JPH06107148A - Brake fluid pressure control device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a brake fluid pressure control device having a traction control function by a fluid pressure generation source, in which the number of valve devices is reduced, and the device is small, lightweight and inexpensive. [Structure] Drive wheel side hydraulic pressure control valves (31 to 34) connected to each of the wheel cylinders (51, 52) of the drive wheels (DR, DL) and a supply side of an auxiliary hydraulic pressure source (21). A normally open first on-off valve (61) is interposed between the two. First
The discharge side is connected between the on-off valve and the introduction side of the drive-wheel-side hydraulic pressure control valve, and the suction side is connected to the low-pressure reservoir (4) to raise the brake fluid in the low-pressure reservoir and discharge it. A source (70) is provided. A normally closed second on-off valve (6) is provided between the discharge side of the hydraulic pressure generation source and the introduction side of the drive wheel side hydraulic pressure control valve.
Insert 2). Then, the first and second opening / closing valves (61, 62) are opened / closed and the driving wheel side hydraulic pressure control valves (31-34) are controlled according to the rotation state of the driving wheels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake fluid pressure control system for a vehicle, and more particularly, when the vehicle is suddenly started or suddenly accelerated, a braking force is applied in accordance with the rotational state of the drive wheel to prevent the drive wheel from excessively rotating. The present invention relates to a brake fluid pressure control device provided with a traction control function for preventing.

[0002]

2. Description of the Related Art A brake having an anti-skid control function for controlling a braking force by reducing, increasing or maintaining a brake fluid pressure to a wheel cylinder of each wheel so that the wheels do not lock during sudden braking of a vehicle. Hydraulic pressure control devices are in widespread use. Furthermore, when the drive wheels are rotated at high speeds during sudden start or sudden acceleration, excessive driving force causes the wheels to idle, causing so-called acceleration slip.Therefore, in order to prevent this, the driving force on the drive wheels is limited. Brake fluid pressure control devices that also have a traction control function to prevent rotation have become widespread. Such a brake fluid pressure control device is disclosed in, for example, Japanese Patent Laid-Open No. 1-119461.

[0003]

In the vehicle brake device described in the above publication, the braking force is applied to the drive wheels by the brake fluid pressure of the accumulator during the traction control, but the traction control is performed. Three valve devices, a first to a third switching valve, are required for switching to. For this reason, the entire apparatus becomes large in size, resulting in an increase in weight and an increase in cost.

Therefore, the present invention is provided with a hydraulic pressure source in addition to an auxiliary hydraulic pressure source such as a hydraulic pump for anti-skid control, and at least a brake hydraulic pressure having a traction control function by the hydraulic pressure source. It is an object of the present invention to provide a brake fluid pressure control device which is small in size, light in weight, and inexpensive in a control device by reducing the number of valve devices.

[0005]

In order to achieve the above object, the present invention provides a wheel cylinder provided on each wheel of a driving wheel and a driven wheel, and a brake fluid from a low pressure reservoir in response to an operation of a brake pedal. A master cylinder for boosting the pressure to apply a brake fluid pressure to each of the wheel cylinders, and a brake fluid from the introduction side and the discharge side of the brake fluid interposed between the master cylinder and each of the wheel cylinders. Brake fluid provided with a fluid pressure control valve for controlling the brake fluid pressure by discharging the fluid, and an auxiliary fluid pressure source that sucks in the brake fluid from the discharge side of the fluid pressure control valve and pressurizes and supplies it to the introduction side. In the pressure control device, a normally open first on-off valve interposed between an introduction side of a drive wheel side hydraulic pressure control valve connected to each of the drive wheel wheel cylinders and a supply side of the auxiliary hydraulic pressure source. , A discharge side is connected between the first on-off valve and the introduction side of the drive wheel side hydraulic pressure control valve, and a suction side is connected to the low pressure reservoir to boost and discharge the brake fluid in the low pressure reservoir. At least the drive wheel, and a normally closed second on-off valve interposed between the discharge side of the fluid pressure generation source and the introduction side of the drive wheel side hydraulic pressure control valve. The first and second opening / closing valves are opened / closed and the drive wheel side hydraulic pressure control valve is controlled in accordance with the rotation state of the.

Further, according to the present invention, a wheel cylinder provided on each wheel of a drive wheel and a driven wheel, and a brake fluid pressure from a low pressure reservoir is increased in response to an operation of a brake pedal to apply a brake fluid pressure to each of the wheel cylinders. And a hydraulic pressure for controlling the brake fluid pressure by interposing between the master cylinder and each of the wheel cylinders and introducing the brake fluid from the introduction side and discharging the brake fluid from the discharge side. In a brake fluid pressure control device including a control valve and an auxiliary fluid pressure source that sucks in brake fluid from the discharge side of the fluid pressure control valve and boosts and supplies the brake fluid to the introduction side, A normally open on-off valve interposed between the introduction side of the drive wheel side hydraulic pressure control valve connected to each and the supply side of the auxiliary hydraulic pressure source, and the on-off valve and the drive wheel side hydraulic pressure control valve Introduction A discharge side connected to the low pressure reservoir and a suction side connected to the low pressure reservoir, and a hydraulic pressure generation source that pressurizes and discharges the brake fluid in the low pressure reservoir, a discharge side of the hydraulic pressure generation source, and the drive wheel. A check valve that is interposed between the side hydraulic pressure control valve and the introduction side and that blocks the flow of the brake fluid to the low pressure reservoir side and allows the flow in the reverse direction; and at least the rotation state of the drive wheel According to the above, the opening / closing valve may be opened / closed and the drive wheel side hydraulic pressure control valve may be controlled.

[0007]

In the brake fluid pressure control device having the above structure, when the brake pedal is operated, the brake fluid pressure is applied from the master cylinder to each wheel cylinder via each fluid pressure control valve, so that the drive wheels and the driven wheels of the vehicle are driven. Braking force is applied to each. At the time of this brake operation, the first on-off valve is in the open state and the second on-off valve is in the closed state.

Even when the brake operation is not performed, the first
And the second on-off valve is in the same state as above, but if over-rotation of the drive wheels occurs during sudden start or rapid acceleration of the vehicle, the first on-off valve is closed and the second on-off valve is opened. The valve is opened. Then, the brake fluid pressure is supplied from the fluid pressure generation source to the introduction side of the fluid pressure control valve of each drive wheel via the second opening / closing valve,
Each hydraulic control valve is controlled according to the rotation state of each drive wheel, an appropriate braking force is applied to each drive wheel, and excessive rotation is prevented. At this time, the brake fluid from the discharge side of the hydraulic pressure control valve of each drive wheel is returned to the master cylinder via the auxiliary hydraulic pressure source.

Further, in the brake fluid pressure control device equipped with the on-off valve and the check valve described above, the on-off valve is in the open state when the brake is inoperative, but the on-off valve is opened when the drive wheel is excessively rotated. Closed. Then, the brake fluid pressure is supplied from the fluid pressure generation source to the introduction side of the fluid pressure control valve of each drive wheel through the check valve, and each fluid pressure control valve is controlled according to the rotation state of each drive wheel. It The brake fluid from the discharge side of the hydraulic pressure control valve of each drive wheel is returned to the master cylinder via the auxiliary hydraulic pressure source.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a brake fluid pressure control device according to an embodiment of the present invention, which includes a master cylinder 2a and a booster 2b driven by a brake pedal 3 and drive wheels DR, D.
The pump 2 is connected to the hydraulic pressure path connected to each of the wheel cylinders 51 to 54 arranged on the L and the driven wheels NR and NL.
1, 22 and control reservoirs 23, 24, and electromagnetic valves 31 to 38 and electromagnetic valves 61, 62 are interposed.
DR indicates the driving wheel on the rear right side as viewed from the driver's seat, and D
L indicates the rear left drive wheel, NR indicates the front right driven wheel, and NL indicates the front left driven wheel. That is, the rear wheel drive system is adopted in this embodiment.

A hydraulic pressure passage 8 connecting one output port of the master cylinder 2a and each of the wheel cylinders 51 and 52.
1 and 82 are solenoid valves 31 and 32 and solenoid valves 33 and 34, respectively.
And the pump 21 and the control reservoir 23 are arranged in parallel to the solenoid valves 31 and 32 and the solenoid valves 33 and 34. Similarly, the solenoid valves 35 and 36 and the solenoid valve 3 are respectively connected to the hydraulic pressure passages 83 and 84 that connect the other output port of the master cylinder 2a and the wheel cylinders 53 and 54.
7, 38 are interposed, and the solenoid valves 35, 36 and the solenoid valve 3
The pump 22 and the control reservoir 24 are arranged in parallel to the valves 7 and 38. Thus, the solenoid valves 31, 32, the solenoid valves 33, 34, the solenoid valves 35, 36, and the solenoid valves 37,
Each of the reference numerals 38 constitutes a hydraulic control valve according to the present invention.

The pumps 21 and 22 are driven by the electric motor 20, and the brake fluid sucked through the control reservoirs 23 and 24 is boosted to a predetermined pressure and supplied to the supply port O.
It is supplied from P1 to the normally open solenoid valves 31 and 33. The pumps 21 and 22 each have a built-in check valve (not shown) at the input / output port. The discharge side hydraulic pressure paths of the normally closed solenoid valves 32 and 34 are connected to the suction side of the pump 21 via the control reservoir 23, and the discharge side hydraulic pressure paths of the normally closed solenoid valves 36 and 38 are also the control reservoir. It is connected to the suction side of the pump 22 via 24. The control reservoirs 23 and 24 are provided with pistons and springs, respectively, and the solenoid valves 32 and 3
4, 36, 38 to the discharge side hydraulic passages and pumps 21, 22
The brake fluid discharged through the suction ports IP1 and IP2 on the suction side is stored and is recirculated to the solenoid valves 31, 33, 35 and 37 when the pumps 21 and 22 are operated. Thus, the pumps 21 and 22 and the control reservoirs 23 and 24 constitute the auxiliary hydraulic pressure source according to the present invention.

On the drive wheels DR, DL side, the pump 2
A normally open electromagnetic valve 61, which is the first on-off valve according to the present invention, is interposed between the first discharge side supply port OP1 and the electromagnetic valves 31 and 33. The introduction sides of the solenoid valves 31, 33 are connected to the low pressure reservoir 4 of the master cylinder 2a via a hydraulic pressure passage 85, and the hydraulic pressure passage 85 is connected to the hydraulic pressure pump unit 70 which is a hydraulic pressure generation source according to the present invention. A normally closed solenoid valve 62, which is a second on-off valve, is provided. A check valve 64 is arranged in parallel with the solenoid valve 61, and if the brake fluid pressure is output from the master cylinder 2a even after the solenoid valve 61 is closed, the wheel cylinder is supplied via the supply port OP1. 51 to 54.

The hydraulic pump unit 70 includes a pump 71,
The pump 71 has an accumulator 72 and a relief valve 73, and the pump 71 is driven by an electric motor 75.
Of the brake fluid is boosted and output, and the output brake fluid pressure is accumulated in the accumulator 72. Relief valve 73
Is to open when the output brake fluid pressure of the pump 71 becomes equal to or higher than a predetermined value, and to circulate the brake fluid to the low-pressure reservoir 4 to reduce the pressure. The connection between the discharge side of the pump 71 and the accumulator 72 is A pressure sensor 74 is provided. Thus, the brake fluid pressure of a predetermined value is discharged from the fluid pressure pump unit 70.

The solenoid valves 31 to 38 are 2-port 2-position solenoid directional control valves, each of which is shown in FIG.
, The wheel cylinders 51 to 54 are connected to the master cylinder 2a and the pump 21 or 22.
Is in communication with. When the solenoid coil is energized, it is in the second position, and the wheel cylinders 51 to 54 are disconnected from the master cylinder 2a and the pump 21 or 22 and communicate with the control reservoir 23 or 24. Incidentally, C in FIG.
The symbol with H is a check valve, the symbol with OR is an orifice, and the symbol with DP is a damper.

Thus, by controlling the energization and de-energization of the solenoid coils of the solenoid valves 31 to 38, the brake fluid pressure in the wheel cylinders 51 to 54 can be increased, reduced or maintained. For example, when the solenoid coils of the solenoid valves 61 and 62 are not energized (OFF) and when the solenoid coils of the solenoid valves 31 to 38 are not energized (OFF), the wheel cylinders 51 to 54 have the master cylinder 2a and / or the pump 21 or When the brake fluid pressure is applied from 22, the pressure is increased, and when energized (ON), it is communicated with the control reservoirs 23 and 24 to reduce the pressure. If the solenoid coils of the solenoid valves 31, 33, 35 and 37 are energized and the solenoid coils of the other solenoid valves are de-energized, the brake fluid pressure in the wheel cylinders 51 to 54 is maintained. As the hydraulic pressure control valve, solenoid valves 31 to 3 are used.
Instead of 8, half of the 3-port 2-position electromagnetic switching valve may be used.

The solenoid valves 31 to 38 and the solenoid valves 61,
Reference numeral 62 is connected to the electronic control unit 10 and controls energization and de-energization of each solenoid coil. The electric motors 20 and 75 are also connected to the electronic control unit 10 and drive-controlled by them. In addition, the drive wheels DR, DL and the driven wheels N
Wheel speed sensors 41 to 44 are provided in the R and NL, respectively, and these are arranged together with the pressure sensor 74 and the like in the electronic control unit 10.
And is configured to input the rotation speed of each wheel, that is, a wheel speed signal to the electronic control unit 10. The wheel speed sensors 41 to 44 are well-known electromagnetic induction type sensors and output a voltage having a frequency proportional to the rotation speed of each wheel.
An optical sensor or the like may be used.

The electronic control unit 10 is, as shown in FIG.
A microcomputer 1 having a CPU 14, a ROM 15, a RAM 16 and the like, which is connected to an input port 12 and an output port 13 via a common bus and performs input / output with the outside.
1 is provided. The detection signals of the wheel speed sensors 41 to 44 and the pressure sensor 74 are amplified by the amplifier circuits 17a to 17e.
Via the input port 12 to the CPU 14.
Then, from the output port 13, the drive circuits 18a to 18
solenoid valves 31 to 38 and solenoid valves 61, 6 via j, respectively.
2 outputs a control signal to the drive circuit 18k, 1
Control signals are output to the electric motors 20 and 75 via 8l, respectively. A program for executing anti-skid control and traction control is stored in the CPU 14 of the electronic control unit 10, and these controls are performed according to a predetermined logic. For example, regarding the drive wheels DR and DL, the solenoid valves 31 to 34 and The solenoid valves 61 and 62 are driven as shown in Table 1, but the operation in each control is well known, and the description thereof is omitted.

[Table 1]

The operation of the embodiment having the above structure will be described below. First, during normal brake operation, the solenoid valves 31 to 38 and the solenoid valves 61 and 62 are in the state shown in FIG. 1, and the output brake hydraulic pressure of the master cylinder 2a is output to the hydraulic pressure passages 81 to 84. As a result, the output brake fluid pressure of the master cylinder 2a is increased by the solenoid valve 6 in the open state.
1 and solenoid valves 31, 33, 35, 37 to the wheel cylinders 51 to 54.

When the slip of any wheel is detected during the brake operation and the control shifts to the anti-skid control, the electric motor 20 is driven by the electronic control unit 10 and the pump 2
The electronic control unit 10 appropriately opens and closes the solenoid valves 31 to 38 to control the brake fluid pressure in the wheel cylinders 51 to 54 while driving the valves 1 and 22. That is, as is well known, the braking force is controlled so that the drive wheels DR and DL and the driven wheels NR and NL are not locked.

When the vehicle starts or suddenly accelerates, the drive wheels DR and D are detected based on the detection outputs of the wheel speed sensors 41 and 42.
When the excessive rotation of L is detected, the electronic control unit 10 shifts to traction control. This traction control is controlled according to the flowchart shown in FIG. 3 for the drive wheels DR, for example, and is similarly controlled for the drive wheels DL.
First, in step 101, the slip state of the drive wheels DR is detected based on the wheel speed of the drive wheels DR, and when it is determined that the traction control is started, the routine proceeds to step 102, where the solenoid valve 61 is excited (“ON” in FIG. 3). (Shown as “”), and the solenoid valve 62 is excited to be opened. As a result, on the introduction side of the solenoid valve 31, the communication between the master cylinder 2a and the pump 21 via the solenoid valve 61 is blocked, and the hydraulic pump unit 70 via the hydraulic passage 86 and the opened solenoid valve 62. Communicate with.
At this time, the brake pedal 3 is not operated and the pumps 21 and 22 are also in a stopped state, whereas the hydraulic pump unit 70 discharges a brake hydraulic pressure of a predetermined value.

In this state, the acceleration slip state is judged in step 103, and step 104 is executed according to the judgment result.
Proceeding to 106, the brake fluid in the wheel cylinder 51 is boosted, depressurized or held. That is, when the solenoid valve 31 is opened and the solenoid valve 32 is closed in step 104 as in the steady state, the solenoid valve 62 in the open state is opened.
Since the output brake fluid pressure of the fluid pressure pump unit 70 is supplied to the wheel cylinder 51 and increased in pressure via the, the braking force is applied to the drive wheels DR, over-rotation is suppressed, and slip is prevented. In this way, the output brake hydraulic pressure of the hydraulic pump unit 70 is applied to the wheel cylinders 51, so that the wheel cylinder 51 rises quickly, excessive rotation of the drive wheels DR is quickly suppressed, and slippage is appropriately prevented.

On the other hand, when the solenoid valve 31 is closed and the solenoid valve 32 is opened in step 105, the brake fluid in the wheel cylinder 51 causes the solenoid valve 32, the input port IP1, the pump 21, and the supply port OP1 to flow. It is returned to the master cylinder 2a and then to the low pressure reservoir 4 via.
Therefore, the pressure in the wheel cylinder 51 is reduced, and the drive wheel D
The braking force on R is removed. At this time, the pump 21 is also driven and the brake fluid is returned to the master cylinder 2a, but unlike the case of the anti-skid control, the pump 2
Since 1 is substantially unloaded, the operating noise is low. However, if the valve opening pressure of the check valve (not shown) in the pump 21 is set lower than the operation start pressure of the control reservoir 23, the pump 21 does not need to be operated.

Further, in step 106, the solenoid valves 31, 3 are
Both 2 are closed, and the brake fluid pressure in the wheel cylinder 51 is maintained. Then, in step 107, the above steps are repeated until the acceleration slip of the drive wheels DR disappears and the traction control is no longer necessary. When it is determined to be completed, the solenoid valves 61 and 62 are turned off in step 108, and the solenoid valves 61 and 62 in FIG. Return to the state. The solenoid valves 31 and 32 and the solenoid valves 33 and 34 are individually controlled according to the rotation states of the drive wheels DR and DL. Moreover, since the brake fluid pressure of a predetermined value is always supplied from the hydraulic pump unit 70, an excessive brake fluid pressure is not applied to the wheel cylinders 51 and 52 of the drive wheels DR and DL.

As described above, in this embodiment, the communication between the master cylinder 2a and the pump 21 is cut off when the pressure is increased in the traction control, and the brake fluid is returned to the master cylinder 2a through the pump 21 when the pressure is reduced. As a valve device for switching traction control, a solenoid valve 6
The number can be reduced to 1 and 62, and the size and weight can be reduced and the cost can be reduced. Further, during traction control, the electric motor 20 and the pump 21 are operated in a substantially no-load state, and can be further stopped. Therefore, the operating noise is reduced as compared with the case where these are used for traction control. The check valve 64 is provided so as to be able to apply the braking force when the brake operation is performed during the traction control, but the traction control is stopped at the same time as the brake operation and the solenoid valve 61 is turned on. It is not necessary to provide it if it is opened.

FIG. 4 shows another embodiment of the present invention.
As the hydraulic pressure generation source, the hydraulic pump unit 70 of the above-described embodiment is removed from the hydraulic pump unit 70s except the accumulator 72 and the pressure sensor 74, and the solenoid valve 6 is used.
Instead of 2, the check valve 63 is provided. Since other configurations are similar to those of the embodiment of FIG. 1, the same reference numerals are given and description thereof is omitted.

In this embodiment, the electric motor 75 is driven at the start of the traction control and the brake fluid pressure of a predetermined value is discharged without controlling the hydraulic pump unit 70s to always discharge the brake fluid pressure of a predetermined value. This is supplied to the introduction side of the solenoid valves 31, 33 via the check valve 63. Then, during normal brake operation and anti-skid control, the check valve 63 blocks the flow of brake fluid from the master cylinder 2a to the hydraulic pump unit 70s. Thus, according to the present embodiment, by constructing the hydraulic pump unit 70s having a good rising characteristic, the traction control switching valve device is the solenoid valve 61.
Only one is sufficient, and the size can be reduced, the weight can be reduced, and the cost can be reduced. Incidentally, instead of the hydraulic pump unit 70 in the embodiment of FIG. 1, the hydraulic pump unit 70 of the present embodiment.
s may be used.

[0028]

Since the present invention is constructed as described above, it has the following effects. That is, in the brake fluid pressure control device of the present invention, since the fluid pressure generation source, the first and second opening / closing valves, etc. are arranged as described above, the first and second valve devices for traction control switching are provided. Only the second on-off valve is required, and it is possible to construct a small size, light weight, and low cost.

Further, in the brake fluid pressure control device equipped with the on-off valve and the check valve described above, since only one on-off valve is required, the size and weight can be further reduced.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a brake fluid pressure control device of the present invention.

FIG. 2 is a block diagram showing a configuration of an electronic control device according to an embodiment of the present invention.

FIG. 3 is a flowchart showing processing of a subroutine in traction control according to an embodiment of the present invention.

FIG. 4 is an overall configuration diagram of another embodiment of the brake fluid pressure control device of the present invention.

[Explanation of symbols]

 2a Master cylinder 2b Booster 3 Brake pedal 4 Control reservoir 10 Electronic control device 20 Electric motor 21,22 Pump 23, 24 Control reservoir 31-38 Electromagnetic valve (hydraulic control valve) 41-44 Wheel speed sensor 51-54 Wheel Cylinder 61 Solenoid valve (first opening / closing valve) 62 Solenoid valve (second opening / closing valve) 63, 64 Check valve 70, 70s Hydraulic pump unit (hydraulic pressure source) 71 Pump 72 Accumulator 73 Relief valve 74 Pressure sensor 75 Electric motor DR, DL Drive wheel NR, NL Driven wheel

Claims (2)

[Claims] 1. A wheel cylinder provided on each wheel of a drive wheel and a driven wheel, and a master for applying a brake fluid pressure to each of the wheel cylinders by boosting a brake fluid from a low pressure reservoir in response to an operation of a brake pedal. A cylinder, and a hydraulic control valve that is interposed between the master cylinder and each of the wheel cylinders to control the brake fluid pressure by introducing the brake fluid from the introduction side and discharging the brake fluid from the discharge side, In a brake fluid pressure control device including an auxiliary fluid pressure source that sucks in brake fluid from the discharge side of the fluid pressure control valve and boosts and supplies the brake fluid to the introduction side, the brake fluid pressure control apparatus is connected to each of the wheel cylinders of the drive wheels. A normally open first on-off valve interposed between the introduction side of the drive wheel side hydraulic pressure control valve and the supply side of the auxiliary hydraulic pressure source, the first on-off valve and the drive wheel side hydraulic pressure control With the introduction side of the valve A discharge side connected to the low pressure reservoir and a suction side connected to the low pressure reservoir to increase the pressure of the brake fluid in the low pressure reservoir and discharge the same, and the discharge side of the hydraulic pressure generation source and the drive wheel side. A normally closed second on-off valve interposed between the fluid pressure control valve and the introduction side of the fluid pressure control valve, wherein the first and second on-off valves are opened and closed according to at least the rotation state of the drive wheel. A brake fluid pressure control device characterized in that a drive wheel side fluid pressure control valve is controlled. 2. A wheel cylinder provided on each wheel of a drive wheel and a driven wheel, and a master for applying a brake fluid pressure to each of the wheel cylinders by boosting a brake fluid from a low pressure reservoir in response to an operation of a brake pedal. A cylinder, and a hydraulic control valve that is interposed between the master cylinder and each of the wheel cylinders to control the brake fluid pressure by introducing the brake fluid from the introduction side and discharging the brake fluid from the discharge side, In a brake fluid pressure control device including an auxiliary fluid pressure source that sucks in brake fluid from the discharge side of the fluid pressure control valve and boosts and supplies the brake fluid to the introduction side, the brake fluid pressure control apparatus is connected to each of the wheel cylinders of the drive wheels. A normally open on-off valve interposed between the introduction side of the drive wheel side hydraulic pressure control valve and the supply side of the auxiliary hydraulic pressure source; and the on-off valve and the introduction side of the drive wheel side hydraulic pressure control valve. Discharge side between And a suction side connected to the low-pressure reservoir, and a hydraulic pressure generation source that pressurizes and discharges the brake fluid in the low-pressure reservoir, and a discharge side of the hydraulic pressure generation source and the drive-wheel-side hydraulic pressure control valve. A check valve that is interposed between the inlet side and the low pressure reservoir side and blocks the flow of the brake fluid to the low pressure reservoir side and allows the flow in the opposite direction; and the on-off valve according to at least the rotation state of the drive wheel. And a brake fluid pressure control device for controlling the drive wheel side fluid pressure control valve.