JP2000219120A - Brake controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance controlling precision by preventing insufficient pressure intensification at the time of simultaneous pressure intensification of two wheels, in a brake controller having such structure as a plurality of wheel cylinders are connected to one system of a brake circuit. SOLUTION: This controller is provided with a controlling means (g) executing such automatic control as braking force is generated without a driver's braking operation by actuating both a fluid pressure controlling valve (e) and a supply switching means (j), based on the input from a vehicle-behavior detecting means (f). In this case, when the pressure of only one cylinder (b) of the same system is to be intensified, the operation of the liquid pressure control valve (e) is controlled, based on a first target value calculated by a target pressure intensifying/reducing value calculating means (g1). When the pressure of two cylinder wheels (b), (b) of the same system is to be intensified at the same time, the operation of the liquid pressure control valve (e) is controlled, based on a second target value, which is calculated by a second target value calculating means (g2) and is greater than the first target value.

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, and more particularly, to a brake control device even if a driver does not perform a braking operation.
Automatically generates braking force according to vehicle behavior and running conditions,
The present invention relates to a device that executes automatic braking control such as control for automatically decelerating or suppressing a driving force, or control for generating a yaw moment in a vehicle to stabilize the vehicle posture.

[0002]

2. Description of the Related Art Conventionally, so-called ABS control for preventing wheels from locking during braking, and automatic generation of braking force in accordance with vehicle behavior and running conditions even when a driver does not perform a braking operation. A brake control device that performs automatic braking control is known.

[0003] As such a conventional technique, for example, an apparatus described in Japanese Patent Publication No. 7-501506 is known. In this prior art, as a brake circuit connecting a master cylinder and a four-wheel wheel cylinder, two brake circuits connected to two-wheel wheel cylinders are provided, and each wheel cylinder is provided in the middle of each brake circuit. A hydraulic control valve capable of independently increasing and decreasing the pressure is provided.
Each of the brake circuits of the system is provided with a return pump for returning the brake fluid drained from the hydraulic pressure control valve to the upstream of the hydraulic pressure control valve, and a suction circuit is connected to the suction side of the return pump. Further, a charging piston is provided upstream of the brake circuit. The charging piston is configured to supply a predetermined amount of brake fluid to the suction circuit when the charging pump is driven.

Therefore, in this prior art, even when the driver is not performing a braking operation, when the charging pump and the return pump are driven, a predetermined amount of brake fluid is supplied from the suction circuit to the brake circuit, By activating the hydraulic pressure control valve, a required amount of brake fluid can be supplied to a wheel cylinder of a required wheel, and an arbitrary braking force can be generated.

[0005]

However, the above-mentioned prior art has the following problems to be solved.

In the above-described prior art, the calculation of the pressure increase time T when executing the automatic braking control is performed independently for each wheel. That is, the discharge amount of the pump per unit time is constant as shown in FIG. 23. Therefore, if the pressure increase time T is determined, the pressure increase amount is also determined. Therefore, the pressure increase time T according to the target pressure increase / decrease amount * △ P is determined for each wheel. However, the brake circuit in which the return pump discharges the brake fluid has a configuration in which two wheel cylinders are connected to one brake circuit. Therefore, when the two wheel cylinders of the same system, which are in substantially the same pressure state, are both supposed to be pressurized to the target pressure increase / decrease amount * △ P by the automatic braking control, the target pressure increase / decrease amount * で P alone for one wheel. If the pressure increase control is performed on both wheels based on the pressure increase time T for realizing the above, the supply amount from the pump is dispersed into two, and as shown in FIG. Was.

Further, during execution of the automatic braking control,
When the wheel cylinder pressures of the two wheels of the same system are already different, that is, when one is controlled to a high pressure state and the other to a low pressure state, the high pressure side holds the wheel cylinder pressure from this state, while the low pressure side When the control of increasing the pressure is performed, due to the relationship between the hydraulic pressure difference and the pump supply amount, if the pump supply amount is not sufficient, the hydraulic pressure upstream of the hydraulic pressure control valve is higher than the wheel cylinder pressure on the high pressure side. The pressure decreases and the high-pressure wheel cylinder pressure escapes to the low-pressure wheel cylinder via the check valve provided in parallel with the hydraulic pressure control valve, and the high-pressure wheel cylinder pressure becomes different from the control pressure. There was a problem that would. By the way, when the driver loses his / her intention to brake and releases the brake pedal during the ABS control, the wheel cylinder is operated in accordance with this operation. It is necessary to instantaneously release pressure to the master cylinder side, and cannot be eliminated.

The present invention has been made in view of the above-mentioned conventional problems. A plurality of wheel cylinders are connected to one brake circuit, and only one supply source is provided. In a brake control device having a structure in which a check valve is provided in parallel with a hydraulic pressure control valve that adjusts the brake pressure of each wheel cylinder, the pressure is insufficiently increased when two wheels are simultaneously increased, or the pressure is already controlled to a high pressure. It is an object of the present invention to improve the control accuracy by solving the conventional problem that the wheel cylinder pressure of another wheel may be reduced when the wheel cylinder of another wheel is increased.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention, as shown in the claim correspondence diagram of FIG. 1, uses the hydraulic pressure of a brake operation hydraulic pressure source a generated in response to a brake operation for each wheel. The brake pipes to be supplied to the wheel cylinders b are composed of two systems of brake pipes c and c connected respectively to the two wheel cylinders. The brake pipes are connected to the brake pipes c and c, respectively. Is a control hydraulic pressure source d which is an independent hydraulic pressure source, and supply source switching means for switching the hydraulic pressure supply source to the wheel cylinder b to either the brake operating hydraulic pressure source a or the control hydraulic pressure source d. j, a hydraulic control valve e for controlling the hydraulic pressure of each wheel cylinder b, a vehicle behavior detecting means f for detecting the behavior of the vehicle, and the hydraulic control valve based on an input from the vehicle behavior detecting means f. e and supply source switching means j And a control means g for executing automatic braking control for generating a braking force by causing the first target, which is an increasing / decreasing amount of each wheel cylinder b, to be set during the automatic braking control. The target pressure increasing / decreasing amount calculating means g1 for calculating the value, and the pressure increasing value of the two wheel cylinders b, b connected to the brake pipe c of the same system, which is larger than the first target value. A second target value calculating means g2 for calculating a second target value;
In the case of increasing the pressure of only one wheel cylinder b of the same system, the operation of the hydraulic pressure control valve e is controlled based on the first target value, while the two-wheel pressure increasing of the two wheel cylinders of the same system is performed. Sometimes, based on the second target value, the hydraulic pressure control valve e
Characterized in that it is configured to control the operation of. Therefore, when the two wheel cylinders b and b of the brake pipe c of the same system are simultaneously increased in pressure during the automatic braking control, a value larger than the first target value which is the pressure increase target value of the wheel cylinder b of one wheel is used. In this case, compared with the case where two wheels are simultaneously controlled toward the first target value, an increase in the supply amount of the control hydraulic pressure source d is increased. Pressure shortage can be alleviated. According to a second aspect of the present invention, in the brake control device according to the first aspect, the control means g determines a smaller pressure increase when the pressure increase amounts for the two wheels to be controlled are different during the two-wheel pressure increase. Up to the pressure increase amount, the operation of the hydraulic pressure control valve e is controlled for the two wheel cylinders based on the second target value. It is preferable to control the operation of the hydraulic control valve e based on one target value. Therefore, 2
When the wheel cylinders b of the wheels are simultaneously pressurized, the control can be simplified as compared with the case where pressures are individually increased for different target values.

In order to achieve the above object, the invention according to claims 3 to 6 provides a hydraulic pressure source for a brake operation hydraulic pressure source a generated in response to a brake operation, as shown in the claim correspondence diagram of FIG. Is supplied to the wheel cylinders of the respective wheels, and is constituted by two systems of brake pipes c and c connected to the wheel cylinders b of the two wheels, respectively. A control hydraulic pressure source d which is a hydraulic pressure source independent of the source a, and a supply for switching the hydraulic pressure supply source to the wheel cylinder b between the brake operating hydraulic pressure source a and the control hydraulic pressure source d. Source switching means j
And a hydraulic pressure control valve e for controlling the hydraulic pressure of each wheel cylinder b
A valve h provided in parallel with the hydraulic pressure control valve e to allow only the flow of the brake fluid of the wheel cylinder b to return to the hydraulic pressure sources a and d, and a vehicle behavior detection for detecting the behavior of the vehicle Means f, and control means g for executing automatic braking control for generating a braking force by operating the hydraulic pressure control valve e and the supply source switching means j based on the input from the vehicle behavior detecting means f. In the brake control device, the control means g comprises a comparison means g11 for comparing the hydraulic pressures of two wheel cylinders b, b connected to the same system during automatic braking control, and a wheel cylinder b for each wheel. Target pressure increasing / decreasing amount calculating means g1 for calculating the target pressure increasing / decreasing amount, and when increasing the pressure of only the low-pressure wheel cylinder in a state where the fluid pressures of the two wheel cylinders b, b of the same system are different, the target value To Characterized in that it is configured to control the operation of the fluid pressure control valves e to cause pressure slow increase Te.
That is, between the hydraulic pressure control valve e and the supply source switching means j,
When the pressure becomes lower than that of the wheel cylinder b, the hydraulic pressure of the wheel cylinder b escapes to the brake circuit c side via the one-way valve h, but when the pressure on the low pressure side of the two wheel cylinders b, b of the same system increases, When the pressure is increased, the wheel cylinder b
, The supply amount of the brake fluid between the hydraulic pressure control valve e and the supply source switching means j decreases. Therefore, since the pressure at this portion is hardly reduced, the high pressure side wheel cylinder b
Liquid pressure hardly decreases. According to a fourth aspect of the present invention, in the brake control device according to the third aspect, the control means g is configured to execute the gentle pressure increase by alternately repeating pressure increase and hold. Is preferred. Therefore, the state of the gradual pressure increase can be controlled based on the pressure increase time, and the control becomes easy. According to a fifth aspect of the present invention, in the brake control device according to the third or fourth aspect, a predetermined relief pressure is provided between the hydraulic pressure control valve e and the supply switching means j in the brake pipe c. Is provided, a relief valve k for releasing the brake fluid to one of the hydraulic pressure sources is provided. When the control means g gradually increases the pressure, the hydraulic pressure between the hydraulic pressure control valve e and the supply source switching means j is increased. It is preferable that the pressure is controlled so as not to be lower than the relief pressure. Therefore, the hydraulic pressure between the hydraulic pressure control valve e and the supply source switching means j does not drop below the maximum pressure of the wheel cylinder b, and accordingly, the two wheel cylinders b, When increasing the pressure of only the wheel cylinder b on the low pressure side of b, the hydraulic pressure of the wheel cylinder b on the high pressure side does not decrease. According to a sixth aspect of the present invention, in the brake control device according to the fifth aspect, a pump is provided as the control hydraulic pressure source d, and the gradual increase in the pressure of the control means g depends on the discharge capacity of the pump. It is preferable to execute it.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) First, the entire configuration of a brake circuit portion of a brake control device according to an embodiment of the present invention will be described with reference to FIG. In the figure, WC is a wheel cylinder, MC
Is the master cylinder, BP is the brake pedal, RT is the reservoir tank, WCFR is the wheel cylinder for the front right wheel, WC
FL is a wheel cylinder for the left front wheel, WCRR is a wheel cylinder for the right rear wheel, and WCRL is a wheel cylinder for the left rear wheel.

The master cylinder MC and each wheel cylinder W
C (all wheel cylinders or simply WC when indicating an unspecified wheel cylinder) is connected by two brake circuits 1 and 2, that is, the rear wheel wheel cylinder WCRR. , WCRL through the brake circuit 1 and the wheel cylinder W of the front wheel.
CFR and WCFL are connected via a brake circuit 2. The master cylinder MC corresponds to a brake operation hydraulic pressure source in the claims, and generates a hydraulic pressure according to a driver's brake operation. However, the present invention is not limited to this. For example, a unit that electrically detects a driver's brake operation and generates a control pressure corresponding to the brake operation may be used.

Hereinafter, the configuration will be described in detail. Since the configuration of each of the brake circuits 1 and 2 is the same, the following will be described.
Only the configuration relating to the brake circuit 1 will be described, and the description of the configuration in the brake circuit 2 will be omitted by attaching the same reference numerals.

The brake circuit 1 is branched into two branch circuits 1f, 1r toward each wheel cylinder WCRR, WCRL at a branch point 1d, and each of the branch circuits 1f, 1r.
Are provided with an inflow valve 5 and an outflow valve 6 which constitute a hydraulic pressure control valve. The inflow valve 5 is provided with a one-way valve 1g in parallel, and the outflow valve 6 is provided with a wheel cylinder WC.
Is connected to a drain circuit 10 for releasing the brake fluid to the reservoir 7.

The drain circuit 10 is provided with a recirculation circuit 4f for returning the brake fluid of the reservoir 7 to the upstream of the inflow valve 5 of the brake circuit 1 and the main pump 4. Further, one end of a feeding circuit 32 is connected to the suction side of the main pump 4. The feeding circuit 32 has the other end connected to the feeding chamber 51a of the feeding piston 51, and an intermediate portion connected to the brake circuit 1 via the first relief circuit 34 and the second relief circuit 35. The first relief circuit 34 is provided with a first relief valve 43, and the second relief circuit 35 is provided with a second relief valve 44.

The supply piston 51 has a cylinder 52 defined by a supply chamber 51a and a pressure introduction chamber 51b, and a piston 53 is slidably provided. This piston 53
Is urged by a return spring 54 in a direction to contract the pressure introducing chamber 51b, and the piston 53 has a land 53a for communicating the brake circuit 1 with the feeding circuit 32.
A check valve 55 is provided to close the valve.

The pressure introduction chamber 51b of the charging piston 53
The two are connected by a pressure introduction circuit 33, and a supply / discharge circuit 8 a of the supply pump 8 is connected to the pressure introduction circuit 33. Further, a charging / discharging circuit 8b of the charging pump 8
Is connected to the reservoir tank RT of the master cylinder MC. Incidentally, 45 is a circulation switching valve, and 46 is a third relief valve.

Further, in the brake circuit 1, a normally-opened out-side gate valve 41 is provided between the feeding piston 51 and the inflow valve 5, and a normally-closed in-side valve is provided in the middle of the feeding circuit 32. A gate valve 42 is provided. Also,
The check valve 21 is provided in parallel with the out-side gate valve 41.

The main pump 4 and the feed pump 8 are configured to be driven by a single motor M. As shown in FIG. 3, the motor M and the inlet valve 5, the outlet valve 7, and the The operations of the side gate valve 41, the in-side gate valve 42, and the circulation switching valve 45 are controlled by the control unit CU. This control unit CU
Has a sensor group SG including a wheel speed sensor S, a yaw rate sensor YR, a steering angle sensor H, a brake sensor BS, and the like as input means.

Next, the basic operation of the brake control device will be described. a) During normal brake operation Normally, each of the valves 5, 5, 6, 6, 41, 42, and 45 is in a non-operating state as illustrated on the brake circuit 2 side. When the pedal BP is depressed, the brake fluid pressure generated in the master cylinder MC is transmitted to each wheel cylinder WC through each of the brake circuits 1 and 2,
The wheels are braked according to the depression force of the brake pedal BP. When the driver finishes the brake operation, the brake fluid supplied to the wheel cylinder WC flows through the brake circuits 1 and 2 in the opposite manner to the above, and returns to the master cylinder MC.

B) At the time of the ABS control When the control unit CU detects that the wheels are locked or is about to be locked during the above-described brake operation, the slip ratio of the wheels is set within a predetermined range, and the wheel slip is set. ABS control for preventing locking is performed.
That is, in the ABS control, the brake fluid pressure is reduced, held, and increased so that the wheels are not locked during braking, and the slip rate of one of the wheels is set to a predetermined value by the brake fluid pressure generated by the above-described brake operation. As described above, the control unit CU first closes the out-side gate valve 41, starts driving the motor M, and further connects the branch circuit connected to the wheel cylinder WC for braking the wheel which is likely to lock. The inlet valves 1r and 1f are closed, and the outlet valve 6 is opened. When the outflow valve 6 is opened, the brake fluid in the wheel cylinder WC is discharged to the reservoir 7 through the drain circuit 10, and the wheel cylinder WC
Is reduced, and the braking force is weakened. The brake fluid discharged to the reservoir 7 is returned to the brake circuit 1 as needed by driving the main pump 4.

If the wheel slip ratio falls below a predetermined value as a result of the reduction of the braking force, the control unit CU stops supplying power to the outflow valve 6 and closes the outflow valve 6 to thereby control the wheel cylinder. When the hydraulic pressure of the WC is held, and the slip rate is reduced to a value less than another predetermined value as a result of the holding operation, the control unit CU cuts off the power supply to the inflow valve 5 and opens the valve. The high-pressure brake fluid in the brake circuit 1 is supplied to the wheel cylinder WC, and the braking force is increased again.

By repeating the above operations, the ABS control that maintains the slip ratio of each wheel within a predetermined range while the brake pedal BP is being depressed and prevents the locking of the wheels while obtaining the maximum braking force. Is performed.

In the above ABS control, the motor M
As a result, the feeding pump 8 is also driven.
At the time of the BS control, the circulation switching valve 45 is opened, the feeding pump 8 is in an idling state for simply circulating the brake fluid, and the feeding pump 8 does not become a load. As described above, the charging pump 8 does not perform any work, so that the pressure introducing chamber 51 is not used.
No pressure is introduced into c, and the piston 53 is maintained at the position located at the left end of the cylinder 52 as shown. Also, during the ABS control, the in-side gate valve 42 is kept closed as in the case of the normal brake operation described above, so that even if pressure is generated in the master cylinder MC, the brake fluid is supplied from the supply circuit 32. It is not supplied to the charging pump 8.

After that, the driver finishes the braking operation,
When the ABS control is completed, the control unit CU
Opens the out side gate valve 41 to bring the brake circuit 1 into a communicating state, and returns the inflow valve 5 and the outflow valve 6 to the original state. Therefore, the brake fluid supplied to the wheel cylinder WC flows back through the brake circuit 1 and returns to the master cylinder MC. The brake fluid discharged to the reservoir 7 is also returned to the brake circuit 1 by the drive of the main pump 4 and then returns to the master cylinder MC. After a lapse of time required for this, the drive of the motor M is stopped. You. c) At the time of automatic braking control The control unit CU controls the driving force to keep the slip ratio within a predetermined range in accordance with the increase of the slip ratio of the drive wheels due to sudden start and sudden acceleration, and the posture of the vehicle is likely to be disturbed. As needed, in the yaw moment control that generates the braking force and applies the yaw moment of the vehicle in a stable direction to stabilize the vehicle attitude, or in the automatic tracking control that automatically tracks the preceding vehicle, And performing automatic braking control including at least one of automatic braking control for automatically performing braking.

At the time of automatic braking control, the control unit CU closes the circulation switching valve 45 and closes the out-side gate valve 41 as shown on the brake circuit 1 side in FIG. The in-side gate valve 42 is opened, and the motor M is driven.

The drive of the motor M drives the feed pump 8 to drive the reservoir tank R of the master cylinder MC.
The brake fluid in T is sucked and discharged to the pressure introduction circuit 33, and is introduced into the pressure introduction chamber 51 b of the supply piston 51. By this pressure introduction, the piston 53 slides rightward in the drawing, and the brake fluid in the supply chamber 51a is discharged to the supply circuit 32 by an amount corresponding to a volume change due to the stroke of the piston 53. Then, the brake fluid in the supply circuit 32 is sucked into the main pump 4 via the in-side gate valve 42 and discharged to the branch circuits 1f and 1r. Therefore, the inflow valve 5,
The outflow valve 6 can be opened and closed as needed to optimally control each wheel cylinder pressure. That is, when the automatic braking control is started, the brake fluid is not stored in the reservoir 7 unless the ABS control is performed immediately before the automatic braking control.
, The brake fluid cannot be sucked in, and no discharge pressure is generated. Therefore, the above-described operation can be performed by driving the supply pump 8 to supply the brake fluid from the supply piston 51 to the suction side of the main pump 8.

At this time, if the pressure in the brake circuit 1 becomes too high, the second relief valve 44 is opened and the second relief valve 44 is opened.
The pressure is reduced to the valve opening pressure of the relief valve 4, whereby, in the charging piston 51, the volume of the charging chamber 51 a is expanded by the amount of the return of the brake fluid, and the piston body 53 is pushed back.

At the time of the above operation, the pressure introducing circuit 33
In this case, when the pressure of the pressure introducing passage 33 becomes higher than a predetermined pressure by driving the feeding pump 4, the third relief valve 4
6 is opened to be sucked into the feeding pump 8, and therefore, the pressure introduction path 33 does not become higher than the valve opening pressure of the third relief valve 46.

Thereafter, when ending the automatic braking control, the out-side gate valve 41 and the circulation switching valve 45 are opened and the driving of the motor M is stopped. Accordingly, in the feeding piston 51, the feeding pressure by the feeding pump 8 is lost, and the piston 53 is pushed back by the return spring 54, and the wheel cylinder WC or the main pump 4
Brake fluid returned to the brake circuit 1 from the supply chamber 51
Return to a. Further, the brake fluid introduced into the pressure introduction chamber 51b returns to the reservoir tank RT.

Next, a control flow during the automatic braking control according to the first embodiment of the present invention will be described in detail. FIG. 8 is a flowchart showing the automatic braking control. After performing a predetermined initialization in step 101, the routine proceeds to step 102, where the wheel speed Vw of each wheel is calculated, and the pseudo speed is calculated based on the wheel speed Vw. The vehicle speed Vi is calculated. In step 103, the pseudo vehicle speed Vi and the wheel speed Vw
Then, the target pressure increase / decrease amount * △ P is calculated for each wheel based on the relationship. The part that executes this processing corresponds to the target pressure increase / decrease amount calculating means in the claims. In step 104, a two-wheel simultaneous pressure increase pulse T2ch for each wheel in the same system is calculated. The part that executes this processing corresponds to the second target value calculating means in the claims. In step 105, it is determined whether or not the two wheels of the same system are pressure increasing (T2chA> 0 and T2chB> 0).
In the case of pressure increase (YES) for both wheels of the same system, the process proceeds to step 106; otherwise (NO), the process proceeds to step 107 to clear the two-wheel individual pressure increase flag ftdef to 0.

In step 106, it is determined whether or not both wheels of the same system have the same pulse (T2chA = T2chB).
If hA = T2chB, the routine proceeds to step 109, where each wheel increasing / decreasing pulse raw value Tr = T2chA = T2c of the target wheel.
hB, a process of setting the two-wheel individual pressure increase flag ftdef = 0. On the other hand, in step 106, T2chA ≠ T2
In the case of chB, the routine proceeds to step 109, where the two-wheel individual pressure increasing flag ftdef is set to 1, and
Proceeding to 10, the target value for pressure increase of each of the two wheels is calculated.
The two-wheel individual pressure increase flag ftdef is a flag that is set to 1 when the pressure of the two wheels of the same system is increased but the pressure increase / decrease pulses are different.

In the following step 111, the wheel increasing / decreasing pulse raw value Tr is calculated, in the following step 112, each wheel increasing / decreasing pulse T is calculated, and in step 113, the estimated wheel cylinder pressure Pw / c of each wheel is calculated. I do.

The above control is executed every 10 ms. At step 114, the elapse of 10 ms is determined, and after the elapse of 10 ms, the process returns to step 102.

Next, a description will be given of how to obtain the target wheel pressure increase / decrease amount * △ P in step 103. First, in the case of the motion stabilization control, for example, when there is a possibility that a spin may occur due to the occurrence of a moment M as shown in FIG. 4 in the vehicle, in the device of the first embodiment, the braking force F is applied to the left front wheel. To generate a moment that suppresses the moment M in the vehicle. The braking force F at this time has a relationship of M ≦ F × L2, where L2 is a value of １ ／ of the dimension between the wheels of the axle. Then, the braking force F can be represented by F = kW (in addition,
k is the road surface μ, W is the wheel load), the target wheel cylinder pressure * P is determined from the characteristics of the wheel cylinder pressure Pw / c and k shown in FIG. 5, and the current estimated wheel cylinder pressure Pw / c and A target pressure increase / decrease amount * 目標 P is obtained from the target wheel cylinder pressure * P. By the way, * △ P = * P-Pw / c
It is.

Alternatively, in a case where the driving force control for suppressing the slip of the driving wheels is performed, as shown in FIG. 6, when the wheel speed Vw exceeds the pseudo vehicle speed Vi, the wheel speed Vw is reduced to the target wheel speed. The target pressure increase / decrease amount * △ P is determined based on the characteristics of the slip ratio and the wheel cylinder pressure Pw / c shown in FIG.

Next, the flow of the calculation of the two-wheel simultaneous increasing / decreasing pulse T2ch in step 104 will be described in detail with reference to FIG. In this control, first, in step 201, it is determined whether or not the target pressure increase / decrease amount * △ P is negative. If NO, the process proceeds to step 202 to execute pressure increase control, and a master memory stored in advance is executed. The raw pump discharge amount △ Q ′ per unit time (10 ms in the present embodiment) corresponding to the cylinder pressure Pm / c is obtained, and the process proceeds to step 204, where it is set in advance based on the specifications of the apparatus. Pump discharge amount per unit time based on the two-wheel simultaneous pressure increase gain K and the raw pump discharge amount {Q 'obtained in step 203}
Calculate Q. Then, the routine proceeds to step 205, where the wheel cylinder pressure Pw / c when the unit time pressure increase is performed based on the wheel cylinder pressure Pw / c characteristic with respect to the pump discharge amount Q set in advance based on the specifications of the apparatus. The pressure increase / decrease amount ΔP10 of c is calculated. Further, the routine proceeds to step 206, where it is determined whether or not the target pressure increase / decrease amount * ΔP is greater than the pressure increase / decrease amount per unit time ΔP10.
In the case of 10 (the target increase / decrease amount * △ P is a negative value)
, The two-wheel simultaneous pressure increase pulse T2ch is controlled at a control cycle (10 m
Set to s). On the other hand, if * △ P <△ P10,
T2ch = (* 増 P /
ΔP10) × 10 ms

On the other hand, in step 201, * △ P <
In the case of 0, the process proceeds to step 203 to execute the pressure reduction control, and the two-wheel simultaneous pressure increase pulse T2ch = 0 is set.

Next, referring to FIG. 10, the details of the one-wheel pressure increasing target value calculation process in step 110 during two-wheel pressure increasing will be described. In step 301, the two-wheel simultaneous pressure increasing pulse T2chA of one of the two wheels of the same system and the two-wheel simultaneous pressure increasing pulse T2chB of the other wheel are compared in magnitude with each other.
If> T2chB, the process proceeds to step 302, where T2ch
If A <T2chB, the process proceeds to step 303. In step 302, the simultaneous pressure increase amount P2chA for one wheel
And the single pressure increase amount PErr2chA are obtained. That is,
When T2chA> T2chB, as shown in FIG.
Even if the pressure is increased only by the two-wheel simultaneous pressure increase pulse T2chB of the other wheel ((a) in the figure), the target pressure increase / decrease amount * △ P is not reached. It is necessary to increase the pressure alone for the time shown in (b), and these values are obtained in step 302. Similarly, for step 303, these values P2ch for the other wheel
B, PErr2chB are obtained.

Next, the calculation processing of the wheel increasing / decreasing pulse raw value Tr in step 111 will be described in detail with reference to FIG. In step 401, the pressure increase / decrease amount per unit time ΔP10 of each wheel is obtained again. In step 402, it is determined whether the required pressure increase / decrease amount can be obtained in one control cycle.
It is determined whether or not P |> １０P10. If YES, that is, if pressure increase is required for one or more control cycles, the process proceeds to step 403, where it is determined whether * △ P is positive or negative to increase or decrease pressure. It is determined, and in the case of pressure increase, the process proceeds to step 404 to set each wheel increasing / decreasing pulse T = control cycle (= 10 ms). 10 ms).

On the other hand, if it is determined in step 402 that one control cycle is sufficient, the routine proceeds to step 406, where it is determined whether or not the two-wheel individual pressure increase flag ftdef = 1, and fteddf = 1, that is, 2 If a different amount of simultaneous pressure increase is to be performed for the wheels, proceed to step 407,
For the wheel with the higher boosting amount, the single boosting amount PErr2
On the basis of chA, a single boost pulse TPE is given by TPE =
(PErr2chA / △ P10) × 10 ms, and based on this, each wheel increase / decrease pulse T is calculated as T = TPE
+ T2chB In addition, T = T2chB for the wheel having the smaller pressure increase amount. Note that this step 407 shows a case where T2chA> T2chB, and a case where T2chA <T2chB.
A and B are exchanged.

On the other hand, if the two-wheel individual pressure increasing flag ftdef = 1 is not set at step 406, the pressure is increased by the same pressure for the two wheels of the same system at step 408. = (* △ P
/ △ P10) × 10 ms.

Next, the process of calculating the pressure increase / decrease amount per unit time ΔP10 in step 401 will be described with reference to FIG. In step 501, the target pressure increase / decrease amount * △ P = 0
Is determined, if * △ P = 0, it is determined to be a holding request, and the routine proceeds to step 502, where the pressure increase / decrease amount per unit time 単 位 P10 = 0 is set. On the other hand, if * △ P is not 0, the routine proceeds to step 503, where it is determined whether the request is a pressure increase request or a pressure decrease request by * △ P> 0, and if it is a pressure increase request, the routine proceeds to step 504. Step 202 in FIG.
The raw pump discharge amount △ Q ′ per unit time is obtained based on the characteristics indicated by. If it is determined in step 503 that it is a pressure reduction request, the process proceeds to step 505, in which the estimated wheel cylinder pressure Pw / c is set to P1 and the reservoir pressure Pr is set to P2.
6 and calculate the flow rate per unit time (△ Q) as △ Q = C
(Πd / 4) ² {(2 / ρ) (P1-P2) ^1/2 } =
It is determined from the equation of C ′ (P1−P2) ^1/2 . Note that C is a flow coefficient, d is an orifice diameter, and ρ is a brake fluid density.

In the following step 507, it is determined again whether the pressure increase request or the pressure decrease request is based on whether * △ P> 0, and in the case of the pressure increase request, the routine proceeds to step 508, where the two-wheel individual pressure increase flag ftdef is set. Is determined to be 1 or not, and if ftdef = 1, the routine proceeds to step 509, where the pressure increase / decrease amount per unit time during one wheel pressure increase in the same system simultaneous pressure increase cycle shown in FIG. P10_n is calculated. If ftdef is not 1 in step 508, that is, if the target pressure increase / decrease amount * 量 P of both wheels is the same, the pressure increase / decrease amount per unit time △ P10 is determined in step 510 based on the existing wheel cylinder hydraulic pressure characteristic data. And calculate.

On the other hand, if it is determined in step 507 that the request is a pressure reduction request, the flow advances to step 511 to proceed to step 5
The calculation is based on the existing wheel cylinder hydraulic pressure characteristic data similar to that shown in FIG.

Next, the estimated wheel cylinder pressure Pw / c in step 113 of FIG. 8 will be described with reference to the flowchart of FIG. In step 601, it is determined whether or not each wheel increasing / decreasing pulse Tr is longer than the control cycle (10 ms). If longer than one control cycle, the process proceeds to step 602 to determine whether Tr> 0. It is determined whether the pressure is increased or reduced, and when the pressure is increased, a process of setting ΔP = △ P10 is performed, and when the pressure is reduced, a process of setting ΔP = − △ P10 is executed. On the other hand, if each wheel increase / decrease pulse Tr is shorter than the control cycle, step 6
In step 05, it is determined whether or not the two-wheel individual pressure increase flag ftdef is set to 1. If it is set, the flow proceeds to step 606, where 1 is set in the two-wheel simultaneous pressure increase cycle.
The pressure increase / decrease amount ΔP is determined from the pressure increase amount ΔP1 of the wheel alone and the pressure increase amount ΔP2 in the two-wheel simultaneous pressure increase cycle. On the other hand, 2
If the wheel-specific pressure increase flag ftdef is not set to 1, the routine proceeds to step 607, where the pressure increase / decrease amount ΔP is obtained from the pressure increase / decrease pulse Tr and the pressure increase / decrease amount ΔP10 per unit time. Then, in step 608, the current estimated wheel cylinder pressure Pw / c is obtained by adding the previous estimated wheel cylinder pressure Pw / c and the current increase / decrease amount ΔP.

In the first embodiment configured as described above, even if the pressure is increased for two wheels of the same system at the same time and the pressure increase amounts are different, for example, as shown in FIG.
In the section (a) where two wheels are simultaneously boosted, the pressure increase amount P2chA is obtained based on the pump discharge amount characteristic of the two-wheel simultaneous pressure increase. Since the pressure increase amount PErr2chA is obtained based on the pump pressure increase characteristics, the target pressure increase / decrease amount * △ P can be reliably increased, and excellent control accuracy is obtained and control quality is improved. .

(Embodiment 2) Next, Embodiment 2 will be described. The second embodiment is also applied to the brake control device having the configuration shown in FIGS. 2 and 3, and the control content is different from the first embodiment. Therefore, the description of the configuration is omitted, and the steps that perform the same processing as in the first embodiment even in the flowchart showing the control flow are given the same reference numerals as in the first embodiment, and the description is omitted.

In two wheels of the same system (the rear wheels will be described as an example of these two wheels), the wheel cylinder pressure Pw
When the pressure of the wheel cylinder on the low pressure side is increased in a state where differential pressures are generated in / cRR and Pw / cRL, the one-way valve 21, the inflow valves 5, 5, and 5 are provided in the brake circuit 1, the recirculation circuit 4f and the second relief circuit 35. If the brake pressure (hereinafter referred to as PMLP) confined between the main pump 4, the out-side gate valve 41, and the second relief valve 44 is lower than the wheel cylinder pressure Pw / c on the high pressure side, the pressure increases. If the pressure is greater than the supply amount of the main pump 4, the brake fluid in the high-pressure wheel cylinder WC may open the one-way valve 1g and flow to the low-pressure side. The second embodiment prevents this.

FIG. 16 shows a control flow according to the second embodiment. Steps 101 → 102 → 103 → 111b
→ 112b → 113b → 114 is executed. Of these steps, the processing contents of steps 111b, 112b, and 113b are different from those of the first embodiment, and the details thereof will be described below.

FIG. 17 shows the process of calculating the pressure increase / decrease pulse raw value Tr of each wheel in step 111b. Here, after determining the pressure increase / decrease amount per unit time ΔP10 in step 401b, FIG. Step 402 shown in
405 and 408, the increasing / decreasing pulse raw value Tr of each wheel is obtained. FIG. 18 shows step 401b of FIG.
The pressure increase / decrease amount per unit time ΔP10 is calculated based on the processing of steps 501 to 507 and 510 and 511 in the first embodiment shown in FIG.

FIG. 19 is a flowchart showing the processing for calculating the pressure increase / decrease pulse T in step 112b of FIG.
Step 801 is a part corresponding to the comparing means in the claims, and determines which of the two wheels (here, the left and right rear wheels) of the same system is at a low pressure by Pw / cRR> Pw / cRL.
If Pw / cRR> Pw / cRR, the routine proceeds to step 802, where it is determined whether the master cylinder pressure Pmc is higher than the wheel cylinder pressure Pw / cRR of the right rear wheel, and Pmc> Pw / cRR. In this case, the process proceeds to step 803. Also, in step 801, Pw / cRR ≦ P
In the case of w / cRL, the routine proceeds to step 804, where the master cylinder pressure Pmc is changed to the wheel cylinder pressure Pw / c of the left rear wheel pressure.
It is determined whether it is higher than RL, and the process also proceeds to step 803 when Pmc> Pw / cRL. And step 80
In 3, the pressure increase / decrease pulses TRR and TRL of each wheel are set to TRR = TrRR and TRL = TrRL, respectively. In other words, when the pressure is higher than the wheel cylinder pressure on the high pressure side of the two wheels, the brake fluid of the wheel cylinder WC on the high pressure wheel does not flow into the wheel cylinder WC on the low pressure wheel, so the increasing / decreasing pulse raw value Tr is directly increased or decreased. Let it be a pressure pulse T.

On the other hand, when the master cylinder pressure Pmc is lower than the wheel cylinder pressure Pw / c on the high pressure side in step 802 or 804, the process proceeds to step 805 or 806, and the pressure increase / decrease pulse T has a positive value. It is determined whether or not the pressure is increasing. If the pressure is reduced or maintained, the process proceeds to step 803. If the pressure is increased, the process proceeds to step 807 or 808.

In steps 807 and 808, the maximum pressure increase pulse Tmax of the low-pressure wheel where the wheel cylinder pressure Pw / c on the high-pressure side does not decrease is obtained based on a previously input map. That is, the brake pressure PMLP confined in the brake circuit 1 and the like as described above
Is considered to correspond to the relief pressure of the second relief valve 44. Therefore, if the pressure increase amount is such that the relief pressure is maintained by the discharge of the pump 4, even if the pressure increase is performed in one control cycle, the high-pressure side wheel cylinder WC
Brake fluid does not escape from Therefore, a pressure-increasing pulse capable of executing such pressure-increasing is set as the maximum pulse Tmax. In step 807 or 808, the smaller value of the maximum pulse Tmax or the pressure-increasing / decreasing pulse raw value Tr is selected. The increase / decrease pulses TRR and TRL are created. Incidentally, the maximum pulse Tmax is obtained in advance by an experiment. Then, after performing the processing of step 803 in the case of pressure reduction or holding, step 81
After setting the pressure reduction holding flag FLIM to 1 at 0 and performing the processing of step 807 or step 808 to execute the pressure increase, the pressure reduction holding flag FLIM is reset to 0 at step 809 or 811 and thereafter , Step 812, each step 8
03, 807, 808 the pressure increase pulse TR set
R and TRL are output.

FIG. 20 is a flowchart showing the pressure-intensifying pulse output process in step 812 in detail. First, in step 812a, the pressure-intensifying timer Tp is counted. The pressure increase timer TP measures the time required for the discharge side of the main pump 4 to increase to the relief pressure of the relief valve 44 when the pressure increase process is performed. Is a timer for preventing the pressure increase from being performed until the time is counted up. In step 812b, it is determined whether or not the pressure increase timer Tp has counted up to the set value N, and if it has counted up, the flow proceeds to step 812c to execute processing for setting Tp = N. In a succeeding step 812d, the decompression holding flag FL
It is determined whether or not IM is set to 1;
Proceeding to e, a pulse output process is performed. Step 8
In the case of FLIM ≠ 1 in 12d, pressure increase is executed, and the routine proceeds to step 812f, where the pressure increase timer T
It is determined whether or not p is equal to or greater than a set value N.
Is reset to 0. On the other hand, if Tp <N, the routine proceeds to step 812h, where the pressure increase / decrease pulses TRR, TRL are returned to 0 based on the processing of 812h to 812m. That is,
The pressure-increasing timer Tp always counts, and Tp ≧ N when the first pressure-increasing / decreasing pulses TRR and TRL are output. Therefore, at the time of the first pressure increase, steps 812a → 812b → 812c → 812d → 812f →
With the flow of 812g → 812e, the pressure increase / decrease pulse TRR,
TRL is output, and thereafter, 812f → 812h → 812j or 812k → until the pressure increase timer Tp reset in step 812g becomes the set value N again.
By 812m, the pressure increase / decrease pulses TRR, TRL are set to 0, and the pressure increase / decrease pulses TRR, TRL are not output. That is, in step 807 or 808, the pressure increase / decrease pulse TRR, TRR,
After outputting the TRL, the pressure increasing / decreasing pulse T is maintained until the time required for the main pump 4 to return to the relief pressure (= the time for the pressure increasing timer Tp to count the set value N) elapses.
RR and TRL are not output.

Next, FIG. 21 is a flowchart showing the calculation processing of the estimated wheel cylinder pressure Pw / c in step 113b. This processing is performed in steps 601 to 604 and 607 and 608 shown in FIG. It is executed by performing the processing of.

Next, the operation of the embodiment will be described with reference to FIG. FIG. 1A shows the case of the prior art. As shown in FIG. 1, when the inflow valve on the low-pressure wheel side is opened,
Since the valve opening time corresponds to only the pressure increase amount on the low-pressure wheel side, the pressure MPL between the discharge side of the main pump 4 and the inflow valve 5 decreases, and accordingly, the wheel on the high-pressure wheel side The hydraulic pressure of the cylinder flowed out to the discharge side of the main pump 4 via the one-way valve 1g, and the wheel cylinder pressure of the high-pressure wheel became lower than the control pressure PH0 (PH1). On the other hand, in the second embodiment, the pressure MPL between the discharge side of the main pump 4 and the inflow valve 5 becomes lower than the relief pressure of the relief valve 44 as shown in FIG. As shown in the figure, the pressure MPL is decreased from the control pressure PH0 on the high-pressure wheel side because the pressure is slowly increased according to the count of the pressure-intensification timer Tp only by opening the valve (TRR, TRL) without time. Nothing. Therefore, the wheel cylinder pressure on the high-pressure wheel side can be maintained at the control pressure PH0, and control accuracy can be improved.

[0058]

According to the brake control device of the first and second aspects, when the pressures of two wheel cylinders of the same system brake pipe are simultaneously increased during the automatic braking control, one wheel cylinder of the wheel cylinder is controlled. Since the control is performed based on the second target value which is larger than the first target value which is the pressure increase target value, compared with the case where the two wheels are simultaneously controlled toward the first target value, the control hydraulic pressure source is not used. The effect of reducing the pressure increase shortage due to the supply amount being dispersed and improving the control accuracy can be obtained. Further, the brake control device according to the second aspect of the present invention simplifies the control when simultaneously increasing the pressures of the two wheel cylinders of the same system brake pipe as compared to individually increasing the pressures for different target values. Can be achieved.

In the brake control device according to the third to sixth aspects, when only the wheel cylinder on the low pressure side of the two wheel cylinders of the same system is pressure-increased, the wheel cylinder is gradually increased. The supply amount of the brake fluid between the hydraulic pressure control valve and the supply source switching means is reduced,
Therefore, it is difficult for the hydraulic pressure of the high-pressure wheel cylinder to escape from the one-way valve to the brake pipe, and it is possible to maintain the hydraulic pressure of the high-pressure wheel cylinder at the control pressure, thereby improving control accuracy. It has the effect of being able to do so. In the brake control device according to the fourth aspect, when the pressure on the low pressure side of the two-wheel wheel cylinder of the same system is gradually increased, the pressure increase and the holding are alternately repeated. Can be controlled based on the pressure increase time, and the control becomes easy. In the brake control device according to claims 5 and 6, when the low pressure side of the two-wheel wheel cylinder of the same system is gradually increased, the hydraulic pressure between the hydraulic pressure control valve and the supply source switching means is: Since the pressure is not reduced below the relief pressure, the fluid pressure at this portion does not drop below the maximum pressure of the wheel cylinder,
There is an effect that the high pressure side wheel cylinder does not drop below the control pressure, and high control accuracy is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a brake control device of the present invention.

FIG. 2 is an overall view of a brake control device according to an embodiment.

FIG. 3 is a block diagram of a main part of the embodiment.

FIG. 4 is an explanatory diagram of the embodiment.

FIG. 5 is an explanatory diagram of the embodiment.

FIG. 6 is an explanatory diagram of the embodiment.

FIG. 7 is an explanatory diagram of the embodiment.

FIG. 8 is a flowchart illustrating a control flow according to the first embodiment.

FIG. 9 is a flowchart of a main part of a control flow according to the first embodiment.

FIG. 10 is a flowchart of a main part of a control flow according to the first embodiment.

FIG. 11 is an operation explanatory diagram of the first embodiment.

FIG. 12 is a flowchart of a main part of a control flow according to the first embodiment.

FIG. 13 is a flowchart of a main part of a control flow according to the first embodiment.

FIG. 14 is a pressure increase amount calculation characteristic diagram of the first embodiment.

FIG. 15 is a flowchart of a main part of a control flow according to the first embodiment.

FIG. 16 is a flowchart illustrating a control flow according to the second embodiment.

FIG. 17 is a flowchart of a main part of a control flow according to the second embodiment.

FIG. 18 is a flowchart of a main part of a control flow according to the second embodiment.

FIG. 19 is a flowchart of a main part of a control flow according to the second embodiment.

FIG. 20 is a flowchart of a main part of a control flow according to the second embodiment.

FIG. 21 is a flowchart of a main part of a control flow according to the second embodiment.

FIG. 22 is an operation explanatory view of the second embodiment.

FIG. 23 is an operation explanatory view of the conventional technique.

FIG. 24 is an operation explanatory view of the conventional art.

[Explanation of symbols]

 WC wheel cylinder MC master cylinder (brake operation fluid pressure source) BP brake pedal RT reservoir tank WCFR wheel cylinder WCFL wheel cylinder WCRR wheel cylinder WCRL wheel cylinder CU control unit (control means) S wheel speed sensor (vehicle behavior detecting means) YR yaw rate Sensor (vehicle behavior detecting means) H Steering angle sensor (vehicle behavior detecting means) BS Brake sensor (vehicle behavior detecting means) SG sensor group (vehicle behavior detecting means) 1 brake circuit 1d branch point 1f branch circuit 1g one-way valve 1r branch circuit Reference Signs List 4 Main pump (control hydraulic pressure source) 4f Recirculation circuit 5 Inflow valve (hydraulic pressure control valve) 6 Outflow valve (hydraulic pressure control valve) 7 Reservoir 8 Supply pump (control hydraulic pressure source) 8a Supply / discharge circuit 8b Supply / discharge Circuit 10 Drain circuit 21 Check valve 32 Supply circuit 33 Pressure introduction circuit 34 First relief circuit 35 Second relief circuit 41 Out side gate valve 42 In side gate valve 43 First relief valve 44 Second relief valve 45 Circulation switching valve 46 Third relief valve 51 Supply piston (control pressure source) 51a Supply chamber 51a Supply chamber 51b Pressure introduction chamber 52 Cylinder 53 Piston 53a Land 54 Return spring 55 Check valve

Claims (6)

[Claims] 1. A brake pipe for supplying hydraulic pressure of a brake operating hydraulic pressure source generated in response to a brake operation to a wheel cylinder of each wheel is provided by two systems of brake pipes connected to the wheel cylinders of two wheels, respectively. A control hydraulic pressure source which is connected to each brake pipe and is independent of the brake operation hydraulic pressure source, and a hydraulic pressure supply source to the wheel cylinder is a brake operation hydraulic pressure source and a control hydraulic pressure source. Supply source switching means for switching to one of the pressure sources, a hydraulic pressure control valve for controlling the hydraulic pressure of each wheel cylinder, vehicle behavior detecting means for detecting vehicle behavior, and an input from the vehicle behavior detecting means. Control means for performing automatic braking control for generating a braking force without a driver's brake operation by operating the hydraulic pressure control valve and the supply switching means based on the brake control apparatus. Te, the control unit, during automatic braking control, the target pressure increase amount calculation means for calculating a first target value is increase and decrease amount of each wheel cylinder, and is connected to the brake pipe of the same strain 2
A second target value calculating means for calculating a second target value which is a value for increasing the pressure of one of the wheel cylinders and which is larger than the first target value; and increases the pressure of only one wheel cylinder of the same system. In this case, the operation of the hydraulic control valve is controlled based on the first target value, while the hydraulic control valve is controlled based on the second target value during two-wheel pressurization for increasing the pressure of two wheel cylinders of the same system. A brake control device configured to control the operation of a brake. 2. The control device according to claim 2, wherein when the pressure increase for the two wheels to be controlled is different at the time of the two-wheel pressure increase, the two wheels are controlled based on a second target value until the pressure increase amount of the two wheels becomes smaller. The operation of the hydraulic control valve is controlled for the cylinder, and after this control, the operation of the hydraulic control valve is controlled based on the first target value for the wheel cylinder having the larger pressure increase amount. The brake control device according to claim 1, wherein: 3. A brake pipe for supplying a hydraulic pressure of a brake operation hydraulic pressure source generated in response to a brake operation to a wheel cylinder of each wheel is a brake pipe of two systems connected to the wheel cylinders of two wheels, respectively. A control hydraulic pressure source which is connected to each brake pipe and is independent of the brake operation hydraulic pressure source, and a hydraulic pressure supply source to the wheel cylinder is a brake operation hydraulic pressure source and a control hydraulic pressure source. Supply source switching means for switching to any one of the pressure sources, a hydraulic pressure control valve for controlling the hydraulic pressure of each wheel cylinder, and a brake fluid for the wheel cylinder which is provided in parallel with the hydraulic pressure control valve and which is connected to the hydraulic pressure source A one-way valve that allows only the flow in the direction returning to the vehicle, a vehicle behavior detecting means for detecting the behavior of the vehicle, and a driver that operates the hydraulic pressure control valve and the supply switching means based on the input from the vehicle behavior detecting means. Control means for performing automatic braking control for generating a braking force without involving the brake operation of the brake control apparatus, wherein the control means comprises two wheels connected to the same system during the automatic braking control. A comparison means for comparing the hydraulic pressures of the cylinders; and a target pressure increase / decrease amount calculating means for calculating a target pressure increase / decrease amount for each wheel cylinder of each wheel.
When increasing the pressure of only the low-pressure wheel cylinder in a state where the hydraulic pressures of the two wheel cylinders are different, the operation of the hydraulic pressure control valve is controlled so as to gradually increase the pressure toward the target value. Brake control device. 4. The brake control device according to claim 3, wherein the control means is configured to execute the gradual pressure increase by alternately repeating pressure increase and hold. 5. In the brake pipe, a relief valve is provided between the hydraulic pressure control valve and the supply switching means to release brake fluid to one of the hydraulic pressure sources when a predetermined relief pressure is exceeded, 5. The control device according to claim 3, wherein the gradual pressure increase of the control unit is performed so that the hydraulic pressure between the hydraulic pressure control valve and the supply source switching unit does not drop below the relief pressure. Brake control device. 6. The brake control device according to claim 5, wherein a pump is provided as the control hydraulic pressure source, and the gradual pressure increase of the control means is performed according to a discharge capacity of the pump.