amount in.

[0005]

However, the above-mentioned prior art has the following problems to be solved. That is, in the above-described conventional technology, the flow rate that can be supplied from the sub-pump to the feeding piston is a value obtained by subtracting the return amount in the low-pressure relief valve and the return path from the flow rate of the sub-pump. Has characteristics as shown by a dotted line in FIG. However, there is a problem that the initial response in the automatic braking control cannot be sufficiently obtained with such a boost characteristic. Therefore, if the boost characteristic as shown by the solid line in FIG. 1 is obtained, the initial control response during the automatic braking can be improved. The only option is to increase the amount. In this case, the size of the hydraulic unit is increased and the cost is disadvantageous.

The present invention has been made in view of the above-mentioned conventional problems, and can execute automatic braking control for automatically generating a braking force when a driver is not performing a braking operation. In a brake control device configured to be able to supply the brake fluid from the sub pump to the main pump during execution of the automatic braking control, it is necessary to increase the supply responsiveness to the hydraulic pressure control valve without increasing the discharge amount of the sub pump. It is an object of the present invention to make it possible to secure initial control responsiveness while having a compact and low-cost configuration.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a brake operation hydraulic pressure source a for generating a brake hydraulic pressure in response to a brake operation, as shown in the claim correspondence diagram of FIG. A brake circuit c for supplying the brake fluid pressure of the brake fluid pressure source a to the wheel cylinders b of each wheel;
The pressure reduction for draining the hydraulic pressure of the wheel cylinder b to the drain circuit d and the hydraulic pressure of the brake circuit c
A hydraulic pressure control valve e for increasing pressure, a main pump f for returning the brake fluid drained to the drain circuit d to the brake circuit c, and a brake fluid source g for sucking brake fluid from the brake fluid source g. A sub-pump h capable of directly or indirectly supplying a control hydraulic pressure to the pressure control valve e; and control means j for controlling the operation of the hydraulic control valve e, the main pump f, and the sub-pump h. In a brake control device configured to be able to execute automatic braking control for arbitrarily increasing or decreasing the brake fluid pressure of a wheel cylinder b by supplying a control fluid pressure to a fluid pressure control valve e by a sub pump h even during non-braking operation. A circulation circuit k is provided in parallel with the sub-pump h to connect the discharge side and the suction side of the sub-pump h. In the circulation circuit k, the vibration supplied to the hydraulic pressure control valve side upon completion of the automatic braking control is provided. A relief valve n having a valve opening pressure capable of returning the liquid to the brake fluid source g is provided, and a circulation switching valve m capable of opening and closing a circulation circuit k is provided in series with the relief valve n. The control means j is provided with a circulation switching valve control means j1 for closing the circulation switching valve m for a predetermined time from the start of the control during automatic braking control, and keeping the circulation switching valve m open otherwise.

Therefore, at the time of the automatic braking control, at least the sub-pump h is operated to supply the brake fluid to the hydraulic pressure supply valve e, and the desired wheel cylinder b of the desired wheel is operated based on the operation of the hydraulic pressure control valve e. To generate a desired braking force. At this time, the circulation switching valve control means j1 closes the circulation switching valve m until a predetermined time elapses from the start of the automatic braking control. The brake fluid is supplied to the pressure control valve e side, and the brake fluid can be supplied to the wheel cylinder b with good rising response. Thereafter, after a predetermined time has elapsed and the discharge hydraulic pressure of the sub-pump h has risen, the circulation switching control valve j1 opens the circulation switching valve m. Is returned to the suction side of the sub-pump h via the relief valve n, and the supply amount by the sub-pump h is a value obtained by subtracting the return amount by the relief valve n from the total discharge amount of the sub-pump h. The hydraulic pressure does not become too high, and at the end of the automatic braking control, the brake fluid supplied to the hydraulic pressure control valve e opens the relief valve n to supply the brake fluid through the circulation circuit k. Will be returned immediately.

[0009] As described in claim 2, claim 1
In the brake control device described above, the brake operation hydraulic pressure source a is constituted by a master cylinder, and the brake operation
May be used as a reservoir for the master cylinder. Further, as described in claim 3, in the brake control device according to claim 1 or 2, it is preferable that the circulation switching valve m is provided upstream of the relief valve n. Therefore, the relief valve n
Can perform the relief operation only when the circulation switching valve m is open.

[0010] Also, as described in claim 4, claim 1
In the brake control device according to any one of the first to third aspects, the sub-pump h may be configured to discharge the brake fluid to the suction side of the main pump f. According to a fifth aspect of the present invention, in the brake control device according to the first to third aspects, the inside of the cylinder is divided into a supply chamber and a pressure introduction chamber by a piston, and the piston narrows the pressure introduction chamber. A charging piston biased to is provided, the charging chamber is connected to a suction side of a main pump, while the pressure introduction chamber is connected to a discharge side of a sub-pump,
When the sub-pump operates, the brake fluid in the supply chamber may be supplied to the suction side of the main pump as the piston of the supply piston strokes in a direction to narrow the supply chamber. Therefore, by setting the volume of the supply chamber to the required volume in the wheel cylinder during the automatic braking control, the sub pump h does not supply the brake fluid more than necessary, and the excess brake fluid is supplied to the brake fluid source g. No configuration to return to the side is required.

[0011] Also, as described in claim 6, claim 1
6. The brake control device according to any one of claims 5 to 5, wherein the sub-pump h and the main pump f are configured to operate by driving one common motor, and the circulation switching valve control means j
1 is preferably configured to open the circulation switching valve during non-automatic braking control. Therefore, it is possible to reduce the number of motors to simplify the configuration and reduce costs, and when there is no need to supply the brake fluid from the sub-pump h, the circulation switching valve m may be opened. Even if the sub-pump h is driven, the brake fluid merely circulates in the circulation circuit k, so that no load is applied to the sub-pump h and wasteful energy consumption can be suppressed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) First, the configuration of a brake circuit of a brake control device according to Embodiment 1 of the present invention will be described with reference to FIG. In the figure, WC is a wheel cylinder, MC is a master cylinder, BP is a brake pedal, and RT is a reservoir tank. The master cylinder MC and the four wheel cylinders WC of the four wheels are connected by two brake circuits 1 and 2. The master cylinder MC corresponds to a brake operation hydraulic pressure source in the claims, and generates a hydraulic pressure according to a driver's brake operation. However, the present invention is not limited to this, and means for electrically detecting a driver's brake operation and generating a control pressure corresponding to the brake operation may be used.

Hereinafter, the configuration will be described in detail. Since the configuration of each of the brake circuits 1 and 2 is the same, the following will be described.
Only the configuration relating to the brake circuit 1 will be described, and the description of the configuration in the brake circuit 2 will be omitted by attaching the same reference numerals.

The brake circuit 1 is branched into two branch circuits 1f, 1r toward each wheel cylinder WC, WC at a branch point 1d, and each branch circuit 1f, 1r has an inflow valve constituting a hydraulic pressure control valve. 5 and an outflow valve 6 are provided. The inflow valve 5 is provided with a one-way valve 1g in parallel, and the outflow valve 6 is connected to a drain circuit 10 for releasing the brake fluid of the wheel cylinder WC to the reservoir 7.

The drain circuit 10 is provided with a recirculation circuit 4f for returning the brake fluid of the reservoir 7 to a branch point 1d upstream of the inflow valve 5 of the brake circuit 1, and a main pump 4. The recirculation circuit 4f is provided with a damper 4d for absorbing pulsation, and the main pump 4 is provided with a suction valve 4h and a discharge valve 4b for preventing backflow.

Further, immediately downstream of the suction valve 4h of the main pump 4, one end of a charging circuit 32 is connected, and the other end of the charging circuit 32 is connected to the charging chamber 5 of the charging piston 51.
1a is connected. A normally closed in-side gate valve 42 that opens and closes the charging circuit 32 is provided in the middle of the charging circuit 32.

The supply piston 51 has a cylinder 52 defined by a supply chamber 51a and a pressure introduction chamber 51b, and a piston 53 is slidably provided. This piston 53
The check valve 55 is urged by a return spring 54 in a direction to shrink the pressure introducing chamber 51b, and the piston 53 is provided with a check valve 55 for closing a passage connecting the brake circuit 1 and the supply circuit 32.

Further, in the brake circuit 1, a normally open outside gate valve 41 for opening and closing the brake circuit 1 and a check valve 21 are provided in parallel upstream of the branch point 1d. Then, in the brake circuit 1, a downstream position of the out side gate valve 41 and the feeding circuit 3
2 is connected to a position upstream of the in-side gate valve 42 by a relief circuit 34. When the brake circuit 1 has a high pressure exceeding a predetermined pressure, a brake fluid is supplied to the relief circuit 34. A relief valve 43 is provided on the side.

The pressure introduction chambers 51b of the supply piston 53 are connected to each other by a pressure introduction circuit 33. The pressure introduction circuit 33 is connected to a supply / discharge circuit 8a of the sub pump 8.
Is connected. The sub-pump 8 has a supply / suction circuit 8b connected to the reservoir tank RT of the master cylinder MC, and discharges the brake fluid from the reservoir tank RT toward the pressure introduction circuit 33 during operation.
The sub pump 8 has a suction valve 8c and a discharge valve 8d.
Is provided, and a filter 8 is provided in the charging suction circuit 8b.
e is provided.

Further, the supply and suction circuit 8b and the pressure introduction circuit 33 are connected by two circulation circuits 38a and 38b. Each of the circulation circuits 38a and 38b is provided with normally open circulation switching valves 45a and 45b that can open and close the circulation circuits 38a and 38b, respectively.
8b, a relief valve 4 is provided downstream of the circulation switching valve 45b.
6 are provided. The relief valve 46 is configured to open at a low pressure so that when the operation of the sub-pump 8 is stopped, all the brake fluid discharged toward the supply piston 51 can be returned to the reservoir RT. I have.

The main pump 4 and the sub-pump 8 are configured to be driven by one motor M. As shown in FIG. 3, the motor M and the inflow valve 5, the outflow valve 7, and the out side The operations of the gate valve 41, the in-side gate valve 42, and the circulation switching valves 45a, 45b are controlled by the control unit CU. The control unit CU has a sensor group SG including, as input means, a wheel speed sensor S, a yaw rate sensor YR, a steering angle sensor H, a brake sensor BS, and the like.

Next, the basic operation of the brake control device will be described. a) During normal brake operation Normally, each valve 5, 5, 6, 6, 41, 42, 45a, 45
b is a non-operating state shown in the figure, and when the brake pedal BP is depressed in this state, the brake fluid pressure generated in the master cylinder MC is transmitted to each wheel cylinder WC through each of the brake circuits 1 and 2. The braking of the wheels is performed according to the depression force of the brake pedal BP. When the driver finishes the brake operation, the brake fluid supplied to the wheel cylinder WC flows through the brake circuits 1 and 2 in the opposite manner to the above, and returns to the master cylinder MC.

B) At the time of the ABS control When the control unit CU detects that the wheels are locked or is likely to be locked during the above-described brake operation, the slip ratio of the wheels is set within a predetermined range, and the wheel slip rate is reduced. ABS control for preventing locking is performed.
That is, in the ABS control, the brake fluid pressure is reduced, held, and increased so that the wheels are not locked during braking, and the slip rate of one of the wheels is set to a predetermined value by the brake fluid pressure generated by the above-described brake operation. As described above, the control unit CU first closes the out-side gate valve 41, starts driving the motor M, and further connects the branch circuit connected to the wheel cylinder WC for braking the wheel which is likely to lock. The inlet valves 1r and 1f are closed, and the outlet valve 6 is opened. When the outflow valve 6 is opened, the brake fluid in the wheel cylinder WC is discharged to the reservoir 7 through the drain circuit 10, and the wheel cylinder WC
Is reduced, and the braking force is weakened. The brake fluid discharged to the reservoir 7 is returned to the brake circuit 1 as needed by driving the main pump 4.

When the wheel slip ratio falls below a predetermined value as a result of the reduction of the braking force, the control unit CU stops supplying power to the outflow valve 6 and closes the outflow valve 6 to thereby control the wheel cylinder. When the hydraulic pressure of the WC is held, and the slip rate is reduced to a value less than another predetermined value as a result of the holding operation, the control unit CU cuts off the power supply to the inflow valve 5 and opens the valve. The high-pressure brake fluid in the brake circuit 1 is supplied to the wheel cylinder WC, and the braking force is increased again.

By repeating the above-mentioned operations, the ABS control which maintains the slip ratio of each wheel within a predetermined range while the brake pedal BP is being depressed and prevents the locking of the wheels to obtain the maximum braking force. Is performed.

In the above ABS control, the motor M
As a result, the sub pump 8 is also driven.
During the BS control, the circulation switching valves 45a and 45b are opened, and the total amount of the brake fluid discharged from the sub-pump 8 is 2
Since it is circulated through the two circulation circuits 38a and 38b, it is in an idling state, and the sub pump 8 does not become a load. As described above, since the sub pump 8 does not perform work, no pressure is introduced into the pressure introduction chamber 51c, and the piston 53 is maintained at one end by the urging force of the return spring 54. Also, during the ABS control, similarly to the above-described normal brake operation, the in-side gate valve 4 is operated.
2 is kept closed, so that the master cylinder MC
, The brake fluid is not supplied from the supply circuit 32 to the sub-pump 8.

Thereafter, the ABS control is terminated when an ABS control termination condition such as a driver's termination of a brake operation or a vehicle speed falls below a predetermined value is satisfied. The valve 41 is opened to bring the brake circuit 1 into a communicating state, and the inflow valve 5 and the outflow valve 6 are returned to the original state. Therefore, the brake fluid supplied to the wheel cylinder WC flows back through the brake circuit 1 and returns to the master cylinder MC. In addition, reservoir 7
Is returned to the brake circuit 1 by the drive of the main pump 4, and then returns to the master cylinder MC. After the time required for this, the drive of the motor M is stopped.

C) At the time of automatic braking control The control unit CU controls the driving force to keep the slip ratio within a predetermined range in response to the increase in the slip ratio of the drive wheels due to sudden start and sudden acceleration, and to control over-steer and over-steer. Vehicle attitude stabilization control that stabilizes the vehicle attitude by generating a braking force in response to the vehicle's attitude becoming disturbed, such as understeer, and applying the yaw moment of the vehicle in a stable direction, or automatically tracking the preceding vehicle Automatic braking control, which automatically brakes as necessary in automatic tracking control,
The automatic braking control that includes at least one of the above is performed.

At the time of automatic braking control, as shown in FIG. 4, the control unit CU starts driving the motor M, closes (turns on) the circulation switching valves 45a and 45b, and sets the out-side gate valve. Close valve 41 (ON
), While opening the in-side gate valve 42 (ON
).

The sub-pump 8 is driven by the driving of the motor M, and the reservoir tank R of the master cylinder MC is driven.
The brake fluid in T is sucked and discharged to the pressure introduction circuit 33, and is introduced into the pressure introduction chamber 51 b of the supply piston 51. By this pressure introduction, the piston 53 slides against the urging force of the return spring 54, and the brake fluid in the supply chamber 51a is discharged to the supply circuit 32 by an amount corresponding to a volume change due to the stroke of the piston 53. Then, the brake fluid in the supply circuit 32 is sucked into the main pump 4 via the in-side gate valve 42 and discharged to the branch circuits 1f and 1r. Therefore, each of the wheel cylinder pressures can be optimally controlled by opening and closing the inflow valve 5 and the outflow valve 6 as needed. That is, when the automatic braking control is started, the brake fluid is not stored in the reservoir 7 unless the ABS control is performed immediately before the automatic braking control, and the brake fluid is immediately sucked and discharged only by driving the main pump 4. No discharge pressure occurs. Therefore, the above-described operation can be performed by driving the sub-pump 8 to supply the brake fluid from the supply piston 51 to the suction side of the main pump 8.

At this time, if the brake circuit 1 becomes too high in pressure, the relief valve 43 is opened and the pressure is reduced to the valve opening pressure of the relief valve 43. The volume of the supply chamber 51a is enlarged by the amount of the return of the brake fluid, and the piston body 53 is pushed back.

By the way, in the first embodiment, when the automatic braking control is started, the two circulation switching valves 45a, 45
5b is closed, and one of the circulation switching valves 45b is closed.
Is a period from the start of the automatic braking control to the elapse of a predetermined time T, as shown in FIG. 4, and when the predetermined time T elapses, one of the circulation switching valves 45b is opened (OFF). It is. The other circulation switching valve 45a is closed during execution of the automatic braking control, and is opened when the automatic braking control ends.

As described above, the two circulation switching valves 45a, 45a,
As a result of closing valve 45b, during the predetermined time T, the entire discharge amount of sub pump 8 is supplied to charging piston 51, and as a result, the rate of increase in the flow rate supplied from charging piston 51 to main pump 4 is shown. In the wheel cylinder WC, a boost characteristic excellent in the rising edge as shown by the solid line in the figure is obtained.

Thereafter, when ending the automatic braking control, the out-side gate valve 41 and the circulation switching valve 45 are opened and the driving of the motor M is stopped. Therefore, in the feeding piston 51, the feeding pressure by the sub pump 8 is lost, and the piston 53 is pushed back by the return spring 54, and the wheel cylinder WC or the main pump 4
Brake fluid returned to the brake circuit 1 from the supply chamber 51
Return to a. Further, the brake fluid introduced into the pressure introduction chamber 51b returns to the reservoir tank RT.

As described above, in the first embodiment, the relief valve 46 for returning the brake fluid from the supply piston 51 to the reservoir RT at the end of the automatic braking control is provided. The circulation circuit 38b in which the relief valve 46 is provided is shut off for a predetermined time T, and the entire discharge amount of the sub pump 8 is
1, the high control responsiveness can be obtained without using a sub-pump 8 having a large discharge capacity regardless of the configuration in which the relief valve 46 is provided.

Further, in the first embodiment, one motor M
, The two pumps 4 and 8 are operated, so that the overall configuration can be made compact. In addition, since two circulation circuits 38a and 38b are connected to the sub-pump 8, during the ABS control, By circulating the entire discharge amount of the sub-pump 8, the sub-pump 8 does not become a load and is excellent in energy efficiency.

(Embodiment 2) Embodiment 2 is an example in which the discharge pressure of the sub-pump 8 is directly supplied to the supply circuit 32 without providing the supply piston 51. In the following description of the second embodiment, components common to the first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted.

FIG. 5 is a view showing the configuration of the second embodiment. A supply / discharge circuit 8a of the sub-pump 8 is connected to the suction side of the main pump 4, and a circulation circuit 38 is provided in parallel with the sub-pump 8. The circulation circuit 38 is provided with a normally open circulation switching valve 45 and a relief valve 46.

Therefore, even in the second embodiment, during the automatic braking control in which the supply is performed by the sub-pump 8, the circulation switching valve 45 is provided for a predetermined time T from the start of the control.
To supply the entire discharge amount of the sub-pump 8 to the main pump 4, and then open the circulation switching valve 45 so that the function of the relief valve 46 can be obtained.
As in the first embodiment, high control responsiveness can be obtained, and the discharge pressure of the sub-pump 8 does not become too high.

Although the embodiments have been described with reference to the drawings, the present invention is not limited to the illustrated embodiments. For example, in the embodiment, the example has been described in which the brake fluid discharged from the sub-pump is supplied to the main pump. However, the brake fluid discharged from the sub-pump may be supplied to the brake circuit. .

[0041]

As described above, in the invention described in all the claims of the present application, in the brake control device provided with the sub-pump, the circulation circuit connecting the discharge side and the suction side of the sub-pump in parallel with the sub-pump is provided. In this circulation circuit, a low-pressure relief valve and a circulation switching valve for opening and closing the circulation circuit are provided, and during automatic braking control, the circulation switching valve is closed for a predetermined time from the start of control. For a predetermined time from the start of the control, the entire amount of the discharge amount of the sub-pump is supplied to the hydraulic control valve side, and the brake fluid can be supplied to the wheel cylinder with a good start-up response, and the discharge capacity of the sub-pump is increased. An effect that the initial responsiveness can be improved in a compact and low-cost configuration without any problem can be obtained. In the invention described in claim 4, since the sub-pump and the main pump are connected in series, at the time of automatic braking control, suction is performed only from the main pump toward the hydraulic pressure control valve by the main pump alone. The brake fluid is supplied with higher responsiveness than in the case, and high control responsiveness is obtained. According to the fifth aspect of the present invention, since the supply piston is provided and a predetermined amount of brake fluid in the supply chamber is supplied to the suction side of the main pump when the sub pump is operated, the sub pump h However, there is no need to supply the brake fluid more than necessary, and there is no need to provide a structure for returning the excess supply of the brake fluid to the brake fluid source g.

According to the sixth aspect of the present invention, the number of motors can be reduced, the structure can be simplified, the cost can be reduced, and when there is no need to supply the brake fluid from the sub-pump, By opening the circulation switching valve, a load is not applied to the sub-pump, and unnecessary energy consumption can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a brake control device of the present invention.

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

FIG. 3 is a block diagram of a main part according to the first embodiment;

FIG. 4 is a time chart showing the operation of the first embodiment.

FIG. 5 is a brake circuit diagram of a brake control device according to a second embodiment.

[Explanation of symbols]

 a Brake operating fluid pressure source b Wheel cylinder c Brake circuit d Drain circuit e Hydraulic pressure control valve f Main pump g Brake fluid source h Subpump j Control means j1 Circulation switching valve control means k Circulation circuit m Circulation switching valve n Relief valve WC Wheel Cylinder MC Master cylinder (brake operating fluid pressure source) BP Brake pedal RT Reservoir tank CU Control unit (Control means) S Wheel speed sensor YR Yaw rate sensor H Steering angle sensor BS Brake sensor SG Sensor group 1 Brake circuit 1d Branch point 1f Branch circuit 1g One-way valve 1r Branch circuit 4 Main pump 4b Discharge valve 4h Suction valve 4f Recirculation circuit 5 Inflow valve (hydraulic pressure control valve) 6 Outflow valve (hydraulic pressure control valve) 7 Reservoir 8 Sub pump 8a Supply / discharge circuit 8b Supply / supply circuit 8c Intake Valve 8d Discharge valve 10 Len circuit 21 Check valve 32 Supply circuit 33 Pressure introduction circuit 34 Relief circuit 38a Circulation circuit 38b Circulation circuit 41 Out side gate valve 42 In side gate valve 43 Relief valve 45a Circulation switching valve 45b Circulation switching valve 46 Relief valve 51 Supply piston 51a Supply Chamber 51b Pressure introduction chamber 52 Cylinder 53 Piston 54 Return spring 55 Check valve

Claims (6)

[Claims] 1. A brake operation pressure source for generating a brake pressure in response to a brake operation, a brake circuit for supplying the brake pressure of the brake pressure source to a wheel cylinder of each wheel, A hydraulic pressure control valve that performs pressure reduction for draining hydraulic pressure to the drain circuit and pressure increase for supplying hydraulic pressure of the brake circuit to the wheel cylinder; and a main pump that returns the brake fluid drained to the drain circuit to the brake circuit; A sub-pump capable of sucking brake fluid from a brake fluid source and supplying a control fluid pressure directly or indirectly to the fluid pressure control valve, and controlling operations of the fluid pressure control valve, the main pump, and the sub-pump. Control means for supplying brake fluid pressure to the wheel cylinder by supplying hydraulic fluid for control to the fluid pressure control valve by the sub pump even during non-braking operation. In a brake control device configured to be able to execute automatic braking control to increase or decrease, a circulation circuit that connects a discharge side and a suction side of the sub-pump is provided in parallel with the sub-pump. Accordingly, a relief valve having an opening pressure capable of returning the brake fluid supplied to the hydraulic pressure control valve side to the brake fluid source is provided, and a circulation switching valve for opening and closing a circulation circuit in series with the relief valve. It is provided that the control means is provided with a circulation switching valve control means for closing the circulation switching valve for a predetermined time from the start of control during automatic braking control, and opening the circulation switching valve otherwise. A characteristic brake control device. 2. The brake control device according to claim 1, wherein the brake operation fluid pressure source is a master cylinder, and the brake fluid source is a reservoir of the master cylinder. 3. The brake control device according to claim 1, wherein the circulation switching valve is provided upstream of a relief valve. 4. The brake control device according to claim 1, wherein the sub-pump is configured to discharge brake fluid to a suction side of a main pump. 5. A cylinder inside the cylinder is divided into a supply chamber and a pressure introduction chamber by a piston, and a supply piston urged in a direction to narrow the pressure introduction chamber is provided, and the supply chamber is a main pump. The pressure introduction chamber is connected to the discharge side of the sub-pump,
The brake fluid in the supply chamber is supplied to the suction side of the main pump as the piston of the supply piston strokes in a direction to narrow the supply chamber when the sub-pump is operated. The brake control device according to any one of claims 1 to 3. 6. The sub-pump and the main pump are operated by driving a common single motor, and the circulation switching valve control means opens the circulation switching valve during non-automatic braking control. 5. The brake control device according to claim 1, wherein the brake control device is configured as described above.