JPH05294224A - Vehicular braking force control device - Google Patents

Abstract

PURPOSE:To make the improvement of sound/vibration performance during traction brake control compatible with the guarantee of pressure reduction controllability in the case of anti-skid brake control being performed after the traction brake control in a vehicular braking force control device provided with a TCS-ABS shared braking liquid pressure control actuator. CONSTITUTION:In addition to basic control of not rotating a pump (g) at the traction brake control time but rotating the pump (g) at the anti-skid braking pressure reducing control time, a pump control means (g) performs pump control of rotating the pump (g) for the specified time in the case of detecting braking operation preceding the anti-skid brake control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traction control system (TCS; traction control is performed by using engine output and a brake together, but the brake side is hereinafter referred to as "traction brake control") and an anti-skid brake control system (ABS). The present invention relates to a braking force control device for a vehicle having a brake fluid pressure control actuator that is shared with the above.

[0002]

2. Description of the Related Art Conventionally, as this type of vehicle braking force control device, for example, one disclosed in Japanese Patent Application Laid-Open No. 58-122246 is known.

The above-mentioned conventional source has a hydraulic pressure control valve and a pump for returning the brake fluid stored in a reservoir to an accumulator. During traction brake control, control is performed based on the hydraulic pressure from an external hydraulic pressure source, and antiskid is performed. There is shown a device including a shared brake hydraulic pressure control actuator that controls on the basis of hydraulic pressure from a master cylinder during brake control.

During the traction brake control and the anti-skid brake control, when reducing the wheel cylinder fluid pressure, the fluid pressure control valve is switched to the pressure reducing side and the brake fluid in the wheel cylinder is returned to the reservoir. At the same time, rotate the pump to return the brake fluid stored in the reservoir to the accumulator,
There is always a reserve of brake fluid that can be accumulated during decompression.

[0005]

However, in the above-mentioned conventional vehicle braking force control device, the device that rotates the pump during the wheel cylinder hydraulic pressure reduction during both the traction brake control and the anti-skid brake control. Therefore, the traction brake control, which has a longer control interval than the anti-skid brake control, causes the wheel cylinder hydraulic pressure decompression time to be longer, which causes noise and vibration caused by the rotation of the pump motor to cause discomfort to the driver and passengers. Easy to give.

Therefore, there is a solution to the above problem by making the pump non-rotating during the traction brake control and rotating the pump only during the anti-skid brake pressure reduction control. However, in this case, if continuous control of the traction brake is performed, a large amount of brake fluid will be accumulated in the reservoir at the end of the traction brake control. The brake fluid in the wheel cylinders does not drain to the reservoir side, and it takes time to reduce the pressure when the anti-skid brake control requires a pressure reduction.

The present invention has been made in view of the above problems, and in a vehicle braking force control device having a shared brake hydraulic pressure control actuator for TCS and ABS, a sound vibration performance during traction brake control. It is an object to achieve both improvement and ensuring pressure reduction control performance when anti-skid brake control is performed after traction brake control.

[0008]

In order to solve the above-mentioned problems, the vehicle braking force control apparatus of the present invention has a basic control in which the pump control is non-rotating during traction brake control and is rotating during anti-skid brake pressure reducing control. In addition, when the braking operation preceding the anti-skid brake control is detected, the control is performed to rotate for a predetermined time.

That is, as shown in the claim correspondence diagram of FIG. 1, a master cylinder a which produces a brake fluid pressure by a braking operation, an external fluid pressure source b which produces a brake fluid pressure independently of the braking operation, and a fluid pressure switching valve. c and hydraulic control valve d
And a pump g for returning the brake fluid stored in the reservoir e to the accumulator f, which is controlled based on the hydraulic pressure from the external hydraulic pressure source b during traction brake control, and the master cylinder a during antiskid brake control.
A shared brake hydraulic pressure control actuator h that is controlled based on the hydraulic pressure from the vehicle, a wheel cylinder i that applies a braking force to wheels according to the brake control pressure from the shared brake hydraulic pressure control actuator h, and a braking operation are detected. Pump control means for outputting a command to rotate the braking operation detecting means j and the pump f during non-rotation during traction brake control and rotate during anti-skid brake pressure reduction control, and to rotate for a predetermined time when braking operation is detected. k
It is characterized by having and.

[0010]

When the traction brake control is performed to reduce the traction transmitted to the wheels by the braking force during traveling such that a drive wheel slip occurs, the pump control means k basically issues a command to make the pump g non-rotating. Is output.

During this traction brake control, in the shared brake hydraulic pressure control actuator h, the brake hydraulic valve d is increased in pressure increasing mode based on the hydraulic pressure from the external hydraulic pressure source b by the operation of the hydraulic pressure switching valve c. Position, the brake hydraulic pressure from the external hydraulic pressure source b is supplied to the wheel cylinder i, and in the holding mode, the brake hydraulic pressure valve d is set to the holding position to cut off the supply of the brake hydraulic pressure to the wheel cylinder i to reduce the pressure. In the mode, the brake fluid pressure valve d is set to the pressure reducing position to drain the brake fluid from the wheel cylinder i, and the drained brake fluid is stored in the reservoir e.

When a braking operation is performed before or after the end of the traction brake control, the braking operation detecting means j detects the braking operation, and the pump control means k outputs a command to rotate the pump g for a predetermined time. The reservoir e is controlled by the decompression control of the traction brake control.
The brake fluid stored in is returned to the accumulator f by the rotation of the pump g.

When the wheel tends to lock when the braking operation is an abrupt operation or an operation on a low μ road, the anti-skid brake control is started.

During this anti-skid brake control,
In the shared brake hydraulic pressure control actuator h, based on the hydraulic pressure from the master cylinder a due to the operation of the hydraulic pressure switching valve c, the brake hydraulic pressure valve d is set to the increased pressure position in the pressure increasing mode to change the brake hydraulic pressure from the master cylinder a. The brake fluid pressure is supplied to the wheel cylinder i, and the brake fluid pressure valve d is set to the holding position in the holding mode to cut off the supply of the brake fluid pressure to the wheel cylinder i, and the brake fluid pressure valve d is set to the depressurizing position in the depressurization mode. The brake fluid in the wheel cylinder i is drained to the reservoir e.

At the time of depressurization at the beginning of the anti-skid control, the brake fluid in the reservoir e is drained in advance based on the braking operation. Therefore, the brake fluid in the wheel cylinder i can be drained to the reservoir e, and the depressurizing performance is secured. To be done.

Further, the brake fluid stored in the reservoir e at the time of the subsequent pressure reduction is returned to the accumulator f by rotating the pump f in response to a command from the pump control means k.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

The configuration will be described.

FIG. 2 is a system diagram showing a vehicle braking force control apparatus of an embodiment of the present invention for independently controlling the braking forces of the left and right rear wheels, which are driving wheels.

As shown in FIG. 2, the vehicle braking force control system of the embodiment has a master cylinder 2 which produces a brake fluid pressure by a braking operation on a brake pedal 1, and an external cylinder which produces a brake fluid pressure independently of the braking operation. Hydraulic pressure source 3, first hydraulic pressure switching valve 4 and second hydraulic pressure switching valve 5 (corresponding to hydraulic pressure switching valve), right rear wheel pressure increasing valve 6, right rear wheel pressure reducing valve 7, left rear wheel pressure increasing ABS for returning the brake fluid stored in the valve 8, the left rear wheel pressure reducing valve 9 (these valves correspond to hydraulic pressure control valves) and the reservoir 10 to the accumulator 11.
A pump 12 (corresponding to a pump) is provided, which is controlled based on the hydraulic pressure from the external hydraulic pressure source 3 during traction brake control, and is controlled based on the hydraulic pressure from the master cylinder 2 during antiskid brake control. The brake fluid pressure control actuator 13 is provided with a right rear wheel wheel cylinder 14 and a left rear wheel wheel cylinder 15 that apply braking force to the left and right rear wheels according to the brake control pressure from the shared brake fluid pressure control actuator 13. ..

Brake pedal 1 and master cylinder 2
A hydraulic booster 16 is provided between the booster accumulator 18 and the hydraulic booster 16, and the booster accumulator 18 accumulates pressure from the external hydraulic pressure source 3 via the check valve 17.
A boosting action is performed based on the hydraulic pressure from. Incidentally, 19 is a relief valve.

The master cylinder 2 is provided with a reservoir 20 for storing the brake fluid used in the master cylinder 2 and the external hydraulic pressure source 3.

The external hydraulic pressure source 3 is provided with a hydraulic pump 23 having check valves 21 and 22 in its input / output path, a hydraulic pump motor 24 for rotationally driving the hydraulic pump 23, and an output pipe. And the hydraulic accumulator 25.

A check valve 26 for supplying the master cylinder hydraulic pressure to the hydraulic pressure control valve side when a brake hydraulic pressure is generated from the master cylinder 2 when the valve is closed, is provided in a bypass passage bypassing the first hydraulic pressure switching valve 4. Is provided.

In the bypass passage bypassing the right rear wheel pressure increasing valve 6 and the left rear wheel pressure increasing valve 8, the hydraulic pressure on the hydraulic pressure switching valve side is low and the hydraulic pressure on the wheel cylinder side is high when the valves are closed. Check valves 27, 28 for returning the wheel cylinder hydraulic pressure to the hydraulic pressure switching valve side are provided.

An orifice 29 is provided in the hydraulic pressure passage connecting the accumulator 11 and the hydraulic pressure control valve input passage.

Check valves 30 and 31 are provided in the input / output path of the ABS pump 12 to regulate the flow direction of the brake fluid from the reservoir 10 to the accumulator 11. An ABS pump motor 32 is connected to the ABS pump 12.

The valves 4, 5, 6, 7, 8, 9 are
It has a 2-position switching solenoid valve structure. Also,
Although not shown, the front wheel side also has a brake fluid pressure control actuator having a similar configuration.

The valves 4, 5, 6, 7, 8, 9 and the pumps 12, 23 are operated and controlled by electronic control. As an electronic control system, wheel speed sensors 33 for the front and rear wheels and a stop are provided. Control for inputting detection signals from the lamp switch 34 (corresponding to braking operation detecting means) and other sensors 35 and outputting control commands for performing traction brake control, anti-skid brake control, hydraulic pump control, ABS pump control. A unit 36 is provided.

The traction brake control is performed by applying a braking force to the left and right rear wheels in combination with throttle valve closing control or the like in order to obtain the best stable running with higher traction ability under various driving conditions. The anti-skid brake control is performed by controlling the wheel cylinder hydraulic pressure, which is the braking force, in order to prevent wheel lock during short braking, low μ road braking, etc. to reduce the vehicle stability and braking distance. ..

The hydraulic pump control is performed by controlling the rotation and non-rotation of the hydraulic pump motor 24 in order to keep the hydraulic pressures of the accumulators 18 and 25 at a predetermined level. AB
The S pump control enables the ABS pump motor 32 to accumulate the brake fluid from the wheel cylinders 14 and 15 in the reservoir 10 at the time of starting the anti-skid pressure reduction control and at the time of the subsequent pressure reduction control while improving the sound and vibration performance during the traction brake control. It is performed by controlling the rotation and non-rotation of.

The operation will be described.

FIG. 3 is a flow chart showing the flow of the ABS pump control operation performed by the control unit 36, and each step will be described below (corresponding to pump control means).

At step 50, necessary information such as a switch signal from the stop lamp switch 34, a traction control in-progress signal, an anti-skid pressure reducing control signal, etc. is read.

In step 51, it is determined whether the stop lamp switch signal is within the set time ta after the ON signal indicating the braking operation.

If NO at step 51, the routine proceeds to step 52, at which it is judged whether or not traction control is being performed.

If YES is determined in step 52, the process proceeds to step 53, and a command for deactivating the ABS pump motor 32 is output.

On the other hand, if YES is determined in the step 51, the process proceeds to a step 54 and the ABS pump motor 3
A command to rotate 2 is output.

If NO at step 52, the routine proceeds to step 55, at which it is determined whether the set time tb has passed since the first anti-skid pressure reduction control was started. If NO is determined in step 55, the process proceeds to step 53 in which the motor is not rotating and step 55
If YES is determined, the process proceeds to step 54 of motor rotation.

Next, the control operation during running in which traction control is performed and then antiskid control is performed will be described.

When the traction brake control for reducing the traction transmitted to the rear wheels by the braking force is performed when the rear wheel slip amount exceeds the traction brake control threshold value, step 50 → The flow proceeds from step 51 → step 52 → step 53, and a command to deactivate the ABS pump 12 is output.

During this traction brake control, the shared brake hydraulic pressure control actuator 13 makes the first
Based on the hydraulic pressure from the external hydraulic pressure source 3 by the switching operation in which both the hydraulic pressure switching valve 4 and the second hydraulic pressure switching valve 5 are turned on, in the pressure increasing mode, the pressure increasing valves 6 and 8 are in the communicating position by being turned off. By setting the pressure reducing valves 7 and 9 to the shut-off position by turning OFF, the brake fluid pressure from the external hydraulic pressure source 3 is supplied to the wheel cylinders 14 and 15, and in the holding mode, the pressure increasing valves 6 and 8 are turned to the shut-off position. Pressure reducing valve 7,
The brake fluid pressure supply to the wheel cylinders 14 and 15 is cut off by setting 9 to the OFF cut-off position, and in the pressure reduction mode, the pressure increase valves 6 and 8 are set to the ON cut-off positions to communicate the pressure reduction valves 7 and 9 by ON. The brake fluid in the wheel cylinders 14 and 15 is drained by setting the position, and the drained brake fluid is stored in the reservoir 10.

When a braking operation is performed before or after the end of the traction brake control, the stop lamp switch 34 detects the braking operation, and the process proceeds from step 50 to step 51 to step 54 in the flowchart of FIG. Flow, ABS pump 1
A command to rotate 2 for the set time ta is output.

Therefore, the brake fluid stored in the reservoir 10 by the pressure reduction control of the traction brake control is AB
It is returned to the accumulator 11 by the rotation of the S pump 12.

When the braking operation is an abrupt operation or an operation on a low μ road, and the rear wheels tend to lock, the anti-skid brake control is started.

During this anti-skid brake control,
In the shared brake hydraulic pressure control actuator 13, a switching operation of turning off both the first hydraulic pressure switching valve 4 and the second hydraulic pressure switching valve 5 is performed based on the hydraulic pressure from the master cylinder 2 to increase the pressure in the pressure increasing mode. Turn valves 6 and 8 to O
The brake hydraulic pressure from the external hydraulic pressure source 3 is supplied to the wheel cylinders 14 and 15 by setting the communication position by the FF and the depressurizing valves 7 and 9 to the shut-off position by turning off the pressure increasing valves 6 and 8 in the holding mode. The brake pressure supply to the wheel cylinders 14 and 15 is cut off by setting the pressure reducing valves 7 and 9 to the OFF position to reduce the pressure, and in the pressure reducing mode, the pressure increasing valves 6 and 8 are turned to the ON position to reduce the pressure. The brake fluid of the wheel cylinders 14 and 15 is drained to the reservoir 10 by setting the valves 7 and 9 to the communication position by turning them on. At the time of the first depressurization, the depressurization performance is secured because the brake fluid in the reservoir 10 is drained in advance based on the braking operation.

Further, when the pressure is reduced thereafter, the flow proceeds from step 50 to step 51 to step 52 to step 55 to step 54 in the flowchart of FIG. 3, and the ABS pump 32 is rotated for the set time tb, so that the ABS pump 32 can be changed at any time. The brake fluid stored in the reservoir 10 is returned to the accumulator 11.

Next, the control operation when the driver simultaneously operates the right foot accelerator and the left foot brake to output an anti-skid control request during the traction control will be described with reference to the time chart of FIG.

When the stop lamp switch 34 is turned on at the time t1 during the traction control, the ABS pump motor 32 is turned on for the set time ta up to the time t4.
Is output. Then, the traction control shifts from the pressure reducing mode (t2 to t3) to the holding mode (t3 to t5) in response to the ABS request output at time t2 after a predetermined time has passed since the stop lamp switch 34 was turned on. Then, at time t5, the second hydraulic pressure switching valve 5 is turned from ON to OFF, and tc (1
The first hydraulic pressure switching valve 4 is switched from ON to OFF at time t6 which is delayed by about 0 msec. This is to prevent the master cylinder hydraulic pressure from flowing back to the external hydraulic pressure source 3 side. Then, at time t7, the anti-skid pressure reduction control is started, and at the same time, the ABS pump motor 3
2 is turned on for the set time tb. The ABS pump motor 32 may be turned on from the start of the antiskid pressure reduction control to the end of the antiskid control.

As described above, even when the anti-skid control is performed subsequent to the traction control, the depressurizing performance in the anti-skid control is secured by draining the brake fluid from the reservoir 10 in advance based on the braking operation.

The effect will be described.

(1) In a vehicle braking force control device having a shared brake hydraulic pressure control actuator 13 for TCS and ABS, the ABS pump 12 is controlled so that it does not rotate during traction brake control and rotates during antiskid brake pressure reduction control. In addition to the basic control described above, when the braking operation preceding the anti-skid brake control is detected, the control for rotating for the set time ta is performed.
In the case where the anti-skid brake control is performed after the traction brake control by improving the sound vibration performance by keeping the ABS pump 12 stopped during the traction brake control and by draining the brake fluid from the reservoir 10 in advance based on the braking operation. It is possible to achieve compatibility with the pressure reduction control performance.

(2) Since the stop lamp 34 used in the anti-skid brake control is used as the braking operation detecting means, a new sensor is not required for controlling the pump, which is a cost-effective device. can do.

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, the stop lamp 34 is used as the braking operation detecting means. However, the accelerator release state at which the traction control ends is detected, and the indirect braking is performed after a predetermined time from the accelerator off. It may be used as operation detection.

In the embodiment, the two-position solenoid valve is shown as the hydraulic pressure switching valve and the hydraulic pressure control valve, but a three-position solenoid valve may be used to reduce the number of valves.

[0057]

As described above, according to the present invention, in a vehicle braking force control device having a shared brake hydraulic pressure control actuator for TCS and ABS, pump control is set to non-rotation during traction brake control. , In addition to the basic control to rotate during anti-skid brake pressure reduction control, as a means to perform control to rotate for a predetermined time when a braking operation preceding anti-skid brake control is detected, it is possible to improve sound vibration performance during traction brake control. There is an effect that the decompression control performance can be ensured at the same time when the anti-skid brake control is performed after the traction brake control.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a vehicle braking force control device of the present invention.

FIG. 2 is a system diagram showing a vehicle braking force control device according to an embodiment of the present invention, which independently controls the braking forces of the left and right rear wheels, which are driving wheels.

FIG. 3 is a flowchart showing a flow of an ABS pump control processing operation performed by a control unit of the embodiment apparatus.

FIG. 4 is a time chart showing a control action in the case where the driver simultaneously performs a right foot accelerator operation and a left foot brake operation, and an anti-skid control request is output during the traction control.

[Explanation of symbols]

 a master cylinder b external hydraulic pressure source c hydraulic pressure switching valve d hydraulic pressure control valve e reservoir f accumulator g pump h shared brake hydraulic pressure control actuator i wheel cylinder j braking operation detection means k pump control means

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 3, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (1)

[Claims] 1. A master cylinder for producing a brake fluid pressure by a braking operation, an external fluid pressure source for producing a brake fluid pressure independently of the braking operation, a fluid pressure switching valve, a fluid pressure control valve, and a brake fluid stored in a reservoir. A shared brake hydraulic pressure control that has a pump that returns to the accumulator, controls based on the hydraulic pressure from the external hydraulic pressure source during traction brake control, and controls based on the hydraulic pressure from the master cylinder during anti-skid brake control. An actuator, a wheel cylinder that applies a braking force to wheels according to the brake control pressure from the shared brake fluid pressure control actuator, a braking operation detection unit that detects a braking operation, and the pump is non-rotating during traction brake control, In addition to the basic control that rotates during anti-skid brake pressure reduction control, It comprises a pump control means for moving the operation to output a command to rotate a predetermined time upon detecting a vehicle braking force control apparatus according to claim.