JPH08108841A - Braking force distribution control device - Google Patents

Abstract

PURPOSE: To appropriately control braking force distribution according to the turning state of a vehicle, and operate stable braking even at braking during turning of the vehicle. CONSTITUTION: The deceleration state of a vehicle is judged by a deceleration state judging means DS, and the turning state of the vehicle is judged by a turning state judging means DM. In a beginning judging means SM, a control territory allowing beginning of drive of a liquid pressure control device FV by a drive means AM is set based on the deceleration state and the turning state of the vehicle, and it is judged whether the vehicle is in the control territory or not according to the judged results of the turning state judging means DM and the deceleration state judging means DS. According to the judged results, drive of the drive means AM is begun, so as to adjust the braking force of rear wheels RL, RR in the fixed relation against the braking force of front wheels FL, FR. In addition a target slip ratio is set according to the turning state, a control mode is set based on this, and hence the braking force is applied while maintaining cornering force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force distribution control device for adjusting a braking force of a wheel behind a vehicle to a predetermined relationship with a braking force of a wheel in front of a vehicle during vehicle braking.

[0002]

2. Description of the Related Art Generally, when a running vehicle is braked, the load on the front and rear axles of the vehicle is different due to movement of the load, and the four wheels are locked at the front of the vehicle to lock simultaneously. The power and the braking force on the rear wheels are not in a direct proportional relationship but in a relationship called an ideal braking force distribution, and this distribution also differs depending on the presence or absence of a load.

In this regard, if the braking force applied to the rear wheels exceeds the braking force applied to the front wheels, the directional stability of the vehicle is impaired. Therefore, in order to make the braking force distribution as close as possible to the ideal braking force distribution while keeping it lower than this. A proportional pressure reducing valve, a so-called proportioning valve, is provided between the wheel cylinder and the master cylinder. According to this, the distribution line has a break point, but considering the load difference between the inner and outer wheels when turning, it is necessary to keep the braking force on the rear wheel considerably lower than the braking force on the front wheel.
However, if the brake fluid pressure is always limited via the proportioning valve, the distribution of the braking force to the wheels behind the vehicle is reduced, and a large brake pedal force is required to obtain the predetermined deceleration, and The burden on the braking device for the wheels of the vehicle becomes large.

In order to solve such a problem, JP-A-6-
In JP-A-144174, a switching valve is provided upstream of a hydraulic booster and a hydraulic control valve provided between a master cylinder and a wheel cylinder, and the switching valve is switched and the hydraulic control valve is controlled. There has been proposed a braking force distribution control device that adjusts the brake fluid pressure of the rear wheel wheel cylinder to a predetermined relationship by doing so.

[0005]

[Patent Document 1] Japanese Patent Application Laid-Open No. 6-144
According to the device described in Japanese Patent No. 174, etc., since the braking force of the rear wheels can be approximated to the ideal braking force distribution, good braking characteristics can be obtained during braking while the vehicle is traveling straight, but the vehicle is turning. Since the cornering force with respect to the rear wheels is reduced during braking, the stability of the vehicle may be impaired depending on the deceleration state of the vehicle.

Therefore, it is conceivable that the above braking force distribution control is not performed during braking in a turning state where the stability of the vehicle is impaired. However, although this makes it possible to ensure the stability of the vehicle, the braking performance may be sacrificed. Therefore, it is necessary to provide an appropriate braking force while ensuring the cornering force and to achieve both the stability and the braking performance of the vehicle.

Therefore, the present invention relates to a braking force distribution control device for adjusting a braking force of a wheel behind a vehicle to a predetermined relationship with a braking force of a wheel ahead of a vehicle, and a braking force distribution control according to a turning state of the vehicle. The purpose is to be able to do properly.

It is another object of the present invention to provide a braking force distribution control device that provides an appropriate braking force while ensuring cornering force even when braking while the vehicle is turning to perform a stable braking operation.

[0009]

In order to achieve the above object, a braking force distribution control device according to a first aspect of the present invention has wheels FL, F on the front left and right sides of a vehicle as shown in the outline of the configuration.
Wheel cylinders for front wheels Wfl and Wfr, which are attached to each of the R and apply braking force, and wheels RL and RR on the rear left and right of the vehicle.
Wheel cylinder for rear wheel Wr mounted on the vehicle and applying braking force
1 and Wrr, and the brake fluid is boosted in accordance with the operation of the brake pedal BP, and the front and rear wheel wheel cylinders Wf
1, Wfr, Wrl, Wrr, and a hydraulic pressure generator PG for applying a brake hydraulic pressure to each of them, and a brake hydraulic pressure interposed between the hydraulic pressure generator PG and at least the rear wheel wheel cylinders Wrl, Wrr. And a hydraulic pressure control device FV for controlling the left and right wheels FL, FR, RL on the front side and the rear side of the vehicle.
Wheel speed detecting means WS for detecting the wheel speed of each RR
1 to WS4 and the hydraulic pressure control device FV based on the detection outputs of the wheel speed detecting means WS1 to WS4 to drive the braking force of the wheels RL, RR on the rear left and right of the vehicle to the braking force of the wheels FL, FR on the front left and right of the vehicle. In the braking force distribution control device including the drive means AM that adjusts to a predetermined relationship, a deceleration state determination means DS that determines the deceleration state of the vehicle, a turning state determination means DM that determines the turning state of the vehicle, A control region is set that allows the drive means AM to start driving the hydraulic pressure control device FV based on the deceleration state and turning state of the vehicle,
A start determination means SM for determining whether or not the vehicle is in the control area is provided according to the determination result of the turning state determination means DM and the determination result of the deceleration state determination means DS, and the drive means is provided according to the determination result of the start determination means SM. The control is made so as to start driving the AM.

Further, as described in claim 2 and as shown in the outline of the configuration in FIG. 22, a front wheel wheel cylinder Wf mounted on each of the front left and right wheels FL, FR to apply a braking force.
1, Wfr and rear wheel cylinders Wr for attaching braking force to the left and right wheels RL, RR on the rear side of the vehicle.
1 and Wrr, and the brake fluid is boosted in accordance with the operation of the brake pedal BP, and the front and rear wheel wheel cylinders Wf
1, Wfr, Wrl, Wrr, and a hydraulic pressure generator PG for applying a brake hydraulic pressure to each of them, and a brake hydraulic pressure interposed between the hydraulic pressure generator PG and at least the rear wheel wheel cylinders Wrl, Wrr. A hydraulic pressure control device PG for controlling the vehicle, a turning state determination means DM for determining the turning state of the vehicle, wheels FL, FR on the front left and right of the vehicle, and wheels R on the left and right of the vehicle.
Wheel speed detecting means WS1 to WS4 for detecting the wheel speed of each of L and RR, and each of the vehicle rear left and right wheels RL and RR with respect to the vehicle front left and right wheels FL and FR based on the detection outputs of these wheel speed detecting means. Slip ratio calculation means SC for calculating the slip ratio, and target slip ratio setting means for correcting the slip ratio calculated by this slip ratio calculation means SC based on the judgment result of the turning state judgment means DM to set the target slip ratio. TS, a control mode setting means CM for setting a control mode on the basis of the target slip ratio set by the target slip ratio setting means TS, and a hydraulic pressure control device PG according to the control mode set by the control mode setting means CM. To adjust the braking force of the left and right wheels RL, RR behind the vehicle to a predetermined relationship with the braking force of the left and right wheels FL, FR in front of the vehicle. Or equal to those with a driving means AM.

As described in claim 3, the turning state determining means DM may be provided with a lateral acceleration detecting means YS for detecting a lateral acceleration of the vehicle or a yaw rate detecting means YR for detecting a yaw rate of the vehicle. The deceleration state determination means DS may include a longitudinal acceleration estimation means for estimating the longitudinal acceleration of the vehicle based on the detection outputs of the wheel speed detection means WS1 to WS4. Alternatively, it may be provided with a longitudinal acceleration detecting means for directly detecting the longitudinal acceleration of the vehicle. The yaw rate detecting means YR calculates the wheel speed difference between the wheel located inside and the wheel located outside during turning of the vehicle from the detection output of the wheel speed detecting means for the non-driving wheel side of the wheels. ,
The yaw rate of the vehicle can be obtained based on this wheel speed difference. Further, the lateral acceleration detecting means YS
Can calculate the vehicle body speed of the vehicle based on the detection outputs of the wheel speed detecting means WS1 to WS4, and obtain the lateral acceleration of the vehicle from the difference between the vehicle body speed and the wheel speed.

When the turning state determining means DM determines that the vehicle is near the turning limit of the vehicle, the control mode setting means CM causes the wheels RL, RR on the left and right sides of the vehicle rear.
The control mode may be set based on the larger slip ratio among the slip ratios.

As described in claim 5, when the driving means AM starts adjusting the braking force of one of the wheels RL, RR on the rear side of the vehicle, the wheel R on the rear side of the vehicle is adjusted.
The adjustment start sensitivity of the other braking force of L and RR can be set to be high.

[0014]

In the braking force distribution control device according to claim 1, which has the above-mentioned structure, when the brake pedal BP is operated, the front and rear wheel cylinders Wfl, Wfr, Wrl, Wrr are operated from the hydraulic pressure generator PG. Brake fluid pressure is supplied to each of the wheels, and a braking force is applied to each of the wheels FL, FR, RL, RR, but there is fluid between the fluid pressure generator PG and at least the rear wheel wheel cylinders Wrl, Wrr. A pressure control device FV is interposed, and the hydraulic pressure control device FV controls the brake hydraulic pressure applied to the rear wheel wheel cylinders Wrl, Wrr. In this case, the wheel speed detecting means WS1 to WS4 detect the wheel speed of each wheel, and the driving means AM drives the hydraulic pressure control device FV based on the detected outputs, and the wheel rear left and right wheels RL and RR of the vehicle are detected. The braking force is on the left and right wheels F of the vehicle
It is adjusted so as to have a predetermined relationship with the braking force of L and FR, that is, to approximate the ideal braking force distribution.

Further, the deceleration state determination means DS determines the deceleration state of the vehicle and the turning state determination means DM.
The turning state of the vehicle is determined by. On the other hand, in the start determination means SM, a control region is set that allows the drive means AM to start driving the hydraulic pressure control device FV based on the deceleration state and the turning state of the vehicle.
Whether or not it is within the control region is determined according to the determination result of M and the determination result of the deceleration state determination means DS. Then, the drive of the drive means AM is started according to the determination result of the start determination means SM. As a result, even when the braking force distribution control is started while the vehicle is turning, sufficient cornering force for the rear wheels RW is ensured and the vehicle stability is maintained.

In the braking control device according to claim 2 and shown in FIG. 22, the slip ratio calculating means SC controls the vehicle for the wheels FL, FR on the left and right in front of the vehicle based on the detection outputs of the wheel speed detecting means WS1 to WS4. Rear left and right wheels R
The slip rate of each of L and RR is calculated, and this slip rate is corrected by the target slip rate setting means TS based on the determination result of the turning state determination means DM to set the target slip rate. Then, the control mode setting means CM sets the control mode based on the target slip ratio, the driving means AM drives the hydraulic pressure control device PG in accordance with the control mode, and the braking force of the wheels RL, RR on the rear left and right sides of the vehicle. Is adjusted to have a predetermined relationship with the braking force of the wheels FL and FR on the left and right of the front of the vehicle. Therefore, even when the braking force distribution control is being performed while the vehicle is turning, a sufficient cornering force is ensured for the rear wheels RW, and the stability of the vehicle is maintained.

According to the turning state determining means DM of the third aspect, the lateral acceleration of the vehicle is detected by the lateral acceleration detecting means YS, or the yaw rate of the vehicle is detected by the yaw rate detecting means YR. The turning state of the vehicle is determined based on the detected output.

According to the braking force distribution control device of the fourth aspect, when the turning state determination means DM determines that the vehicle is in the vicinity of the turning limit, the control mode setting means CM causes the wheels RL on the left and right sides of the vehicle rear, The control mode is set based on the larger slip ratio of the RR slip ratios.

In the braking force distribution control device according to the fifth aspect of the present invention, the drive means AM are used to drive the wheels RL on the left and right sides of the vehicle rearward.
When the adjustment of the braking force of one of the RRs is started, the adjustment start sensitivity of the other braking force of the left and right wheels RL, RR on the rear side of the vehicle is set high.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a brake fluid pressure control device according to an embodiment of the present invention, which is provided with a master cylinder MC and a regulator RG which constitute the fluid pressure generation device of the present invention, and which are operated in response to an operation of a brake pedal BP. Driven. An auxiliary hydraulic pressure source AP is connected to the regulator RG, and these are connected to the low pressure reservoir RS together with the master cylinder MC. The auxiliary hydraulic pressure source AP has a hydraulic pump HP and an accumulator ACC. The hydraulic pump HP is driven by an electric motor (not shown), and the low pressure reservoir R
The brake fluid of S is boosted and output, and this brake fluid is supplied to the accumulator ACC via the check valve CV1.
Accumulated. Thus, the so-called power hydraulic pressure is appropriately supplied from the accumulator ACC to the regulator RG. The electric motor is driven in response to the hydraulic pressure in the accumulator ACC falling below a predetermined lower limit value, and is stopped in response to the hydraulic pressure in the accumulator ACC exceeding a predetermined upper limit value.

The regulator RG receives the output hydraulic pressure of the auxiliary hydraulic pressure source AP, regulates the output hydraulic pressure of the master cylinder MC as a pilot pressure, and adjusts the regulator hydraulic pressure in proportion to the pilot hydraulic pressure. Since it is disclosed in Japanese Patent Publication No. 476664, detailed description will be omitted. The regulator RG of the present embodiment is configured to adjust the control hydraulic pressure to a predetermined ratio with respect to the output brake hydraulic pressure of the master cylinder MC (that is, the pressure proportional to the output brake hydraulic pressure of the master cylinder MC). The regulator RG can be configured separately from the master cylinder MC. Also,
Instead of the regulator RG, a hydraulic booster may be used in the hydraulic pressure generator of the present invention.

On the other hand, wheel cylinders Wfl, Wfr, Wrl, Wrr are mounted on the wheels FL, FR, RL, RR, respectively, and a hydraulic pressure passage connecting the master cylinder MC and each of the wheel cylinders Wfl, Wfr in front of the vehicle. The first valve device EV1 to the sixth valve device EV6 are interposed in the. Further, the seventh valve device EV7 to the tenth valve device EV10 and the proportional pressure reducing valve P are provided in the hydraulic passages connecting the regulator RG and the wheel cylinders Wrl, Wrr on the rear side of the vehicle.
V is installed. These first valve devices EV1 to ninth
The fluid pressure control device according to the present invention is configured by the valve device EV9, and the tenth valve device EV10 corresponds to the valve device of the present invention. In addition, the wheel FL indicates the wheel on the front left side when viewed from the driver's seat, hereinafter the wheel FR indicates the front right side, the wheel RL indicates the rear left side, and the wheel RR indicates the rear right wheel. As is clear from FIG. In the example, the front and rear pipes are divided into a hydraulic control system for the front wheels and a hydraulic control system for the rear wheels.
A so-called X pipe may be used. Further, in this embodiment, the wheels RL, RR on the rear side of the vehicle are drive wheels and the wheels FL, FR on the front side are so-called rear wheel drive related wheels, but they may be front wheel drive.

In the front wheel hydraulic system, the master cylinder M
The first valve device EV1 and the second valve device EV2 are respectively provided in the hydraulic paths that connect C and the wheel cylinders Wfl and Wfr on the front wheel side.
Are installed in the control passage Pfl,
The fifth valve device EV5 and the sixth valve device E are respectively connected via Pfr.
It is connected to V6. The fifth valve device EV5 and the sixth valve device EV6 are further connected to the third valve device EV4 via the fourth valve device EV4.
It is connected to the valve device EV3 and communicates with the regulator RG or the accumulator ACC. The first valve device EV1 and the second valve device EV2 are 3-port / 2-position electromagnetic switching valves, which are in the first position shown in FIG. 1 in a non-operating state, and the wheel cylinders Wfl and Wfr are both connected to the master cylinder MC. However, when the solenoid coil is excited and switched to the second position, the wheel cylinders Wfl and Wfr are both disconnected from the master cylinder MC, and the wheel cylinders Wfl and Wfr are respectively in the fifth position.
It communicates with the valve device EV5 and the sixth valve device EV6.

The third valve device EV3 and the fourth valve device EV4 are also 3-port / 2-position electromagnetic switching valves, and the third valve device EV3
Disconnects the fourth valve device EV4 and the proportional pressure reducing valve PV from the regulator RG in the first position in the non-operating state, and disconnects the fourth valve device EV4 and the proportional pressure reducing valve PV from the regulator RG in the second position in the operating state. Communication with the accumulator ACC. The fourth valve device EV4 communicates the third valve device EV3 with the fifth valve device EV5 and the sixth valve device EV6 in the first position in the non-actuated state, and disconnects these communication in the second position in the actuated state. , The fifth valve device EV5 and the sixth valve device EV6 communicate with the low pressure reservoir RS.

On the other hand, both the fifth valve device EV5 and the sixth valve device EV6 are 2-port / 2-position electromagnetic open / close valves, which are in the open position as shown in FIG. Then, the valve is closed and the hydraulic passage is shut off. The check valve CV2 and the throttle passage OR1 are connected in parallel to the fourth valve device EV4 and the fifth valve device EV5, and the check valve C4 is parallel to the fourth valve device EV4 and the sixth valve device EV6. The CV3 and the throttle passage OR2 are connected to each other, the inflow side of the check valve CV2 is connected to the control passage Pfl, and the inflow side of the check valve CV3 is connected to the control passage Pfr.

The throttle passage OR1 is provided with the first valve device EV3 when the third valve device EV3 is inactive when the brake pedal BP is operated.
When the first, fourth, and fifth valve devices EV4, EV5 are activated, the brake fluid from the regulator RG is provided to gently flow into the wheel cylinder Wfl. Is also the same. Further, the check valve CV2 causes the brake fluid pressure of the wheel cylinder Wfl to quickly follow the decrease in the output fluid pressure of the regulator RG when the brake pedal BP is released when the first valve device EV1 is in the operating state. It is provided for the purpose of allowing the flow of the brake fluid in the direction of the third valve device EV3 and blocking the flow in the opposite direction.
The same applies to the check valve CV3.

Next, the rear wheel side hydraulic system will be explained.
The tenth valve device EV10 is arranged in parallel with the third valve device EV3.
And a proportional pressure reducing valve PV are connected. Tenth valve device E
V10 is a 3-port 2-position electromagnetic switching valve, which is in the first position shown in FIG. 2 in a non-actuated state, and directly connects the seventh valve device EV7 and the regulator RG to establish a proportional pressure reducing valve PV and a third valve. The communication with the regulator RG via the device EV3 is cut off. When the tenth valve device EV10 is switched to the operating second position, the seventh valve device EV7 is disconnected from the direct communication with the regulator RG, and is connected to the third valve device EV3 via the proportional pressure reducing valve PV. Third valve device EV3
It is connected to the accumulator ACC or the regulator RG depending on the operation / non-operation of the.

The proportional pressure reducing valve PV is a regulator RG.
Is supplied to the wheel cylinders Wrl, Wrr of the rear wheels via the third valve device EV3 and the tenth valve device EV10, the hydraulic pressure on the output side (the hydraulic pressure on the tenth valve device EV10 side) is The hydraulic pressure on the output side is made equal to the hydraulic pressure on the input side (the hydraulic pressure on the third valve device EV3 side) until the hydraulic pressure on the output side rises to a predetermined hydraulic pressure. The rate of increase in pressure is adjusted so as to be kept small at a predetermined rate with respect to the increase in hydraulic pressure on the input side, which is generally known as a proportioning valve. Instead of this, a liquid pressure limiting valve may be used. this is,
The hydraulic pressure on the output side is made to match the hydraulic pressure on the input side until the hydraulic pressure on the output side rises to a predetermined hydraulic pressure, but the hydraulic pressure on the output side does not rise even if the hydraulic pressure on the input side further increases. Is something
It is generally known as a limiting valve.

The seventh valve device EV7 is a 3-port / 2-position electromagnetic switching valve and has the same relationship as the fourth valve device EV4 of the front wheel side hydraulic system. That is, the first position in the non-actuated first position
0 valve device EV10, 8th valve device EV8 and 9th valve device E
V8 is communicated with, and the communication is cut off in the second position in the operating state, and the eighth valve device EV8 and the ninth valve device EV9 are switched so as to communicate with the low pressure reservoir RS.
The eighth valve device EV8 and the ninth valve device EV9 also include the fifth valve device EV8.
Similar to the valve device EV5 and the sixth valve device EV6, it is a 2-port 2-position electromagnetic on-off valve, which is in the valve open position in the non-operating state, and in the valve operating position the valve is closed and the hydraulic passage is shut off.

Further, the seventh valve device EV7 and the eighth valve device E
The check valve CV4 and the throttle passage OR3 are connected in parallel with V8, and the seventh valve device EV7 and the ninth valve device E are connected.
The check valve CV5 and the throttle passage OR4 are connected in parallel to V9, the inflow side of the check valve CV4 is connected to the wheel cylinder Wrl, and the inflow side of the check valve CV5 is connected to the wheel cylinder Wrr. The throttle passage OR3 (or the throttle passage OR4) is the first when the brake pedal BP is operated.
When the seventh valve device EV7 and the eighth valve device EV8 (or the seventh valve device EV7 and the ninth valve device EV9) are activated while the zero valve device EV10 is in the inoperative state, the regulator R
There is also one provided so that the brake fluid from G gently flows into the wheel cylinder Wrl (or the wheel cylinder Wrr). Further, the check valves CV4 and CV5 are provided for quickly causing the brake fluid pressures of the wheel cylinders Wrl, Wrr to follow the decrease in the output fluid pressure of the regulator RG when the brake pedal BP is released. Thus, the flow of the brake fluid in the direction of the tenth valve device EV10 is allowed and the flow in the reverse direction is blocked.

In the brake fluid pressure control device having the above-described structure, the main operation in response to the control by the first valve device EV1 to the tenth valve device EV10 will be described. Valve devices EV1 to EV1
All the zero valve devices EV10 are in the non-actuated state and are set to the first position shown in FIG. Thus, the brake fluid pressure is supplied from the master cylinder MC to the wheel cylinders Wfl or Wfr via the first valve device EV1 or the second valve device EV2 in accordance with the operation of the brake pedal BP, and the master fluid is supplied from the regulator RG. The regulator hydraulic pressure proportional to the output of the cylinder MC is output, and the tenth valve device EV1
0, the seventh valve device EV7 and the eighth valve device EV8 or the ninth valve device EV9 are supplied to the wheel cylinders Wrl or Wrr. Then, the tenth valve device EV10
Is controlled to be switched to the second position, the output of the regulator RG is depressurized at a predetermined rate via the proportional pressure reducing valve PV and supplied to the wheel cylinders Wrl, Wrr.

In the braking force distribution control for the front and rear wheels, the seventh valve device EV7 is activated during the operation of the brake pedal BP, and the eighth valve device EV8 and the eighth valve device EV8 are operated in accordance with the behavior of the wheels RL, RR on the rear sides of the vehicle. The 9-valve device EV9 is controlled to open and close,
The hydraulic pressure in the wheel cylinders Wrl, Wrr is lower than the output hydraulic pressure of the regulator RG, and the braking force on the rear wheel side is adjusted to have a predetermined relationship with the braking force on the front wheel side,
The characteristics are controlled so as to approximate the ideal braking force distribution curve. According to the present embodiment, various controls including the anti-skid control described later, including this braking force distribution control, can be performed. However, the electronic control unit ECU described later receives the brake switch BS and the wheels as its control input. Signals from the speed sensors WS1 to WS4, the lateral acceleration sensor YS (or the yaw rate sensor YR), etc. are supplied.

Next, when one of the wheels tends to lock during braking, the control shifts to anti-skid (ABS) control. For example, when the anti-skid control is performed on the front wheel FL, the first valve device EV1 and the fourth valve device EV4 with the third valve device EV3 kept in the inoperative state.
Is activated and, depending on the locked state of the wheels FL, the fifth
The valve device EV5 is controlled to open and close. As a result, the wheel cylinder Wfl is disconnected from the master cylinder MC, and instead communicates with the regulator RG. At this time,
When the fifth valve device EV5 is in the valve open state, the brake fluid in the wheel cylinder Wfl passes through the first valve device EV1, the fifth valve device EV5 and the fourth valve device EV4 and the low pressure reservoir R.
It flows out to S and the hydraulic pressure in the wheel cylinder Wfl is reduced. At this time, the sixth valve device EV6 is activated to prevent the brake fluid from the regulator RG from being wasted. On the other hand, when the fifth valve device EV5 is closed, the output hydraulic pressure of the regulator RG is supplied to the wheel cylinder Wfl via the third valve device EV3, the throttle passage OR1 and the first valve device EV1, and the hydraulic pressure in the wheel cylinder Wfl is increased. Is gradually increased (slow pressure increase operation). In this way, the pressure reducing operation and the gradual pressure increasing operation are repeated, and an appropriate braking force is applied while preventing the wheels FL from being locked. If a larger amount of brake fluid is required to compensate for the decrease in brake fluid due to the pressure reducing operation at this time, the fifth valve device E is used.
V5 is opened and the pressure is rapidly increased. Incidentally, the wheel FR
The same applies to the side. Also, the wheels FL, FR
In the case where both sides of the wheel are subjected to anti-skid control, when one wheel, for example the wheel FL side, is in a depressurizing operation, the other wheel FR side cannot be intensifying operation, so
In response to the pressure increase request from the side, a slow pressure increase operation is used.

When anti-skid control is performed on the rear wheel RL, the seventh valve device EV7 is activated while the third valve device EV3 and the tenth valve device EV10 remain inoperative. , The seventh valve device EV7 is the tenth
The communication with the valve device EV10 is cut off and the low pressure reservoir RS
Communicate with In this state, when the eighth valve device EV8 is in the open state, the brake fluid in the wheel cylinder Wrl flows out to the low pressure reservoir RS via the eighth valve device EV8 and the seventh valve device EV7, and the pressure is reduced. At this time, the ninth valve device E
V9 is activated so that the brake fluid from the regulator RG is not wasted. On the other hand, when the eighth valve device EV8 is closed, the regulator RG
Output hydraulic pressure of the tenth valve device EV10 and the throttle passage OR3
Is supplied to the wheel cylinder Wrl via the, and the pressure is gradually increased. When a larger amount of brake fluid is required to compensate for the decrease in brake fluid due to the depressurization operation at this time, the eighth valve device EV8 is opened and brought into a rapid pressure increase operation state. Although the same process is performed on the wheel RR side, when the wheel RR side is in the pressure reducing operation, the wheel RL side is in the gradually increasing pressure operation. Thus, the eighth valve device EV8
The slow pressure increasing operation and the pressure reducing operation are repeated according to the opening / closing control of the valve (or the ninth valve device EV9).

Next, for example, so-called traction control is performed in order to prevent the wheels RL and RR on the drive wheel side from slipping due to acceleration slip when the vehicle starts moving. As a part of this, so-called traction control is performed. Acceleration slip is prevented by applying power. During this traction control, the third valve device EV3 and the tenth valve device EV10
Is activated and, for example, when the pressure is gradually increased, the eighth valve device E
When V8 is closed, the output power hydraulic pressure of the accumulator ACC is supplied to the wheel cylinder Wrl via the third valve device EV3, the proportional pressure reducing valve PV, the tenth valve device EV10 and the throttle passage OR3, and also increases rapidly. In the case of pressure, the eighth valve device EV8 is opened and braking force is applied to the wheels RL. Conversely, when the seventh valve device EV7 is activated and the eighth valve device EV8 is opened, the wheel cylinder Wrl communicates with the low-pressure reservoir RS via the activated seventh valve device EV7. , Wheel cylinder W
The brake fluid in rl flows out and the pressure is reduced. Thus, an appropriate braking force is applied to the wheels RL according to the opening / closing control of the eighth valve device EV8. The wheels RR are also controlled in the same manner.

The first valve device EV1 to the tenth valve device E
V10 is connected to the electronic control unit ECU shown in FIG. 3 to control the operation and non-operation of each. The electric motor (not shown) that drives the hydraulic pump HP is also an electronic control unit ECU.
And is driven and controlled by this. Also, the wheel F
Wheel speed sensors WS1 to W are provided for L, FR, RL, and RR.
S4 is provided, these are connected to the electronic control unit ECU, and the rotational speed of each wheel, that is, the wheel speed signal is input to the electronic control unit ECU. Further, a brake switch BS that is turned on when the brake pedal BP is depressed, a lateral acceleration sensor YS that detects a lateral acceleration of the vehicle, and the like are connected to the electronic control unit ECU.

As shown in FIG. 3, the electronic control unit ECU includes a microcomputer CMP including a processing unit CPU, a memory ROM, a RAM, a timer TMR, an input port IPT and an output port OPT which are interconnected via a bus. I have it. Wheel speed sensor W
The output signals of S1 to WS4, the brake switch BS, the lateral acceleration sensor YS, etc. are input to the processing unit CPU from the input port IPT via the amplifier circuit AMP, respectively. Further, from the output port OPT, the first valve device EV1 through the first valve device EV1 are connected via the drive circuit ACT.
A control signal is output to the zero valve device EV10. In the microcomputer CMP, the memory ROM stores the program corresponding to the flowcharts shown in FIG. 4 and subsequent figures, the processing unit CPU executes the program while the ignition switch (not shown) is closed, and the memory RAM stores the program. Temporarily stores variable data required for execution of.

In the present embodiment configured as described above, the electronic control unit 10 performs a series of processes such as anti-skid control and the seventh valve device EV7 through the tenth valve device EV10 are used as the braking force distribution control. Is controlled. That is, in the microcomputer 11, when the ignition switch (not shown) is closed, execution of the program corresponding to the flowcharts of FIGS. 4 to 7 starts. The above-mentioned traction control is omitted in the following flowcharts.

First, in FIG. 4 showing the main routine,
At step 101, the microcomputer 11 is initialized and various calculated values are cleared. Next step 10
2, the detection signals of the wheel speed sensors WS1 to WS4 are read and the detection signals of the lateral acceleration sensor YS are read, and step 103 is performed based on these signals.
At four wheel speeds VwFR, VwFL, VwRR, V
wRL is calculated. In step 104, the wheel speeds are differentiated and the wheel accelerations DVwFR, D of the wheels are calculated.
VwFL, DVwRR and DVwRL are calculated. An acceleration sensor may be provided and the detection signal thereof may be used. Further, in step 105, the estimated vehicle body speed Vso and the acceleration DVso which is a differential value thereof are calculated based on the wheel speed.
Is calculated. The estimated vehicle body speed Vso is set as a vehicle body speed, for example, on the assumption that the wheel speed during braking is decelerated at a predetermined deceleration, and even one of the four wheels exceeds this value. Sometimes, the value when the vehicle is decelerated again with a predetermined deceleration is set as the vehicle body speed, which is the same as the reference speed used for the conventional anti-skid control.

Next, in step 300, it is determined whether or not the antiskid control start condition is satisfied. If the start condition is satisfied and the antiskid control start is determined, the antiskid control is executed in step 400. Transition. When it is determined in step 300 that the anti-skid control start condition is not satisfied, step 500
It is determined whether or not the braking force distribution control start condition is satisfied, and if so, the process proceeds to step 600. If not, the process proceeds to step 700 and whether or not the traction control start condition is satisfied. To be judged. If this start condition is satisfied, traction control is performed in step 800, and if not satisfied, the process returns to step 102. When each of the above-mentioned controls is completed, step 10
Return to 2.

The braking force distribution control in the above step 600 comprises the routine shown in FIG. 5. First, in step 601, various constants for setting the starting condition of the braking force distribution control are set. Then, at step 602, the wheel speeds VwFR, VwFL of the wheels FR, FL, RR, RL,
The reference speeds VwsFR, VwsFL, VwsRR, and VwsRL are calculated by predetermined calculation processing based on VwRR and VwRL. This arithmetic processing will be described later with reference to FIG. 7. Further, in step 603, reference speed differences (VwsRR-VwsFR) and (VwsRL-VwsFL) between the front and rear wheels are calculated as DVwsRR and DVwsRL, respectively. And
After proceeding to steps 604 and 605 and calculating the braking force distribution control mode of the wheels RR and RL, step 606 is performed.
The braking force distribution control operation is performed at.

FIG. 6 shows a subroutine of the braking force distribution control mode calculation for the wheels RR in step 604 of FIG. 5, and the braking force distribution control mode calculation for the wheels RL in step 605 is similarly processed. First step 62
If it is determined at 0 that the control is being performed and the control flag indicating that the braking force distribution control is being performed is not set (0), the process proceeds to steps 621 to 626, and if it is set. For (1), step 627
Through 629.

In step 621, it is determined whether or not the braking force distribution control can be started for the wheels RR. The start condition is, for example, that the brake switch BS is in the ON state and the estimated vehicle body speed Vso is equal to or higher than a predetermined speed K1 (for example, 15 km / h), which will be described later with reference to FIG. When these conditions are satisfied, it is determined that the control can be started, the control-in-progress flag is set (1) in step 622, and the process proceeds to step 623. If the control start condition is not satisfied, the process returns to the routine of FIG. .

At step 623, the slip ratio SpRR and the like are calculated based on the reference speed VwsRR and the like,
The control reference values TsRR and DfRR are calculated. The control reference value DfRR is calculated as a change in the reference speed difference DVwsRR, that is, a difference between the previous value and the current value (DVwsRR _(n) -DVwsRR _(n-1) ). The slip rate SpRR is the slip rate ((Vws) of the reference speed VwsRR of the wheel RR on the rear right side of the vehicle with respect to the reference speed VwsFR of the wheel FR on the front right side of the vehicle.
RR-VwsFR) / VwsFR), and the integrated value I
SpRR is calculated, and these functions f (SpRR, DfRR,
The control reference value TsRR is calculated as ISpRR, K3RR). The K3RR will be described later. The control reference value TsRL for the wheel RL is calculated in the same manner.

Specifically, the control reference values TsRR and D
The control map shown in FIG. 8 is constructed based on fRR, and the control mode is set in step 624 according to this control map. In the figure, the vertical axis represents the slip ratio SpRR and the integrated value I.
SpRR is added to obtain the control reference value TsRR,
The horizontal axis is the control reference value DfRR, and X1 (G) and Y1
It divides into two regions P and D by a line segment connecting the intersection of (%) and the intersection of X2 (G) and Y2 (%) and a line parallel to the X axis. The region P is in the slowly increasing pressure mode and the region D is in the pressure reducing mode, and the control cycle TbRR and the control mode (RR) are set in both regions. The control cycle TbRR is, for example, X1, Y1 and X2, Y from an arbitrary point on the control map.
Let L be the length of the perpendicular to the line segment connecting 2 (Tb
RR = Kb−Kc · L) (where Kb,
Kc is a constant). Thus, in step 625 or 626, the pressure reducing operation or the gradual pressure increasing operation is performed based on the control mode and the control cycle TbRR. Regarding the control mode, in FIG. 6, only the pressure reducing mode, the slow pressure increasing mode, and the normal pressure increasing mode are used. However, by performing the intermittent control and duty control of each valve device shown in FIG. be able to.

On the other hand, when it is determined in step 620 that the control flag is set (1), step 62
At 7, it is determined whether the control end condition is satisfied. The termination condition is that the brake switch BS is turned off and the reference acceleration DVso is a predetermined value (-0.
25 G), etc., and if any of these conditions is satisfied, it is determined that the control can be ended, the control-in-progress flag is reset in step 628 (0), and the normal pressure increase control is performed in step 629. If the control end condition is not satisfied, the routine proceeds to step 623, where the braking force distribution control is continued.

FIG. 7 shows the calculation processing of the reference speed in step 602 of FIG. In the figure, an example of the wheel RR on the rear right side of the vehicle is shown, but the remaining wheels are similarly processed. From step 103, the wheel speed VwRR of the wheel speed RR is supplied in a predetermined calculation cycle and sequentially stored in the memory. First, at step 651, the current value (n times) VwRR _(n) is set to A. Next, in step 652, a predetermined value α _UP · t is added to the previous value VwRR _(n-1) to make it B. Then step 6
At 53, the predetermined value α _DN · t is subtracted from the previous value to obtain C.

Then, in step 654, the median values of A, B and C are calculated, and this is set as the reference value VwsRR. It should be noted that α _UP is a value that sets an acceleration with respect to the wheel speed VwRR, that is, a limit for the rate of increase of the wheel speed VwRR, for example, 2
G (where G is gravitational acceleration) is set. t is a calculation cycle, and α _DN is a value that sets a deceleration with respect to the wheel speed VwRR, that is, a limit of a reduction rate of the wheel speed VwRR. In the present embodiment, a value (α ₁ ) of a predetermined value to the acceleration DVwRR of the differential value thereof.
Is added (DVwRR + α ₁ ). In a vehicle equipped with an acceleration sensor, α _DN is calculated as (G ₀ + α ₀ ) (where G ₀ is the detection value of the acceleration sensor,
α ₀ is the tilt correction value).

FIG. 9 shows the target slip ratio bias setting for the wheel RR, which is processed as part of the constant setting in step 601 of FIG. First step 63
In 1, the turning state of the vehicle is determined, and this determination method will be described later. Next, the routine proceeds to step 632, where the turning direction is determined, and if it is a left turn, for example, step 6
The program proceeds to 33 and the inner wheel flag is set (1). If turning right, the inner wheel flag is reset (0) in step 634.
To be done. For the wheel RL, set the inner ring flag /
The reset state has the opposite relationship.

Then, in step 635, the target slip ratio bias SpzRR of the wheel RR is calculated according to the map of FIG.
Is set. In the map of FIG. 10, the characteristics for the inner wheel shown by the solid line and the characteristics for the outer wheel shown by the broken line are prepared, and the turning state of the vehicle is determined by the absolute value of the turning state output and the inner / outer wheel information, that is, the state of the inner wheel flag. The target slip ratio bias SpzRR is set in accordance with Based on the target slip ratio bias SpzRR set in this way, the reference speed VwsFR on the front wheel side is multiplied by the target slip ratio bias SpzRR in step 636 to obtain the slip ratio bias speed VwsFR · SpzRR, and this and the bias speed Vwz. Is added to obtain a predetermined speed K3RR. The bias speed Vwz is appropriately set, for example, according to the state of the road surface on which the vehicle travels. Thus, the difference between the control reference value TsRR including the slip ratio SpRR and the predetermined speed K3RR (TsRR-K3R
The braking force on the wheels RR is controlled so that R) becomes zero. Thus, as described above, the function for calculating the control reference value TsRR includes the predetermined speed K3RR, and the control reference value T
The control mode is set according to the control map of FIG. 9 in which sRR and the like are input, and the control cycle TbRR is set.

FIG. 11 shows an example of determination of the start condition of the braking force distribution control in step 621 of FIG. 6, and it is determined in step 641 whether or not the brake switch BS is in the on state, and if it is on, step 642. If it is off, the start condition is not satisfied and the routine proceeds to the next routine. In step 642, the estimated vehicle body speed Vso is compared with a predetermined speed K1 (for example, 15 km / h), and if it is more than this, the process proceeds to step 643, otherwise the start condition is not satisfied. Subsequently, in step 643, it is determined whether or not the control area is set based on the turning state and the deceleration state of the vehicle, that is, whether or not the control start state is set. If it is within the control area, it is determined that the control start state is set. Then, the process proceeds to step 644, and if it is not in this control area, the start condition is not satisfied. Further, in step 644, the reference speed Vws of the wheels RR
RR is compared with a predetermined reference value (VwsFR-K3RR), and if it falls below this, it is determined that the start condition is satisfied, and step 645.
Then, the in-control flag relating to the wheels RR and RL is set (1), and if not, the routine proceeds to step 646, and the same determination is made for the wheel RL. If the reference speed VwsRL is lower than the reference value (VwsFL-K3RL), the process proceeds to step 645. If not, the start condition is not satisfied. Note that K3RR used for the calculation of these reference values is the predetermined speed K3RR obtained in step 636 of FIG. 9 described above, and K3RL is similarly calculated.

In step 643, the deceleration state of the vehicle is determined based on the longitudinal acceleration DVso (including the deceleration of the vehicle body as a negative value). In addition, the turning state of the vehicle is determined by the lateral acceleration sensor YS (or the yaw rate sensor YS).
It is determined based on the lateral acceleration Gy (or yaw rate γ) which is the output of R). Further, the turning determination can be performed based on the output of the steering angle sensor (not shown). In this embodiment, the longitudinal acceleration DVso and the lateral acceleration Gy
Based on the above, the control area is set as shown in FIGS. 14 to 17, for example. That is, using the longitudinal acceleration DVso and the lateral acceleration Gy as parameters, the reference values Kd1 to Kd10 for the longitudinal acceleration DVso and the reference values Ky1 to Ky10 for the lateral acceleration Gy are used in FIGS.
, And the control area shown by the stippling in the figure is set. In these figures, the lateral acceleration Gy is positive when turning to the right and negative when turning to the left, and is therefore expressed as an absolute value.

Although the longitudinal acceleration DVso is calculated by differentiating the estimated vehicle body speed Vso in this embodiment, a separate (vehicle) longitudinal acceleration sensor may be provided and directly measured. On the other hand, although the lateral acceleration Gy is directly measured by the lateral acceleration sensor YS as described above in the present embodiment, the wheels on the non-driving wheel side (that is,
The wheel speed difference between the inner wheel (inner wheel) and the outer wheel (outer wheel) at the time of turning of the vehicle based on the detection outputs of the wheel speed sensors WS1 and WS2 for the driven wheels and the front wheels in the case of a rear-wheel drive vehicle. Can be calculated and Gy = ΔVf · Vso / Tr can be obtained based on this wheel speed difference and the above-mentioned estimated vehicle body speed Vso. Here, ΔVf represents the front / rear wheel speed difference between the inner and outer wheels (in the case of a rear-wheel drive vehicle), and Tr represents the tread length.

18 to 21 show an embodiment in which the turning state of the vehicle is judged based on the longitudinal acceleration DVso and the yaw rate γ. In these figures as well, the yaw rate γ is shown.
Is expressed as an absolute value. In this case, the yaw rate γ can be directly measured by the yaw rate sensor YR, but can also be obtained from γ = ΔVf / Tr from the inner / outer wheel speed difference (ΔVf) when the vehicle turns on the non-driving wheel side. Also in this embodiment, the longitudinal acceleration DVs and the yaw rate γ are used as parameters to determine the longitudinal acceleration DVs.
Reference values Kd1 to Kd10 for o and yaw rate γ
18 to 21 are divided by the reference values Kγ1 to Kγ10 with respect to, and the control area shown by the dotted lines in the drawing is set.

FIG. 12 shows an example of the processing of the braking force distribution control operation in step 606 of FIG. 5, which relates to the braking force control of the wheels on the left and right of the rear of the vehicle, depending on the turning state of the vehicle or the state of the vehicle. Simultaneous select control is performed. That is, in step 661, the value representing the turning state (or vehicle state) of the vehicle is compared with a predetermined value Kr, and when it is determined that the turning state is equal to or more than the predetermined value Kr, the process proceeds to step 662, and the wheels RR and RL are simultaneously controlled. Power control is performed. On the other hand, if it is determined that the vehicle is not in the turning state with the value less than the predetermined value Kr, the process proceeds to step 663 and the braking force control of the wheels RR and RL is independently performed.

The vehicle state determined in step 661 is a running state of the vehicle. For example, the vehicle body side slip angle (β) representing the vehicle body slip in the traveling direction of the vehicle or the vehicle body side slip angular velocity (β) which is a differential value thereof. It is determined based on dβ / dt). These values can be directly detected by the sensor, but can also be calculated from lateral acceleration or yaw rate. Alternatively, the vehicle state can be determined based on the yaw rate deviation Δγ, the lateral acceleration deviation ΔGy, and the like. The former Δγ is the difference between the target yaw rate and the detected value of the yaw rate sensor YR or the yaw rate estimated value, and the latter ΔGy is the detected value of the lateral acceleration sensor YS and the output of the yaw rate sensor YR or the yaw rate estimated value. It is the difference from the multiplied value.

The low-select simultaneous control performed in step 662 is a control mode for the wheel on the side where the slip ratio SpRR, SpRL of the rear wheels RR, RL with respect to the front wheels FR, FL of the vehicle is large (that is, the low-speed side wheel). According to
The hydraulic control of the wheels RR and RL is performed at the same time,
As a result, it is possible to appropriately perform the braking operation while ensuring the cornering force and maintaining the stability of the vehicle.
In this control, when the controls for the left and right wheels RR and RL are in the same control mode (pressure reduction mode or slow pressure increase mode), the same control mode is used to prevent hunting of the wheel cylinder hydraulic pressure due to variations in the slip ratio. Sometimes the previous control mode is maintained.

Further, in the above embodiment, the control start conditions are simultaneously determined for the wheels RR and RL as shown in FIG. 11, so that when one wheel is in control, the other wheel is also in control. . Therefore, by performing the duty control based on the control map of FIG. 8 and adjusting the brake fluid pressure, it is possible to prevent the generation of an inappropriate rotational moment due to the braking force difference between the wheels RR and RL.

Further, not only the target slip ratio bias SpzRR, SpzRL may be changed between the inner wheel side and the outer wheel side, but also the start condition may be set so as to increase the control start sensitivity. FIG. 13 shows an example in which the wheel RR is used as a calculation target. The turning state output (for example, the output of the lateral acceleration sensor YS), the state of the control flag of the wheel RR or RL (1 or 0), the inner ring Flag status (1 or 0),
Then, the target slip ratio bias SpzRR is set according to the control map shown in FIG. 13 based on the function that receives the calculation target wheel information (wheel RR in the example of FIG. 13). In this case, when the control is started, the values of X1 to X3 on the vertical axis are multiplied by the predetermined ratio Kt, and after the control is started, the values are returned to the values of X1 to X3, so that the sensitivity at the start of the control is high. Therefore, it is possible to prevent the generation of an inappropriate rotational moment.

In the above embodiment, either a hydraulic booster or a vacuum booster may be used as a pressure booster for the master cylinder MC, and the output brake hydraulic pressure of the master cylinder equipped with the vacuum booster is divided into two systems. It is also possible to apply to the system of giving.

[0061]

Since the present invention is configured as described above, it has the following effects. That is, in the braking force distribution control device according to the first aspect of the present invention, the control region that allows the drive means to start driving the hydraulic pressure control device based on the deceleration state and the turning state of the vehicle is set, and the turning state determination means Whether the vehicle is in the control area or not is determined according to the determination result and the determination result of the deceleration state determination means, and the driving of the drive means is started according to the determination result. Accordingly, the control force distribution control can be appropriately performed, and the stability of the vehicle can be maintained.

In the braking force distribution control device according to the second aspect, the slip ratios of the left and right wheels behind the vehicle with respect to the front left and right wheels of the vehicle are calculated based on the detection output of the wheel speed detecting means, and the slip ratios are calculated. The target slip ratio is set by being corrected based on the judgment result of the turning state judging means, the control mode is set on the basis of this target slip ratio, and the hydraulic control device is driven in accordance with the control mode. Therefore, even during braking while the vehicle is turning, appropriate braking operation can be performed while maintaining the stability of the vehicle.

As the turning state determining means, the third aspect of the present invention is provided.
As described above, the lateral acceleration detecting means or the yaw rate detecting means can be used, and the turning state can be easily and reliably determined.

According to the braking force distribution control device of the fourth aspect, when the turning state determining means determines that the vehicle is in the vicinity of the turning limit, the larger slip ratio of the slip ratios of the wheels on the rear left and right of the vehicle is set. Since the control mode is set on the basis of the reference, it is possible to perform an appropriate braking operation while maintaining the stability of the vehicle even during braking while the vehicle is turning.

According to the braking force distribution control device of the fifth aspect, when the adjustment of the braking force of one of the left and right wheels behind the vehicle is started, the adjustment start sensitivity of the other braking force is set high. Therefore, even when the vehicle is braking during turning, it is possible to perform an appropriate braking operation while maintaining the stability of the vehicle.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a braking force distribution control device according to claim 1.

FIG. 2 is an overall configuration diagram of an embodiment of a braking force distribution control device of the present invention.

FIG. 3 is a block diagram illustrating a configuration of the electronic control device of FIG. 2;

FIG. 4 is a flowchart showing a process for braking force control in one embodiment of the present invention.

FIG. 5 is a flowchart showing a process for braking force distribution control in one embodiment of the present invention.

FIG. 6 is a flowchart showing a subroutine processing of a braking force distribution control of wheels RR in the embodiment of the present invention.

FIG. 7 is a flowchart showing a process of calculating a reference speed for braking force distribution control according to an embodiment of the present invention.

FIG. 8 is a graph showing a control map used for braking force distribution control of wheels RR in one embodiment of the present invention.

FIG. 9 is a flowchart showing a process of setting a target slip ratio bias in one embodiment of the present invention.

FIG. 10 is a graph showing a map used for setting a target slip ratio bias in one embodiment of the present invention.

FIG. 11 is a flowchart showing a process of determining a starting condition for braking force distribution control in one embodiment of the present invention.

FIG. 12 is a flow chart showing a process of a braking force distribution control operation in one embodiment of the present invention.

FIG. 13 is a graph showing another example of the map used for setting the target slip ratio bias in the embodiment of the present invention.

FIG. 14 is a graph showing a control region set based on lateral acceleration and longitudinal acceleration in control condition start determination in one embodiment of the present invention.

FIG. 15 is a graph showing a control region set based on lateral acceleration and longitudinal acceleration in control condition start determination in one embodiment of the present invention.

FIG. 16 is a graph showing a control region set on the basis of lateral acceleration and longitudinal acceleration in control condition start determination in one embodiment of the present invention.

FIG. 17 is a graph showing a control area set based on lateral acceleration and longitudinal acceleration in control condition start determination in one embodiment of the present invention.

FIG. 18 is a graph showing a control region set based on the yaw rate and the longitudinal acceleration in the control condition start determination in the embodiment of the present invention.

FIG. 19 is a graph showing a control region set based on the yaw rate and the longitudinal acceleration in the control condition start determination in the embodiment of the present invention.

FIG. 20 is a graph showing a control region set based on the yaw rate and the longitudinal acceleration in the control condition start determination in the embodiment of the present invention.

FIG. 21 is a graph showing a control region set based on the yaw rate and the longitudinal acceleration in the control condition start determination in the embodiment of the present invention.

FIG. 22 is a block diagram showing an outline of a braking force distribution control device according to claim 2;

[Explanation of symbols]

 BP brake pedal BS brake switch RS low pressure reservoir MC master cylinder RG regulator HP hydraulic pump, ACC accumulator AP auxiliary hydraulic pressure source EV1 to EV10 valve device CV1 to EV4 check valve OR1 to OR4 throttle passage Pfr, Pfl control passage Wfr, Wfl , Wrr, Wrl Wheel cylinders WS1 to WS4 Wheel speed sensors FR, FL, RR, RL Wheels

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masanobu Fukami 2-1-1 Asahi-cho, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Jun 2-1-2 Asahi-cho, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. Incorporated (72) Inventor Takayuki Ito 2-1, Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Yoshiharu Nishizawa 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. ( 72) Inventor Shingo Sugiura 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Norio Yamazaki 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Akio Sakai 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (5)

[Claims] 1. A wheel cylinder for a front wheel, which is mounted on each of the front left and right wheels of the vehicle to apply a braking force, and a wheel cylinder for a rear wheel, which is mounted on each of the rear left and right wheels of the vehicle to apply a braking force, and a brake pedal. Between a hydraulic pressure generator that increases the brake fluid in response to an operation and applies a brake hydraulic pressure to each of the front wheel cylinder and the rear wheel wheel cylinder, and the hydraulic pressure generator and at least the rear wheel wheel cylinder. A hydraulic pressure control device for controlling the brake hydraulic pressure, wheel speed detection means for detecting the wheel speed of each of the vehicle front left and right wheels and the vehicle rear left and right wheels, and the detection output of the wheel speed detection means. A braking force distribution control device comprising: drive means for driving the hydraulic pressure control device based on the driving force to adjust the braking force of the left and right wheels behind the vehicle to a predetermined relationship with the braking force of the left and right wheels in front of the vehicle. And a deceleration state determination means for determining a deceleration state of the vehicle, a turning state determination means for determining a turning state of the vehicle, and a hydraulic pressure control device by the driving means based on the deceleration state and the turning state of the vehicle. The start region is set by setting a control region that allows the driving start, and the start region determining unit determines whether or not it is within the control region according to the determination result of the turning state determination unit and the determination result of the deceleration state determination unit. A braking force distribution control device, which controls to start driving of the driving means according to a judgment result of the judging means. 2. A front wheel wheel cylinder mounted on each of the front left and right wheels of the vehicle to apply braking force, a rear wheel wheel cylinder mounted on each of the rear left and right wheels of the vehicle to apply braking force, and a brake pedal. Between a hydraulic pressure generator that increases the brake fluid in response to an operation and applies a brake hydraulic pressure to each of the front wheel cylinder and the rear wheel wheel cylinder, and the hydraulic pressure generator and at least the rear wheel wheel cylinder. A hydraulic pressure control device for controlling the brake hydraulic pressure, a turning state determination means for determining a turning state of the vehicle, and wheel speeds of the front left and right wheels of the vehicle and the rear left and right wheels of the vehicle are detected. Wheel speed detecting means, and a slip ratio calculating means for calculating a slip ratio of each of the vehicle rear left and right wheels with respect to the vehicle front left and right wheels based on the detection output of the wheel speed detecting means. And a target slip ratio setting means for correcting the slip ratio calculated by the slip ratio calculating means based on the judgment result of the turning state judging means to set the target slip ratio, and a target set by the target slip ratio setting means. Control mode setting means for setting a control mode on the basis of a slip ratio, and driving the hydraulic pressure control device according to the control mode set by the control mode setting means, the braking force of the wheels on the left and right sides of the rear side of the vehicle A braking force distribution control device, comprising: a driving unit that adjusts a braking force of front left and right wheels to a predetermined relationship. 3. The turning state determining means comprises a lateral acceleration detecting means for detecting a lateral acceleration of the vehicle or a yaw rate detecting means for detecting a yaw rate of the vehicle. Braking force distribution control device. 4. When the turning condition determination means determines that the vehicle is in the vicinity of a turning limit, the control mode setting means controls the control mode based on a large slip ratio of the slip ratios of the left and right wheels behind the vehicle. The braking force distribution control device according to claim 2, wherein the braking force distribution control device is configured to set. 5. When the drive means starts adjusting the braking force of one of the left and right wheels behind the vehicle, the adjustment start sensitivity of the other braking force of the left and right wheels behind the vehicle is set high. The braking force distribution control device according to claim 2, wherein the braking force distribution control device is configured to: