JPH09309420A - Brake control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase vehicle braking force and shorten a braking distance, by adjusting a brake pressure applied to each of a plurality of wheel braking force generating means, and applying a second brake pressure relating to the wheel brake force generating means of non-execution wheel of this brake pressure adjustment, based on a detection result in a slip condition detection means. SOLUTION: In an electronic control circuit ECU6, based on various signals from a wheel sensor group 1, an oil pressure sensor group 2, an acceleration sensor 3, a steering sensor 4 and a switch group 5, an arithmetic process is performed, a control signal is applied to a brake actuator 7 adjusting a brake oil pressure. Based on this decision result, by the brake actuator 7 as an antiskid control means, a brake pressure applied to each of a plurality of wheel brake force generating means is adjusted, relating to the wheel brake force generating means of non-execution wheel of this brake pressure adjustment, a second brake pressure higher than a first brake pressure, based on pedal operation, is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake control apparatus for appropriately distributing and controlling a braking force applied to a plurality of wheels of a vehicle.

[0002]

2. Description of the Related Art Conventionally, there has been known an anti-skid control device for reducing or increasing the brake pressure applied to a wheel cylinder of each wheel so as to optimize the slip state of the wheel at the time of vehicle braking and hold the brake pressure.

[0003]

However, in the conventional anti-skid control, the brake pressure applied to the wheel cylinder is adjusted only by adjusting the brake pressure applied to the wheel cylinder only when the wheel slips. Is adjusted to be lower than the master cylinder pressure.

That is, the conventional anti-skid control is
If the brake pressure according to the operation of the brake pedal by the occupant is not enough to cause the wheels to lock, the brake pressure adjustment is not executed. Only the control on the pressure reducing side for the so-called wheel cylinder pressure is performed. Met. Therefore, an object of the present invention is to positively increase the vehicle braking force and shorten the braking distance by increasing the wheel cylinder pressure in the non-target wheel of the anti-skid control above the master cylinder pressure.

[0005]

According to the present invention, the second brake fluid pressure generating means forms the second brake pressure higher than the first brake pressure based on the pedal operation. The brake pressure is applied to the wheel braking force generating means corresponding to the non-target wheel of the anti-skid control by the brake pressure increasing means. As a result, the wheel braking force exerted by the wheels can be increased, the vehicle braking force can be positively improved, and the braking distance can be shortened.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in the drawings. First, in the block diagram showing the overall configuration of FIG. 2, 1 is a wheel sensor group including a wheel speed sensor such as an electromagnetic pickup for detecting the speed of each wheel of the vehicle, and 2 is a hydraulic pressure of a master cylinder and each wheel cylinder. Hydraulic sensor group, 3 is an acceleration sensor that detects the longitudinal and lateral acceleration of the vehicle, 4 is a steering sensor that detects the steering angle of the steering wheel, 5 is a switch group such as a brake switch and pressure switch, and 6 is electronic control It is a circuit (ECU) and includes a wheel sensor group 1, a hydraulic pressure sensor group 2, an acceleration sensor 3, a steering sensor 4,
A brake actuator 7 that adjusts the brake hydraulic pressure by performing arithmetic processing based on various signals from the switch group 5.
Is controlled by adding a control signal to the control signal. The brake actuator 7 includes a pressure switching valve 7a and a variable pressure device 7b, 7c, 7d, 7 arranged in a brake system of each wheel of a vehicle.
e.

Further, FIG. 3 is a hydraulic system diagram showing a hydraulic system of the brake actuator 7 in FIG. A brake pedal 101, which is a brake operating means, is connected to a master cylinder 103 connected to a reservoir 104. When the brake pedal 101 is stepped on, the master cylinder 103 generates a brake hydraulic pressure according to the stepping force. The master cylinder 103 has two chambers that generate hydraulic pressure, and a first main pipe 151 and a second main pipe 153 are connected to each chamber. The first main pipe branches into a first branch pipe 155 and a second branch pipe 157, and the second main pipe 153 branches into a second branch pipe 159 and a fourth branch pipe 161. The first branch pipe 155 is connected to the wheel cylinder 105 arranged on the right front wheel, and the second branch pipe 157 is connected to the wheel cylinder 107 arranged on the left front wheel. The third branch pipe 159 is connected to a wheel cylinder 109 arranged on the right rear wheel, and
The branch pipe 161 is connected to a wheel cylinder 111 arranged on the left rear wheel. Since each branch pipe and each wheel cylinder have exactly the same configuration, only the first branch pipe and the wheel cylinder 105 will be described. Electric motor 1
Reference numeral 15 is for driving the hydraulic pump 117. Hydraulic pump 117 driven by this electric motor 115
Is for sucking up the oil stored in the reservoir 180 from the inlet pipe 122 and discharging it to the outlet pipe 120. A check valve 123 is arranged on the inlet pipe 122, and a check valve 121 is arranged on the outlet pipe 120. The hydraulic pressure discharged from the hydraulic pump 117 to the discharge pipe passes through the discharge pipe 120, and the accumulator (constant pressure source) 11
3 The accumulator 113 is connected to the pressure pipe 170, and the pressure accumulated in the accumulator 113 passes through the pressure pipe 170 and the variable pressure device 21.
Lead to zero.

A return pipe 125 connecting the discharge side and the suction side of the hydraulic pump 117 is arranged so as to connect the outlet pipe 120 and the inlet pipe 122. A safety valve 127 is arranged in the return pipe 125, and the safety valve 127 opens when the discharge pressure from the hydraulic pump 117 is equal to or higher than a predetermined pressure. Then, the pressure higher than the predetermined pressure is returned to the reservoir 180 side by using the reflux pipe 125 as a handle.

A pressure switch 1 is provided on the outlet pipe 120.
19 are arranged to detect the pressure accumulated in the accumulator 113. When the pressure in the accumulator 113 becomes equal to or lower than a predetermined value, the electric motor 115 is rotated to drive the hydraulic pump 117, and when the pressure in the accumulator 113 becomes equal to or higher than the predetermined pressure, the electric A signal is transmitted to stop driving of the motor 115.

A pressure cut valve 510 and a cut valve 310 are arranged in a first branch pipe 155 branched from the first main pipe 151 and communicated with the wheel cylinder 105. A pressure branch pipe 171 is branched to the pressure pipe 170 and is connected to the first port 501 of the pressure switching valve 500. The pressure switching valve 500 includes a first port 501 and a second port 5
02 and a third port 503, which is an electromagnetic switching valve that switches to a first position that communicates the second port and the third port and a second position that communicates the first port 501 and the third port 503. . The second port 502 is connected to the reservoir 180 by a return pipe 631. The third port 503 is connected to a pilot pressure pipe 610, and the pilot pressure pipe 610 branches into a pilot pipe 600. In addition, this pilot tube 600
Introduces a reference pressure into the pressure cut valve 510 via a branch pipe 620, and further introduces the reference pressure into the cut valve 310. The pilot pressure pipe 610 also guides the reference pressure to the pressure regulation cut valve 700.

An upstream side and a downstream side of the pressure cut valve 510 are connected by a return passage 511 having a check valve 512. A pilot pipe 175 is branched from the first branch pipe 155 to introduce a reference pressure into the cut valve 310. When the pressure of the first branch pipe 155 is introduced from the pilot pipe 175 or the pressure of the accumulator 113 is introduced into the cut valve 310 from the pilot pipe 600, the cut valve 310 is switched and the first branch pipe 1 is switched.
Block 55.

The modulatable pressure device 210 has a first port 211.
And a second port 212 and a third port 213. The first port 212 is connected to the pressure pipe 170, and the second port 212 is connected to the reservoir 180 by a return pipe 172. Further, the third port 213 is connected to the modulator 410 via the input pipe 173. The input pipe 173 is branched into a first input pipe 173a and a second input pipe 173b. The tunable pressure modulator 21
0 is a switch between a first position connecting the second port 212 and the third port 213 and a second position connecting the first port 211 and the third port 213. The variable pressure device 210 is a so-called spool type valve, and the pilot pipe 1 branched from the first branch pipe 155 is used.
56 and the reference pressure from the second pilot pipe 190 branched from the input pipe 173 are compared, and by the pressure difference,
It switches. The variable pressure device 210 is also switched by an electromagnetic force, and depending on the electromagnetic force, the communication amount between the first port 211 and the third port 213 or the second port 212 and the third port 213.
Can be controlled to an arbitrary value.

Next, the structure of the modulator 410 will be described. The modulator 410 has a first cylinder 450 and a second cylinder 452. A movable piston 411 and a second pressure adjusting piston 431 are arranged in the first cylinder 450. An input chamber 412 is provided at one end of the movable piston 411.
Is formed on the other end side, that is, the second pressure regulating piston 43
An output chamber 413 is formed on the surface facing 1.
A first pressure adjusting chamber 434 is formed on the other end side of the second pressure adjusting piston 431.

The first input pipe 17 is provided in the input chamber 412.
3a is connected, an output pipe 174 is connected to the output chamber 413, and is connected to the wheel cylinder 105. The first pressure regulation chamber 434 has the second input pipe 1
73b is connected, and a pressure regulating cut valve 700 is arranged in the second input pipe 173b. The pressure cut valve 700 normally shuts off the second input pipe 173b, and receives the pilot pressure from the pilot pressure pipe 610 and switches the second input pipe 173b so as to communicate with it.

A bypass pipe 710 connecting the upstream side and the downstream side of the pressure cut valve 700 is connected to the second input 173b. A check valve 711 is arranged in the bypass pipe 710 to allow only the flow from the variable pressure regulator 210 to the first pressure adjusting chamber 434. A pressure spring 414 is arranged between the movable piston 411 and the second pressure adjusting piston 431, and the second pressure adjusting piston 431 is disposed in the output chamber of the first pressure adjusting chamber 434. A second pressure spring 435 that is biased in the 413 direction is arranged.

Inside the second cylinder 452, a first pressure adjusting piston 432 is arranged. A second pressure adjusting chamber 437 is formed on one end side of the first pressure adjusting piston 432. The pressure in the first branch pipe 155 is introduced into the second pressure adjusting chamber 437 by a branch pipe 630 branched from the first branch pipe 155. The third pressure adjusting chamber 436 communicates with the reservoir 180 by a return pipe 633.
A rod 432a is formed on the first pressure adjusting piston 432, and passes through the inside of the input chamber 412 and abuts on the movable piston 411.

Although not described in detail, the second branch pipe 157 is provided with a cut valve 320, a variable pressure regulator 220, a modulator 420, a pressure cut valve 520, and a pressure regulation cut valve 720. Further, a cut valve 33 is provided in the third branch pipe 159.
0, modulatable pressure device 230, modulator 430, pressure cut valve 5
30, and a pressure regulating cut valve 730.
The branch pipe 161 includes a cut valve 340, a variable pressure regulator 240, a modulator 440, a pressure cut valve 540, and a pressure regulation cut valve 740.
Are arranged respectively. And these cut valves,
The variable pressure regulator, the modulator, the pressure cut valve, and the pressure regulation cut valve are the cut valve 310, the variable pressure regulator 210, and the modulator 41 described above.
0, the pressure cut valve 510, and the pressure regulation cut valve 710 have exactly the same configuration.

Further, the present embodiment shows an example when applied to a so-called FR vehicle. Next, the operation of the present embodiment will be described. First, the basic operation of the hydraulic system will be described with reference to FIG. First, when the brake is not operated without depressing the brake pedal 101, the pressure switching valve 500 is in the first position, and the pressure cut valve 510 and the cut valve 310 are in the communicating position. Further, the modulatable pressure device 210 is in the first position as shown in FIG. 3, and maintains the neutral position of the movable piston 411 of the modulator 410.

Next, when the brake oil pressure is generated in the master cylinder 103 by depressing the brake pedal 101, the brake oil pressure is applied to the first main pipe 151 and the first branch pipe 1.
It is derived toward 55. The hydraulic pressure flowing through the first branch pipe 155 is transmitted via the pilot pipe 156 to the variable pressure regulator 210.
And receives the pilot oil pressure,
Reference numeral 10 switches from the first position to the second position. Then, from the accumulator 113 via the pressure pipe 170,
The guided constant hydraulic pressure is changed from the first port 211 to the third port 2
13 and further from the input pipe 173 to the first output pipe 173.
Through a, it flows into the input chamber 412 of the pressure regulator 410.
Then, the movable piston 411 receives the pressure in the input chamber 412 and moves to the output chamber 413 side.
The volume inside 3 decreases and the pressure rises, and the pressure is transmitted to the wheel cylinder 105 via the output pipe 174.

At this time, in the first pressure adjusting chamber 434, the pressure adjusting cut valve 700 blocks the second output pipe 173b, and the check valve 711 prevents the outflow from the first pressure adjusting chamber 435. Therefore, the pressure in the first pressure adjusting chamber 434 is kept constant. Therefore, the second pressure regulating piston 431
Remains fixed in position. Further, the pressure flowing in the first branch pipe 151 is also introduced into the second pressure adjusting chamber 437 via the conduit 630, and the first pressure adjusting piston 432 is connected to the movable piston 4 via the rod 432a.
11 is urged to the output chamber 413 side. Further, the cut valve 310 receives the pressure flowing through the first branch pipe 155 as a reference pressure via the pilot pipe 175, and when the pressure is introduced into the first branch pipe 155, the first cut valve 310 is set to this. The first branch pipe 155 is shut off.

The variable pressure device 210 introduces the reference pressure from the pilot pipe 156 and the reference pressure from the second pilot pipe 190, respectively. That is, the first
The pressure difference between the pressure flowing through the branch pipe 155 and the pressure flowing through the input pipe 173 is detected and switched. At this time, the variable pressure device 210 has a pressure receiving area which receives the pressure from the pilot pipe 156, which is larger than that of the second pilot pipe 19.
It is larger than the pressure receiving area received from zero.
Here, when the ratio of the pressure receiving area is α, the pressure received from the pilot pipe 156 is higher than the pressure received from the second pilot pipe 1.
When the pressure received from 90 becomes α times, the variable pressure device 210 switches from the second position to the original first position and connects the input pipe 173 to the return pipe 172. In other words, a pressure α times the pressure flowing through the first branch pipe 155 flows through the input pipe 173.

The hydraulic pressure flowing through the input pipe 173 is the first
When the hydraulic pressure flowing through the branch pipe 155 becomes α times or more, the variable pressure device 210 is switched to the first position shown in FIG. 3 as described above, and the pilot pipe 175 passes through the third port 213 and the second port 212. The pressure in the input chamber 412 is returned to the reservoir 180 via the input pipe 173 and the return pipe 172. Therefore,
The pressure flowing through the input pipe 173, that is, the input chamber 4
The pressure introduced into 12 is always suppressed to α times the hydraulic pressure flowing through the first branch pipe 155.

In the modulator 410, the pressure receiving area of the first pressure adjusting piston 432 on the second pressure adjusting chamber side and the movable piston 411.
The pressure receiving area of the spring 41 is set to be equal.
Since 4 is also set relatively weak, the pressure generated in the output chamber 413 is substantially equal to the sum of the master cylinder pressure of the pipe 155 and the pressure of the pipe 173. Therefore, the pressure of the wheel cylinder 105 becomes (α + 1) times the pressure from the master cylinder 103, and a boosting action is performed.

By energizing the variable pressure device 210, the α can be made variable. That is, in FIG. 3, when current is supplied to the variable pressure regulator 210 so that a force is generated in the right direction, the variable pressure regulator tends to be depressurized, the pressure in the input pipe 173 is suppressed low, and α becomes small. On the other hand, when a current is supplied so that a force is generated in the left direction, the variable pressure device 210 tends to increase the pressure and the input pipe 173
Is increased and α increases.

Therefore, by controlling the current supplied to the variable pressure regulator 210 by the ECU 6, the above-mentioned pressure signal ratio α is controlled and variable boosting control can be performed. Therefore, based on the signals from the sensor groups 1 to 5, the ECU 6 controls the modulatable pressure devices 210 to 240 so that the front-rear braking force distribution becomes appropriate, which will be described later in detail. This system also has an anti-skid function to prevent wheel lock during sudden braking, and a traction function to prevent wheel spin of the driving wheels during start and acceleration, which will be described below.

First, a case where the driver suddenly depresses the brake pedal 101 to suddenly stop the vehicle will be described. When the wheel speed sensor provided on each wheel determines that the wheel tends to lock, first, the ECU switches the pressure switching valve 5
A switching signal is transmitted to 00. Upon receiving this signal, the pressure switching valve 500 switches to the second position, and the first port 50
1 and the third port 503 are communicated. Then, the pressure accumulated in the accumulator 113 becomes the pressure pipe 17
0, the pressure branch pipe 171, the first port 501, and the third port 503 to the pilot pressure pipe 610 and the pilot pipe 600, respectively.

The pressure delivered to the pilot pipe 600 is
It acts on the pressure cut valve 510 via the pilot pipe 620 and closes the pressure cut valve 510. Further, the pressure led to the pilot pipe 600 is the same as that of the cut valve 310.
And the cut valve 310 is closed. Also,
The pressure introduced to the pilot pressure pipe 610 acts on the pressure regulation cut valve 700 to bring the second input pipe 173b into a communication state. Then, E is applied to the
The switching signal is further supplied from the CU, and the
Is switched to the first position.

As a result, the third port 213 and the second port 212 of the variable pressure regulator 210 communicate with each other, and the pressures of the input chamber 412 and the first pressure regulating chamber 434 are respectively transmitted through the first input pipes 172, 631. And is led to the reservoir 180. The movable piston 411 moves to the input chamber 412 side, and the second pressure adjusting piston 431 moves to the first pressure adjusting chamber 434.
Move to the side. As a result, the volume of the output chamber 413 increases, and the pressure in the wheel cylinder 105 is increased by the output pipe 1.
It will be returned to this output chamber 413 via 74. Therefore, the wheel cylinder pressure of the wheel having the lock tendency is reduced, and the lock tendency is eliminated.

Next, when the wheel slips during a sudden start, the engine torque of the vehicle is reduced and
High pressures from the hydraulic pump 117 and the accumulator 113 are introduced to the brake system of the driving wheels, and the braking force to the driving wheels is adjusted in the same manner as above, so that the idling of the driving wheels can be suppressed and a smooth start can be performed. Next, the braking force distribution control by the ECU 6 will be described.

When the vehicle turns, a lateral acceleration due to a centrifugal force causes a load transfer from the inner wheel side to the outer wheel side.
The tire loads on the left and right wheels differ greatly. If braking is performed at this time, the load is further moved from the rear wheel side to the front wheel side due to the deceleration of the vehicle body, so that the load of each wheel has a value that is significantly different from that when the wheel is stationary. Therefore, at the time of turning braking, the braking force on the inner wheel side is reduced and the braking force on the outer wheel side is increased according to the turning state, thereby increasing the lock limit of the wheels and enhancing the braking effect.

Details of the braking force distribution control by the ECU 6 will be described with reference to the flowchart of FIG. First, step 10
At 00, the wheel speeds of the four wheels V _FL , V _FR , V _RL , V _RR (F
L-left front wheel, FR-right front wheel, RL-left rear wheel, RR-right rear wheel), and in step 1001, the vehicle body longitudinal acceleration

[0032]

[Outside 1]

And lateral acceleration

[0034]

[Outside 2]

Enter, and in step 1002,
Linda oil pressure P_M, Each wheel brake hydraulic pressure P_FL, P_FR,
P_RL, P_RRAnd in step 1003, the steering angle δ
input. Then, in step 1004, each wheel speed
And vehicle speed V from vehicle longitudinal acceleration_BAnd calculate
In step 1005, each wheel speed and step 1004
Body speed V obtained by_BTo determine the slip ratio. For example
For the left front wheel, S_FL= (V_B-V_FL) / V_BIt is. Soshi
In step 1006, the master cylinder hydraulic pressure P_MOr
Target brake oil pressure P for each wheel_FL ^* _,P_FR ^*, P_RL ^*,
P_RR ^*Is determined as follows.

P _FL ^* = P _FR ^* = C _F1 × P _M + C _F2 × P _M ² (1) P _RR ^* = P _FL ^* = C _F1 × P _M −C _F2 × P _M ² ... ( 2) Here, C _F1 , C _F2 , C _R1 and C _R2 are numerical values determined from vehicle specifications and brake specifications. And Step 100
In step 7, the braking force distribution of the left and right wheels is corrected. Considering a case where the vehicle is turning left, the brake hydraulic pressures of the left front wheel and the left rear wheel, which are the inner wheels, are reduced, and the brake pressures of the right front wheel and the right rear wheel, which are the outer wheels, are increased.

[0037] In other _{^{words, P'FL * = P FL *}} × (1-α F) ...... (3) P'RL * = P RL * × (1-α R) ...... (4) P'FR * = ^{_{P FR * × (1 + α}} F) ...... (5) P'RR * = P RR * × (1 + α R) computes the ... (6). Here, α _F and α _R are the left and right braking force movement rates, and the steering angle δ and the left-right acceleration

[0038]

[Outside 3]

It is calculated from the vehicle speed V _B. That is, steering angle δ, lateral acceleration

[0040]

[Outside 4]

Vehicle speed V_BFrom the current turning state,
Left and right load transfer rate β_F, Β_RAsk for. And below
From the formula, the left and right braking force transfer rate α_F, Α_RAsk for. α_F= Γ_F× β_F …… (7) α_R= Γ_R× β_R (8) where γ_F, Γ_RIs the braking force against the load movement
Is the ratio of whether to move, γ_F= Γ_RLeft and right at 0
Normal braking without power movement, γ_F= Γ_R= 1, each tie
The braking is performed by the distribution of the braking force according to the yaw load. γ_F, Γ
_RIncreases the wheel lock limit and the braking distance
It can be shortened, but the braking force on the outer ring increases,
The yaw moment in the direction opposite to the turning direction increases.
Understeer tendency. Therefore, this γ_F,
γ_RHas an appropriate value for γ_F, Γ _RIs the vehicle speed V_Bof
Function at low speed, giving priority to turning performance and γ_F, Γ_RSmall
At high speed, priority is given to stability and safety at high speeds._F, Γ_R
Is largely determined.

From the above, equations (7), (8), and equation (3)
(4) (5) by the operation of (6), left and right brake force distribution corrected target brake hydraulic _{^{P'FL *, P'FR *,}} P'RL *,
Seek _P'RR ^*. Then, in step 1008, the target brake hydraulic pressure calculated in step 1007 is corrected according to the magnitude of the slip ratio calculated in step 1005, and the slip ratio corrected target brake hydraulic pressures P _FL ^** _, P _FR ^** , P _RL ^** ,
_Calculate P _RR ^** . That is, the brake pad friction coefficient,
Since the actual braking state varies due to changes in vehicle weight, etc., the braking force distribution of the four wheels is adjusted to decrease the hydraulic pressure when the slip ratio is too large, and to increase the hydraulic pressure when the slip ratio is too small. To do.

However, when the friction coefficient of the road surface is different between the left and right, if the above slip ratio correction is performed, the braking force on the high friction coefficient side exceeds the braking force on the low friction coefficient side, so the yaw moment is increased. Occurs, and straight running stability is impaired. Therefore, when the steering angle δ is near zero, the left and right slip ratio corrections are prohibited. Then, in step 1009, each target brake oil pressure Pi ^* (i = FL, FR, RL, RR)
Is compared with the master cylinder oil pressure P _M, and when it is larger than the master oil pressure P _M , the pressure switching valve 500 is turned off in step 1010.
F, except for that condition, the pressure switching valve 500 is turned on in step 1011 and the process proceeds to the next step 1012, where each wheel is determined from the difference between the wheel brake oil pressure input in step 1002 and the slip ratio correction brake oil pressure obtained in step 1008. Adjustable pressure devices 210, 220, 23 provided in the
Supply current to solenoids 0 and 240 i _FL, i _FR, i
_RL, i _RR can be obtained, and in step 1013, current can be supplied to each solenoid to control the pressure and adjust the appropriate braking force distribution.

Next, FIG. 5 shows the configuration of the essential parts of the second embodiment according to the present invention. This embodiment has a normal negative pressure booster, and corrects the left-right braking force distribution only on the rear wheel side by using a solenoid valve. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In FIG. 5, reference numeral 102 designates the master cylinder 1 to boost the pedaling force of the brake pedal 101.
Negative pressure booster transmitted to 03, 800 is master cylinder 1
03 is a first main pipe for supplying brake oil pressure to the wheel cylinders 105, 107 of the front wheels, and 801 is a second main pipe for supplying brake oil pressure to the wheel cylinders 109, 111 of the rear wheels from the master cylinder.
3 is connected. 802 is the accumulator 1
It is a pressure pipe for supplying 13 pressure fluid, and is connected to a 3-port 2-position valve 803. The 3-port 2-position valve 803 is a solenoid valve, which connects the second main pipe 801 and the conduit 804 when current is not supplied (OFF), and when energized (ON),
The pressure pipe 802 communicates with the conduit 804. The three-port three-position valve 805 is a solenoid valve that switches between three positions according to the current value, and the three ports are a conduit 804, a branch pipe 807 communicating with the wheel cylinder 109 of the rear right wheel, and a conduit communicating with the reservoir 104. It is connected to 809, and when not energized,
Only the conduit 804 and the branch pipe 807 are communicated with each other, the communication of all ports is cut off during the first energization, and the current is further increased.
At the time of energization, only the branch pipe 807 and the conduit 809 communicate. 3
The port 3 position valve 806 and the branch pipe 808 are also the same as those of the aforementioned 3 port 3
This is the same as the position valve 805 and the branch pipe 807.

In this embodiment, the 3-port 2-position valve 8
03 and the 3-port 3-position valves 805 and 806 are driven to perform a normal proportioning valve function and left and right braking force distribution control. The control operation of the ECU 6 will be described with reference to the flowchart of FIG. First, in step 1100, the wheel speeds V _{RL and} V _{RR of the} rear wheels ( _RL- left rear wheel, RR-right rear wheel) are input, and in step 1101, the vehicle body longitudinal acceleration is input.

[0046]

[Outside 5]

And lateral acceleration

[0048]

[Outside 6]

The master cylinder hydraulic pressure P _M and the rear wheel brake hydraulic pressures P _{RL and} P _RR are input in step 1102, and the steering angle δ is input in step 1103. Then, in step 1104, the vehicle body speed V _B is calculated from the wheel speed and the vehicle body longitudinal acceleration. And step 1
At 105, the master cylinder hydraulic pressure P _M and a predetermined pressure P _M
O (for example, 25 _kg f / _cm ² ) is compared, and if P _M ≦ P _O , the target brake hydraulic pressure of the rear wheels is made equal to the master cylinder in step 1106, and the process proceeds to step 1108.
On the other hand, in step 1105, P _M ≦ P _O is not established,
That is, if P _M > P _O, the rear wheel target brake hydraulic pressure is given by the following equation in step 1107.

P _RL ^* = P _RR ^* = P _O + K × (P _M −P _O ) ... (9) Here, K <1 and, for example, K = 0.37. By this processing, when the master cylinder hydraulic pressure P _M exceeds the predetermined pressure P _O , the rear wheel hydraulic pressure becomes lower than the front wheel hydraulic pressure equal to the master cylinder hydraulic pressure, and the normal proportioning valve function is obtained. Then, the process proceeds to step 1108.
In step 1108, the left and right braking force distribution corrections
Similarly to step 1007 in the flowchart of FIG. 4 of the embodiment, the correction target brake oil pressure P ′ is performed for the rear wheels.
_RL ^*, seek _P'RR ^*.

In step 1109, step 1102
The energization state of each solenoid valve is controlled according to the difference between the rear wheel brake hydraulic pressure input in step 1 and the corrected target brake hydraulic pressure determined in step 1108. That is, when performing pressure correction, first, the 3-port 2-position valve 803 is energized to guide the accumulator pressure to the 3-port 3-position valves 805, 806. And
3 depending on the magnitude relationship between each brake oil pressure and the corrected brake oil pressure
The port 3 position valves 805 and 806 are switched. That is,
When we describe the rear right ^{_{wheel, P RR <P'RR * i}} RR = 0 ...... (10) when the _{^{P RR ≒ P'RR * i RR}} = i 1 ...... (10) when the P _RR ≧ P When _RR ^* , i _RR = i ₂ (10) and the current is controlled. Where i _RR is a 3-port 3-position valve 8
I is a current to be supplied to H.05 and i _{1 and} i ₂ are predetermined currents (0 <i ₁ <i ₂ ). By the above process, when P _RR is low, the pressure oil of the accumulator 113 increases the pressure,
Because when P _RR is high is reduced in pressure to the reservoir 104, P _RR is the pressure is held approximately equal to _P'RR, P _RR
Is controlled to the target hydraulic pressure P ′ _RR ^* . In step 1109, the current value i _{R of the} 3-port 2-position valve 803 is set as described above.
(ON / OFF) After calculating the current values i _RR and i _RL of the three-port three-position valves 805 and 806, in step 1110, the solenoid is driven by the calculated current value of each solenoid valve,
Performs pressure control of the rear left and right wheels.

In the above-described first embodiment, the anti-skid control means corresponds to step 1008 of the flowchart of FIG. 4, and the turning detection means is the steering sensor 4, the lateral acceleration sensor 3, and the wheel sensor group 1. The control means corresponds to step 1007 in the flowchart of FIG.

[Brief description of drawings]

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

FIG. 2 is an overall block diagram showing one embodiment of the present invention.

FIG. 3 is a hydraulic system diagram showing a hydraulic system in FIG.

FIG. 4 is a flowchart showing a calculation process of an ECU of FIG. 2;

FIG. 5 is a configuration diagram showing a main part configuration of a second embodiment of the present invention.

FIG. 6 is a flowchart showing a calculation process of electronic control.

[Explanation of symbols]

 a brake operating pressure source b left wheel c right wheel f, g brake system i, j first and second pressure adjusting device k turning detection means m control means 4 steering sensor 6 turning control means 6 ECU 7 actuator

Front Page Continuation (72) Inventor Haruhiko Uno 1-1, Showa-cho, Kariya, Aichi Prefecture DENSO CO., LTD. (72) Inventor, Yuzo Imoto 1-1-1, Showa-cho, Kariya City, Aichi DENSO CORPORATION

Claims (2)

[Claims] 1. A first brake pressure generating means for generating a first brake pressure based on an operation of a brake pedal by an occupant during vehicle braking, and a wheel braking force for each wheel by the brake pressure action during vehicle braking. A plurality of wheel braking force generating means, the first brake pressure generating means, and the first and second
A pipe line communicating with the wheel braking force generation unit of the second brake pressure generation unit, a second brake pressure generation unit that is provided in the pipe line and that generates a second brake pressure higher than the first brake pressure, Slip condition detecting means for detecting a slip condition of a wheel; anti-skid control means for adjusting a brake pressure applied to each of the plurality of wheel braking force generating means based on a detection result in the slip condition detecting means; A brake control device for a vehicle, comprising: a brake pressure increasing unit that applies the second brake pressure to a wheel braking force generation unit that does not perform brake pressure adjustment by the skid control unit. 2. The brake pressure increasing means includes a load movement detecting means for detecting a load movement according to a running state of the vehicle, and executes the movement according to a magnitude of the load movement. 1. The vehicle brake control device according to 1.