JP2000289594A - Brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow smooth shift to braking pressure control based on master cylinder pressure, while ensuring running stability, in the event that braking pressure generating means or pressure control valves are in abnormal while braking pressure is being controlled by the pressure control valves. SOLUTION: A master cylinder 1 is connected to wheel cylinders 5FL-5RR via first solenoid on-off valves 3FL-3RR and the braking pressure of a braking pressure generating mechanism 6 is supplied to the supply sides of pressure control valves 11FL-11RR via a second solenoid on-off valve 10. The output sides of the pressure control valves are connected to the wheel cylinders and the return sides of the pressure control valves are connected to a reservoir 1a via a third solenoid on-off valve 12. The output pressure of the master cylinder 1 is supplied to a stroke simulator 14 via a fourth solenoid on-off valve 13, and if the braking pressure generating mechanism 6 is in abnormal, pressure reducing control is performed so that a first variation is attained during pressure reduction time in which a braking pressure command value for each of the pressure control valve 11FL-11RR is set. Thereafter, the first solenoid on-off valve is opened and the second to fourth solenoid on-off valves are closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control device for generating a braking force when a brake pedal is depressed by controlling a braking pressure of a braking pressure generating means different from a master cylinder pressure.

[0002]

2. Description of the Related Art As a conventional brake control device, for example, one described in Japanese Patent Application Laid-Open No. Hei 6-191393 is known. In this conventional example, a hydraulic pressure control device is a proportional electromagnetic hydraulic pressure control device that controls the hydraulic pressure of a hydraulic pressure source to a height proportional to a current supplied to a coil, and detects an operation amount of a brake operation member. Operation amount detection means for performing
The control means sets the target wheel cylinder pressure based on the detection result of the operation amount detection means, and controls the supply current to the coil of the proportional electromagnetic hydraulic pressure control device so that the hydraulic pressure of the hydraulic pressure source is adjusted to the target wheel cylinder pressure. In the wheel cylinder, a hydraulic pressure of a value commensurate with the operation amount of the brake operation member, for example, a liquid pressure proportional to the operation amount or a vehicle body deceleration proportional to the operation force is obtained. Pressure is supplied to suppress wheel rotation. If an abnormality occurs in the electrically controlled hydraulic brake and the hydraulic pressure from the hydraulic pressure source cannot be supplied to the wheel cylinder, switch to the mechanical brake that supplies the hydraulic pressure from the master cylinder directly to the wheel cylinder. I have to.

[0003]

However, in the above-mentioned conventional brake control device, when an abnormality occurs in the electric control type hydraulic brake, the hydraulic pressure from the master cylinder is directly supplied to the wheel cylinder. It is designed to switch to a brake, and with an electrically controlled hydraulic brake,
Hydraulic pressure that is proportional to the brake operation amount and hydraulic pressure that provides deceleration proportional to the brake operation force are supplied to the wheel cylinder, so the hydraulic pressure of the wheel cylinder controlled by this electrically controlled hydraulic brake is The value becomes higher than the hydraulic pressure from the master cylinder, and when an abnormality occurs in the electric control type hydraulic brake and switching to the mechanical brake, the hydraulic effect of the wheel cylinder changes greatly and the braking effect changes greatly. There is an unsolved problem of giving an uncomfortable feeling to the driver.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and controls a pressure control valve based on a braking pressure command value to generate a braking pressure for a braking means. It is possible to reliably suppress the driver from feeling uncomfortable when the brake cylinder generates an abnormality and the master cylinder pressure output from the master cylinder is directly supplied to the braking means. It is intended to provide a simple brake control device.

[0005]

According to a first aspect of the present invention, there is provided a brake control apparatus comprising: a master cylinder for outputting a working fluid having a braking pressure corresponding to an amount of depression of a brake pedal; Braking means for generating a braking force, a stroke simulator for absorbing a working fluid output from the master cylinder, a braking pressure generating means having a fluid pump and an accumulator for accumulating the discharge pressure thereof, A pressure control valve that controls the pressure for braking generated by the means to reduce the pressure based on the braking pressure command value and outputs an arbitrary braking pressure to the braking means; and a pressure control valve interposed between the master cylinder and the braking means. 1, an electromagnetic on-off valve, a second electromagnetic on-off valve interposed between the accumulator and the pressure control valve, a return port of the pressure control valve, and a reservoir of the master cylinder. A third solenoid on-off valve interposed therebetween, a fourth solenoid on-off valve interposed between the master cylinder and the stroke simulator, and a brake depression amount detecting means for detecting a depression amount of the brake pedal; Abnormality detecting means for detecting a low pressure abnormality of the braking pressure generating means,
The pressure control valve, the first solenoid on-off valve, the second solenoid on-off valve, and the third solenoid on-off valve based on at least the brake pedal depression amount detected by the brake depression amount detection means and the detection result of the abnormality detection means. A braking control means for controlling a fourth electromagnetic on-off valve and a fluid pump, wherein the braking control means is configured to perform the second control when the abnormality detection means detects that the braking pressure generation system is normal. The first solenoid on / off valve is controlled to be in a closed state, the second to fourth solenoid on / off valves are respectively controlled to be in an open state, and a ratio of a brake pressure command value output to the pressure control valve to the brake pedal depression amount is predetermined. When the abnormality detecting means detects an abnormality of the braking pressure generating means, the ratio of the braking pressure command value to the brake pedal depression amount is reduced by a first change amount during a predetermined time. Let After a predetermined time, the the first switch valve opened state of, and the second to fourth electromagnetic on-off valve is characterized in that is configured to respectively control the closed state.

In the invention according to the first aspect, when the braking pressure generating means is normal, the first solenoid on-off valve is closed by the braking control means, so that the master output from the master cylinder is provided. When the cylinder pressure is cut off from being supplied to the braking means, and the fourth solenoid on-off valve is opened, the master cylinder pressure is absorbed by the stroke simulator, and a predetermined pedal depression feeling is obtained. When the second and third solenoid on-off valves are opened and a brake pressure command value set to a predetermined ratio times the brake pedal depression amount is output to the pressure control valve, the brake pedal depression amount from the pressure control valve is increased. Is supplied to the braking means, and a braking force corresponding to the driver's required deceleration is generated.

When an abnormality occurs in the fluid pump, the accumulator or the like from the normal state of the braking pressure generating means and the generated braking pressure decreases, the braking pressure command value output to the pressure control valve corresponds to the brake depression amount. The ratio is reduced so as to be the first change amount during the predetermined time, and in response thereto, the braking pressure output from the pressure control valve, that is, the braking pressure of the braking means gradually decreases. When the braking pressure approaches the master cylinder pressure, the fourth solenoid valve is closed, so that the supply of the master cylinder pressure output from the master cylinder to the stroke simulator is interrupted. When the first solenoid on-off valve is opened, the master cylinder pressure output from the master cylinder is directly supplied to the braking means to secure the braking force.
At this time, the second and third solenoid on-off valves connected to the pressure control valve are also controlled to be closed, and the flow path reaching the braking pressure generating means and the reservoir via the pressure control valve is shut off. In this state, the braking pressure output from the pressure control valve to the braking means has decreased near the master cylinder pressure, and the pressure change that occurs in the braking means when switching from the braking pressure of the pressure control valve to the master cylinder pressure is suppressed. can do.

[0008] In the brake control device according to the second aspect, in the invention according to the first aspect, the brake control means may determine the predetermined time and the first amount of change when decreasing the braking pressure command value by changing the vehicle speed or the vehicle speed. The present invention is characterized in that the braking pressure command value is changed according to the braking pressure command value immediately before the start of the reduction. In the invention according to the second aspect, the predetermined time and the first amount of change in controlling to decrease the braking pressure command value are changed according to the vehicle speed or the braking pressure command immediately before the braking pressure command value is started to decrease. As a result, the brake pressure command value can be decreased by performing optimal reduction control of the brake pressure command value according to the driver's brake depression amount and the vehicle speed when an abnormality occurs.

In a third aspect of the present invention, in the first aspect of the present invention, the brake control means controls the brake pressure of the brake means to be constant while the brake pressure command value of the pressure control valve is being reduced. When it does not change until the time elapses, it is determined that the pressure control valve is abnormally depressurized, the fluid pump is stopped, and a brake pressure command value output to the pressure control valve on the opposite side of the vehicle from the corresponding pressure control valve in the left-right direction. The ratio of the braking pressure command value output to the pressure control valve on the opposite side in the vehicle front-rear direction with respect to the brake depression amount is controlled to decrease the ratio of the brake depression amount to the second variation amount during a predetermined time. It is characterized in that reduction control is performed so that the third change amount is larger than the second change amount during a predetermined time.

According to the third aspect of the present invention, when the braking pressure command value output to the pressure control valve is controlled to decrease and the braking pressure of the braking means does not change until a predetermined time elapses, the pressure control valve The port on the braking means side is connected to the supply port on the braking pressure generating means side and is judged not to be connected to the return port. A pressure control valve that has a pressure reduction abnormality due to securing a return flow path from the pressure control valve to the reservoir through the fluid pump and reducing the braking pressure at this time is smaller than when the pressure control valve is normal. Means that the ratio of the braking pressure command value output to the pressure control valve on the opposite side in the vehicle left-right direction to the brake depression amount is controlled so as to be a relatively small second change amount during a predetermined time. The difference between the braking forces of the left and right braking means is suppressed, and the reduction in these braking forces is output to the remaining pressure control valves. By setting the third variation larger than the second variation during the time, the braking force of the braking means corresponding to the third variation is reduced, and the fluctuation of the total braking force of the four wheels is suppressed.

Further, in the brake control device according to a fourth aspect of the present invention, in the invention according to the third aspect, the brake control means may include a predetermined time and a first time when the brake pressure command value is reduced.
To the third change amount in accordance with the braking pressure command value immediately before the vehicle speed or the braking pressure command value is started to be reduced, and the condition of the braking pressure command value immediately before the vehicle speed or the braking pressure command value is started to be reduced is one. In this case, the change amount is set so that the change amount becomes smaller in the order of the third change amount, the first change amount, and the second change amount.

In the invention according to the fourth aspect, the predetermined time when the brake pressure command value is controlled to decrease and the first to third times are controlled.
The amount of change is changed according to the vehicle speed or the braking pressure command value immediately before the braking pressure command value starts to be reduced, and optimal reduction control is performed according to the driving situation and the braking situation, and the braking immediately before the occurrence of the vehicle speed or the abnormality is performed. When the conditions of the pressure command value match,
By setting the third change amount to be larger and the second change amount smaller than the first change amount, the total braking force of the four wheels is matched when the pressure control valve is normal. .

Still further, according to a fifth aspect of the present invention, in the brake control device, the brake control means may be configured such that, while the brake pressure command value of the pressure control valve is being controlled to increase, the brake pressure of the brake means does not increase until a predetermined time elapses. The pressure increase of the pressure control valve is judged to be abnormal, and the ratio of the brake pressure command value output to the pressure control valve and the pressure control valve opposite to the pressure control valve in the vehicle left-right direction to the brake depression amount is determined for a predetermined time. And the ratio of the braking pressure command value output to the remaining pressure control valve to the brake pedal depression amount is smaller than the fourth variation amount during a predetermined time. It is characterized in that reduction control is performed so as to be the fifth change amount.

According to a fifth aspect of the present invention, in the first aspect of the present invention, if the braking pressure of the braking means does not increase until a predetermined time elapses during the increasing control of the braking pressure command value of the pressure control valve, It is determined that a pressure increase abnormality has occurred in which the port between the braking pressure generating means side and the braking means side port of the pressure control valve is in a disconnected state and the communication between the braking means side port and the reservoir side port is maintained. In this state, the pressure control valve in which the abnormality has occurred cannot perform the pressure decrease control, and it is determined that the amount of the pressure decrease is larger than that in the normal state of the pressure control valve. In addition, by increasing the fourth variation of the ratio of the braking pressure command value output to the pressure control valve on the opposite side of the vehicle left-right direction to the brake depression amount during a predetermined time, the left and right braking forces are balanced. Sa By controlling the fifth change amount of the ratio of the braking pressure command value to the brake depression amount during a predetermined period of time to output the amount of reduction of these braking forces to the remaining pressure control valves to a small value, Suppress fluctuations in total braking force.

According to a sixth aspect of the present invention, in the brake control device according to the fifth aspect, the braking control means includes a predetermined time when the braking pressure command value is reduced, and a first time, a fourth time, and a fifth time. The amount of change is changed in accordance with the braking pressure command value immediately before the vehicle speed or the braking pressure command value is started to decrease, and the condition of the braking pressure command value immediately before the vehicle speed or the braking pressure command value is started to be matched is matched. Sometimes, the amount of change is set to be smaller in the order of the fourth amount of change, the first amount of change, and the fifth amount of change.

According to the present invention, when a pressure increase abnormality occurs in the pressure control valve, the predetermined time when the braking pressure command value is decreased, the first, fourth, and fifth change amounts are determined. Is changed according to the vehicle speed or the braking pressure command value immediately before the occurrence of the abnormality, thereby controlling the optimal reduction of the braking pressure command value in accordance with the braking condition and the running condition, and at the same time, the vehicle speed or the braking pressure command value immediately before the occurrence of the abnormality. When the conditions of
The fourth change amount is increased with respect to the change amount of
By setting the amount of change to be small, the total braking force of the four wheels is matched when the pressure control valve is normal.

Further, the brake control device according to claim 7 is the brake control device according to any one of claims 1 to 6, wherein the brake depression amount detecting means includes:
The present invention is characterized in that it is configured to detect at least one of the depression force of the brake pedal and the master cylinder pressure. In the invention according to the seventh aspect, by detecting any one of the stroke of the brake pedal, the depression force of the brake pedal, and the master cylinder pressure, the required deceleration of the driver due to the depression of the brake pedal is reliably detected. Can be.

[0018]

According to the first aspect of the present invention, when an abnormality occurs in the braking pressure generating means and the system shifts to the fail-safe state in which the braking pressure of the master cylinder is directly supplied to the braking means, the pressure control is performed first. Controlling the ratio of the brake pressure command value output to the valve to the brake depression amount to be a first change amount during a predetermined time, and after a predetermined time has elapsed, the first electromagnetic on-off valve is opened, Since the second to fourth solenoid on-off valves are controlled to be in the closed state, the brake pressure supplied to the braking means from the pressure control valve approaches the master cylinder pressure, and then the supply of the braking pressure to the braking means is performed by the pressure control valve. Can be switched to the master cylinder, and a great change in pressure can be suppressed at the time of switching, so that it is possible to prevent the driver from feeling uncomfortable by gradually changing the braking force.

According to the second aspect of the present invention, when an abnormality occurs in the braking pressure generating means, a predetermined time and a predetermined time are set according to the vehicle speed at that time or the braking pressure command value to the pressure control valve immediately before the abnormality occurs. By changing the first change amount, it is possible to perform the optimal control of decreasing the braking pressure command value according to the braking condition or the driving condition. It is possible to obtain the effect that it is possible to prolong the operating time, secure as large a braking force as possible, and to surely prevent the driver from feeling uncomfortable.

Further, according to the third aspect of the invention, when the brake pressure command value output to the pressure control valve is controlled to decrease, a pressure reduction abnormality occurs in the pressure control valve, and the pressure control valve reduces the pressure. When it becomes impossible to perform the operation, the fluid pump is stopped, the return flow path is secured, and the brake pressure command output to the pressure control valve on the opposite side of the pressure control valve in the vehicle left-right direction from the pressure control valve in which the pressure reduction abnormality has occurred. The ratio of the brake pressure command value to the brake depression amount is controlled to decrease to a relatively small second change amount during a predetermined time, and the ratio of the braking pressure command value to the remaining pressure control valve to the brake depression amount is determined by a predetermined value. Since the decrease control is performed so that the third change amount is larger than the second change amount during the time, it is possible to suppress the occurrence of a difference between the braking forces of the left and right braking means, and to change the total braking force of the four wheels. Effect that can be suppressed It is obtained.

Further, according to the fourth aspect of the present invention, the predetermined time and the first time when the braking pressure command value is controlled to decrease are determined.
In addition, by changing the third variation amount according to the vehicle speed or the braking pressure command value immediately before the braking pressure command value is started to decrease, it is possible to perform the optimal reduction control according to the driving situation or the braking situation, and Alternatively, when the condition of the braking pressure command value immediately before the occurrence of the abnormality matches, the third change amount is set to be larger and the second change amount is set to be smaller with respect to the first change amount. Thus, the effect is obtained that the total braking force of the four wheels is matched when the pressure control valve is normal, so that the fluctuation of the total braking force can be reliably suppressed.

According to the fifth aspect of the present invention, when the brake pressure command value output to the pressure control valve is controlled to increase, a pressure increase abnormality occurs in the pressure control valve. When the pressure cannot be increased by the pressure control valve, the braking means side port and the reservoir side port of the pressure control valve are in communication with each other, and the pressure reduction control cannot be performed. Reduces the braking force on the opposite side to maintain the balance between the left and right braking forces, and secures by increasing the ratio of the braking pressure command value to the brake depression amount that outputs the reduced braking force to the remaining pressure control valves. As a result, the effect of suppressing the fluctuation of the total braking force of the four wheels can be obtained.

According to the sixth aspect of the present invention, the predetermined time and the first, fourth, and fifth amounts of change when the braking pressure command value is controlled to decrease are reduced by reducing the vehicle speed or the braking pressure command value. By changing the braking pressure command value immediately before the start, it is possible to perform the optimal reduction control according to the driving situation and the braking situation, and the conditions of the vehicle speed or the braking pressure command value immediately before the occurrence of the abnormality match. In this case, by setting the fourth change amount to be larger and the fifth change amount to be smaller than the first change amount, the total braking force of the four wheels can be properly controlled by the pressure control valve. The effect is obtained that the fluctuation of the total braking force can be reliably suppressed by matching the timing.

Further, according to the present invention, at least one of the stroke of the brake pedal, the depression force of the brake pedal, and the master cylinder pressure is detected, so that the driver's required deceleration due to the depression of the brake pedal is detected. Can be reliably detected.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment in which the present invention is applied to a rear-wheel drive vehicle. In the drawing, reference numeral 1 denotes a driven wheel, for example, a front wheel side and a drive wheel according to the amount of depression of a brake pedal 2. 2 for the rear wheel side as a wheel
It has a common pressurizing chamber for generating a working fluid of the front wheel side master cylinder pressure PMf and a working fluid of the rear wheel side master pressure PMr of the system, and supplies both master cylinder pressures PMf and PMr to the front wheel side output port p1 and the rear wheel, respectively. This is a master cylinder that outputs from the side output port p2.

The working fluid of the front wheel side master pressure PMf output from the master cylinder 1 is supplied to one of the input ports p1 of the first solenoid on-off valves 3FL and 3FR at the two-port two position.
And the working fluid of the rear-wheel master pressure PMr is also supplied to the first solenoid-operated switching valves 3RL and 3R at the same 2-port 2-position.
R is supplied to one input port p1 of R. The other ports p2 of the solenoid valves 3FL, 3FR and 3RL, 3RR are provided with wheel cylinders 5FL, 5FR as braking means for applying a braking force to the left and right front wheels 4FL, 4FR and the left and right rear wheels 4RL, 4RR. 5RL,
It is connected to 5RR.

Here, each of the solenoid valves 3FL to 3RR is set to the normal position when the control signal _SD supplied from the control unit 30 to be described later, which is supplied to the solenoid s1, is in the OFF state, and the ports p1 and p2 The ports p1 and p2 are cut off at the offset position where the control signal _SD supplied to the solenoid s1 is in the ON state.

On the other hand, the reservoir 1a of the master cylinder 1
Is connected to a braking pressure generating mechanism 6 as braking pressure generating means. The braking pressure generating mechanism 6 is connected to the reservoir 1
a hydraulic pump 8 as a fluid pump that is rotationally driven by an electric motor 7 having a suction side connected to the hydraulic pump 8, and a discharge side of the hydraulic pump 8 connected via a check valve 9 a for preventing backflow to the hydraulic pump 8. And an accumulator 9 serving as pressure accumulating means. The accumulator 9 accumulates the pressure through a second electromagnetic opening / closing valve 10 at a 2-port 2 position.
R and the supply ports ps of the pressure control valves 11RL and 11RR on the rear wheel side.

Here, when the accumulated pressure of the accumulator 9 becomes equal to or lower than a first set pressure set in advance, the hydraulic pump 8 is driven by the electric motor 7 being driven to rotate by a control unit 30 which will be described later. 9 is increased to a second set pressure higher than the first set pressure. The second electromagnetic valve 10, while the port p1 and the port p2 becomes normal position is blocked when the control signal S _E from the control unit 30 to be described later is supplied to the solenoid s1 is turned off, port p1 and switched to the offset position when the control signal S _E is supplied to the solenoid s1 is on
And p2 are communicated.

Further, as shown in FIG. 2, each of the pressure control valves 11FL to 11RR has a cylindrical shape with a bottom, and a small-diameter cylindrical portion 11a is formed on the bottom side and a large-diameter cylindrical portion 11b is formed on the opening side. A housing 11c, a spool 11f in which a small-diameter land portion 11d slidingly contacting the small-diameter cylindrical portion 11a and a large-diameter land portion 11e slidingly contacting the large-diameter cylindrical portion 11b are formed at a predetermined interval; 11f
Spring 11g as an elastic body interposed between the small-diameter land portion 11d for urging the housing toward the opening side and the bottom of the housing 11c, and a control according to a braking pressure command value supplied from a controller 30 described later. Signal CS _F, CS _R
And a solenoid 11h that generates an electromagnetic force that slides the spool 11e toward the bottom side against the return spring 11g in accordance with the current value.

Here, the large-diameter cylindrical portion 11 of the housing 11c
In b, when the exciting current value of the spool 11f supplied to the solenoid 11h is zero and the spool 11f takes the lowest pressure position shown by the one-dot chain line by the return spring 11g, the spool 11f is not opposed to the large-diameter land portion 11e and is opened. In this state, the spool 11f is moved leftward by the electromagnetic force of the solenoid 11h, and gradually shifts to the closed state, and is completely closed just before the maximum pressure position shown by the solid line where the exciting current value becomes maximum. A return port pd is formed,
When the spool 11f assumes the minimum pressure position, the small-diameter cylindrical portion 11a is closed by the small-diameter land portion 11d, and from this state, the spool 11f moves to the left and the return port pd is closed, and then gradually opened. Is formed, and the small-diameter cylindrical portion 11b of the large-diameter cylindrical portion 11b is further formed.
A control port pc is formed at the end on the a side.

[0032] Then, Each of the pressure control valve 11FL～11RR, as shown in FIG. 3, the braking pressure Pc _F and a value proportional to the control signal CS _FL and CS _FR becomes a current value inputted to the electromagnetic solenoid s1 It is configured to output Pc _R. Further, the pressure control valves 11FL, 11FR and 1
The control ports pc of 1RL and 11RR are directly connected to the wheel cylinders 5FL and 5FR and 5RL and 5RR, respectively, and the return port pd is connected to the reservoir 1a of the master cylinder 1 via the third solenoid on-off valve 12.

Further, a stroke simulator 14 is connected to the rear wheel output port p2 of the master cylinder 1 via a fourth solenoid valve 13. The stroke simulator 14 simulates the amount of oil consumed when the braking pressure is controlled by the pressure control valves 11FL to 11RR, and absorbs and consumes the amount of oil discharged from the master cylinder 1 to provide a brake. It is configured to ensure the feeling of stepping on the pedal.

As shown in FIG. 1, a specific configuration of the stroke simulator 14 is as follows. 17a and lower chamber 17b
A piston 18 defined in the two chambers, a coil spring 19 as an elastic body disposed in the lower chamber 17b to urge the piston 18 upward, and an inner peripheral surface of the housing 17 on an outer peripheral surface of the piston 18. Closely arranged seal member 20
The upper chamber 17 a is connected to the fourth electromagnetic on-off valve 13 via the input / output port 21.

The brake pedal 2 is provided with a stroke sensor 22 for detecting a stroke when the brake pedal 2 is depressed. A master pressure sensor 23 is provided as master cylinder pressure detecting means for detecting a master cylinder pressure PM of the working fluid to be performed.

Further, a pressure accumulation sensor 24 for detecting the accumulated pressure is provided in the accumulator 9, a current sensor 25 is provided in an energizing circuit of the electric motor 7, and a pipe near the wheel cylinders 5FL to 5RR is provided. Are wheel cylinder pressure sensors 26FL to 26RR for detecting braking pressure
The vehicle is further provided with a vehicle speed sensor 27 for detecting a vehicle speed V.

Then, the first solenoid on-off valves 3FL to 3R
R, second electromagnetic on-off valve 10, pressure control valves 11FL to 11
RR, third solenoid on-off valve 12 and fourth solenoid on-off valve 13
, Including, for example, a microcomputer
Control by the control unit 30 as control means
Is controlled. This control unit 30 includes
Pedal stroke PS and mass detected by the
Master cylinder pressure PM detected by the
The accumulator pressure PA detected by the sensor 24 and the current
Motor current IM detected by sensor 25, wheel cylinder
Braking pressure PW detected by pressure sensors 26FL to 26RR _FL~
PW_RRAnd the vehicle speed V detected by the vehicle speed sensor 27 are input.
Based on these, predetermined arithmetic processing is performed, and the first
Solenoid on-off valves 3FL to 3RR, second solenoid on-off valve 10, pressure
Force control valves 11FL to 11RR, third solenoid on-off valve 12 and
And the fourth solenoid on-off valve 13 is controlled.

That is, when the hydraulic pump 8 and the accumulator 9 operate normally and the braking pressure generating mechanism 6 is normal, the first solenoid valves 3FL to 3RR are closed, and the second and third solenoid valves 3FL to 3RR are closed. And fourth solenoid on-off valves 10, 12 and 1
3 is controlled to the open state, and the required deceleration is obtained based on the master cylinder pressure PM detected by the master pressure sensor 23. The braking is higher by a predetermined ratio than the master cylinder pressure PM which becomes the deceleration corresponding to the required deceleration. While calculating the pressure command value CP, when there are braking pressure command values from the other anti-lock brake control device 31, traction control device 32, and side slip suppression control device 33, the braking pressure command corrected by these braking pressure command values The value CP is calculated, and based on the calculated value, the pressure control valves 3FL to 3RR are controlled to be in a by-wire brake state. An abnormality occurs in the hydraulic pump 8 or the accumulator 9 and the braking pressure generating mechanism 6 normally generates the braking pressure. If not possible, the ratio of the braking pressure command value CP output to the pressure control valves 3FL to 3RR to the master cylinder pressure PM is set to a predetermined time Δt The first electromagnetic on-off valves 3FL to 3RR are opened, and the second, third, and fourth electromagnetic on-off valves are opened when a predetermined time Δt has elapsed. The minimum required braking force is ensured by switching to a backup brake state in which 10, 12, and 13 are closed.

Next, the operation of the above embodiment will be described with the braking control process and the abnormal process shown in FIGS. That is, the control unit 30 always executes the braking control process shown in FIG. 4, first reads the motor current IM detected by the current sensor 25 in step S1, and then proceeds to step S2 to execute the braking control process. It is determined whether or not the electric motor 7, that is, the hydraulic pump 8 is rotating normally, based on the value,
When the hydraulic pump 8 is normal, the process proceeds to step S3, where the accumulator pressure P
A is read, and then the process proceeds to step S4, where it is determined whether the accumulator pressure PA is equal to or higher than a preset low pressure abnormality threshold PA _S , and if PA ≧ PA _S, it is determined that the accumulator 9 is normal. Then, the process proceeds to step S5 to read the master cylinder pressure PM detected by the master pressure sensor 23.

Next, the process proceeds to step S6, in which the first solenoid on-off valves 3FL to 3RR are closed with a logical value "1".
Outputs a control signal S _D, and outputs a control signal S _E, S _F and S _G of a logical value "1" to the remaining second to fourth solenoid valve 10, 12 and 13 in the open state Then, the process proceeds to step S7. In step S7, a braking pressure command value CP (n) capable of generating a required braking force according to the deceleration requested by the driver by performing the calculation of the following equation (1) based on the master cylinder pressure PM. Is calculated and updated and stored in a predetermined storage area of the storage device, and then the process proceeds to step S8.

CP (n) = R.PM (1) where R is a preset magnification and is "1".
Is set to an arbitrary value exceeding “2.5”, for example.
You. In step S8, the above-described anti-lock blur
Rake control device 31, traction control device 32 and skidding
Braking pressure command value is input from the braking control device 33.
The braking pressure command value is input from these
If not, the process directly proceeds to step S10 and the storage device
Current value according to the braking pressure command value CP (n) stored in
Control signal CS_FF~ CS_RRFor each of the pressure control valves 11FL-1
Output to 1RR, brake pressure command value input from other control device
If so, the process proceeds to step S9, and the
Pressure command value BP from the brake control device 31_FL~
BP_RR, These braking pressure command values BP_FL~ B
P_RRTo the braking pressure command value CP (n) calculated in step S7.
Prioritized braking pressure command value CP_FL~ CP_RRAs storage device
Update storage in the specified storage area of the remaining traction control
With the braking pressure command value of the device 32 and the side slip suppression control device 33
In some cases, these braking pressure command values are calculated in step S7.
The value added to the issued braking pressure command value CP is used as a new braking pressure finger.
Quote CP_FL~ CP _RRTo the specified storage area of the storage device as
After the new storage, the process proceeds to step S10.

In step S10, the braking pressure command value CP stored in the predetermined storage area of the storage device is individually output to each of the pressure control valves 11FL to 11RR, and the process returns to step S1. Further, when the result of determination in step S2 is that the hydraulic pump 7 is in an abnormal state,
If the determination result is PA <PA _S and the accumulator 9 is abnormally low pressure, the routine proceeds to step S11, where the abnormality processing shown in FIG. 5 is started and then the braking control processing is ended.

As shown in FIG. 5, this abnormal process is executed as a timer interrupt process at predetermined time intervals (for example, 10 msec). First, at step S21, a predetermined time ΔT1 for controlling to reduce a brake pressure command value described later. It is determined whether or not a timer for measuring the time is set. If the timer is not set, the process proceeds to step S22. In this step S22, the vehicle speed V detected by the vehicle speed sensor 27 is read, and then the process proceeds to step S23 to refer to a decompression time calculation map and a first change amount calculation map set in advance based on the vehicle speed V. The predetermined time ΔT1 and the first variation Δ
Calculate P1v.

Here, as shown in FIG. 6, the decompression time calculation map takes the vehicle speed V on the horizontal axis and the reduction time ΔT1 on the vertical axis.
v, when the vehicle speed V is low, the depressurization time ΔT1v is also short, but when the vehicle speed V increases from this state, the deceleration time ΔT1v is increased in a predetermined curve ΔT1v so as to increase with respect to the increase. The decompression time ΔT1v is set to increase.

As shown in FIG. 7, the first change amount calculation map has the horizontal axis representing the vehicle speed V and the vertical axis representing the first change amount ΔP1v. Quantity Δ
P1v is also short, but when the vehicle speed V increases from this state, the first change amount ΔP1 is formed in a quadratic curve so that the increase amount of the first change amount ΔP1v increases with respect to the increase amount.
v is set to increase.

Next, the process proceeds to step S24 to read the previous braking pressure command value CP _i (n-1) (i = FF, FR, RL, RR) stored in the predetermined storage area of the storage device. Then, the process proceeds to step S25, referring to the predetermined time calculation map and the first change amount calculation map based on the read braking pressure command values CP _FL (n-1) to CP _RR (n-1). The decompression times ΔT1p and ΔP1p are calculated.

Here, as shown in FIG. 8, the decompression time calculation map takes the previous braking pressure command value CP _i (n-1) on the horizontal axis and the decompression time ΔT1p on the vertical axis, and When the pressure command value CP _i (n-1) is low, the pressure reduction time ΔT1p is also short, but from this state, the braking pressure command value CP _i (n-1)
Is increased by a predetermined time ΔT1p in a quadratic curve so that the increase in the decompression time ΔT1p increases with respect to the increase.
Is set to increase.

As shown in FIG. 9, the first change amount calculation map shows that the first change amount ΔP1p is also short when the previous braking pressure command value CP _i (n-1) is low, as shown in FIG. When the braking pressure command value CP _i (n-1) increases from this state, the first change amount in the form of a quadratic curve is increased so that the increase amount of the first change amount ΔP1p gradually increases with the increase amount. ΔP1p is set to increase.

Next, the process proceeds to step S26, in which the depressurizing time ΔT1v and ΔT1p calculated in steps S24 and S25 are added to calculate the depressurizing time ΔT1, and then the process proceeds to step S27 to calculate in steps S24 and S25. The first change amount ΔP1 is calculated by adding the first change amounts ΔP1v and ΔP1p. Next, step S2
8 and the pressure reduction time ΔT calculated in step S26.
1 is divided by the timer interrupt cycle t _T of the abnormal processing, and the decompression time Δ
The number N of abnormal processes during T1 is calculated, and then step S
The flow shifts to 29, where the master cylinder pressure PM detected by the master pressure sensor 23 is read, and then the flow shifts to step S30.

In this step S30, the following equations (2) and (3) are operated to calculate the ratio Rs _i of the braking pressure command value CP _i (n-1) to the master cylinder pressure PM at the start of pressure reduction.
And the master cylinder pressure PM at the end of pressure reduction.
Pressure command value CP _i (n-1) -ΔP1 ratio Re _i
Is calculated. Rs _i = CP _i (n−1) / PM (2) Re _i = {CP _i (n−1) −ΔP1} / P1 (3) Then, the process proceeds to step S31. By calculating the following equation (4), the change amount Δ of the ratio of the braking pressure command value CP _i (n-1) to the master cylinder pressure PM for each timer interrupt cycle t _T is calculated.
To calculate the R _i.

ΔR _i = (Rs _i −Re _i ) / N (4) Then, the process proceeds to step S32, in which the timer is preset to the decompression time ΔT1 calculated in step S26, and time counting is started. Next, the routine proceeds to step S33, where the braking pressure command value CP _i (n-1) for the current master cylinder pressure PM is obtained.
The ratio R _i new ratio value obtained by subtracting the amount of change [Delta] R _i from R _i of
After this is updated and stored in the predetermined storage area of the storage device, the process proceeds to step S34.

In step S34, a braking pressure command value CP _i (n) is calculated based on the ratio R _i stored in the storage device by performing the same calculation as in the above equation (1). Proceeding to S35, the braking pressure command values CP _FL (n) to C
Pressure control valves 11FL to 11 having current values corresponding to P _RR (n)
After outputting the control signals CS _{FF to} CS _RR for _RR , the timer interrupt processing ends.

On the other hand, if the result of determination in step S21 is that the timer has been set, the flow shifts to step S36 to determine whether or not the timer has timed out, that is, "0". If not, it is determined that the decompression process is being performed, and step S3 is performed.
7, the master cylinder pressure PM is read, and then the routine proceeds to the step S33. When the time is up, the routine proceeds to the step S38, where the first solenoid on-off valve 3F
A control signal _SD of a logical value “0” for maintaining the open state for L to 3RR is output, and the remaining second to fourth solenoid valves 10, 12, and 13 are maintained in the closed state. After outputting the control signals S _E , S _F and S _G having the logical value “0”, the timer interruption processing is stopped.

Therefore, if the vehicle is running with the hydraulic pump 8 and the accumulator 9 in a normal state, the process proceeds from step S4 to step S5 in the braking control process of FIG. In the released non-braking state, the master cylinder pressure PM is substantially “0”, and the routine proceeds to step S6, where the first solenoid on-off valve 3FL
To 3RR are closed, the second to fourth solenoid on-off valves 10, 1
Since the master cylinder pressures PMf and PMr are directly controlled by the stroke simulator
At this time, the pressure control valves 11FL to 11RR
Is also substantially "0", and the output pressures of the pressure control valves 11FL to 11RR, that is, the braking pressures are also controlled to be substantially "0".
The cylinder pressure supplied to the FR is also “0” and maintains the non-braking state.

When the accelerator pedal is released from the non-braking state, and the brake pedal 2 is depressed in place of the accelerator to bring the braking state, the front-wheel and rear-wheel master pressures PMf and PMr of the master cylinder 1 are correspondingly changed. These are supplied to the stroke simulator 14 and
While maintaining a predetermined stepping sensation, the master cylinder pressure P
The braking pressure command value CP is calculated in accordance with M, and is output to the pressure control valves 11FL to 11FR, so that the braking pressure proportional to the master cylinder pressure PM is directly applied to the front and rear wheel cylinders 5FL to 5RR. Is entered into the by-wire brake control state.

By shifting to the turning state in the braking state, when the vehicle side slip is larger than the target side slip, the side slip is made to coincide with the target side slip.
When a braking pressure command value for increasing the braking force for a predetermined wheel is input to the control unit 30, the process shifts from step S8 to step S9 in response to the braking pressure command value based on the master cylinder pressure PMr for the corresponding wheel. The braking pressure command value for side skid suppression is added to the value CP, and the added value is supplied to the wheel cylinders 5FL, 5RL or 5FR, 5RR as a braking pressure command value. The side slip suppression control can be performed while performing.

Also, when a braking pressure command value for suppressing the slipping of the drive wheels is input from the traction control device 31 to the control unit 30 in the non-braking state where the brake pedal 2 is not depressed, the process proceeds to step S8. The process proceeds to S9, in which the braking pressure according to the traction control braking pressure command value is output from the rear wheel side pressure control valves 11RL and 11RR serving as driving wheels to the rear wheel side wheel cylinders 5RL and 5RR. Traction control is performed with the slip of the drive wheels suppressed.

During this traction control, when the vehicle enters a turning state and a braking pressure command value for suppressing the amount of side slip is supplied to the control unit 30, the braking pressure command value for the corresponding wheel is increased, and the traction control is performed. The sideslip suppression control is simultaneously executed. On the other hand, when an abnormality occurs in the electric motor 7 that drives the hydraulic pump 8 and the rotation of the hydraulic pump 8 is reduced or stopped, the process proceeds from step S2 to step S11 in the process of FIG.
After the abnormality processing shown in (1) is started, the braking control processing is stopped.

At the start of the abnormal processing, the timer is not set, so that the processing shifts to step S22 via step S21, and after reading the vehicle speed V, the processing proceeds to step S23.
And the pressure reduction time ΔT1v corresponding to the vehicle speed V and the first
ＰP1v is calculated, and in step S24, the previous braking pressure command value, that is, the braking pressure command value CP _i (n-1) immediately before the braking pressure generating mechanism 6 becomes abnormal is read, and then the process proceeds to step S25. Then, the pressure reduction time ΔT1p and the first variation ΔP1p according to the braking pressure command value CP _i (n−1) are calculated.

Next, in steps S26 and S27, the decompression time ΔT1v and ΔT1p are added to add the decompression time ΔT1
And the first variation amounts ΔP1v and ΔP1p
Are added to calculate a first change amount ΔP1. For this reason,
As shown in FIG. 10, in the braking state in which the master cylinder pressure PM is constant, if an abnormality occurs in the braking pressure generating mechanism 6 at time t1, the pressure reduction time ΔT1 and the pressure control valve 11i (i
= FF, FR, RL, and the first pressure reduction amount ΔP1 to determine lowered to what extent the ratio of the master cylinder pressure PM of the current braking pressure command value CP _i that controls the RR) is determined.

In this state, the first electromagnetic on-off valve 3i is controlled to be closed, and the second to fourth electromagnetic on-off valves 10, 12, and 13 are controlled to be open. ing. Next, in steps S28 to S31, the reduction amount ΔR of the ratio R of the braking pressure command value CP _i (n) to the master cylinder pressure PM is calculated. Next, in step S32, the timer is preset to the pressure reduction time ΔT1, and then in step S33. the ratio R _i is reduced by the reduction amount [Delta] R _i, then the reduced ratio R at step S34 to calculate the braking pressure command value CP _i (n) based on the calculated braking pressure command value CP _i (n) pressure control valve control signal CS _i corresponding to 1
1i.

Thereafter, each time the timer interrupt period t _T elapses, the timer is set.
From step S36 to step S37, the master cylinder pressure PM at that time is read, and then to step S33, as shown in FIG. 10, the braking pressure command value CP _i (n ) Is gradually reduced, and the wheel cylinder 5
The braking pressure PWi of _i is also gradually reduced.

When this pressure reduction state reaches the pressure reduction time ΔT1,
When the timer expires at time t2 in FIG. 10, the process proceeds from step S36 to step S38, where the first solenoid on-off valve 3i is switched to the open state, and the remaining second solenoid-operated valve 3i is opened.
-The fourth electromagnetic on-off valves 10, 12, and 13 are switched to the closed state, and the state shifts to the backup brake state. At this time, the braking pressure P supplied to the wheel cylinder 5i
Since _Wi is sufficiently reduced to a value near the master cylinder pressure PM, it is possible to reliably prevent the master cylinder pressure PM from greatly fluctuating, and to suppress a so-called kickback phenomenon in which the brake pedal is pushed up. it can.

In addition, since the braking pressure of the wheel cylinder 5i is gradually reduced during this time, it is possible to prevent a sudden change in the braking pressure, to surely prevent the driver from feeling uncomfortable, and to gradually reduce the braking pressure. It is possible to make the driver recognize that the vehicle is being switched from the by-wire brake state to the backup brake state by the power change. If the brake pedal 2 is further depressed in this pressure reduction control state, the master cylinder pressure PM will increase by this amount, and the braking pressure command value CP calculated in step S34 will be increased.
_{When i} (n) increases, the braking force increases. Conversely, when the amount of depression of the brake pedal 2 is reduced, the master cylinder pressure PM decreases by this amount, so that step S
As the braking pressure command value CP _i (n) calculated in step 34 decreases, the braking force decreases. When the brake pedal 2 is released, the master cylinder pressure PM becomes “0”. Calculated braking pressure command value CP
_{Since i} (n) also becomes “0”, the braking state is immediately released when the state shifts to the non-braking state, even within the depressurization time ΔT1.

According to the first embodiment, the depressurizing time ΔT1 and the first variation ΔP1 increase as the vehicle speed V increases. Therefore, when the vehicle is running at low speed, the amount of depression of the brake pedal 2 is small. Since the ratio R of the braking pressure command value CP _i (n) to the cylinder pressure PM is also small, the decompression time ΔT1 and the first variation ΔP1 corresponding to these are calculated, and as the vehicle speed V increases from this low speed running state, As the depression amount of the brake pedal 2 increases, the braking pressure command value CP _i (n) also takes a large value, and a large decompression time ΔT1 and a first variation ΔP1 corresponding to these values are calculated, and the running state of the vehicle is calculated. Optimum pressure reduction control according to the pressure can be performed.

The decompression time ΔT 1 and the first variation Δ
Since P1 increases as the braking pressure command value CP _i (n-1) immediately before the occurrence of an abnormality increases, the depressurization time ΔT1 and the first variation ΔP1 become small values during gentle braking and conversely become large during sudden braking. since the value, it is possible to obtain a braking force by effectively utilizing the braking pressure PW _i output from the pressure control valve 11i.

In the first embodiment, the case where the abnormality of the hydraulic pump 8 is detected by the detection value of the motor current sensor 25 has been described. However, the present invention is not limited to this. The number may be detected by an encoder or the like, and the abnormality of the hydraulic pump 8 may be directly detected. Further, the abnormality of the hydraulic pump 8 may be detected from the detection value of the pressure accumulation sensor 24 for detecting the accumulated pressure of the accumulator 9. Is also good.

Next, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 25 will be described. In the second embodiment, when an abnormality occurs in the pressure control valves 11FL to 11RR, the pressure control valves are switched to the backup brake state while performing pressure reduction control. That is, in the second embodiment, as shown in FIG. 11, the braking control process executed by the controller 30 is omitted from the processes of steps S1 to S4 and S11 in the process of FIG. 4 in the first embodiment described above. Instead, in the abnormality detection processing described later,
A step S41 for determining whether or not the abnormal state flag FA is set to "1" is provided.
When the result of the determination at 41 is that the abnormal state flag FA has been reset to "0", the process proceeds to step S5, and when the abnormal state flag FA has been set to "1", the braking control process is terminated. Except for this, the same processing as in FIG. 4 is performed, and the processing corresponding to FIG.

On the other hand, the controller 30 executes the abnormality detection processing shown in FIG. 12 as a timer interruption processing every predetermined time (for example, 10 msec). This abnormality detection processing
First, it is determined in step S51, reads the braking pressure PW _i of the wheel cylinder 5i detected by brake pressure sensor 26i, and then the process proceeds to step S52, whether the braking pressure command value CP _i is depressurized. This determination is based on the current braking pressure command value CP _i from the previous braking pressure command value CP _i (n-1).
This is performed by determining whether the value obtained by subtracting (n) is positive, and when CP _i (n−1) −CP _i (n)> 0, it is determined that the pressure is in a reduced pressure state. S53 proceeds to transitions from cleared to "0" to the count value C _I-increasing pressure monitoring counter to be described later to step S54.

In step S54, the previous braking pressure P
It is determined whether or not a value obtained by subtracting the current braking pressure PW _i (n) from W _i (n-1) is positive. The result of this determination is PW _i (n-
1) When −PW _i (n)> 0, the pressure control valve 11
It is determined that i is under normal pressure reduction control, and step S
Moves to 55 and returns under reduced pressure the count value C _D decompression monitoring counter that counts the duration of the monitoring state "0" is cleared to exit the timer interrupt process to a predetermined main program.

The result of the determination in step S54 is PW_i
(n-1) -PW_iWhen (n) ≦ 0, the pressure control valve 1
1i, it is determined that the pressure reduction control is not being performed, and
The process proceeds to step S56, where the count value C of the pressure reduction monitoring counter
_DIs incremented by "1", and then step S57
And the count value C_DIs the preset value C _DS
It is determined whether or not the above is satisfied, and C_D<C_DSWhen
Finishes the timer interrupt processing and
Return to the program, C_D≧ C_DSWhen is the decompression finger
Pressure control is started while the
The supply side port ps of the pressure control valve 11i continues the open state.
It is determined that the decompression
The process proceeds to step S58 and sets the abnormal state flag FA to “1”.
After setting, the process proceeds to step S59, and the pressure reduction abnormality process is performed.
Execute

[0072] The reduced pressure anomaly processing, as shown in FIG. 13, first, at step S70, the stops supplying the driving current I _M relative to the electric motor 7, then the process proceeds to step S71, is set below timer It is determined whether or not the pressure reduction control has been performed, and if it has not been set, it is determined that pressure reduction control has not been performed, and the flow proceeds to step S72.

In this step S72, the vehicle speed V is read, and then the process proceeds to step S73, where the read vehicle speed V is read.
The decompression time ΔT1v is calculated with reference to the decompression time calculation map of FIG. 6 based on the above, and the second change amount calculation map showing the relationship between the vehicle speed V and the second change amount shown in FIG. The pressure control valve 11a (a = F
L, FR, RL, and RR) calculate a second change amount ΔP2v that sets the pressure reduction amount for the pressure control valve 11j (j = FL, FR, RL, RR) on the opposite side in the vehicle left-right direction.

Here, the second change amount calculation map is shown in FIG.
As shown by the solid line in FIG. 4, compared to the increase in the first change ΔP1v with respect to the increase in the vehicle speed V in the first change calculation map of FIG. 7 in the first embodiment shown by the one-dot chain line, Second variation ΔP2 with respect to increase in vehicle speed V
The increment of v is set to a small value of about 0.8 times.

Next, the processing shifts to step S74,
Brake pressure command value CP_FL(n-1)-CP _RRRead (n-1),
Next, proceeding to step S75, the previous braking pressure command value
CP _j(n-1) based on the decompression time calculation map shown in FIG.
The decompression time ΔT1p is calculated with reference to FIG.
The previous braking pressure command value CP shown in FIG._j(n-1) and the second change
Referring to the second change amount calculation map representing the relationship with the amount,
The opposite side of the pressure control valve 11a that has become normal in the vehicle left-right direction
The second variable for setting the reduced pressure amount for the pressure control valve 11j of FIG.
Calculated amount ΔP1p is calculated.

Here, the second change amount calculation map is shown in FIG.
As shown by the solid line in FIG. 5, the first change amount ΔP1 with respect to the increase amount of the braking pressure command value CP in the first change amount calculation map of FIG.
Compared to the increase in p, the increase in the second change ΔP2p with respect to the increase in the braking pressure command value CP is set to a small value of about 0.8 times.

Next, the flow shifts to step S76, where the depressurization time ΔT1 is calculated by adding the depressurization times ΔT1v and ΔT1p calculated in steps S74 and S75. The second change amount ΔP2 is calculated by adding the second change amounts ΔP2v and ΔP2p. Next, step S7
8 and referring to the third change amount calculation map showing the relationship between the vehicle speed V and the third change amount shown in FIG. A third change amount ΔP3v that sets a reduced pressure amount for the pressure control valves 11kL and 11kR on the opposite side in the vehicle front-rear direction is calculated.

Here, the third change amount calculation map is shown in FIG.
As shown by the solid line in FIG. 6, the vehicle speed is compared with the increase amount of the first change amount ΔP1v with respect to the increase amount of the vehicle speed V in the first change amount calculation map of FIG. Third variation ΔP3v with respect to increase in V
Is set to a large value of about 1.2 times.

Next, the process shifts to step S79 and
Brake pressure command value CP_kL(n-1)_,CP _kLFigure based on (n-1)
Between the previous braking pressure command value CP shown in FIG.
Referring to the third change amount calculation map representing the relationship,
Pressure control valve 11a and the pressure on the opposite side in the vehicle longitudinal direction.
No. for setting the pressure reduction amount for the control valves 11 kL and 11 kR
3 is calculated.

Here, the third change amount calculation map is shown in FIG.
7, the first change amount ΔP1 with respect to the increase amount of the braking pressure command value CP in the first change amount calculation map of FIG. 9 in the first embodiment shown by the one-dot chain line.
Compared to the increase in p, the increase in the third change ΔP3p with respect to the increase in the braking pressure command value CP is set to a value as large as about 1.2 times.

Next, the process shifts to step S80, where the third variation ΔP3v calculated in steps S78 and S79 is obtained.
And ΔP3p are added to calculate the third change amount ΔP3, and then the flow shifts to step S81. In step S81, steps S28 to S28 in the first embodiment described above are performed.
By performing the same processing as the processing of step S31, the expressions (2) and (3) are calculated for each of the second change amount ΔP2 and the third change amount ΔP3, and the master at the start of depressurization is obtained. The braking pressure command value CP _j (n-
1) The ratio Rs _j , Rs _{kL of} CP _kL (n-1) and CP _kR (n-1)
And it calculates the Rs _kR, braking pressure command value with respect to the master cylinder pressure PM at the vacuum terminated CP _j (n-1) -ΔP
2. Calculate the ratios Re _j , Re _kL, and Re _kR of CP _kL (n-1) -ΔP2 and CP _kL (n-1) -ΔP2, and calculate the master cylinder pressure by calculating equation (4). Braking pressure command values CP _j (n-1), CP _kL (n-1) and CP _kL for PM
The amount of change ΔR _j , ΔR in the ratio of (n-1) for each timer interrupt cycle t _T
Calculate R _kL and ΔR _kR .

Next, the routine proceeds to step S82, in which the timer is preset to the decompression time ΔT1 calculated in step S76 to start measuring the time, and then to step S83, the braking pressure command value for the current master cylinder pressure PM. From the ratios R _j , R _kL and R _{kR of} CP _j (n-1), CP _kL (n-1) and CP _kR (n-1), the amounts of change ΔR _j , ΔR _kL and ΔR
_The values obtained by subtracting _kR are used as new ratios R _j , R _kL, and R _kR . These values are updated and stored in a predetermined storage area of the storage device, and then the process _proceeds to step S84.

In step S84, the same calculation as in the above (1) is performed based on the ratios R _j , R _kL and R _kR stored in the storage device, and the braking pressure command value CP _a (n),
CP _j (n), CP _kL (n) and CP _kR (n) are calculated, and then the process proceeds to step S85, where the braking pressure command value CP _a (n)
, CP _j (n), CP _kL (n) and CP _kR (n) output control signals CS _{FF to} CS _RR for the pressure control valves 11 FL to 11 _RR at current values corresponding to CP _kR (n). The timer interrupt processing ends.

On the other hand, if the result of determination in step S71 is that the timer is set, it is determined that pressure reduction control is being performed, and the flow advances to step S86 to determine whether the timer has timed out. When the time is not up, the process proceeds to step S83, and when the time is up, the process proceeds to step S87, where the first electromagnetic on-off valves 3FL to 3RR are opened, and the second to fourth electromagnetic on-off valves 10, After controlling each of the switches 12 and 13 to the closed state, the pressure-decrease abnormality detection processing is terminated.

Returning to the abnormality detection processing of FIG.
And the determination result of step S52 is CP _i(n-1) -CP_i
When (n) ≦ 0, the control for the pressure control valve 11i is
Dynamic pressure command value CP_iIs not in reduced pressure,
It is determined that the state is the force holding state, and the process proceeds to step S60.
You. In step S60, the counter of the pressure reduction monitoring counter
Value C_DIs cleared to "0", and then step S61
To the previous braking pressure command value CP_i(n-1) to present
Brake pressure command value CP_i(n) is zero or negative
To determine whether or not the pressure is increasing.
Is determined, and the CP_i(n-1) -CP_i(n) = 0
Determines that the state is the pressure holding state, and proceeds to step S62.
And a count value C of a pressure increase monitoring counter described later._ITo
After clearing to “0”, the abnormality detection process is terminated and
Return to the main program,_i(n-1) -CP_i(n)
If <0, it is determined that the pressure is increasing and the
The process moves to step S63.

In step S63, the previous braking pressure P
It is determined whether a value obtained by subtracting the current braking pressure PW _i (n) from W _i (n-1) is negative. The result of this determination is PW _i (n-
1) When −PW _i (n) <0, the pressure control valve 11
i is determined to be under normal pressure increase control, and step S
The process proceeds to 64, where the count value C _I of the pressure increase monitoring counter that counts the duration of the pressure increase monitoring state is cleared to “0”, and then the timer interrupt processing is terminated to return to the predetermined main program.

Further, the result of the determination in step S65 is PW_i
(n-1) -PW_i(n) When ≧ 0, the pressure control valve 1
In step 1i, it is determined that the pressure increase control is not being performed.
The process proceeds to step S65, where the count value C of the pressure increase monitoring counter is
_IIs incremented by "1", and then step S66
And the count value C_IIs the preset value C _IS
It is determined whether or not the above is satisfied, and C_I<C_ISWhen
Finishes the timer interrupt processing and
Return to the program, C_I≧ C_ISWhen is the intensifier finger
Pressure increase control is started while the
The return port pd of the pressure control valve 11i continues to be open.
It is determined that the pressure increase
The flow proceeds to step S67 to set the abnormal state flag FA to "1".
And then proceeds to step S68 to perform the pressure increase abnormality process.
Execute

In this pressure increase abnormality process, as shown in FIG. 18, first, at step S90, it is determined whether or not a timer is set. When the timer is not set, the pressure reduction control is not performed. In step S91, the vehicle speed V detected by the vehicle speed sensor 27 is read. Then, the process proceeds to step S92, and based on the read vehicle speed V, the first embodiment shown in FIG. The decompression time ΔT1v is calculated with reference to the decompression time calculation map, and the abnormal pressure is determined with reference to the fourth change amount calculation map showing the relationship between the vehicle speed V and the fourth change amount ΔP4v shown in FIG. The control valve 11a calculates a fourth variation ΔP4v that sets the pressure reduction amount for the pressure control valve 11j on the opposite side in the vehicle left-right direction.

Here, the fourth change amount calculation map is shown in FIG.
As shown by the solid line in FIG. 9, as compared with the increase amount of the first change amount ΔP1v with respect to the increase amount of the vehicle speed V in the first change amount calculation map of FIG. Fourth variation ΔP4 with respect to increase in vehicle speed V
The increment of v is set to a large value of about 1.2 times.

Next, the processing shifts to step S93,
Brake pressure command value CP_FL(n-1)-CP _RRRead (n-1),
Next, proceeding to step S94, the previous braking pressure command value
CP _j(n-1) based on the decompression time calculation map shown in FIG.
The decompression time ΔT1p is calculated with reference to FIG.
Previous braking pressure command value CP (n-1) shown as 0 and the fourth variation
See the fourth variation calculation map showing the relationship with ΔP4p
The pressure control valve 11a that has become abnormal
A pressure reducing amount for the pressure control valve 11j on the opposite side is set.
4 is calculated.

Here, the fourth change amount calculation map is shown in FIG.
As indicated by the solid line at 0, the first change amount ΔP1 with respect to the increase amount of the braking pressure command value CP in the first change amount calculation map of FIG.
Compared to the increase in p, the increase in the fourth variation ΔP4p with respect to the increase in the braking pressure command value CP is set to a small value, for example, about 1.2 times.

Next, the flow shifts to step S95, where the depressurization time ΔT1 is calculated by adding the depressurization times ΔT1v and ΔT1p calculated in steps S92 and S94. Then, the flow shifts to step S96 to calculate in steps S92 and S94. The second change amount ΔP4 is calculated by adding the fourth change amounts ΔP4v and ΔP4p. Next, step S9
7, and based on the vehicle speed V, referring to the fifth change amount calculation map showing the relationship between the vehicle speed V and the fifth change amount ΔP5v shown in FIG. Calculates a fifth change amount ΔP5v that sets a reduced pressure amount for the pressure control valves 11kL and 11kR on the opposite side in the vehicle front-rear direction.

Here, the fifth change amount calculation map is shown in FIG.
As shown by the solid line in FIG. 1, as compared with the increase in the first change ΔP1v with respect to the increase in the vehicle speed V in the first change calculation map of FIG. Fifth variation ΔP5 with respect to increase in vehicle speed V
The increment of v is set to a small value, for example, about 0.8 times.

Next, the processing shifts to step S98,
Brake pressure command value CP_kL(n-1)_,CP _kLFigure based on (n-1)
22 and the fifth change amount ΔP
With reference to a fifth change amount calculation map representing the relationship with 5p
Opposite to the abnormal pressure control valve 11a in the longitudinal direction of the vehicle
Set the pressure reduction amount for the pressure control valves 11kL and 11kR on the side.
A fifth change amount ΔP5p to be determined is calculated.

Here, the third change amount calculation map is shown in FIG.
As shown by the solid line in FIG. 2, the first change amount ΔP1 with respect to the increase amount of the brake pressure command value CP in the first change amount calculation map of FIG.
Compared to the increase in p, the increase in the fifth change ΔP5p with respect to the increase in the braking pressure command value CP is set to a small value, for example, about 0.8 times.

Next, the flow shifts to step S99, where the fifth variation ΔP5v calculated in steps S97 and S98 is used.
And ΔP5p are added to calculate the fifth variation ΔP5, and then the flow shifts to step S100. This step S10
In the case of 0, the same processing as the processing of step S81 in the above-described pressure reduction abnormality processing state of FIG. ) To calculate the braking pressure command value CP _j (n-1) for the master cylinder pressure PM at the start of pressure reduction.
, CP _kL (n-1) and CP _kR (n-1), Rs _j , Rs _kL
And it calculates the Rs _kR, braking pressure command value with respect to the master cylinder pressure PM at the vacuum terminated CP _j (n-1) -ΔP
2. Calculate the ratios Re _j , Re _kL, and Re _kR of CP _kL (n-1) -ΔP2 and CP _kL (n-1) -ΔP2, and calculate the master cylinder pressure by calculating equation (4). Braking pressure command values CP _j (n-1), CP _kL (n-1) and CP _kL for PM
The amount of change ΔR _j , ΔR in the ratio of (n-1) for each timer interrupt cycle t _T
Calculate R _kL and ΔR _kR .

Next, the routine proceeds to step S101, in which the timer is preset to the decompression time ΔT1 calculated in step S92 to start measuring time. From the ratios R _j , R _kL and R _{kR of} CP _j (n-1), CP _kL (n-1) and CP _kR (n-1), the amounts of change ΔR _j , ΔR _kL and ΔR
_The values obtained by subtracting _kR are used as new ratios R _j , R _kL, and R _kR . These values are updated and stored in a predetermined storage area of the storage device, and then the process proceeds to step S103.

In step S103, the same calculation as in the above (1) is performed based on the ratios R _j , R _kL and R _kR stored in the storage device, and the braking pressure command value CP _a (n),
CP _j (n), CP _kL (n) and CP _kR (n) are calculated, and then the process proceeds to step S104, where the braking pressure command value CP
_a (n), CP _j (n), CP _kL (n) and CP _kR (n) output control signals CS _{FF to} CS _RR to the pressure control valves 11FL to 11RR with current values corresponding to the pressure increase abnormalities. The process ends, and the timer interrupt process ends.

On the other hand, if the result of the determination in step S90 is that the timer is set, it is determined that pressure reduction control is being performed, and the flow shifts to step S105 to determine whether or not the timer has expired. When the time is not up, the process proceeds to step S102, and when the time is up, the process proceeds to step S106, where the first electromagnetic on-off valves 3FL to 3RR are opened and the second to fourth electromagnetic on-off valves 10, 12 are opened. And 13 are respectively controlled to be in the closed state, and then the pressure-decrease abnormality detection processing is terminated.

According to the second embodiment, each pressure control
When the valves 11FL to 11RR are normal, each pressure control
Braking pressure command value CP for control valves 11FL to 11RR_FL~
CP _RRFor example, when the pressure is reduced,
Braking pressure PW of Linda 5FL-5RR_FL~ PW_RRIs given
The abnormality is detected after the delay time, as shown in FIG.
The process proceeds from step S54 to step S55.
And the count value C of the pressure reduction monitoring counter_DIs cleared to “0”
The process proceeds from step S57 to step S58.
The abnormal state flag FA is set to "1"
And the abnormal state flag FA has been reset to "0".
Therefore, the brake control process shown in FIG.
Of the depressed pedal 2 and other control devices 31 to 33
Pressure control valves 11FL to 11RR based on a braking pressure command value
Is controlled to brake the wheel cylinders 5FL to 5RR.
The pressure is controlled.

Similarly, each of the pressure control valves 11FL to 11RR
Pressure command value CP for_FL~ CP _RRIs in a pressure increasing state
The braking pressure of the wheel cylinders 5FL to 5RR
PW _FL~ PW_RRIs increased after a predetermined delay time
Thus, in the abnormality detection process of FIG.
Proceed to step S64 to count the pressure increase monitoring counter.
Value C_iIs cleared to "0".
The process proceeds to step S67, and the abnormal state flag FA
It is not set to “1” and the pressure control valve 11FL
Of wheel cylinders 5FL to 5RR by 11RR
Pressure control is performed.

From the state in which the pressure control valves 11FL to 11RR are normal, the amount of depression of the brake pedal 2 is increased as shown between time points t0 and t1 in FIG. Pressure command value CP _FL ~
During the pressure increasing control for increasing the CP _RR , for example, the front left wheel 4
It is assumed that the supply-side port ps is fixed in an open state due to, for example, dust or the like adhering to the spool at the pressure control valve 11FL of the FL, and the pressure reduction control is disabled.

As described above, when the pressure control valve 11FL is brought into the pressure reduction abnormal state, the time t1 in FIG.
Since the pressure increase state is continued, the pressure increase is performed even in the abnormal pressure control valve 11FL. Therefore, when the abnormality detection processing of FIG.
60 proceeds to, vacuum monitoring the count value C _D of the counter is cleared to "0", then the processing proceeds to step S61, since it is pressure increasing control state, the process proceeds to step S63, the pressure control valve 11FL~11RR The braking pressures PW _{FL to} PW _RR output from the ECUs are also in a pressure increasing state, so that it is determined that each of the pressure control valves 11FL to 11RR is normal, and the process proceeds to step S64 to count the count value C _{I of the} pressure increasing monitoring counter. Is cleared to "0", and then the timer interrupt processing is terminated.

However, when the depression amount of the brake pedal 2 is reduced at time t1 to be in a reduced pressure state, the braking pressure command value CP calculated in the braking control process of FIG.
_{FL to} CP _RR start to decrease and three normal pressure control valves 1
For 1FR to 11RR, the braking pressures PW _{FR to} PW _RR output therefrom start to decrease after the delay time has elapsed. Therefore, when the abnormality detection processing of FIG. 12 is executed, the processing proceeds from step S52 to step S53. Step S
Moves to 54, and it is determined that the pressure control valve 11FR~11RR is normal and proceeds to step S55, and terminates the timer interrupt processing is cleared to "0" to the count value C _D decompression monitoring counter Is abnormal pressure control valve 1
As for 1FL, the state where the return port pd is kept closed is continued.
Shifts from step S54 to step S56, increments the count value C _D of vacuum monitoring counter.

[0105] Therefore, when the pressure reduction control state continues, by maintaining a state in which the braking pressure PW _FF is not reduced output from the pressure control valve 11FL, which has become abnormal, the count value C _D decompression monitoring counters 12 Is incremented each time the timer interrupt cycle of the counter arrives, and at time t2, the count value C _D
If There reaches the set value C _DS, and proceeds from step S57 to step S58, the abnormal state flag FA is set to "1".

For this reason, in the braking control process of FIG. 11, the braking control is terminated by setting the abnormal state flag FA to “1”, whereas in the abnormality detecting process of FIG. 12, the process proceeds to step S59. Then, the pressure reduction abnormality processing shown in FIG. 13 is executed. In this vacuum abnormality processing, first, the output of the drive current I _M relative to the electric motor 7 is stopped, the fluid pump 8 is stopped in braking pressure generating mechanism 6, the supply of braking pressure to the accumulator 9 is stopped Is done.

For this reason, the accumulated pressure of the accumulator 9 depends on the amount of leakage between the supply side port ps and the return side port pd of each of the pressure control valves 11FL to 11RR, and the normal pressure control valve 11
Depending on the consumption amount in FR to 11RR, as shown by the characteristic line L0 shown by the one-dot chain line in FIG. On the other hand, the pressure control valve 11FR on the opposite side in the left-right direction from the abnormal pressure control valve 11FL.
13, the pressure reduction time ΔT1 and the second value smaller than the first change amount ΔP1 based on the vehicle speed V and the braking pressure command value CP _FR (n−1) immediately before the vehicle becomes abnormal in steps S73 to S77 in FIG. variation ΔP2 is calculated by the braking pressure command value CP _FR (n) is calculated on the basis of this, the braking pressure command value CP _FR (n) is abnormal, as shown by the characteristic line L1 in FIG. 23 And gradually decreases along the braking pressure PWPW _FL output from the pressure control valve 11FL.

For this reason, the pressure control valve 1 in which the pressure reduction abnormality
Braking pressure P braking pressure PW _FL and that this output from 1FL output from the pressure control valve 11FR opposite in the lateral direction
When _WFR is close to the above value, one-sided application of the brake on the front wheel side can be reliably prevented, and traveling stability can be ensured. In contrast, the abnormal pressure control valve 11F
L, pressure control valves 11RL, 11R on the opposite side in the front-rear direction.
For R, steps S78 to S80 in FIG.
And the braking pressure command value CP _RL (n-
1) and CP _RR (n-1) first variation ΔP1 is greater than the third variation .DELTA.P3 _RL based on the (n) and .DELTA.P3 _RR (n) is calculated, the braking pressure command value CP on the basis of these By calculating _RL (n) and CP _RR (n), these braking pressure command values CP _RL (n) and CP _RR (n) decrease relatively sharply as shown by the characteristic line L2 in FIG. .

As a result, the pressure reduction state on the front wheel side is moderate.
Reduce the amount of reduction in braking force on the normal rear wheel side
By increasing the amount of reduction in braking force in a sudden
The change in the total braking force between the two is the same as in the first embodiment described above.
It can be set in the same way to give the driver a sense of incongruity.
Pressure reduction control can be performed without delay. Then, at time t3
When the pressure reducing time ΔT1 has elapsed, the braking pressure command value CP_FL~
CP _RRPressure control is stopped for the first electromagnetic opening and closing
When the valves 3FL to 3RR are open, the second to fourth solenoid on-off valves
10, 12, and 13 are each controlled to the closed state,
The master cylinder pressures PMf and PMr from the cylinder 1 are
Supplied to the wheel cylinders 5FL to 5RR as they are.
Is output from the pressure control valves 11FL to 11RR at the time of
Braking pressure PW_FL~ PW_RRHas been sufficiently reduced,
Prevents sudden changes in dynamic pressure and switches braking pressure without discomfort
be able to.

On the other hand, for example, the pressure control valve 11RR on the rear wheel side
When the pressure increase abnormality that makes the pressure increase control impossible is generated, for example, as shown in FIG.
In the state where the pressure is constant or in the depressurized state, the determination of the pressure increase abnormality is not performed in the abnormality detection processing of FIG.
When the braking pressure command value CP _RR for 1 _RR continuously increases, the abnormality detection processing of FIG. 12 keeps the braking pressure PW _RR output from the abnormal pressure control valve 11 _RR not to increase, The process shifts from step S63 to step S65 to count the pressure C of the pressure increase monitoring counter.
_I counts up and this is the set value C _IS at time t12.
At step S66, the process proceeds from step S66 to step S67, where the abnormal state flag FA is set to "1", whereby the braking control process of FIG.
Is started.

As a result, a pressure increase abnormality occurs and the pressure control valve 1
At 1RR, the return port pd remains open, and the working fluid of the wheel cylinder 5RR flows into the reservoir 1a via the control port pc and the return port pd, so that the braking pressure of the wheel cylinder 5RR is reduced by the dashed line in FIG. As shown by the characteristic line L10, the state decreases with a relatively steep gradient.

At this time, the pressure control valve 1 in which the pressure increase was abnormal
For the pressure control valve 11RL on the opposite side in the left-right direction from 1RR, the decompression time ΔT1 is calculated in steps S91 to S96 in FIG. 18 and the fourth value having a relatively large value as shown in FIG. By calculating the change amount ΔP4, the pressure command value C for the pressure control valve 11RL is calculated.
P _RL is as indicated by a thick solid line shown in the characteristic line L11 in Fig. 24, decreases at a relatively large gradient, in the thin solid line shown in the characteristic line L12 braking pressure PW _RL wheel cylinders 5RL is in Figure 24 in accordance with this as shown, decreases along the decreasing amount of the braking pressure PW _RR of the pressure control valve 11RR side became pressure increase abnormally. For this reason, the pressure control valve 11RR in which the pressure increase was abnormal
Therefore, the braking force with the pressure control valve 11RL on the opposite side in the left-right direction is substantially the same, so that one-sided effect of the braking force can be reliably prevented, and traveling stability can be ensured.

On the other hand, the pressure control valves 11FL and 11FR on the front wheel side opposite to the rear wheel side where the pressure increase abnormality has occurred are relatively small as shown in FIG. 24 in steps S97 to S99 in FIG. A fifth change amount ΔP5 is calculated. Therefore, with respect to the front wheel side of the pressure control valve 11FL and 11FR, as indicated by a thick solid line shown in the characteristic line L13 in Fig. 24, the braking pressure command value CP _FL and CP _FR decrease gradient of becomes gentle, which The wheel cylinders 5FL and 5
Since the decreasing gradient of the FR becomes gentle, a large braking force can be secured on the front wheel side, and the braking force on the rear wheel side is compensated for and the total braking force is reduced by each of the pressure control valves 11FL to 11R.
It is possible to substantially match the total braking force when R is normal, and it is possible to reliably prevent the driver from feeling uncomfortable.

When the timer expires after the elapse of the pressure reduction time ΔT1, the braking pressure command values CP _{FL to} CP _{RR are obtained.}
Is stopped, and the first solenoid on-off valve 3F
When L to 3RR are in the open state, the second to fourth solenoid on-off valves 10,
The master cylinder pressures PMf and PMr from the master cylinder 1 are supplied to the wheel cylinders 5FL to 5RR as they are, and the braking pressure PW _FL output from the pressure control valves 11FL to 11RR at this time. Since .about.PW _RR is sufficiently reduced, it is possible to prevent a sudden change in the braking pressure and to perform the switching of the braking pressure without a feeling of strangeness.

According to the second embodiment, when any one of the pressure control valves 11FL to 11RR has a pressure reduction abnormality or a pressure increase abnormality, the pressure control valve 11a having the abnormality is left and right. the pressure control valve 11a, which has become abnormal braking pressure command value CP _j for the pressure control valve 11j opposite in direction
Because it was made to decrease according to the braking pressure decrease amount of
While the one-sided effect of the braking force can be reliably prevented,
The left and right pressure control valves 11kL and 11kR on the opposite side in the front-rear direction with the abnormal pressure control valve 11a are pressure-reduced so as to offset the insufficient or excessive braking force on the abnormal pressure control valve 11a. Therefore, it is possible to reliably prevent the driver from feeling uncomfortable by adjusting the total braking force of the four wheels to the total braking force of the four wheels when each pressure control valve is normal.

In the second embodiment, when a pressure reduction abnormality occurs in the pressure control valves 11FF to 11RR, the operation of the hydraulic pump 8 is stopped and the accumulator 9 is stopped.
Has been described in which the accumulated pressure of the pressure control valves 11FF to 11RR is reduced due to the natural decrease due to the leakage of the pressure control valves 11FF to 11RR and the consumption of the normal pressure control valves. However, the present invention is not limited to this. As shown, in the configuration of FIG. 1 in the first embodiment described above, the second to second series circuits of the braking pressure generating mechanism 6 and the second electromagnetic on-off valve 10 are arranged in parallel.
A series circuit of a fifth electromagnetic on-off valve 15 and a throttle 16 having the same configuration as the fourth electromagnetic on-off valves 10, 12 and 13 is provided, and this fifth electromagnetic on-off valve 15 is connected to the pressure control valves 11FL to 11FL.
11RR, the accumulated pressure of the accumulator 9 is reduced through the throttle 16 by controlling the open state only when a pressure reduction abnormality occurs in any one of the pressure reduction abnormalities. What is necessary is just to set the braking pressure command value of the control valve.

In each of the above embodiments, the vehicle speed
Pressure command value CP immediately before the detection of abnormalities _ibased on (n-1)
The case where the first to fifth change amounts are set has been described.
However, the present invention is not limited to this.
Previous braking pressure command value CP_i(n-1)
The first to fifth variation amounts may be set based on the
No.

Further, in each of the above embodiments, the second electromagnetic on-off valve 1 common to the pressure control valves 11FL to 11RR is used.
Although the case where the 0 and the third electromagnetic on-off valves 12 are provided has been described, the present invention is not limited to this case. Second and third solenoid on-off valves may be provided for each of the left and right pressure control valves.

Further, in each of the above embodiments,
Although the case where the rear wheels are the drive wheels has been described, the present invention can be applied to the case where the front wheels are the drive wheels. Furthermore, in each of the above embodiments, a case has been described in which traction control and side slip amount control are performed in addition to the braking control.However, the present invention is not limited to this. They can be used together.

Further, in each of the above embodiments, the case where the braking pressure command values from the other control devices 31 to 33 are input to the control unit 30 has been described. However, the present invention is not limited to this. It may be omitted.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic configuration of a pressure control valve applicable to the first embodiment.

FIG. 3 is a characteristic diagram showing an output pressure characteristic with respect to a braking pressure command value of a pressure control valve in the first embodiment.

FIG. 4 is a flowchart illustrating an example of a braking control processing procedure in a control unit.

FIG. 5 is a flowchart illustrating an example of an abnormality processing procedure in FIG. 4;

FIG. 6 is a characteristic diagram showing a decompression time calculation map representing a relationship between a vehicle speed and a decompression time.

FIG. 7 is a characteristic diagram showing a first change amount calculation map representing a relationship between a vehicle speed and a first change amount.

FIG. 8 is a characteristic diagram showing a decompression time calculation map showing a relationship between a braking pressure command value immediately before the start of decompression control and a decompression time.

FIG. 9 is a characteristic diagram showing a first change amount calculation map representing a relationship between a brake pressure command value immediately before the start of pressure reduction control and a first change amount.

FIG. 10 is a time chart for describing an operation of a braking control process according to the first embodiment.

FIG. 11 is a flowchart illustrating an example of a braking control processing procedure according to the second embodiment of the present invention.

FIG. 12 is a flowchart illustrating an example of an abnormality detection processing procedure according to the second embodiment.

FIG. 13 is a flowchart showing a specific example of a pressure reduction abnormality process in FIG.

FIG. 14 is a characteristic diagram illustrating a second change amount calculation map representing a relationship between a vehicle speed and a second change amount.

FIG. 15 is a characteristic diagram showing a second change amount calculation map showing a relationship between a braking pressure command value immediately before the start of pressure reduction control and a second change amount.

FIG. 16 is a characteristic diagram showing a third change amount calculation map representing a relationship between a vehicle speed and a third change amount.

FIG. 17 is a characteristic diagram showing a third change amount calculation map representing a relationship between a braking pressure command value immediately before the start of pressure reduction control and a third change amount.

FIG. 18 is a flowchart illustrating an example of a pressure increase abnormality processing procedure according to the second embodiment.

FIG. 19 is a characteristic diagram illustrating a fourth change amount calculation map representing a relationship between a vehicle speed and a fourth change amount.

FIG. 20 is a characteristic diagram showing a fourth change amount calculation map representing a relationship between a brake pressure command value immediately before the start of pressure reduction control and a fourth change amount.

FIG. 21 is a characteristic diagram illustrating a fifth change amount calculation map representing a relationship between a vehicle speed and a fifth change amount.

FIG. 22 is a characteristic diagram showing a fifth change amount calculation map representing a relationship between a brake pressure command value immediately before the start of pressure reduction control and a fifth change amount.

FIG. 23 is a time chart for explaining an operation at the time of abnormal pressure reduction in the second embodiment.

FIG. 24 is a time chart for explaining an operation when a pressure increase is abnormal in the second embodiment;

FIG. 25 is a schematic configuration diagram showing a modification of the second embodiment.

[Explanation of symbols]

 Reference Signs List 1 master cylinder 2 brake pedal 3FL to 3RR first electromagnetic switching valve 4FL, 4FR front wheel 4RL, 4RR rear wheel 5FL to 5RR wheel cylinder 6 braking pressure generating mechanism 8 hydraulic pump 9 accumulator 10 second electromagnetic switching valve 11FL to 11FL 11RR Pressure control valve 12 Third electromagnetic on / off valve 13 Fourth electromagnetic on / off valve 14 Stroke simulator 22 Stroke sensor 23 Master pressure sensor 25 Motor current sensor 30 Control unit 31 Antilock brake control device 32 Traction control device 33 Side slip amount control device

Claims (7)

[Claims] 1. A master cylinder for outputting a working fluid of a braking pressure corresponding to the amount of depression of a brake pedal, a braking means for generating a braking force for braking a wheel, and absorbing a working fluid output from the master cylinder. A stroke simulator, a braking pressure generating means having a fluid pump and an accumulator for accumulating the discharge pressure thereof, and a braking pressure generated by the braking pressure generating means is controlled by reducing the braking pressure based on a braking pressure command value to perform arbitrary braking. A pressure control valve for outputting a pressure to the braking means, a first solenoid on-off valve inserted between the master cylinder and the braking means, and a first solenoid on-off valve inserted between the accumulator and the pressure control valve. A second solenoid on-off valve, a third solenoid on-off valve interposed between a return port of the pressure control valve and a reservoir of the master cylinder, the master cylinder and a stroke simulator. A fourth electromagnetic opening / closing valve inserted between the motors, a brake depression amount detecting means for detecting a depression amount of the brake pedal, an abnormality detecting means for detecting a low pressure abnormality of the braking pressure generating means, The pressure control valve, based on a brake pedal depression amount detected by the brake depression amount detection unit and a detection result of the abnormality detection unit,
Electromagnetic on-off valve, second electromagnetic on-off valve, third electromagnetic on-off valve,
A braking control means for controlling a fourth electromagnetic on-off valve and a fluid pump, wherein the braking control means is configured to perform the first control when the abnormality detecting means detects that the braking pressure generation system is normal. Of the second to fourth
The electromagnetic opening and closing valves are controlled to be open respectively, and the ratio of the braking pressure command value output to the pressure control valve to the brake pedal depression amount is set to a predetermined set value, and the abnormality detecting means generates the braking pressure. When the abnormality of the means is detected, the ratio of the brake pressure command value to the brake pedal depression amount is reduced by a first change amount during a predetermined time, and after the predetermined time has elapsed, the first electromagnetic on-off valve is operated. A brake control device configured to control each of the second to fourth solenoid on-off valves to a closed state in an open state. 2. The braking control means changes a predetermined time and a first amount of change when decreasing a braking pressure command value according to a vehicle speed or a braking pressure command value immediately before starting to decrease the braking pressure command value. 2. The brake control device according to claim 1, wherein the brake control is performed. 3. The brake control means determines that the pressure control valve is abnormally depressurized when the brake pressure of the brake means does not change until a predetermined time elapses during the control of decreasing the brake pressure command value of the pressure control valve, While the fluid pump is stopped, the ratio of the brake pressure command value output to the corresponding pressure control valve and the pressure control valve on the opposite side of the pressure control valve in the vehicle left-right direction to the brake depression amount is changed for a predetermined time. A third change amount larger than the second change amount during a predetermined period of time, wherein the ratio of the brake pressure command value output to the remaining pressure control valve to the brake depression amount is controlled to decrease to become the change amount of 2. The brake control device according to claim 1, wherein the reduction control is performed such that 4. The braking control means according to claim 1, wherein the predetermined time and the first to third variations in decreasing the braking pressure command value are changed to a vehicle speed or a braking pressure command value immediately before the braking pressure command value is started to decrease. And when the condition of the braking pressure command value immediately before the vehicle speed or the braking pressure command value is started to decrease is matched, the third variation amount, the first variation amount, and the second variation amount in this order. The brake control device according to claim 3, wherein the change amount is set to be small. 5. The brake control means determines that the pressure increase of the pressure control valve is abnormal when the brake pressure of the brake means does not increase until a predetermined time passes during the control of increasing the brake pressure command value of the pressure control valve. The ratio of the brake pressure command value output to the pressure control valve corresponding to the pressure control valve and the pressure control valve opposite to the pressure control valve in the vehicle left-right direction to the brake depression amount is set to be the fourth change amount during a predetermined time. The ratio of the braking pressure command value output to the remaining pressure control valve to the brake pedal depression amount is set to a value smaller than the fourth variation amount during a predetermined time period.
2. The brake control device according to claim 1, wherein the control is performed such that the amount of change is reduced. 6. The braking control means according to claim 1, wherein the predetermined time when decreasing the braking pressure command value and the first, fourth and fifth amounts of change are determined by the braking immediately before the vehicle speed or the braking pressure command value is started to decrease. The fourth change amount, the first change amount and the fifth change amount are changed when the condition of the brake pressure command value immediately before the vehicle speed or the brake pressure command value is started to be decreased is changed according to the pressure command value. 6. The brake control device according to claim 5, wherein the change amount is set to be smaller in the order of the change amount. 7. The apparatus according to claim 1, wherein said brake depression amount detecting means is configured to detect at least one of a stroke of a brake pedal, a depression force of a brake pedal, and a master cylinder pressure. The brake control device according to the above.