JP2000185641A - Brake control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely prevent fluctuation of master cylinder pressure in changing into the master cylinder pressure at the time of abnormality of an external brake pressure generating means or a pressure control valve in controlling brake pressure by pressure reduction control by the pressure control valve to pressure generated by the external brake pressure generating means. SOLUTION: A master cylinder 1 is connected to wheel cylinders 5FL-5RR through first solenoid selector valves 3FL-3RR, accumulated pressure of an accumulator 9 connected to the discharge side of a hydraulic pump 8 is pressure reduction-controlled based on a pressure command value by pressure control valves 11FL-11RR to be supplied to the wheel cylinders 5FL-5RR, and master cylinder pressure is supplied to a stroke simulator 13. When abnormality is generated at an external brake pressure generating means including a hydraulic pump, the pressure command value of each pressure control valve 11FL-11RR is controlled to the master cylinder pressure, a necessary sufficient set time when output pressure of the pressure control valve 11FL-11RR reaches the master cylinder pressure is calculated, and the first solenoid selector valves 3FL-3RR are set in opened conditions after the lapse of this set time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake for performing braking control by other control means such as anti-lock brake control, driving force control, turning performance control, etc. in addition to normal braking control by depressing a brake pedal. It relates to a control device.

[0002]

2. Description of the Related Art A conventional brake control device is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-250402. This conventional example is a braking control device for an electric vehicle that performs normal braking control and regenerative braking control in an electric vehicle, but generates a differential pressure corresponding to regenerative braking between a master cylinder and a wheel cylinder. The differential pressure valve and the duty-controlled switching hydraulic valve are connected in parallel, the switching hydraulic valve is normally closed, and the wheel cylinder pressure is supplied to the wheel cylinder by the differential pressure valve by reducing the pressure equivalent to regenerative braking. An abnormality occurs in braking,
When the regenerative braking force becomes zero, the switching hydraulic valve is duty-controlled to repeatedly open and close to prevent the wheel cylinder pressure from gradually approaching the master cylinder pressure and prevent the brake pedal from becoming deeper. I try to improve the brake feeling.

[0003]

However, in the conventional brake control device described above, the regenerative braking becomes abnormal and the wheel cylinder pressure is gradually increased to the master cylinder pressure so as to be equal. However, there is an unsolved problem that the braking force is increased by gradually increasing the wheel cylinder pressure of the wheel cylinder, but it takes time to compensate for the regenerative braking force, and the braking force is insufficient during this time.

In order to solve this unsolved problem, when the master cylinder and the wheel cylinder are directly connected at the same time as the occurrence of an abnormality, the master cylinder pressure fluctuates, and in particular, braking pressure control based on the amount of depression of a brake pedal, and other factors. When performing brake pressure control by traction control or side-slip suppression control, etc., when the wheel cylinder pressure is controlled to be higher than the master cylinder pressure, the master cylinder pressure increases and kickback occurs on the brake pedal. However, there is an unsolved problem of giving a sense of incongruity to a driver.

Accordingly, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and is provided when an abnormality occurs in a control system for supplying a braking pressure to braking means of each wheel by an external pressure. It is another object of the present invention to provide a brake control device capable of matching a wheel cylinder pressure with a master cylinder pressure in a short time without impairing a pedal depression feeling.

[0006]

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; External braking pressure generation having braking means for generating a braking force, a stroke simulator for absorbing the working fluid output from the master cylinder, a hydraulic pump for pressurizing the working fluid, and a pressure accumulating means for accumulating the output pressure thereof. Means, a pressure control valve for controlling the pressure reduction of the pressure accumulating means to output an arbitrary braking pressure to the braking means, and a first electromagnetic opening / closing valve interposed between the master cylinder and the braking means. A second electromagnetic on-off valve for intermittently controlling the flow of a working fluid inserted between the stroke simulator and the master cylinder, and detecting a depression amount of the brake pedal. Rake depression amount detection means, and controlling the pressure control valve in accordance with a braking pressure instruction value based on the brake pedal depression amount detected by the brake depression amount detection means and a braking pressure instruction value from another control means, A brake control device for controlling the first electromagnetic on / off valve to be in a closed state and the second electromagnetic on / off valve to be in an open state, wherein a master cylinder pressure detecting means for detecting a braking pressure of the master cylinder; Abnormality detecting means for detecting that the external braking pressure generating means is in an abnormal state, and detecting the abnormality when the abnormality detecting means detects the depression of the brake pedal and detecting the depression of the brake pedal by the brake depression amount detecting means. The pressure command value for the control valve is corrected to match the master cylinder pressure detected by the master cylinder pressure detection means,
Abnormality processing means for controlling to switch the first electromagnetic on-off valve to the open state and the second electromagnetic on-off valve to the closed state after the master cylinder pressure and the braking pressure of the braking means coincide with each other. Features.

In the invention according to the first aspect, in a braking state in which the brake pedal is depressed, the first solenoid on-off valve is closed and the second solenoid on-off valve is opened, and the master cylinder pressure is set to the stroke simulator. The braking pressure from the external braking pressure generating means is controlled by the pressure control valve by a pressure command value according to the driver's requested deceleration and other side slip suppression control while ensuring a predetermined pedal feeling. The pressure is reduced based on the pressure command value higher than the master cylinder pressure obtained by adding the pressure command value, and the pressure is supplied to the braking means. Is decreased, the pressure command value is changed stepwise so as to match the master cylinder pressure. In response to this, the braking pressure output from the pressure control valve drops relatively steeply, and after the braking pressure matches the master cylinder pressure, the first solenoid on-off valve is opened and the second solenoid on-off valve is closed. As a result, the master cylinder pressure is directly supplied to the braking means, a normal braking operation is ensured, and the fluctuation of the master cylinder pressure at this time can be reliably prevented.

According to a second aspect of the present invention, there is provided the brake control device according to the first aspect, wherein the abnormality processing means controls switching of the first electromagnetic on-off valve and the second electromagnetic on-off valve. The master cylinder pressure set in accordance with the deviation between the master cylinder pressure and the pressure command value at the time and the braking pressure of the braking means coincide with the braking pressure of the braking means. I have.

In the invention according to claim 2, the first
And the switching control for switching the opening and closing of the second solenoid on-off valve is performed after a set time set based on the deviation between the master cylinder pressure and the pressure command value at the time of occurrence of the abnormality. In addition to this, there is no need to detect the braking pressure of the braking means, and the configuration can be simplified.

Further, a brake control device according to a third aspect of the present invention includes a master cylinder for outputting a working fluid having a braking pressure corresponding to an amount of depression of a brake pedal, a braking means for generating a braking force for braking wheels, and A stroke simulator for absorbing the working fluid output from the cylinder, a hydraulic pump for pressurizing the working fluid and an external braking pressure generating means having a pressure accumulating means for accumulating the pressure on the outlet side thereof; A pressure control valve for outputting an arbitrary braking pressure to the braking means, a first solenoid on-off valve inserted between the master cylinder and the braking means, and an interposed valve between the stroke simulator and the master cylinder. A second solenoid on-off valve for intermittently controlling the flow of the working fluid, a brake depression amount detecting means for detecting a depression amount of the brake pedal, The pressure control valve is controlled in accordance with a braking pressure command value based on a brake pedal depression amount detected by a depression amount detection unit and a braking pressure command value from another control unit, and the first electromagnetic on-off valve is closed. A brake control device for controlling the second electromagnetic on-off valve to be in an open state; and a master cylinder pressure detecting device for detecting a brake pressure of the master cylinder; Control valve abnormality detecting means for detecting that the pressure of the pressure control valve is normal when the control valve abnormality detecting means detects abnormality and the brake pedal depression amount detecting means detects depression of the brake pedal. The command value is corrected stepwise so as to match the offset set pressure lower than the master cylinder pressure detected by the master cylinder pressure detection means. It is characterized in that the braking pressure and a abnormality processing unit that the first electromagnetic on-off valve and the second electromagnetic valve in an open state respectively switching control to the closed state after a match.

According to the third aspect of the present invention, when the pressure control valve fails to reduce the pressure, a pressure command value for the normal pressure control valve is set to a step-off pressure lower than the master cylinder pressure. Therefore, the braking pressure of the braking means on the normal pressure control valve side is controlled to be lower than the master cylinder pressure, and after this reaches the set pressure, the first solenoid on-off valve is opened and the second solenoid on-off Since the valve is closed and the master cylinder pressure is directly supplied to both braking means, the high braking pressure in the braking means in which the pressure reduction abnormality has occurred is canceled by the low braking pressure in the normal braking means.
Variations in the master cylinder pressure can be prevented.

Further, the brake control device according to a fourth aspect of the present invention includes a master cylinder that outputs a working fluid having a braking pressure corresponding to an amount of depression of a brake pedal, a braking unit that generates a braking force for braking a wheel, A stroke simulator for absorbing the working fluid output from the master cylinder,
An external braking pressure generating means having a fluid pressure pump for pressurizing a working fluid and a pressure accumulating means for accumulating an output pressure of the working fluid, and a pressure control for reducing the accumulated pressure of the accumulating means and outputting an arbitrary braking pressure to the braking means A valve, a first electromagnetic opening / closing valve interposed between the master cylinder and the braking means, and a second electromagnetic valve for intermittently controlling the flow of the working fluid interposed between the stroke simulator and the master cylinder. An on-off valve,
A brake depression amount detection means for detecting the depression amount of the brake pedal, a braking pressure instruction value based on the brake pedal depression amount detected by the brake depression amount detection means, and a braking pressure instruction value from another control means. A brake control means for controlling the pressure control valve and for controlling the first solenoid on-off valve to be closed and the second solenoid on-off valve to be open, respectively. Master cylinder pressure detecting means for detecting the pressure control valve, the control valve abnormality detecting means for detecting that the pressure control valve is in a low pressure abnormal state to maintain a low pressure state regardless of the pressure command value,
A master cylinder in which the master cylinder pressure detecting means detects a normal pressure command value for the pressure control valve when the control valve abnormality detecting means detects an abnormality and the brake pedal depression amount detecting means detects a depression of a brake pedal; The first solenoid on-off valve is opened and the second solenoid on / off control is performed after the cancellation on set pressure and the braking pressure of the braking means coincide with each other so as to match the canceling set pressure higher than the pressure. Abnormality processing means for switching control of each valve to a closed state.

[0013] In the invention according to the fourth aspect, the pressure command value is input through the pressure control valve.
When a low pressure abnormality that maintains the state where the braking pressure is low occurs, the braking pressure of the braking means controlled by the abnormal pressure control valve is lower than the master cylinder pressure. Since the pressure command value of the control valve is changed stepwise to the offset set pressure higher than the master cylinder pressure, the braking pressure of the braking means controlled by the normal pressure control valve is controlled to be higher than the master cylinder pressure, In this state, the first solenoid on-off valve is switched to the open state and the second solenoid on-off valve is switched to the closed state, and the master cylinder pressure is directly supplied to both braking means. Since the braking pressure is canceled by the braking pressure of the normal braking means, the fluctuation of the master cylinder pressure can be prevented.

Further, in the brake control device according to a fifth aspect, in the invention according to the third or fourth aspect, the abnormality processing means may be configured to control switching of the first solenoid on-off valve and the second solenoid on-off valve. The master cylinder pressure set in accordance with the deviation between the set offset pressure and the pressure command value at the time of occurrence of an abnormality and the braking pressure of the braking means are set to be performed after a lapse of a set time necessary and sufficient for the braking pressure to match. It is characterized by.

In the invention according to claim 5, the first aspect
The switching control for switching the opening and closing of the second electromagnetic on-off valve is performed after a set time set based on the deviation between the set pressure and the pressure command value when an abnormality occurs, so that the switching control is appropriately performed. In addition to this, there is no need to detect the braking pressure of the braking means, and the configuration can be simplified.

According to a sixth aspect of the present invention, in the brake control device according to the second or fifth aspect, the abnormality processing means includes a fluid temperature detecting means for detecting a working fluid temperature;
When the temperature detected by the fluid temperature detecting means is high, the setting time is corrected to be short, and when the temperature is low, the correcting means is corrected to lengthen the setting time.

In the invention according to the sixth aspect, since the set time is changed in accordance with the temperature of the working fluid, it is possible to set an necessary and sufficient set time by compensating for an error due to a change in viscosity. Further, in the brake control device according to claim 7, in the invention according to any one of claims 2, 5, and 6, the abnormality processing means may include a brake unit that compares a set time for the front wheel with a set time for the rear wheel. It is set to be long according to the fluid pressure-fluid amount characteristic of the above.

In the invention according to claim 7, since the set time is set according to the hydraulic pressure-fluid amount characteristics of the front and rear wheels, the optimum set time can be set by the front and rear braking means.

[0019]

According to the first aspect of the present invention, in a normal state where the braking means is controlled to a braking pressure higher than the master cylinder pressure, an abnormality occurs in the external braking pressure generating means and the supply to the pressure control valve is performed. When the pressure drops, the pressure command value is changed in steps to match the master cylinder pressure,
Since the first solenoid on-off valve is opened and the second solenoid on-off valve is closed after the braking pressure of the braking means matches the master cylinder pressure, the braking pressure of the braking means is set to the master cylinder pressure in a short time. In this state, the master cylinder pressure will be supplied to the braking means, and the brake will return to the normal braking state in a short period of time, while reliably preventing the master cylinder pressure from fluctuating and applying a kickdown force to the brake pedal. Can be surely prevented.

According to the second aspect of the present invention, the first
And the switching control for switching the opening and closing of the second solenoid on-off valve is performed after a set time set based on the deviation between the master cylinder pressure and the pressure command value at the time of occurrence of the abnormality. In addition to this, there is no need to separately provide a sensor for detecting the braking pressure of the braking means, and the configuration can be simplified.

Further, according to the third aspect of the present invention, when a pressure reduction abnormality occurs in which the pressure control valve cannot reduce the pressure,
The pressure command value for the normal pressure control valve was changed stepwise to the offset set pressure lower than the master cylinder pressure, and the braking pressure of the normal pressure control valve side braking means reached the offset set pressure lower than the master cylinder pressure. Later, the master cylinder pressure is supplied directly to both braking means, so that the high braking pressure in the braking means in which the decompression abnormality has occurred is canceled by the low braking pressure in the normal braking means, and the normal braking state is restored in a short time. At the same time, the effect of reliably preventing the master cylinder pressure from fluctuating and preventing the kickdown force from being applied to the brake pedal can be obtained.

Further, according to the present invention, when the pressure control valve has a low pressure abnormality that maintains a low braking pressure regardless of the pressure command value, the pressure command value for the normal pressure control valve is changed. Stepwise change to the offset setting pressure higher than the master cylinder pressure, and after the normal braking pressure of the braking means on the pressure control valve side reaches the offset setting pressure higher than the master cylinder pressure, apply the master cylinder pressure directly to both braking means. By supplying, the low braking pressure in the braking means where the low pressure abnormality has occurred is canceled by the high braking pressure in the normal braking means,
In addition to returning to the normal braking state in a short time, the effect of reliably preventing the master cylinder pressure from fluctuating and preventing the kick down force from being applied to the brake pedal can be obtained.

According to the fifth aspect of the present invention, the switching control for switching the opening and closing of the first and second solenoid on-off valves is set based on the deviation between the set pressure and the pressure command value when an abnormality occurs. Since the switching is performed after the set time elapses, the switching control can be appropriately performed, and it is not necessary to separately provide a sensor for detecting the braking pressure of the braking unit, and the configuration can be simplified. Is obtained.

According to the sixth aspect of the present invention, since the set time is changed in accordance with the temperature of the working fluid, an error due to a change in viscosity can be compensated to set a necessary and sufficient optimum set time. The effect is obtained. Further, according to the seventh aspect of the present invention, since the set time is set according to the hydraulic pressure-fluid amount characteristics of the front and rear wheels, the effect that the optimal set time can be set by the front and rear braking means can be obtained. can get.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention. In the drawing, reference numeral 1 denotes a drive wheel, for example, a front wheel side and a rear wheel side as a driven wheel, which correspond to the amount of depression of a brake pedal 2. Front-wheel master pressure PMf of the system
And a common pressurizing chamber for generating a working fluid of the rear wheel side master pressure PMr.
Are front wheel side output port p1 and rear wheel side output port p2, respectively.
Output from the master cylinder.

The working fluid of the front wheel side master pressure PMf output from the master cylinder 1 is supplied to the first solenoid on-off valve 3FL.
And 3FR are respectively supplied to one input port p1 of the
The working fluid of the rear wheel side master pressure PMr is supplied to one port p1 of the same first electromagnetic switching valves 3RL and 3RR, respectively.

The other ports p2 of the solenoid valves 3FL, 3FR and 3RL, 3RR are connected to the left and right front wheels 4F.
L, 4FR and a wheel cylinder 5F as a braking cylinder for applying a braking force to the left and right rear wheels 4RL, 4RR.
L, 5FR and 5RL, 5RR.

Each of the solenoid valves 3FL to 3RR is set to a 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 solenoid valve 3FL is connected between the port p1 and the port p2. Are communicated to open, 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, and the port is closed.

On the other hand, the reservoir 1a of the master cylinder 1
Is connected to a suction side of a hydraulic pump 8 as a fluid pressure pump rotated and driven by an electric motor 7, and an accumulator 9 as a pressure accumulating means is connected to a discharge side of the hydraulic pump 8. The accumulated pressure of the accumulator 9 is Pressure control valves 11FL, 11FR and 1 having a spool of
It is supplied to supply ports ps of 1RL and 11RR.

Here, when the accumulated pressure of the accumulator 9 becomes equal to or less 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 to be described later. 9 is increased to a second set pressure higher than the first set pressure.

A stroke simulator 13 is connected to the front wheel output port p1 of the master cylinder 1 via a second solenoid valve 12. The stroke simulator 13 simulates the amount of oil consumed and absorbs and consumes the amount of oil discharged from the master cylinder 1 when the braking pressure is controlled by the pressure control valves 11FL to 11RR. It is configured to ensure the feeling of stepping on the pedal.

As shown in FIG. 1, a specific configuration of the stroke simulator 13 includes a cylindrical housing 17 having both ends closed, and a slidably disposed housing 17 inside the housing 17 and an upper chamber. 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 third electromagnetic on-off valve 12 via the input / output port 21.

Further, the control ports pc of the pressure control valves 11FL, 11FR and 11RL, 11RR are directly connected to the wheel cylinders 5FL, 5FR and 5RL, 5RR, and the return port pd is directly connected to the reservoir 1a of the master cylinder 1. . Here, the pressure control valves 11FL-
As shown in FIG. 2, each of 11RRs is a control signal CS _{FL to} CS _RR composed of a current value input to the electromagnetic solenoid s1.
And outputs a braking pressure Pc having a value proportional to.

The brake pedal 2 is provided with an oil temperature sensor 22 for detecting the operating oil temperature, for example, in a pipe provided on the outlet side of the master cylinder 1, and a stroke sensor 22 for detecting its stroke. A master pressure sensor as master pressure detection means for detecting a front wheel side master cylinder pressure PMr of the working fluid discharged from the master cylinder 1 is provided in a hydraulic pipe connected to the rear wheel side port p2 of the master cylinder 1. The accumulator 9 is provided with a pressure accumulation sensor 24 for detecting the accumulated pressure.

Then, the first solenoid on-off valves 3FL to 3R
R, the second electromagnetic on-off valve 12 is controlled by a control unit 30 including, for example, a microcomputer. The control unit 30, oil temperature hydraulic oil temperature To detected by the sensor 22, the accumulator PA is detected by the detection signal DP _M, and accumulator sensor 24 rear wheel side master pressure PMr detected by the master pressure sensor 23 Input, and based on these, perform predetermined arithmetic processing to obtain the first
Of the electromagnetic on-off valves 3FL to 3RR and the second electromagnetic on-off valve 12.

That is, a required deceleration, that is, a required braking pressure is calculated based on the front wheel side master pressure PMr detected by the master pressure sensor 23, and a pressure command value corresponding thereto is obtained. A side slip suppression control device 31, an anti-lock brake control device 32, which maintains a vehicle side slip state in an appropriate state by controlling a braking force;
Based on the pressure command value from the traction control device 33, a target wheel cylinder pressure as a pressure command value for the pressure control valves 11FL to 11RR is calculated, and the wheel cylinder pressure is controlled accordingly. When an abnormality occurs in the external pressure generating means such as the hydraulic pump 8 and the accumulator 9 and the pressure control valves 11FL to 11RR, the wheel cylinder pressure is made to coincide with the master cylinder pressure in a short time, and then the first solenoid on-off valve 3FL is used. ~ 3
RR is opened, the second solenoid valve 12 is closed, and the master cylinder pressure is directly applied to the wheel cylinders 5FL to 5FL.
5RR to return to the normal braking state.

Next, a description will be given of an example of a brake control processing procedure in which the operation of the above embodiment is executed by the control unit 30, with reference to the flowcharts of FIGS.
That is, the control unit 30 executes the brake control process shown in FIG.

In the brake control process, first, in step S1, the accumulator pressure P
A, and then proceeds to step S2 to determine whether or not the read accumulator pressure PA is normal in the external braking pressure generating means constituted by the hydraulic pump 7, the electric motor 8, and the accumulator 9 which is set in advance. It is determined whether or not the pressure is equal to or higher than a relatively high set pressure PAs, which is a threshold for determination. If PA ≧ PAs, it is determined that the external braking pressure generating means is normal, and the process proceeds to step S3.

In step S3, the master pressure sensor 2
The master cylinder pressure PMr detected in step 3 is read, and then the process proceeds to step S4, where the read master cylinder pressure PMr is set to a relatively small predetermined threshold value PMs
(For example, a small value of about 1 MPa) is determined, and when PMr ≦ PMs, the brake pedal 2 is not depressed or the brake is slightly depressed, or the brake is very gentle. Yes, pressure control valve 11FL ~
It is determined that there is no need for the braking control using 11RR, and the process proceeds to step S5.

In step S5, it is determined whether or not pressure command values have been input from the other antilock brake control devices 31, traction control devices 32, and sideslip suppression control devices 33. Then, the process proceeds to step S6, where the first solenoid on-off valve 3FL
To 3RR, a control signal _SD of a logical value "0" for maintaining an open state is output, and the remaining second solenoid valve 1
0F and 10R, and outputs a control signal S _E of a logical value “0” for maintaining a closed state.
The pressure command value CP for 1RR is changed to the master cylinder pressure PM
Then, the process returns to step S1.

On the other hand, if the result of the determination in step S4 is PMr
> PMs, the pressure control valves 11FL to 11R
It is determined that braking control using R is required, and the process proceeds to step S7, where the first electromagnetic on-off valves 3FL to 3R
The R and outputs a control signal S _D of the logic value "1" to the closed state to output a control signal S _E of logic value "1" to the remaining second electromagnetic switching valve 10F, and 10R open state Then, the process proceeds to step S8.

In step S8, a required braking force DB corresponding to the deceleration requested by the driver is calculated based on the master cylinder pressure PMr, and a pressure command value CP capable of generating the required braking force DB is calculated. Then, this is updated and stored in a predetermined storage area of the storage device, and then the process proceeds to step S9.

In step S9, the anti-lock brake control device 31, the traction control device 32
It is determined whether or not a pressure command value has been input from any of the side slip suppression control devices 33, and if a pressure command value has not been input therefrom, the process directly proceeds to step S11 and the pressure stored in the storage device is determined. The command value CP is output to each of the pressure control valves 11FL to 11RR, and the other control devices 31
If the pressure command value has been input from step S33 to step S10, the process proceeds to step S10, where the antilock brake control device 3
When the pressure command value is from 1, the pressure command value is prioritized to the pressure command value CP calculated in step S8, and when the pressure command value is the remaining pressure command value of the traction control device 32 and the side slip suppression control device 33, A value obtained by adding the pressure command value of the pressure command value to the pressure command value CP calculated in step S8 is updated and stored as a pressure command value CP in a predetermined storage area of the storage device, and then the process proceeds to step S11.

In step S11, the 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 the determination in step S2 is PA <PAs, it is determined that an abnormality has occurred in the external braking pressure generating means including the hydraulic pump 7, and the process proceeds to step S12 to perform external braking pressure abnormality processing. Then, the process returns to step S1.

As shown in FIG. 4, this external braking pressure abnormality processing first reads the master cylinder pressure PMr detected by the master pressure sensor 23 in step S21, and then proceeds to step S22 to execute the processing shown in FIG. As in S4, it is determined whether or not the master cylinder pressure PMr is higher than a relatively small set pressure PMs set in advance.
If it is PMs, it is determined that the vehicle is in the braking state, and the routine goes to Step S23.

In step S23, the pressure control valve 11
The current master cylinder pressure PMr is set as the pressure command value CP (n) of FL to 11RR, and this is updated and stored in a predetermined storage area of the storage device.
After outputting to 1RR, the process proceeds to step S24.

In step S24, the above step S
The absolute value of the value obtained by subtracting the master cylinder pressure PMr from the pressure command value CP (n-1) before being set at 23 is used as the pressure deviation ΔP _W1
Then, the process proceeds to step S25 to calculate the front wheel side set time t _1F and the rear wheel side set time t _1R with reference to the set time calculation map shown in FIG. 5 based on the pressure deviation ΔP _W1 . .

Here, the set time calculation map is shown in FIG.
As shown, the horizontal axis shows the pressure deviation ΔP_W1And set the vertical axis
Take time to set the front wheel side set time t_1FFor the pressure deviation Δ
P_W1Is “0” when “0” is
Deviation ΔP_W1Increases as the front wheel side set time t_1FIncreased
Characteristic line L increasing at an inclination angle of approximately 45 degrees _F
Is set, and the rear wheel side set time t_1RAbout the pressure deviation
ΔP_W1Is “0” when “0” is
Force deviation ΔP_W1Increases as the front wheel side set time t_1Fof
The characteristic line L is set so that the amount of increase is about half._FAbout half of
The characteristic line L that increases at an angle of about_RIs set on the front wheel side
And the set time is set according to the fluid pressure-fluid characteristics on the rear wheel side.
It is.

Next, the operation proceeds to step S26, in which the operating oil temperature To detected by the oil temperature sensor 22 is read. Then, the operation proceeds to step S27, in which the read operating oil temperature T is read.
Based on o, the set time correction value Δto is calculated with reference to the correction value calculation map shown in FIG.

Here, as shown in FIG. 6, the correction value calculation map shows that the correction value Δto becomes “1” when the hydraulic oil temperature To is the preset temperature Ts, and the hydraulic oil temperature To is As the temperature decreases, the curvature decreases and becomes steep, and the correction value Δto rapidly increases in a direction larger than “1”. Conversely, as the hydraulic oil temperature To increases beyond the set temperature Ts, the curvature gradually increases and the correction value Δto increases. Δto gradually "1" characteristic curve L _T which decreases to a smaller direction is set, the correction value Δto in accordance with the reduction characteristics of the output pressure at the pressure control valve 11FL~11RR is set.

Next, the process proceeds to step S28, where the set times t _1F and t _1R calculated in step S25 are changed to step S1.
The front wheel side set time t _F and the rear wheel side set time t _R are calculated by multiplying the correction value Δto calculated at 27, and these set times are set in a timer, and then the process proceeds to step S29.

In step S29, it is determined whether or not the rear wheel side set time t _R has elapsed. If not, the process waits until the time elapses. Solenoid on-off valve 3RL, 3RR
The control signal _SDR having the logical value “0” for opening the control signal _SDR is output, and the process proceeds to step S31.

In step S31, it is determined whether or not the front wheel side set time t _F has elapsed. If the time has not elapsed, the process waits until the time elapses. On-off valve 3FL, 3FR
The outputs a control signal S _DF of a logical value "0" to the open state, the external brake pressure from the output of the control signal S _E of logic value "0" to the second electromagnetic valve 12 closed The abnormality processing and the brake control processing of FIG. 3 are terminated.

On the other hand, when the result of the determination in step S22 is PMr≤PMs, it is determined that the vehicle is not in the braking state, and the flow shifts to step S33 to gradually open the first solenoid valves 3FL to 3RR. And outputs the duty control signals S _DF and S _DR that repeat “1” and “0”, and the logical value “0” for closing the second solenoid valve 12.
Outputs a control signal S _E to end the external braking圧異normal processing and the brake control process of FIG. 3 from the.

Therefore, if the external braking pressure generating means composed of the electric motor 7, the hydraulic pump 8, and the accumulator 9 is running in a normal state, the process of FIG. In the non-braking state where the brake pedal 2 is released and the pressure command value is not input from the other control devices 31 to 33, the master cylinder pressure PMr is substantially “0”. From step S5 to step S6, the first solenoid on-off valves 3FL to 3RR are controlled to open and the second solenoid on-off valve 12 is controlled to close, so that the master cylinder pressures PMf and PMr are directly Each wheel 4FL-4R
R is supplied to the wheel cylinders 5FL to 5RR for R. At this time, the pressure command value CP for the pressure control valves 11FL to 11RR also becomes substantially “0”, and the pressure control valve 11FL
By controlling the output pressure of RR to 11RR, that is, the braking pressure, to be substantially "0", the cylinder pressure supplied to each of the wheel cylinders 5FL, 5FR also becomes "0", and the non-braking state is maintained.

From this state, release the accelerator pedal,
When the brake pedal 2 is depressed instead, the front-wheel and rear-wheel master pressures PMf of the master cylinder 1 are correspondingly increased.
And PMr increase, and the front wheel side master pressure PMf becomes the set pressure P
Until Ms is reached, the process proceeds to step S6, where the electromagnetic on-off valves 3FL to 3RR are held at the normal position, and the pressure command values CP of the pressure control valves 11FL to 11RR are maintained.
Is increased in accordance with the increase of the front wheel side and rear wheel side master pressures PMf and PMr so as to coincide therewith.

In this state, when the front-wheel-side master pressure PMr reaches the set pressure PMs, the process shifts from step S4 to step S7, where the first solenoid valves 3FL to 3RR are both switched to the offset positions and closed. At the same time, the second solenoid valve 12 is also switched to the offset position and switched to the open state.

As a result, the front wheel side and rear wheel side master pressures PMf and PMr output from the master cylinder 1 are supplied to the stroke simulator 17 via the second solenoid valve 12, while the master pressure PMf and PMr are changed according to the master cylinder pressure PMr. The pressure command value CP for each of the pressure control valves 11FL to 11RR is calculated individually, and these are calculated by the pressure control valves 11FL to 11F.
By being output to R, the braking pressure corresponding to this is directly supplied to the wheel cylinders 4FL to 4RR on the front wheel side and the rear wheel side.

At this time, the pressure control valves 11FL to 11RR
Are controlled to be equal to the rear wheel side master pressure PMr. Therefore, when switching from the master cylinder pressure to the output pressure of the pressure control valve, the wheel cylinders 4FL to 4F
The braking pressure itself input to R does not fluctuate, and does not give the driver an uncomfortable feeling.

By shifting to the turning state in this braking state, when the vehicle side slip amount is larger than the target side slip amount, the side slip amount is made to coincide with the target side slip amount.
When the pressure command value for increasing the braking force for the predetermined wheel is input to the control unit 30, in step S10, the pressure command value CP based on the master cylinder pressure PMr for the corresponding wheel is changed to the pressure command value for sideslip suppression in step S10. Is added to the wheel cylinder 5FL or 5FR as a pressure command value, so that the braking pressure is increased and the side slip suppression control can be performed while performing the braking control.

When a pressure command value for suppressing the slip of the driving wheels is input from the traction control device 31 to the control unit 30 in a non-braking state in which the brake pedal 2 is not depressed, the master cylinder pressure PMr becomes "0". Is continued from step S4 to step S5.
7, the braking pressure corresponding to the traction control pressure command value is output from the pressure control valves 11RL, 11RR to the wheel cylinders 5RL, 5RR, and traction control is performed with the slip of the drive wheels suppressed.

During the traction control, when the vehicle enters a turning state and a pressure command value for suppressing the amount of side slip is supplied to the control unit 30, the pressure command value for the corresponding wheel is increased, and the traction control and the side slip suppression control are performed. And are executed simultaneously. On the other hand, for example, in the braking turning state, as shown in FIG. 7, one of the pressure control values is obtained by adding the pressure command value CP based on the master cylinder pressure and the pressure command value from the side slip suppression control device 33. Valve 11i
(I = FL, FR, RL, RR) is controlled, and the braking pressure of the wheel cylinder 5i is reduced to the master cylinder pressure PMr
Under the higher control state, at time t ₁ , an abnormality occurs in the electric motor 7, the hydraulic pump 8, the accumulator 9, and the piping, and the accumulator pressure P detected by the pressure accumulation sensor 24.
When A falls below the set pressure PAs, in the process of FIG.
The process proceeds from step S2 to step S12, and the external braking pressure abnormality process of FIG. 4 is executed.

In this external braking pressure abnormality processing, the braking state is established, and the master cylinder pressures PMf and PMr are in a high state. Therefore, the process shifts from step S22 to step S23, and the pressure command value CP (n) is changed to the master cylinder pressure PMr. Is output to each of the pressure control valves 11FL to 11RR at the same time.

For this reason, as shown in FIG. 7, the pressure command value CP immediately decreases to the master cylinder pressure PMr, and the braking pressure WP supplied to the wheel cylinder 5i in response thereto.
Also starts decreasing with a predetermined response delay. In this state, the first electromagnetic on-off valve 3i is kept in the closed state, and the braking pressure control by the pressure control valve 3i has priority.

Then, in step S24, the absolute value of the value obtained by subtracting the master cylinder pressure PMr from the previous pressure command value CP (n-1) is calculated to calculate the pressure deviation ΔP _W1 , and this pressure deviation is calculated. _{Next, the} front wheel side set time t _1F and the rear wheel supplementary set time t _1R are calculated with reference to the set time calculation map of FIG.

[0066] On the other hand, the hydraulic oil temperature To detected by oil temperature sensor 22 with reference to the correction value calculation map in FIG. 6 based on correction values are calculated .DELTA.To, which the front wheel set time t _1F and the rear wheel side By multiplying by the set time t _1R , a front wheel set time t _F and a rear wheel set time t _R are calculated.

Therefore, in the state shown in FIG. 7, the pressure command value by the side slip suppression control is added, the pressure command value CP is higher than the master cylinder pressure PMr, and the pressure deviation ΔP _W1 between them becomes a large value. because there, controlled wheel is when a front wheel is the front wheel set time t _F is set which corresponds to the pressure difference in accordance with the characteristic line L _F in FIG. 5, when a rear wheel of the pressure deviation in accordance with the characteristic line L _R in Fig. 5 A rear wheel side set time t _{R of} about half is set, and this is multiplied by a correction value Δto depending on the operating oil temperature to calculate a relatively long set time t _j (j = F, R).

For this reason, since the first solenoid on-off valve 3i is controlled to be closed until the set time t _j elapses, the braking pressure by the pressure control valve 11i is supplied to the wheel cylinder 5i. And the wheel cylinder 5
i As brake pressure is shown in Figure 7, the decreased in a relatively short period of time by the response characteristic of the pressure control valve 5i, reaches substantially the master cylinder pressure PMr just before the elapse of the set time t _j.

Thereafter, the time t ₂ when the set time t _j has elapsed
Then, the first electromagnetic opening / closing valve 3i is controlled to the open state, and the master cylinder pressure PMf or PMr is directly supplied to the wheel cylinder 5i, and the braking pressure of the wheel cylinder 5i is controlled by the master cylinder pressure PMf or PMr. As a result, the side slip suppression control is stopped, and the vehicle enters the normal braking state, so that the necessary minimum braking force can be secured.

Similarly, the other pressure control valves perform the same processing as described above, so that, for example, for a pressure control valve to which no pressure command value is added by the side slip suppression control, the pressure command value CP is set to the master cylinder. Since the pressure deviation is approximately equal to the pressure PMr, the pressure deviation ΔP _W1 becomes substantially “0”, so that the set time t _j becomes substantially “0”, and the corresponding first solenoid on-off valve is immediately opened from the closed state. Is switched to

As described above, according to the first embodiment, when an abnormality occurs in the external braking pressure generating means composed of the electric motor 7, the hydraulic pump 8, the accumulator 9, and the like, and the braking pressure decreases, In response to the execution of the external braking pressure abnormality processing, the pressure command value is immediately reduced to the master cylinder pressure in the pressure control valve that outputs the pressure command value CP higher than the master cylinder pressure PMr. is reduced brake pressure in a short time to be supplied to the relevant wheel cylinder, which is immediately after reaching the master cylinder pressure PMr, the set time t _j has elapsed, the first electromagnetic on-off valve is switched to the open state, The master cylinder pressure is supplied directly to the wheel cylinders. When switching from the braking pressure controlled by the pressure control valve to the master cylinder pressure, the master cylinder pressure is changed. It is possible to reliably prevent the pressure fluctuates, it is possible to maintain the pedal feeling of the driver.

Incidentally, when an abnormality occurs in the external braking pressure generating means as in the conventional example, the first solenoid on-off valve 3FL
8 through 3RR, the output pressure of the pressure control valve, that is, the braking pressure of the wheel cylinders 5FL-5RR is gradually increased due to the response delay of the pressure control valve, as shown in FIG. Therefore, the braking pressure flows toward the master cylinder side during the lowering, and the master cylinder pressure rises, thereby causing a so-called kickback phenomenon in which the brake pedal 2 is pushed back, giving the driver an uncomfortable feeling.

However, in the first embodiment,
As described above, the first solenoid valves 3FL to 3RR are opened after the braking pressures of the wheel cylinders 5FL to 5RR match the master cylinder pressure, so that fluctuations in the master cylinder pressure can be reliably prevented. Thus, the kickback phenomenon can be reliably prevented, and the driver's pedal depression feeling can be ensured.

Further, the set time t _j is set in accordance with the pressure deviation ΔP _W1 between the pressure command value immediately before the occurrence of the abnormality and the master cylinder pressure, and the hydraulic pressure-fluid amount characteristic between the front wheel side and the rear wheel side. Therefore, even if the switching control of the electromagnetic opening / closing valve is performed by timer control, the first electromagnetic opening / closing operation is performed immediately after the braking pressure of the wheel cylinders 5FL to 5RR matches the master cylinder pressure. Valve 3FL ~
3RR can be switched from the closed state to the open state.

Further, a correction value Δto is calculated for the set time t _{j based} on the hydraulic oil temperature To, and this is calculated as the set times t _1F and t _{1F.
Since 1R} is multiplied, an accurate setting time follows the output pressure at the pressure control valves 11FL to 11RR due to a viscosity change due to a change in hydraulic oil temperature, that is, a change in the reduction rate of the braking pressure of the wheel cylinders 5FL to 5RR. Can be set.

In the first embodiment, the case where the abnormality of the external braking pressure generating means is performed by monitoring the accumulator pressure PA has been described. However, the present invention is not limited to this. The abnormality may be detected by the detection value of the motor current sensor, or the rotation speed of the hydraulic pump 8 may be detected by an encoder or the like, and the abnormality of the hydraulic pump 8 may be directly detected.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, an attempt is made to cope with a case in which an output pressure abnormality occurs in the pressure control valve instead of the external braking pressure abnormality in the above-described first embodiment. In the second embodiment, as shown in FIG. 9, the pressure accumulation sensor 24 is omitted in the configuration of FIG. 1 in the first embodiment, and the output of each of the pressure control valves 11FL to 11RR is replaced with this. Output pressure sensors 35FL to 35RR for detecting pressures are provided, and braking pressures BP _{FL to} BP _FL detected by these output pressure sensors 35FL to 35RR are provided.
P _RR is input to the control unit 30. Further, third electromagnetic on-off valves 41F and 41R are interposed between the accumulator 9 and the supply side ports ps of the pressure control valves 11FL, 11FR and 11RL, 11RR, and the return port pd
Between the solenoid valve and the reservoir 1a.
Except that 2R is interposed, it has the same configuration as in FIG. 1, and the same reference numerals are given to portions corresponding to FIG. 1, and the detailed description thereof is omitted.

The program executed by the controller unit 30
As shown in FIG.
Steps S1, S2 and S12 in FIG. 3 are omitted.
Instead of these, output pressure sensors 35FL to 35RR are used.
The detected braking pressure BP_FL~ BP _RRStep 41 for reading
And any of the read braking pressures BP_i(I = FL to RR)
Is the pressure command value CP_iGiven value x_TwoPressure below the sum of
Force command value CP_iGiven value x_TwoIs greater than or equal to
Step S32 to determine whether or not this step S42
Is BP_i> CP_i+ X_TwoOr BP_i<CP_i
-X_TwoWhen the pressure control valve 11i is abnormal.
Step S43 of determining and executing the pressure control valve abnormality process
Is provided, and the determination result of step S42 is CP_i+ X
_Two≧ BP_FL~ BP_RR≧ CP_iStep when -x
The same processing as in FIG. 3 is performed except for shifting to S3.
The same step numbers are assigned to the processing corresponding to FIG.
The detailed description is omitted here.

Further, as shown in FIG. 11, in the pressure control valve abnormality processing, steps S23 and S24 and steps S28 to S32 in the first embodiment are omitted, and step S44 is performed instead of steps S23 and S24.
4 to S47, and the same processing as in FIG. 4 is performed except that steps S48 to S53 are provided instead of steps S28 to S32, and the processing corresponding to FIG. The detailed description thereof is omitted.

Then, step S44 is replaced with step S2
When the determination result of 2 is PMr> PMs, the braking pressure B
P_iIs the pressure command value CP_iGiven value x_TwoAbove
It is determined whether or not it is rotating, and the result of this determination is BP_i<C
P_i-X_Two, The output pressure is applied to the pressure control valve 11i.
Pressure command value CP_iAbnormal pressure drop, which is much lower
It is determined that it has occurred, and the process proceeds to step S45,
Normal pressure control valve paired with the pressure control valve 11i
Pressure command value CPk (n) for 11k (k = FL to RR)
-1) is the master cylinder pressure PMr
Deviation between output pressure of force control valve 11i and master cylinder pressure
Pressure compensation value Δp that can compensate for_TwoIs set to the value obtained by adding
This is output to the pressure control valve 11k, and is determined in step S44.
Fixed result is BP_i> CP_i+ X_TwoWhen the pressure control valve
11i is the output pressure CP _iIncrease more significantly
It is determined that a pressure increase abnormality has occurred, and step S4
6 and makes a pair with the abnormal pressure control valve 11i.
Pressure for normal pressure control valve 11k (k = FL-RR)
The master cylinder pressure PMr is used as the force command value CPk (n-1).
The output pressure of the pressure control valve 11i
Pressure compensation value Δp that can compensate for the deviation from the pressure_ThreeSubtract
And outputs it to the pressure control valve 11k.
Then, the process proceeds from steps S45 and S46 to step S47.
The pressure immediately before the calculated current pressure command value CPk (n)
From the force command value CPk (n-1) to the current pressure command value CPk (n)
Pressure difference ΔP, which is the absolute value of the value obtained by subtracting_W2Calculate
From step S25 to the pressure deviation ΔP_W2To
Based on the setting time calculation map shown in FIG.
Interval t_1jIs calculated.

On the other hand, after calculating the correction value Δto in step S27, the process proceeds to step S48, and the set time t _j is calculated by multiplying the set time t _1j calculated in step S25 by the correction value Δto calculated in step S27. At the same time, the timer for the set time t _j is started, and then, in step S4
Then, the process proceeds to step S9, and it is determined whether or not the set time t _j has elapsed. If not, the process waits until the time elapses.

In step S50, the above-described steps are performed.
Brake pressure BP as in step S44_iIs the pressure command value CP_iFrom
Predetermined value x_TwoDetermines whether the value is less than the value obtained by subtracting
And PBP_i<CP_i-X_TwoIs the step
The process proceeds to S51 to close the fourth solenoid on-off valve 42j.
Control signal S having a logical value "1"_GAnd then step
Move to S53, BP_i> CP_i+ X_TwoWhen
Moves on to step S52, where the third solenoid on-off valve 41
j is a control signal S of a logical value “1” for closing the state. _FOutput
Then, the process proceeds to step S53.

In step S53, the control signals S _Di and S of logical value “0” for opening the first solenoid valves 3i and 3k corresponding to the pair of pressure control valves 11i and 11k.
After outputting _Dk , the pressure control valve abnormality processing is ended. Therefore, when the pressure control valves 11FL to 11RR are in a normal state, the same operation as that in the first embodiment is performed.
It is assumed that the pressure command value based on the master cylinder pressure and the pressure command value from the side slip suppression control device 33 are added to _FL to set a pressure command value CP _FL higher than the master cylinder pressure. When the output port pc communicates with the return port pd to the valve 11FL for some reason, for example, and the braking pressure BP _FL of the wheel cylinder 5FL becomes “0” as shown in FIG. When this occurs, in the process of FIG.
The process proceeds from S42 to step S43, and the pressure control valve abnormality process of FIG. 11 is executed.

Therefore, since the vehicle is in the braking state, the flow shifts from step S22 to step S44, and the pressure control valve 11F
Since L is a pressure drop abnormality, the process proceeds to step S45, the pressure command value CP _FR for the pressure control valve 11FR forming the pressure control valve 11FL and the pair obtained by adding the compensation value Delta] p ₂ to the master cylinder pressure PMr The value is set to a value, and is output to the pressure control valve 11RL, so that the braking pressure BP _FR output from the normal pressure control valve 11RL is changed as shown in FIG.
As shown in FIG. 2, it starts to decrease with a predetermined response delay.

[0085] At this time, it calculates the pressure deviation [Delta] P _W2 from the deviation of the pressure command value, which from the normal pressure control valve 11FR, based on the reference to the characteristic curve L _F set time calculation map of FIG. 5 based on A required and sufficient set time t _1F is calculated so that the output braking pressure BP _FR reaches a value obtained by adding the compensation value Δp ₂ to the master cylinder pressure PMr.

When the set time has elapsed, the pressure drop is abnormal.
Then, the process goes to 1 to close the fourth electromagnetic on-off valve 42F,
This prevents the brake pressure from being released from the output port pc of the pressure control valve 11FL to the reservoir 1a via the return port pd, and then the first electromagnetic opening and closing 3FL, 3F
R at the same time as the open state, and the second solenoid on-off valve 12
Is closed.

For this reason, as shown in FIG. 12, the braking pressure B in the wheel cylinder 5FL on the pressure control valve 11FL side becomes abnormal with respect to the master cylinder pressure PMf on the front wheel side.
Since P _FL is “0” and the braking pressure BP _FR is higher than the master cylinder pressure PMf in the wheel cylinder of the normal pressure control valve 11FR that is paired with P _FL , the braking pressure BP _FR is abnormally braked by the pressure control valve. The pressure BP _FL can be offset to reliably prevent the master cylinder pressure PMf from fluctuating.

For the normal rear wheel side, similarly to the first embodiment, the pressure command value CP and the master cylinder pressure PM
A set time t _R corresponding to the deviation from r is set, and after the set time elapses, the pressure is switched to the master cylinder pressure PMr. Conversely, the supply side port ps and the output side port pc become in communication with the pressure control valve 11FL for some reason,
As shown in FIG. 13, the braking pressure BP _FL becomes the accumulator pressure P
A, and if a pressure increase abnormality higher than the pressure command value CP _FL occurs, the soot 42
Then, the process shifts to step S43 to execute the pressure control valve abnormality process of FIG.

Therefore, steps S44 to S44
In step 46, the pressure command value CP _FR is calculated by subtracting the compensation value Δp ₃ corresponding to the increase in the braking pressure BP _FL at the abnormal pressure control valve 11FL from the master cylinder pressure PMr. by being output to the pressure control valve 11FR, the output圧即Chi braking pressure BP _FR of the pressure control valve 11FR starts to decrease with a certain response delay, as shown in FIG. 13.

[0090] At this time, it calculates the pressure deviation [Delta] P _W2 from the deviation of the pressure command value, which from the normal pressure control valve 11FR, based on the reference to the characteristic curve L _F set time calculation map of FIG. 5 based on A required and sufficient set time t _1F is calculated for the output braking pressure BP _FR to reach a value obtained by subtracting the compensation value Δp ₃ from the master cylinder pressure PMr.

When the set time elapses, the pressure is always set, so that steps S50 to S5 are performed.
2, the third solenoid on-off valve 41F is closed,
This prevents the supply of the accumulator pressure PA from the supply port ps of the pressure control valve 11FL to the wheel cylinder 4FR via the output port pc, and then simultaneously opens the first electromagnetic switches 3FL, 3FR. At the same time, the second electromagnetic switching valve 12 is closed.

For this reason, as shown in FIG. 13, the braking pressure B in the wheel cylinder 5FL on the pressure control valve 11FL side becomes abnormal with respect to the master cylinder pressure PMf on the front wheel side.
P _FL is the accumulator pressure PA, as this braking pressure BP _FR in normal pressure control valve 11FR of the wheel cylinder of the pair is lower than the master cylinder pressure PMF, braking the brake pressure BP _FR is abnormal pressure control valve The pressure BP _FL can be offset to reliably prevent the master cylinder pressure PMf from fluctuating.

As described above, according to the second embodiment, when an abnormality occurs in any of the pressure control valves 11FL to 11RR, the pressure is canceled by the pressure of the pressure control valve paired with the pressure control valve in which the abnormality has occurred. Therefore, it is possible to reliably prevent the master cylinder pressure from fluctuating when the first electromagnetic on-off valve is in the open state, and to ensure the driver's pedal feeling.

In the second embodiment, the case where the pressure control valve is "0" or abnormal when the accumulator pressure PA is described. However, the present invention is not limited to this case. , The pressure command value CP _i and the braking pressure BP _{i at} that time are exceeded.
By setting the compensation value Δp ₂ or Δp ₃ according to the deviation from the above, any abnormality can be dealt with accurately.

Further, in each of the above-described 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, and regenerative braking in a hybrid vehicle or an electric vehicle is performed. Control can also be used together.

[Brief description of the drawings]

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

FIG. 2 is a characteristic diagram illustrating an output pressure characteristic with respect to a pressure command value of a pressure control valve according to the first embodiment.

FIG. 3 is a flowchart illustrating an example of a braking control processing procedure in a control unit.

FIG. 4 is a flowchart illustrating an example of a pump abnormality processing procedure in FIG. 3;

FIG. 5 is an explanatory diagram of a set time calculation map showing a relationship between a pressure deviation and a set time.

FIG. 6 is an explanatory diagram of a correction value calculation map showing a relationship between a hydraulic oil temperature and a correction value.

FIG. 7 is a time chart for explaining an operation of an external braking pressure abnormality process.

FIG. 8 is a time chart for explaining the operation of a conventional external brake pressure abnormality process.

FIG. 9 is a schematic configuration diagram showing a second embodiment of the present invention.

FIG. 10 is a flowchart illustrating an example of a braking control processing procedure in the control unit.

FIG. 11 is a flowchart illustrating an example of a pump abnormality processing procedure in FIG. 10;

FIG. 12 is a time chart for explaining the operation of the pressure control valve at the time of abnormal pressure drop.

FIG. 13 is a time chart for explaining the operation of the pressure control valve at the time of abnormal pressure increase.

[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 8 hydraulic pump 9 accumulator 11FL to 11RR pressure control valve 12 second electromagnetic switching valve 13 stroke Simulator 22 Oil temperature sensor 23 Master pressure sensor 24 Accumulation sensor 30 Control unit 32 Traction control device 33 Side slip amount control device. 35FL-35RR Output pressure sensor 41F, 41R Third electromagnetic on-off valve 42F, 42R Fourth electromagnetic on-off valve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mihiro Doi Nissan Motor Co., Ltd. F-term (reference) 3D046 BB01 BB05 BB17 BB29 CC02 CC04 EE01 HH02 HH15 HH16 JJ11 KK11 LL05 LL14 LL23 LL30 LL36 LL43 MM03 3D048 BB05 BB33 CC05 CC54 HH13 HH26 HH31 HH38 HH50 HH53 HH58 HH66 HH68 HH77 RR06 RR13 RR21 5H115 PA01 PG04 QE14 QE16 QI04 QI07 QI12 QN12 TO05 TO23 TO26

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 hydraulic pump for pressurizing the working fluid, and an external braking pressure generating means having a pressure accumulating means for accumulating an outlet pressure thereof,
A pressure control valve for controlling the pressure reduction of the pressure accumulating means to output an arbitrary braking pressure to the braking means, a first solenoid on-off valve interposed between the master cylinder and the braking means, A second solenoid on-off valve for intermittently controlling the flow of the working fluid inserted between the simulator and the master cylinder, brake depression amount detection means for detecting the depression amount of the brake pedal, and brake depression amount detection means. The pressure control valve is controlled in accordance with a braking pressure command value based on the detected brake pedal depression amount and a braking pressure command value from another control means, and the first electromagnetic on-off valve is closed and the second solenoid valve is closed.
Wherein the master cylinder pressure detecting means for detecting a braking pressure of the master cylinder and the external braking pressure generating means are in an abnormal state. Abnormality detecting means for detecting that the abnormality is detected by the abnormality detecting means, and when the brake pedal is depressed by the brake depression amount detecting means, a pressure command value for the pressure control valve is detected by a master cylinder pressure detecting means. The first solenoid valve is opened and the second solenoid valve is opened after the master cylinder pressure and the braking pressure of the braking means coincide with each other so as to match the master cylinder pressure detected in the stepwise. And an abnormality processing means for switching control of each of the brakes to a closed state. 2. The abnormality processing means according to claim 1, wherein the switching control of the first solenoid on-off valve and the second solenoid on-off valve is set according to a deviation between a master cylinder pressure and a pressure command value when an abnormality occurs. 2. The brake control device according to claim 1, wherein the control is performed after a lapse of a set time necessary and sufficient for the master cylinder pressure and the braking pressure of the braking means to match. 3. A master cylinder for outputting a working fluid having a braking pressure corresponding to the amount of depression of a brake pedal, a braking means for generating a braking force for braking wheels, and absorbing a working fluid output from the master cylinder. A stroke simulator, a hydraulic pump for pressurizing the working fluid, and an external braking pressure generating means having a pressure accumulating means for accumulating an outlet pressure thereof,
A pressure control valve for controlling the pressure reduction of the pressure accumulating means to output an arbitrary braking pressure to the braking means, a first solenoid on-off valve interposed between the master cylinder and the braking means, A second solenoid on-off valve for intermittently controlling the flow of the working fluid inserted between the simulator and the master cylinder, brake depression amount detection means for detecting the depression amount of the brake pedal, and brake depression amount detection means. The pressure control valve is controlled in accordance with a braking pressure command value based on the detected brake pedal depression amount and a braking pressure command value from another control means, and the first electromagnetic on-off valve is closed and the second solenoid valve is closed.
A brake control device for controlling the electromagnetic on-off valve to be in an open state, wherein the master cylinder pressure detecting means for detecting a braking pressure of the master cylinder and the pressure control valve are in a pressure reduction abnormal state. Control valve abnormality detection means for detecting the abnormality, and when the control valve abnormality detection means detects abnormality, and when the brake pedal depression amount detection means detects the depression of the brake pedal, the normal pressure command value for the pressure control valve The first solenoid on-off valve is corrected in a stepwise manner so as to match a set offset pressure lower than the master cylinder pressure detected by the master cylinder pressure detection means, and after the offset set pressure matches the braking pressure of the braking means. And an abnormality processing means for controlling the switching of the second solenoid on-off valve to a closed state. 4. A master cylinder for outputting a working fluid having a braking pressure corresponding to the amount of depression of a brake pedal, a braking means for generating a braking force for braking wheels, and absorbing the working fluid output from the master cylinder. A stroke simulator, a hydraulic pump for pressurizing the working fluid, and an external braking pressure generating means having a pressure accumulating means for accumulating an outlet pressure thereof,
A pressure control valve for controlling the pressure reduction of the pressure accumulating means to output an arbitrary braking pressure to the braking means, a first solenoid on-off valve interposed between the master cylinder and the braking means, A second solenoid on-off valve for intermittently controlling the flow of the working fluid inserted between the simulator and the master cylinder, brake depression amount detection means for detecting the depression amount of the brake pedal, and brake depression amount detection means. The pressure control valve is controlled in accordance with a braking pressure command value based on the detected brake pedal depression amount and a braking pressure command value from another control means, and the first electromagnetic on-off valve is closed and the second solenoid valve is closed.
A brake control device for controlling the electromagnetic on / off valve to be in an open state, wherein the master cylinder pressure detecting means for detecting the braking pressure of the master cylinder; and A control valve abnormality detecting means for detecting a low pressure abnormality state for maintaining a low pressure state, and an abnormality detected by the control valve abnormality detection means, and when the brake pedal depression amount is detected by the brake depression amount detection means, The pressure command value for the normal pressure control valve is corrected in a stepwise manner so as to match the offset set pressure higher than the master cylinder pressure detected by the master cylinder pressure detection means, and the offset set pressure and the braking pressure of the braking means are corrected. Abnormality processing means for controlling to switch the first electromagnetic on-off valve to the open state and the second electromagnetic on-off valve to the closed state after the coincidence. Brake control apparatus according to symptoms. 5. The abnormality processing means according to claim 1, wherein the switching control of the first solenoid on-off valve and the second solenoid on-off valve is set in accordance with a deviation between a set offset pressure and a pressure command value when an abnormality occurs. 5. The brake control device according to claim 3, wherein the control is performed after a lapse of a set time necessary and sufficient for the master cylinder pressure and the braking pressure of the braking means to match. 6. The abnormality processing unit includes: a fluid temperature detecting unit that detects a working fluid temperature; and a correction unit that corrects a set time short when the temperature detected by the fluid temperature detecting unit is high and corrects the set time long when the detected temperature is low. The brake control device according to claim 2 or 5, further comprising: means. 7. The abnormality processing means according to claim 1, wherein a set time for the front wheel is shorter than a set time for the rear wheel.
The brake control device according to any one of claims 2, 5, and 6, wherein the brake control device is set to be long according to a fluid amount characteristic.