JPH07223527A - Traction control device for vehicle - Google Patents

Abstract

PURPOSE:To return the piston of a booster cylinder to the original position by providing a completion control means which, after a brake traction control has been completed, continues to operate first and second hydraulic pumps and, after a specified time has been collapsed, opens a cut valve and boosting valves, and closes pressure reducing valves so as to stop the first and second hydraulic pumps. CONSTITUTION:After a brake traction control has been completed, a control valve 79 is opened, a cut valve and booster valves 21 and 27 are closed for a specified time from the start of the completion, pressure reducing valves 24 and 29 are opened, and first and second hydraulic pumps 32 and 73 are continued to operate. Then, a completion control means is provided which, after a specified time has been collapsed, opens the cut valve 61 and booster valves 21 and 27, and closes the pressure reducing valves 24 and 29 so as to stop the first and second hydraulic pumps 32 and 73. Thus, the piston of a booster cylinder 66 can be returned securely to the original position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traction control device for a vehicle, and more particularly to an improved traction control device for reliably returning a piston of a pressure increasing cylinder at the end of brake traction control.

[0002]

2. Description of the Related Art Conventionally, in a braking system capable of anti-skid brake control and brake traction control for a brake mechanism of a vehicle drive wheel, a master cylinder connected to a brake pedal is connected to a wheel cylinder by a hydraulic passage. A pressure increasing valve and a pressure reducing valve are connected to this hydraulic passage, and a cut valve that opens and closes the hydraulic passage upstream of the pressure increasing valve is provided between the pressure increasing valve and the cut valve. , A first hydraulic pump for supplying hydraulic pressure to this hydraulic passage,
A pressure increasing cylinder for brake traction control is connected, and a hydraulic pressure input passage leading to an input oil chamber of the pressure increasing cylinder is connected to a second hydraulic pump for brake traction control, and a return pressure is connected to this hydraulic pressure input passage. In the oil passage,
A control valve that opens and closes the oil passage is installed. Japanese Unexamined Patent Publication No. 3-224859 describes a braking system that is substantially the same as the braking system described above.

In the above braking system, when anti-skid brake control is executed to suppress slip of the driving wheels during braking, the cut valve is closed, the first hydraulic pump is operated, and the pressure increasing valve and pressure reducing valve are operated. Through the valve
It controls the hydraulic pressure of the wheel cylinders such as increasing, maintaining and reducing the pressure. In the braking system, when the brake traction control is executed in order to suppress the slip of the driving wheels during acceleration of the vehicle, the cut valve is closed, the first and second hydraulic pumps are operated, and the pressure increasing cylinder is operated. Also makes it possible to supply oil pressure to the oil pressure passage, and controls the increase, retention and pressure reduction of the oil pressure in the wheel cylinders via the pressure increasing valve and the pressure reducing valve.

Here, in the conventional braking system, at the start of the termination of the brake traction control, the cut valve, the control valve and the pressure increasing valve are immediately opened, the pressure reducing valve is closed, and the piston of the pressure increasing cylinder is returned. The operation of at least the first hydraulic pump is continued for a predetermined time period after the end of the brake traction control, and the first hydraulic pump is stopped after the predetermined time period has elapsed.

[0005]

By the way, as described above, conventionally, at the end of the brake traction control,
Since the cut valve is opened immediately, it acts on the hydraulic pressure in the long hydraulic passage that is in communication from the master cylinder to the wheel cylinder, that is, the pressure boosting cylinder, even though the first hydraulic pump is operating for a predetermined time. The first hydraulic pump may stop before the applied hydraulic pressure is sufficiently increased. The pressure-increasing cylinder is provided with a return spring for returning the piston, but when the sliding resistance of the seal member attached to the piston increases, the piston of the pressure-increasing cylinder does not return to its original position. , Traction control may end.

In such a case, when the driver subsequently operates the brake pedal, the hydraulic pressure supplied from the master cylinder is consumed also for returning the piston of the pressure increasing cylinder, so that a braking response is obtained. Performance and braking performance are deteriorated, and the depression stroke of the brake pedal is increased. The purpose of the present invention is to
It is an object of the present invention to provide a traction control device for a vehicle that can surely return the piston of the pressure increasing cylinder to the original position at the end of the brake traction control.

[0007]

According to a first aspect of the present invention, there is provided a vehicle traction control device in which a master cylinder and a master cylinder and a wheel cylinder are connected to a hydraulic pressure supply system for supplying hydraulic pressure to a brake mechanism of a vehicle drive wheel. Pressure increasing valve and pressure reducing valve connected to the hydraulic pressure passage, a cut valve opening and closing the hydraulic pressure passage upstream of the pressure increasing valve, and a first hydraulic pump connected to the hydraulic pressure passage between the pressure increasing valve and the cut valve. A pressure-increasing cylinder connected to the hydraulic passage between the pressure-increasing valve and the cut valve, a second hydraulic pump connected to a hydraulic input passage communicating with the input oil chamber of the pressure-increasing cylinder, and connected to the input oil chamber. In a vehicle braking system having a control valve for opening and closing the return oil passage, at the start of brake traction control, The control valve and the control valve are closed, the first and second hydraulic pumps are actuated to supply the hydraulic pressure from the pressure increasing cylinder to the hydraulic passage, and the control valve is opened at the end of the brake traction control. The cut valve and the pressure increasing valve are closed and the pressure reducing valve is opened and the operation of the first and second hydraulic pumps is continued for a predetermined time from the start of the end, and after the predetermined time has elapsed, the cut valve and the pressure increasing valve are opened and the pressure is reduced. And a termination control means for closing the valve and stopping the first and second hydraulic pumps.

Here, the braking system includes a bypass oil passage for bypassing the pressure increasing valve, and a check valve provided in the bypass oil passage for permitting a hydraulic pressure flow from the wheel cylinder in the return direction. The means may be configured to close the pressure reducing valve for a set time shorter than the predetermined time immediately after the start of the end (claim 2 dependent on claim 1).

[0009]

In the traction control device for a vehicle according to the present invention, in the braking system, the start control means closes the cut valve and the control valve at the start of the brake traction control, and the first and second The hydraulic pump is operated to supply the hydraulic pressure from the pressure increasing cylinder to the hydraulic passage. Then, the hydraulic pressure from the second hydraulic pump is supplied from the hydraulic pressure input passage to the input oil chamber of the pressure increasing cylinder, the hydraulic pressure generated by the forward movement of the piston of the pressure increasing cylinder is supplied to the hydraulic passage, and the hydraulic pressure is supplied to the wheel cylinder. To generate braking force. After that, the hydraulic pressure of the wheel cylinder is appropriately adjusted via the pressure increasing valve and the pressure reducing valve.

By the brake traction control, the slip of the driving wheels is suppressed to a desired state, and when the brake traction control is ended, the end control means opens the control valve at the end of the brake traction control and starts the end. The cut valve and the pressure increasing valve are closed and the pressure reducing valve is opened for a predetermined time from
And, the operation of the second hydraulic pump is continued, and after the lapse of the predetermined time, the cut valve and the pressure increasing valve are opened, the pressure reducing valve is closed, and the first and second hydraulic pumps are stopped. Then, the oil pressure in the input oil chamber of the pressure boosting cylinder is returned from the return oil passage through the control valve. Then, the hydraulic pressure generated in the first hydraulic pump is supplied to the hydraulic passage for a predetermined time after the end of the traction control, but since the pressure increasing valve and the cut valve are closed, the hydraulic pressure in the hydraulic passage is sufficient. Boost. The high oil pressure acts on the piston of the pressure boosting cylinder, and the piston of the pressure boosting cylinder returns to the original position and is reliably returned to the original position.

After the lapse of the predetermined time, the cut valve and the pressure increasing valve are opened, the pressure reducing valve is closed, and the first and second hydraulic pumps are stopped. As described above, the end control means raises the hydraulic pressure in the hydraulic passage for a predetermined time after the end of the brake traction control to act on the piston of the pressure boosting cylinder to reliably return the piston of the pressure boosting cylinder to the original position. Can be made.

According to another aspect of the vehicle traction control device of the present invention, the end control means closes the pressure reducing valve for a set time shorter than the predetermined time immediately after the start of the end, so that the pressure increasing valve is bypassed. Through the bypass oil passage and its check valve, the high hydraulic pressure on the wheel cylinder side is supplied to the hydraulic passage on the upstream side of the pressure increasing valve, and at normal times, that is, the sliding resistance that acts on the piston of the pressure increasing cylinder. When the pressure is small, the return time of the piston of the pressure boosting cylinder is shortened.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is an example in which the present invention is applied to a braking system of a rear wheel drive type vehicle. As shown in FIG. 1, this braking system BS basically includes a tandem master cylinder 2 operated by a brake pedal 1, a wheel cylinder 4 of a caliper of a brake mechanism for a left rear wheel 3, and a right rear wheel 5. A wheel cylinder 6 of a caliper of the brake mechanism, a main hydraulic passage 7 extending from the master cylinder 2, branch hydraulic passages 8 and 9 branched from the main hydraulic passage 7 at a branch point A and connected to the wheel cylinders 4 and 6, respectively. The wheel cylinder 12 of the caliper of the brake mechanism of the left front wheel 11, the wheel cylinder 14 of the caliper of the brake mechanism of the right front wheel 13, the main hydraulic passage 15 extending from the master cylinder 2, and the wheel branched from the main hydraulic passage 15 at a branch point B. Branch hydraulic passages 16 and 17 respectively connected to the cylinders 12 and 14 are provided.

Further, the braking system BS includes a rear wheel ABS hydraulic system 20 and a front wheel ABS hydraulic system 40 for an anti-skid brake control system (ABS) and a rear wheel brake traction control system (TCS). TC
An S hydraulic system 60 and a pump drive motor 18 shared by the hydraulic systems 20, 40 and 60 are provided.

Next, the ABS hydraulic system 20 for the rear wheels will be described. A pressure increasing valve 21 is provided in the branch hydraulic passage 8, and a return oil passage 22 connected to the branch hydraulic passage 8 on the downstream side (wheel cylinder 4 side) of the pressure increasing valve 21 is connected to a reservoir 23. A pressure reducing valve 24 is provided in the return oil passage 22. In the bypass oil passage 25 that bypasses the pressure increasing valve 21, a check valve 26 that allows a hydraulic pressure flow from the wheel cylinder 4 in the returning direction.
Is provided.

Similarly, a pressure increasing valve 27 is provided in the branch hydraulic passage 9, and a return oil passage 28 connected to the branch hydraulic passage 9 on the downstream side of the pressure increasing valve 27 is a return oil passage 22. Connected to the reservoir 23 via the downstream part of
A pressure reducing valve 29 is provided in the return oil passage 28. Bypass oil passage 3 bypassing the pressure increasing valve 27
At 0, a check valve 31 that allows a hydraulic pressure flow from the wheel cylinder 6 in the returning direction is provided. The hydraulic supply passage 33 provided with the hydraulic pump 32 is connected to the reservoir 23.
From the hydraulic pressure supply passage 3 to the branch point A of the main hydraulic pressure passage 7 via the upstream side portion of the hydraulic branch passage 9.
3 includes check valves 3 in order from the reservoir 23 side.
4, hydraulic pump 32, check valve 35, throttle valve 3
6. Check valve 37 is connected. The hydraulic pump 32 is connected to the motor 18 and driven by the motor 18. The pressure increasing valves 21, 27 and the pressure reducing valve 24,
Reference numeral 29 is a duty solenoid valve capable of opening and closing the oil passage and finely adjusting the degree of valve opening.

Next, the ABS hydraulic system 40 for the front wheels will be described. A pressure increasing valve 41 is provided in the branch hydraulic passage 16, and a return oil passage 42 connected to the branch hydraulic passage 16 on the downstream side of the pressure increasing valve 41 is connected to a reservoir 43. A pressure reducing valve 44 is provided. The bypass oil passage 45 that bypasses the pressure increasing valve 41 is provided with a check valve 46 that allows the hydraulic pressure to flow from the wheel cylinder 12 in the returning direction.
Similarly, the pressure increasing valve 47 is provided in the branch hydraulic passage 17.
The return oil passage 48 connected to the branch hydraulic passage 17 on the downstream side of the pressure increasing valve 47 is connected to the reservoir 43, and the return oil passage 48 is provided with a pressure reducing valve 49. The bypass oil passage 50 that bypasses the pressure increasing valve 47 is provided with a check valve 51 that allows a hydraulic pressure flow from the wheel cylinder 13 in the returning direction.

Hydraulic pressure supply path 5 provided with a hydraulic pump 52
3 extends from the reservoir 43 and is connected to the branch point B of the main hydraulic passage 15 via the upstream side portion of the branch hydraulic passage 16. In the hydraulic supply passage 53, check valves 54, The hydraulic pump 52, the check valve 55, the throttle valve 56, and the check valve 57 are connected. The hydraulic pump 52 is connected to the motor 18 and driven by the motor 18. The pressure increasing valves 41, 4
7 and the pressure reducing valves 44 and 49 are duty solenoid valves capable of opening and closing the oil passage and finely adjusting the degree of valve opening.

Next, the rear wheel TCS hydraulic system 60 will be described. The main hydraulic passage 7 is provided with a cut valve 61 capable of opening and closing this passage.
The bypass oil passage 62 that bypasses 1 is provided with a check valve 63 that permits the flow of hydraulic pressure in the downstream direction, and the bypass oil passage 64 that bypasses the cut valve 61.
Is provided with a check valve 65 that allows a hydraulic pressure flow in the upstream direction when a hydraulic pressure higher than the brake hydraulic pressure generated during execution of the brake traction control is applied.

Further, a pressure increasing cylinder 66 is provided for increasing the hydraulic pressure in the main hydraulic pressure passage 7 when the brake traction control is executed. This pressure increasing cylinder 66
The discharge port 67 is connected to the main hydraulic passage 7 via the pressure increasing oil passage 68, and the input oil chamber 69 of the pressure increasing cylinder 66 is
It is connected to the reservoir 75 by a hydraulic pressure input passage 74 having a hydraulic pump 73, and the reservoir 7 is connected to the hydraulic pressure input passage 74.
Check valve 76, hydraulic pump 73,
A check valve 77 is provided, and the hydraulic pump 73
Is connected to a pump driving motor 18, and this motor 18
Driven by. Input oil chamber 69 of the pressure increasing cylinder 66
The return oil passage 78 connected to is connected to the reservoir 75,
The return oil passage 78 is provided with a control valve 79 capable of opening and closing the oil passage. Incidentally, reference numeral 80 is a relief valve that is operated by relief at a predetermined high hydraulic pressure, and the cut valve 61 and the control valve 79 are
It is an open / close solenoid valve.

A seal member 71 is attached to the piston 70 of the pressure increasing cylinder 66. This piston 7
0 is biased toward the input oil chamber 69 by the return spring 72, and when the oil pressure is supplied to the input oil chamber 69, the piston 70 moves in the discharge direction against the return spring 72 and the discharge port 67. The hydraulic pressure is discharged to the main hydraulic pressure passage 7.

The control unit 10 controls the various valves and the motor 18 to perform anti-skid brake control and brake traction control. The control unit 10 shapes the waveforms of various detection signals. And a circuit for A / D conversion, an input / output interface, a microcomputer, a drive circuit for controlling the drive of valves, and the like. The control unit 10 includes a motor 18, a cut valve 61, a control valve 79, pressure increasing valves 21, 27, 41, 47 and pressure reducing valves 24, 2.
These motors 18 are electrically connected to 9,44,49.
The valves and the valves are controlled by the control unit 10. Furthermore,
Although not shown, the control unit 10 controls the wheel speeds of the four wheels of the vehicle, the steering angle, the brake switch signal, the engine speed,
Receiving various detection signals such as throttle opening, accelerator depression amount, etc., based on a predetermined anti-skid brake control control program and predetermined brake traction control control program, anti-skid brake control during braking and acceleration Brake traction control is executed.

Since the brake traction control is a general control, it will be briefly described. When the slip amount of the driving wheels becomes larger than the target slip amount,
The motor 18 is driven, the cut valve 61 and the control valve 79 are closed, the pressure increasing valves 21 and 27 are held in the open position, and the pressure reducing valves 24 and 29 are held in the closed position. , 6 to enhance the braking force, and to control the brake hydraulic pressure so that the slip amount of the drive wheels becomes equal to or less than the target slip amount. However, actually, the brake traction control is individually executed for both the wheel cylinders 4 and 6.

Here, when the brake traction control is ended, the piston 70 of the pressure increasing cylinder 66 is surely returned to the original position even when the sliding resistance of the seal member 71 increases. The control program for the brake traction control of the control unit 10 includes the control program for the valve switching control described below. Next, regarding the routine of the valve switching control,
This will be described with reference to the flowchart of FIG. 2 and the time chart of FIG. In the flow chart, reference numeral S
i (i = 1, 2, 3, ...) Shows each step.

When this valve switching control is started when the engine of the vehicle is started, the R of the microcomputer is turned on.
Initialization such as clearing the AM memory is executed, and then it is determined whether or not the flag F for identifying the execution of the brake traction control is 0 (S1). When the flag F is 0, the brake traction is determined. Based on the slip flag set separately in the control, it is determined whether or not the brake traction control is started (S2), and the determination is N
When it is o, it returns as it is, but the judgment is Ye
When s, in S3, the pump drive motor 18 is operated and valve switching is executed.

In this valve switching, the control valve 79 is in the closed position, the cut valve 61 is in the closed position,
The pressure increasing valves 21 and 27 are in the open position, and the pressure reducing valves 24 and 2 are
9 is switched to the open position, respectively (see FIG. 3). However,
The pressure increasing valves 21 and 27 and the pressure reducing valves 24 and 29 are duty-controlled by brake traction control, and when pressure increasing is required, the pressure increasing valves 21 and 27 are opened and the pressure reducing valves 24 and 29 are closed, and the wheels are controlled. When the hydraulic pressure of the cylinders 4 and 6 is maintained, the pressure increasing valves 21 and 27
The pressure reducing valves 24 and 29 are closed, and when pressure reduction is required, the pressure increasing valves 21 and 27 are closed and the pressure reducing valves 24 and 29 are opened.

By switching the valves as described above, the motor 1
When the hydraulic pumps 32 and 73 are driven by 8, the pressure boosting cylinder 6 passes from the hydraulic pump 73 through the hydraulic pressure input passage 74.
6, the oil pressure is supplied to the input oil chamber 69, and the pressure increasing cylinder 6
When the piston 70 of 6 moves forward to supply hydraulic pressure to the main hydraulic passage 7 and the pressure increasing valves 21 and 27 are in the open position,
The hydraulic pressure is supplied to the wheel cylinders 4 and 6. Next, in S4 of the flowchart, the flag F is set, and then the process returns. After the flag F is set, the process proceeds from S1 to S5, and it is determined in S5 whether or not the end of the brake traction control is started based on the slip flag in the brake traction control. During execution of brake traction control, the determination in S5 is No.
In case of, it returns from S5.

If the slip amount of the drive wheels 3 and 4 converges to the target slip amount or less and the slip flag is reset when the brake traction control is ended, S5
At, it is determined that the end of the brake traction control is started, and the process proceeds from S5 to S6. In S6, the control valve 79 is switched to the open position, the pressure boosting valves 21 and 27 are switched to the closed position, and the pressure reducing valve 24 and the pressure reducing valve 24, in order to release the hydraulic pressure of the input oil chamber 69 of the pressure boosting cylinder 66. 29 is switched to the open position (see FIG. 3).

When the valves are switched as described above, the cut valve 61 is in the closed position and the pressure increase valves 21, 27 are also in the closed position. Therefore, part of the hydraulic pressure in the branch hydraulic passages 8, 9 is
Since the hydraulic pressure is supplied from the hydraulic pump 32 to the main hydraulic passage 7 while being supplied to the main hydraulic passage 7 through the check valves 26 and 31, the main hydraulic passage 7 between the cut valve 61 and the pressure increasing valves 21 and 27 is supplied. The hydraulic pressure is reliably and sufficiently increased. When the control valve 79 is in the open position, no oil pressure is applied to the input oil chamber 69, the oil pressure in the main oil pressure passage 7 is increased, and the spring force of the return spring 72 is also applied. The piston 70 will surely return to the original position.

In S7 following S6, a predetermined time T (for example, about 1000 m from the start of the end of the brake traction control).
s) (see FIG. 3), it is determined whether or not a predetermined time has elapsed, S7 is repeated before the predetermined time elapses, and when the predetermined time T elapses, S
Move to 8. In S8, the pump driving motor 1
8 is stopped, the cut valve 61 is in the open position, the pressure increasing valves 21, 27 are in the open position, and the pressure reducing valve 2
4, 29 are switched to the closed position (see FIG. 3).
Next, in S9, the flag F is reset to 0, and then the process returns. The valve switching control routine shown in FIG. 2 is repeatedly executed every minute time. When the valves are switched as described above, the hydraulic pressure generated in the master cylinder 2 during braking via the brake pedal 1 passes through the main hydraulic passage 7 and the branch hydraulic passages 8 and 9 to the wheel cylinders 4, 4. 6, the hydraulic pressure generated from the master cylinder 2 is supplied to the main hydraulic passage 1
5, it is supplied to the wheel cylinders 12 and 14 through the branch hydraulic passages 16 and 17.

The operation of the valve switching control included in the above-described brake traction control will be described. At the start of the end of the brake traction control, the control valve 79 is opened, the operation of the hydraulic pump 32 is continued for a predetermined time T from the start of the end, the cut valve 61 and the pressure increasing valves 21, 27 are closed, and the pressure reducing valve 2
Since the valves 4, 29 are opened, the cut valve 61 and the pressure increasing valves 21, 27 are controlled by the hydraulic pressure supplied from the hydraulic pump 32.
It is possible to reliably and sufficiently increase the hydraulic pressure in the main hydraulic passage 7 between them, and to reliably return the piston 70 of the pressure increasing cylinder 66 to the original position.

This prevents the hydraulic pressure supplied from the master cylinder 2 from being consumed for the return of the piston 70 of the pressure increasing cylinder 66 when the brake traction control is not executed, and ensures the braking performance. It is possible to prevent the depression stroke of the brake pedal 1 from increasing abnormally. Further, since the pressure reducing valves 24 and 29 are opened during the predetermined time T, the hydraulic pressure in the wheel cylinders 4 and 6 can be surely released. After the elapse of the predetermined time T, the motor 18 is stopped, the cut valve 61 is opened, the pressure increasing valves 21 and 27 are opened, and the pressure reducing valves 24 and 29 are closed.
The desired braking performance can be achieved when braking via the.

Next, another embodiment in which a part of the above embodiment is modified will be described. A flow chart of this valve switching control routine will be described with reference to FIG. 4, but since S20 to S24 are the same as S1 to S5 of the above-mentioned embodiment, the description thereof will be omitted. In S25 corresponding to S6, the control valve 79 is in the open position,
Further, the pressure increasing valves 21 and 27 are switched to the closed position, and the pressure reducing valves 24 and 29 are switched to the closed position. Next, S26
At, from the start of the end of the brake traction control,
It is determined whether or not a set time t (see FIG. 3), which is significantly shorter than the predetermined time T, has elapsed. If the determination is No, S26 is repeated, and if the determination is Yes, the pressure reducing valves 24, 29. Is opened (S27). In this way, since the pressure reducing valves 24 and 29 are switched to the open position, the hydraulic pressure in the wheel cylinders 4 and 6 can be reliably released.

As described above, the pressure reducing valve 2 is operated for the short set time t immediately after the start of the brake traction control.
By closing 4,29, wheel cylinders 4,6
The hydraulic pressure on the side passes through the check valves 26 and 31 and then to the main hydraulic passage 7 between the cut valve 61 and the pressure increasing valves 21 and 27.
Is supplied to the piston 7 of the pressure increasing cylinder 66 during normal operation when the sliding resistance of the piston 70 is small.
The return time of 0 can be surely shortened.

Next, in S28, it is determined whether or not a predetermined time T has elapsed from the start of the termination of the brake traction control. If the determination is Yes, the process proceeds to S29, in the same way as in S8 described above, for pump drive. The motor 18 is stopped,
The cut valve 61 is in the open position, and the pressure increasing valve 21,
27 is switched to the open position, and the pressure reducing valves 24 and 29 are switched to the closed position, after which the flag F is reset to 0 as in S9, and then the process returns. In FIG. 3, the dotted line in the time chart of the pressure reducing valve and the set time t are those in another embodiment.

Incidentally, the correspondence relationship between each configuration of claim 1 and the embodiment will be briefly described. The first hydraulic pump corresponds to the hydraulic pump 32, and the second hydraulic pump corresponds to the hydraulic pump. The pump 73, which corresponds to the start control means, is the control unit 10, and the one which corresponds to the end control means is the control unit 10.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a hydraulic circuit of a vehicle braking system according to an embodiment.

FIG. 2 is a flowchart of a valve switching control routine in brake traction control.

FIG. 3 is a time chart of a pump drive motor and valves.

FIG. 4 is a flowchart of a valve switching control routine according to another embodiment.

[Explanation of symbols]

 BS braking system 2 master cylinder 3,5 drive wheel 4,6 wheel cylinder 7 main hydraulic passage 8,9 branch hydraulic passage 10 control unit 21,27 pressure increasing valve 24,29 pressure reducing valve 25,30 bypass oil passage 26,31 check Valve 32 Hydraulic pump 61 Cut valve 66 Pressure increasing cylinder 70 Control valve 69 Input oil chamber 73 Hydraulic pump 74 Hydraulic input path 79 Control valve

Claims (2)

[Claims] 1. A master cylinder, a pressure increasing valve and a pressure reducing valve connected to a hydraulic passage connected from the master cylinder to the wheel cylinder, in a hydraulic pressure supply system for supplying a hydraulic pressure to a drive wheel brake mechanism of a vehicle. A cut valve that opens and closes the hydraulic passage upstream of the pressure increasing valve, a first hydraulic pump connected to the hydraulic passage between the pressure increasing valve and the cut valve, and a hydraulic passage connected between the pressure increasing valve and the cut valve. Of a vehicle having a pressure increasing cylinder, a second hydraulic pump connected to a hydraulic pressure input passage communicating with an input oil chamber of the pressure increasing cylinder, and a control valve for opening and closing a return oil passage connected to the input oil chamber. In the braking system, at the start of brake traction control, the cut valve and the control valve are closed, and the first and second hydraulic pumps are closed. Is operated and a start control means for supplying the hydraulic pressure from the pressure-increasing cylinder to the hydraulic passage, at the end of the brake traction control, with opening the control valve during a predetermined time period from the completion of the start,
The cut valve and the pressure increasing valve are closed, the pressure reducing valve is opened, and the operation of the first and second hydraulic pumps is continued. After the lapse of the predetermined time, the cut valve and the pressure increasing valve are opened and the pressure reducing valve is closed, and the first and second hydraulic pumps are closed. 2. A traction control device for a vehicle, comprising: a termination control means for stopping the hydraulic pump. 2. The braking system includes a bypass oil passage that bypasses the pressure increasing valve, and a check valve that is provided in the bypass oil passage and allows a hydraulic pressure to flow from the wheel cylinder in a return direction. The traction control device for a vehicle according to claim 1, wherein the pressure reducing valve is configured to be closed for a set time shorter than the predetermined time immediately after the start of the end.