JP3141655B2 - Brake fluid pressure control device - Google Patents

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 device, and more particularly to a brake fluid pressure control device having a rear wheel fluid pressure rise gradient suppression control means for controlling a rise gradient of a brake fluid pressure of a rear wheel. It concerns the device.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 4-218453 discloses a control for suppressing the rising gradient of the brake fluid pressure of the rear wheels from the rising gradient of the brake fluid pressure of the front wheels (hereinafter referred to as the rear wheel hydraulic pressure rising gradient suppression control). A brake fluid pressure control device having a fluid pressure rising gradient suppression control means is described. In the brake fluid pressure control device described in this publication, when the deceleration of the vehicle becomes larger than a set value, the rear wheel hydraulic pressure rise gradient suppression control is started, and when the deceleration becomes smaller than the set value, the suppression control is terminated. It is supposed to be.

[0003]

However, according to the brake fluid pressure control device described in the above publication, there is a problem that a sense of discomfort due to the entry of the brake pedal is large. When the vehicle deceleration becomes equal to or less than the set value, the rear wheel hydraulic pressure rise gradient suppression control is terminated, and at that time, the brake pedal suddenly enters. The vehicle is
Normally, the deceleration becomes smaller than the set value when the vehicle stops, because the brake pedal is decelerated and stopped at a constant deceleration while the brake pedal is being depressed.

On the other hand, if the rear wheel hydraulic pressure rise gradient suppression control is terminated when the driver releases the brake pedal, the brake pedal does not enter, so that the driver feels less or less uncomfortable. be able to.
However, in most cases, the depression of the brake pedal is canceled after the rear wheel hydraulic pressure rise gradient suppression control is started (after the vehicle starts to be decelerated at the deceleration equal to or higher than the set value). This is the case where the vehicle starts after stopping, and in that case, the time during which the rear wheel hydraulic pressure rise gradient suppression control is continuously performed becomes extremely long. It is wasteful that the rear wheel hydraulic pressure rise gradient suppression control is performed during the stop without necessity. Furthermore, if the rear wheel hydraulic pressure rise gradient suppression control means is provided with an actuator such as an electromagnetic valve and is energized during suppression control, the energization time becomes extremely long, and energy is wasted. This causes problems such as shortening of the life of the actuator.

An object of the present invention, while shortening the rear wheel hydraulic pressure increase gradient suppression control duration, to together when alleviate discomfort due to entry of the brake pedal felt by the driver, the brake fluid pressure with an anti-lock control means It is an object of the control device to improve braking stability at the end of the rear wheel hydraulic pressure rise gradient suppression control.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a brake fluid pressure control device having a rear wheel pressure rise gradient suppression control device, comprising: (a) vehicle speed detection means for detecting vehicle speed; (B) detected by the vehicle speed detecting means
When the vehicle speed is higher than the minimum allowable vehicle speed,
When the wheel slip becomes excessive, the brake fluid pressure of the wheel
Control to maintain wheel slip in an appropriate range
(C) the vehicle speed detected by the vehicle speed detecting means is the minimum allowable vehicle speed.
A hydraulic pressure rise suppression control ending means for terminating the control by the rear wheel hydraulic pressure rise suppression control means when the speed decreases to the following set speed is provided.

[0007]

In the brake fluid pressure control device of the present invention, the control by the rear wheel fluid pressure rise gradient suppression control means for suppressing the rise gradient of the brake fluid pressure of the rear wheel with respect to the gradient of the brake fluid pressure of the front wheel, When the vehicle speed falls below the set value, the vehicle speed is ended by the hydraulic pressure rise gradient suppression control ending means. The rear wheel hydraulic pressure rise gradient suppression control means may be a means for reducing the rising gradient of the brake fluid pressure of the rear wheel with respect to the brake fluid pressure of the front wheel, or a means for holding the braking force of the rear wheel. Good. If the brake fluid pressure of the rear wheel is held, the rising gradient of the brake fluid pressure of the rear wheel becomes zero, so that the rising gradient of the brake fluid pressure of the front wheel is suppressed. In any case, according to the rear wheel hydraulic pressure rise gradient suppression control means, the braking force distribution to the front and rear wheels can be made closer to the ideal braking force distribution line.

For example, if the set value is set to a very small value immediately before the vehicle body stops, the time when the rear wheel hydraulic pressure rise gradient suppression control ends and the time when the vehicle turns back immediately before the vehicle stops almost coincide. Will be. For this reason, the brake pedal enters when the vehicle rolls back, so that the driver does not feel much discomfort even if the brake pedal enters. Further, the control time can be made shorter than when the control by the rear wheel hydraulic pressure rise gradient suppression control means is terminated when the brake pedal is released after the vehicle stops.

When the rear wheel hydraulic pressure rise gradient suppression control is terminated, the rear wheel hydraulic pressure is rapidly increased, so that the antilock control is easily started. However, at this time, the vehicle speed is very small, which is equal to or less than the set value. Therefore, when the antilock control is performed, the braking stability may be reduced.

On the other hand, the brake hydraulic pressure according to the present invention
In the control device, the rear wheel hydraulic pressure rise
Set speed below the minimum permissible vehicle speed at which ticlock control is performed
It is made to be terminated when it becomes lower than the degree
After the rear wheel hydraulic pressure rise gradient suppression control ends,
It is possible to avoid starting the lock control.

[0011] Incidentally, the anti-lock control means, as long as it maintains the slip of the rear wheels in the proper range, may be configured to maintain the slipping of both the front and rear wheels within a proper range . Further, at the end of the rear wheel hydraulic pressure rise gradient suppression control, only the antilock control for the rear wheel may not be performed, or the antilock control for both the front wheel and the rear wheel may not be performed.

[0012]

According to the brake fluid pressure control device of the present invention, the uncomfortable feeling due to the entry of the brake pedal can be reduced while shortening the control duration of the rear wheel hydraulic pressure rise gradient suppression control as much as possible. In addition , the braking stability at the end of the rear wheel hydraulic pressure rise gradient suppression control can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An antilock control device as a brake fluid pressure control device according to one embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 3, 10 is a brake pedal, 12 is a master cylinder as a hydraulic pressure source, and 14 to 20 are wheel cylinders. When the brake pedal 10 is depressed, a hydraulic pressure corresponding to the depressing force is generated in the two hydraulic chambers of the master cylinder 12,
These are supplied to the wheel cylinders 14 to 20 of the left front wheel 22, right rear wheel 24, right front wheel 26, and left rear wheel 28, respectively. One hydraulic chamber of master cylinder 12 and wheel cylinder 1
In the middle of the liquid passages 32, 34 connecting the
Position solenoid valves 36 and 38 (hereinafter, referred to as pressure intensifier valves) are provided, and in the middle of fluid passages 40 and 42 connecting the other hydraulic chambers with the wheel cylinders 18 and 20, pressure intensifier valves 4 are also provided.
4, 46 are provided.

In the middle of the fluid passages 50 and 52 connecting the wheel cylinders 14 and 16 and the reservoir 48,
Position electromagnetic valves 54 and 56 (hereinafter, referred to as pressure reducing valves) are provided, and pressure reducing valves 62 and 6 are provided in the middle of the liquid passages 58 and 60 connecting the wheel cylinders 18 and 20 and the reservoir 48.
4 are provided. A pump 72 provided with a motor 70 and check valves 74 and 76 are provided in the middle of the liquid passages 66 and 68 connecting the reservoir 48 and the master cylinder 12. During antilock control, the reservoir 4
The hydraulic fluid in 8 is pressurized and returned to master cylinder 12.

A bypass passage 78 is provided for bypassing the pressure-increasing valves 36, 38, 44, 46, and a check valve 80 is provided in the middle of the bypass passage 78. When the brake is released, the wheel cylinders 14-20
The brake fluid inside is quickly returned to the master cylinder 12 via the bypass passage 78 and the check valve 80.

The pressure increasing valves 46 and the pressure reducing valves 64 for the left and right rear wheels 28 and 24, and the pressure increasing valves 38 and 56 are collectively referred to as a braking force control actuator 81. The valve 54, the pressure increasing valve 44, and the pressure reducing valve 62 are collectively referred to as a braking force control actuator 82. Since the braking force control actuators 81 and 82 are the same, the braking force control actuator 81 for the left and right rear wheels 28 and 24 will be representatively described. The braking force control actuator 81 is always in a pressure-increasing state as shown in FIG.
Are communicated with the hydraulic chamber of the master cylinder 12. When the pressure-increasing valves 46 and 38 and the pressure-reducing valves 64 and 56 are switched together by excitation of a solenoid (not shown), the braking force control actuator 81 enters a pressure-reducing state, disconnects the wheel cylinders 20 and 16 from the master cylinder 12, and communicates with the reservoir 48. Let it. When the pressure increasing valves 46 and 38 are switched and the pressure reducing valves 64 and 56 are maintained at the original positions in the drawing, the braking force control actuator 81 is in a holding state, and the wheel cylinders 20 and 16 are also moved from the master cylinder 12 to the reservoir 48. Also shut off.

The braking force control actuators 81 and 82 are controlled based on a command from a control device 83. Control device 83
Is provided with a computer 84 for calculating vehicle body speed and the like, a hydraulic control computer 86 for antilock control and control for suppressing a rear wheel hydraulic pressure rise gradient, and the like.

The input unit of the computer 84 for calculating the vehicle speed and the like is connected to wheel speed sensors 90 to 96 for detecting the rotational speeds of the wheels 22 to 28, and the output unit is connected to a hydraulic control computer 86. I have. The ROM stores the wheel speed, wheel acceleration, front wheel minimum wheel speed, rear wheel minimum wheel speed, estimated vehicle speed, vehicle deceleration, vehicle slip rate, etc., based on the output signals of the wheel speed sensors 90 to 96. Is stored.

The input unit of the hydraulic control computer 86 includes:
In addition to the computer 84 for calculating the vehicle speed and the like, a brake switch 98 for outputting an ON signal when the brake pedal 10 is depressed is connected, and solenoids and motors 70 of braking force control actuators 81 and 82 are shown at the output part. Not connected via a drive circuit. Also, R
The OM stores a main program (not shown), an antilock control program, a rear wheel hydraulic pressure rise gradient suppression control program shown in the flowchart of FIG.

The hydraulic brake device constructed as described above operates as follows. The anti-lock control is performed independently for each of the wheels 22 to 28. In the antilock control, when the estimated vehicle speed is equal to or higher than the second set value Bkm / h, the output signal of the brake switch
N, and is started when the slip ratio of each of the wheels 22 to 28 becomes excessive. Thereafter, the braking force control actuator 8 is controlled based on both the slip rate and the wheel acceleration.
1 is controlled, and the hydraulic pressure of the wheel cylinder is controlled so that the slip ratio falls within an appropriate range. The motor 70 is driven while the antilock control is being performed, and the
Is pressurized and returned to the master cylinder 12. When the anti-lock control is performed on the left and right rear wheels 28 and 24, the anti-lock control flag is set.

The rear wheel hydraulic pressure rise gradient suppression control is performed by the left and right rear wheels 2.
8 and 24 are performed simultaneously. The rear wheel hydraulic pressure rise gradient suppression control is started when a start condition described later is satisfied, and when the solenoids of the pressure increasing valves 38 and 46 and the pressure reducing valves 56 and 64 are excited, the braking force control actuator 81 is held. Is switched to. As a result, the hydraulic pressure of the wheel cylinders 20, 16 is maintained, so that the rising gradient of the hydraulic pressure of the wheel cylinders 20, 16 becomes
This is suppressed by the rising gradient of the hydraulic pressure of the wheel cylinders 24, 28 of the left and right front wheels 22, 26. in this way,
If the hydraulic pressures of the wheel cylinders 20 and 16 of the left and right rear wheels 28 and 24 are maintained, the braking force to the front and rear wheels is distributed in a state close to the ideal braking force distribution, and the early locking of the rear wheels is performed. It is avoided and braking stability is improved. Further, if the termination condition described later is satisfied, the rear wheel hydraulic pressure rise gradient suppression control is terminated.

In this embodiment, the left and right rear wheels 28, 24
In contrast, the anti-lock control and the rear wheel hydraulic pressure rise gradient suppression control are not performed simultaneously. When the anti-lock control is being performed on the rear wheel, the rear wheel hydraulic pressure rise gradient suppression control is not started, and the rear wheel hydraulic pressure rise gradient suppression control is performed while the rear wheel hydraulic pressure rise gradient control is being performed. When the antilock control is started for the wheels, the braking force control actuator 81 is controlled based on a command from the antilock control computer 86.

As shown in FIG. 2, the start condition of the above rear wheel hydraulic pressure rise gradient suppression control is that the antilock control is not performed for one of the left and right rear wheels 28, 24. ) And the vehicle deceleration is greater than or equal to a set value of 0.5 G, or the vehicle is turning (when the minimum wheel speed of the front wheels−the minimum wheel speed of the rear wheels> 2 km / h) and the deceleration is 0.3 G or more. And the starting condition (b) is satisfied. In the present embodiment, the starting hydraulic pressure of the rear wheel hydraulic pressure rise gradient suppression control is determined based on the deceleration.
Since the deceleration is approximately in accordance with the magnitude of the braking force, it is the same as that determined based on the hydraulic pressure of the wheel cylinders 14 to 20. During turning, the starting hydraulic pressure is determined to be lower.

As shown in FIG. 2, the end condition (a) is that the output signal of the brake switch 98 has changed from ON to OFF, and the condition that the vehicle deceleration is equal to or less than the set value 0.3G continues for 48 msec or more. (B), the estimated vehicle speed V is equal to the first set value Akm / h (in this embodiment, 3 to
6km / h) less than end condition (c), left and right front wheels 2
The condition is satisfied when any one of the end conditions (d) that the anti-lock control is performed on any one of the conditions 2 and 24 is satisfied.

The termination condition (a) is satisfied when the depression of the brake pedal 10 is released. In other words, if the depression of the brake pedal 10 is released, the braking force becomes unnecessary, and naturally the rear wheel hydraulic pressure rise gradient suppression control becomes unnecessary. Further, if the depression of the brake pedal 10 is released, the brake pedal 10 does not enter, so that the driver does not feel uncomfortable even if the hydraulic pressure rise gradient suppression control is terminated.

The termination condition (b) is, for example, when the pumping brake operation is continuously performed for a predetermined time, or
This condition is satisfied when the brake pedal 10 is continuously released for a certain period of time. In this case, the deceleration becomes smaller,
It is not necessary to suppress the rising gradient of the brake fluid pressure of the rear wheels. Since the driver has not depressed the brake pedal 10, there is almost no discomfort due to the entry.

The termination condition (c) is satisfied when the estimated vehicle speed V falls below the first set value Akm / h. The first set value Akm / h is the vehicle speed at the time when the swinging occurs immediately before the vehicle stops. At this point, the rear wheel hydraulic pressure rise gradient suppression control is terminated, and even if the brake pedal 10 enters, the driver does not feel much discomfort. This means
It has been confirmed by experiments using actual vehicles.

The first set value Akm / h is very small,
Since the value is smaller than the second set value Bkm / h as the minimum allowable vehicle speed for performing the antilock control, the antilock control is not started in response to the end of the rear wheel hydraulic pressure rise gradient suppression control. If the driver keeps depressing the brake pedal 10, the vehicle decelerates at a constant deceleration,
It often stops. In that case, the termination condition (c) is satisfied immediately before the stop, and the rear wheel hydraulic pressure rise gradient suppression control is terminated. The braking force of the left and right rear wheels 28, 24 is increased by the end of the rear wheel hydraulic pressure rise gradient suppression control, and the slip ratio of the left and right rear wheels 28, 24 may increase beyond an appropriate range. Control is not started.

If the deceleration is reduced by changing the operation to the pumping brake operation during braking or by depressing the brake pedal 10, the termination condition (b)
Holds. In this case, since the braking force is sufficiently small, the antilock control is not started at the end of the rear wheel hydraulic pressure rise gradient suppression control.

That is, when the brake pedal 10 is depressed to start the rear wheel hydraulic pressure rise gradient suppression control,
At the latest, it will be terminated when the vehicle swings back immediately before stopping. If the termination condition does not include the condition (c) and the rear wheel hydraulic pressure rise gradient suppression control is terminated in response to the release of the depression of the brake pedal 10 at the time of starting after the vehicle stops, In some cases, the duration of the rear wheel hydraulic pressure rise gradient suppression control becomes very long, and the energization time of the solenoid of the braking force control actuator 81 becomes very long. Prolonged energization of the solenoid is not preferable because it wastes energy and leads to a shortened life due to overheating of the solenoid. On the other hand, in this embodiment, since the condition (c) is added to the termination condition, this disadvantage is avoided.

The end condition (d) is determined when the start condition of the rear wheel hydraulic pressure rise gradient suppression control is satisfied while the anti-lock control is being performed on the left and right front wheels 22 and 26, or Left and right front wheels 22, 26 during pressure rise gradient suppression control
Is satisfied when the anti-lock control is started. In such a case, since the hydraulic pressure of both the front and rear wheel cylinders is suppressed, the braking force of the entire vehicle is likely to be insufficient, and the rear wheel hydraulic pressure increase gradient suppression control is not performed. Is desirable. However, when the anti-lock control is performed on the front wheels, it is highly possible that the anti-lock control is also started on the rear wheels. Are terminated and the wheel cylinders 20, 16 of the left and right rear wheels 28, 24 are terminated.
If the hydraulic pressure is increased, the possibility is further increased.

Therefore, in the present embodiment, the hydraulic pressure of the wheel cylinders 20, 16 of the left and right rear wheels 28, 24 with respect to time is increased by alternately switching the braking force control actuator 81 between the pressure increasing state and the holding state. The gradient is suppressed, and the antilock control for the left and right rear wheels 28, 24 is hardly started. Even if the anti-lock control is started and the pressure reduction control is performed, if the rising gradient of the hydraulic pressure of the wheel cylinders 20 and 16 with respect to time is suppressed, the pressure reduction amount at the start of the anti-lock control is reduced. And the delay in the control can be reduced.

Hereinafter, the hydraulic control of the wheel cylinders 20, 16 of the left and right rear wheels 28, 24 will be described more specifically with reference to the flowchart of FIG. Step 1 (hereinafter S
Abbreviated as 1. In the same manner for other steps), it is determined whether or not to perform an arithmetic process for the rear wheel hydraulic pressure rise gradient suppression control. In this embodiment,
The arithmetic processing for the antilock control of each of the four front, rear, left and right wheels and the arithmetic processing for the rear wheel hydraulic pressure rise gradient suppression control common to the left and right rear wheels 28, 24 are sequentially performed by one computer. Therefore, it is determined whether or not a command indicating that the arithmetic processing for the rear wheel hydraulic pressure rise gradient suppression control should be performed is created when the hydraulic pressure control computer 68 executes the main program.

The order in which the arithmetic processing for the rear wheel hydraulic pressure rise gradient suppression control should be performed is determined.
If it is ES, in S2, it is determined whether or not the antilock control flag is set for the left and right rear wheels 28, 24, that is, whether or not the start condition (a) is satisfied. If it is not set, it means that the start condition (a) is satisfied.
In 3, it is determined whether or not the rear wheel pressure rise gradient suppression control is being performed.

On the other hand, when it is not in the order to perform the arithmetic processing for the rear wheel hydraulic pressure rise gradient suppression control, or when the antilock control flag is set, it is determined as NO in S1 or S2. Then, this routine is terminated. In the latter case, the hydraulic pressure of the wheel cylinders 20, 16 of the left and right rear wheels 28, 24 is RO
The control is performed based on a command created as a result of execution of an anti-lock control program (not shown) of M.

When the rear wheel hydraulic pressure rising gradient suppression control is not being performed, S3
If NO is determined in step S4, it is determined in step S4 whether the start condition (b) that the deceleration is equal to or greater than the different decelerations during straight running and turning of the vehicle is satisfied. Initiation condition
If (b) is satisfied, YES is determined, and in S5, a command to switch the braking force control actuator 81 to the holding state is created and output. In response to this command, the braking force control actuator 81 is switched to the holding state, the wheel cylinders 20, 16 are shut off from both the master cylinder 12 and the reservoir 48, and the hydraulic pressure is held. When the start conditions (a) and (b) are satisfied, the rear wheel hydraulic pressure rise gradient suppression control is started. Initiation condition
If (b) is not satisfied and the determination is NO, this routine is terminated.

On the other hand, if it is determined in S3 that the rear wheel hydraulic pressure rise gradient suppression control is being performed and the determination is YES, the process proceeds to S6 to S6.
In S9, it is determined whether or not the end conditions (a) to (d) are satisfied. If the brake pedal 10 is released or loosened during braking, the termination condition
If (a) or the condition (b) is satisfied and the depressed state is maintained until the vehicle stops, the end condition (c) is satisfied, and in S10, the braking force control actuator 81 is changed from the held state to the pressure increasing state. Is switched to. The wheel cylinders 20, 16 are communicated with the hydraulic pressure chamber of the master cylinder 12, and the hydraulic pressure of the wheel cylinders 20, 16 is made equal to the hydraulic pressure of the wheel cylinders 14, 18 of the left and right front wheels 22, 26.

If the anti-lock control is performed on the left and right front wheels 22 and 26 and the end condition (d) is satisfied, the braking force control actuator 81 is started at S11.
Are set to the pulse pressure increasing state. That is, the state is alternately switched between the holding state and the pressure increasing state at predetermined intervals,
As a result, the rising gradient of the hydraulic pressure of the wheel cylinders 20, 16 with respect to time is suppressed. If none of the end conditions (a) to (d) is satisfied, S5 is executed, and the holding state of the braking force control actuator 81 is maintained.

As described above, according to the hydraulic brake device provided with the antilock control device of the present embodiment, the brake pedal can be controlled at the end of the rear wheel hydraulic pressure rise gradient suppression control while keeping the control duration as short as possible. The discomfort felt by the driver due to the entry of 10 can be reduced. In addition, since the start of the antilock control at the end of the rear wheel hydraulic pressure rise gradient suppression control is avoided, the braking stability is improved. Further, since the rear wheel hydraulic pressure rise gradient suppression control can control the braking force of the front and rear wheels to a state close to the ideal distribution of the braking force,
It is possible to obtain the maximum braking force by favorably preventing the rear wheel from being locked. In addition, since an expensive proportioning / bypass valve is not required, the cost can be reduced accordingly. Further, in this embodiment, the anti-lock control prohibiting means is constituted by a portion of the hydraulic control computer 86 which executes S8 and S10.

In the above embodiment, since the start of the rear wheel hydraulic pressure rise gradient suppression control is determined based on the magnitude of the vehicle deceleration, there is an advantage that a hydraulic pressure sensor is not required.
The hydraulic pressure of the wheel cylinders 14 to 20 or the ta cylinder 12 may be detected, and the hydraulic pressure may be determined based on the detection result.

Further, in the above embodiment, the hydraulic pressure of the wheel cylinders 20, 16 of the left and right rear wheels 28, 24 is maintained by the rear wheel hydraulic pressure rising gradient suppression control means. The control may be performed in proportion to the hydraulic pressure of the master cylinder 12. By controlling the pressure increasing valves 38 and 46 and the pressure reducing valves 56 and 64, the rear wheel cylinder 2
The hydraulic pressures 0 and 16 are controlled so as to be proportional to the hydraulic pressure of the master cylinder 12, that is, the hydraulic pressures of the front wheel cylinders 14 and 18, and are closer to the ideal braking force distribution as compared with the above embodiment. It can be in a state.

In the above embodiment, the antilock control is performed independently for each wheel. However, at least one of the control for the left and right front wheels and the control for the left and right rear wheels may be commonly performed. It is possible. Then, at the end of the rear wheel hydraulic pressure rise gradient suppression control, even if both the antilock control for the left and right front wheels and the antilock control for the left and right rear wheels are not performed, only the control for the left and right rear wheels is not performed. It may be. Further, in the brake fluid pressure control device in which the start of the anti-lock control for the rear wheel is allowed during the rear wheel hydraulic pressure rise gradient suppression control, the rear wheel The antilock control will be terminated.

Further, in the above embodiment, the first set value Akm / h is smaller than the second set value Bkm / h.
The first set value Akm / h and the second set value Bkm / h may have the same magnitude. If the anti-lock control for the rear wheels and the rear wheel hydraulic pressure rise gradient suppression control are performed in parallel, the anti-lock control will be terminated at the end of the rear wheel hydraulic pressure rise gradient suppression control. Further, a rear wheel hydraulic pressure rise gradient suppression control flag may be provided, and the anti-lock control may be terminated when the rear wheel hydraulic pressure rise gradient suppression control flag is reset.

Further, in the hydraulic brake apparatus of the above embodiment, the braking force control actuators are the pressure increasing valve and the pressure reducing valve. However, even if the actuator is a three-position solenoid valve, it is an actuator that changes the volume of the variable volume chamber. There may be.

[0045] In addition, the anti-lock control computer is not essential, control may be carried out by independent control device and the anti-lock control. When the rear wheels are drive wheels, they can be shared with a traction control control device, and a dedicated control device can be provided to suppress the hydraulic pressure of the rear wheel cylinder. Thus, in the former case as well as in the latter case, the cost can be reduced by providing a proportioning valve or a proportioning / bypass valve.

In addition, it is also possible to configure the rear wheel hydraulic pressure rise gradient suppression control means mainly by a proportioning valve. For example, a normally open solenoid valve is provided in parallel with the proportioning valve, and when the rear wheel hydraulic pressure rise gradient suppression control is required (for example, when the load is small), the solenoid is excited and closed. Is to open. In this case, when the vehicle is decelerated with the solenoid on-off valve closed, it is desirable to open the solenoid on-off valve immediately before stopping from the viewpoints of energy saving and extension of the life of the solenoid on-off valve.

The present invention is also applicable to the case where the normally open electromagnetic on-off valve is always closed when the vehicle is decelerated to perform the rear wheel hydraulic pressure rise gradient suppression control. For example, from the viewpoint of minimizing damage to the occupant in a rear-end collision, it is desirable to be able to maintain the vehicle in a stopped state with as large a braking force as possible. Since there is no load movement, it is better to make the rear wheels exhibit the maximum braking force. Alternatively, it is better to obtain a sufficient braking force for the entire vehicle while reducing the load on the front wheel brake as much as possible.

Although not specifically exemplified, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a rear wheel hydraulic pressure rise gradient suppression control program stored in a ROM of a hydraulic control computer of an antilock control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing start conditions and end conditions of rear wheel hydraulic pressure rise gradient suppression control by the antilock control device.

FIG. 3 is an overall circuit diagram of a hydraulic brake device including the antilock control device.

[Explanation of symbols]

 Reference Signs List 10 brake pedal 16, 20 wheel cylinder 24, 28 left and right rear wheels 38, 46 pressure increasing valve 56, 64 pressure reducing valve 81 braking force control actuator 83 control device 86 hydraulic pressure control computer 90-96 wheel speed sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-218453 (JP, A) JP-A-5-278585 (JP, A) JP-A-60-209355 (JP, A) 152764 (JP, U) Japanese Patent Application No. 1-47317 (Japanese Utility Model Application No. 2-1366757) Microfilm photographing the contents of the specification and drawings attached to the application (JP, U) Japanese Utility Model Application No. 63-104825 (JP, U) (58) Field of investigation (Int. Cl. ⁷ , DB name) B60T 8/26 -8/28

Claims (1)

(57) [Claims] 1. A brake fluid pressure control device comprising rear wheel fluid pressure rise gradient suppression control means for controlling a rise gradient of a brake fluid pressure of a rear wheel with respect to a rise gradient of a brake fluid pressure of a front wheel. Vehicle speed detecting means for detecting the vehicle speed and the vehicle speed detected by the vehicle speed detecting means.
When the vehicle speed is lower than the low
If the brakes become excessive, control the brake fluid pressure on the wheels.
Anti-slip to maintain wheel slip in the proper range
Tsu and click control unit, the vehicle speed detecting vehicle speed before detected by means
If the speed drops below the minimum allowable vehicle speed
And a hydraulic pressure rise suppression control ending means for ending the control by the rear wheel hydraulic pressure rise suppression control means.