JP2622755B2 - Anti-skid brake control method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid brake control method for each wheel of a vehicle in which a brake system hydraulic piping is a two-system X piping.

[Conventional technology and its problems]

The present applicant has previously described, as an anti-skid device hydraulic pressure control device, a pair of front wheels and a pair of rear wheels having respective wheel cylinders connected by X piping; a first hydraulic pressure generation chamber of a master cylinder and the front wheels. A first hydraulic pressure control valve disposed between the one front wheel cylinder and a brake hydraulic pressure of the front wheel cylinder; a second hydraulic pressure generation chamber of the master cylinder and the other of the front wheels A second hydraulic pressure control valve disposed between the front wheel cylinder and the front wheel cylinder for controlling a brake hydraulic pressure of the front wheel cylinder; a wheel speed sensor provided for each of the front and rear wheels; The skid condition of the wheel is evaluated based on the
1, a control unit for controlling the second hydraulic pressure control valve;
According to the lower one of the brake fluid pressures of the front wheels, which is disposed between the wheel cylinders of the front wheels and the wheel cylinders of the rear wheels and controlled by the first and second hydraulic pressure control valves. A pressure selecting means for outputting pressure; wherein the control unit determines which side of the road surface has a lower coefficient of friction from the result of the evaluation of the skid state of the rear wheels, and designates this as a low side. A command to control the first or second hydraulic pressure control valve for the front wheel by logically combining the evaluation result of the two rear wheels and that of the low side front wheel is issued, and for the front wheel on the other side of the high side, Independently issuing a command for controlling the second or first hydraulic pressure control valve for the front wheel according to the evaluation result thereof, wherein the hydraulic pressure control for the anti-skid device is provided. Proposed location. (JP-A-62-289462)
No.) The above two-channel anti-skid device hydraulic pressure control system allows the rear wheel to lock even if the rear wheel shows a locking tendency earlier than the front wheel, while reducing the size, weight, and cost of the device. Not only can be reliably prevented, but also all wheels can be reliably prevented from being locked.
Drivability and directional stability of the vehicle body can be maintained.

The prevention of the locking of the rear wheels and the accompanying securing of the directional stability of the vehicle body are largely due to the installation of the pressure selecting means as well as the control method by the control unit.

However, for the spread of anti-skid devices,
There is a need for a smaller, lighter, and lower cost hydraulic pressure control device.

JP-A-61-160342 discloses a two-channel anti-lock brake control method for an X-brake piped vehicle having a hydraulic control device without the pressure selecting means. The control method according to the invention is such that "when it is detected that any one of the front wheels is in the state immediately before locking, the hydraulic pressure in the pipe of the system to which the front wheel in the state belongs is reduced, and When it is detected that the rear wheel is in the locked state, the rear wheel is allowed to reach the locked state, and when the other rear wheel also reaches the state immediately before locking, the system to which the rear wheel belongs is detected. To reduce the oil pressure in the piping. "

However, in the above-described device, when both rear wheels are both in the state immediately before locking, locking of one rear wheel is always permitted. Therefore, on a medium μ road surface having a moderate friction coefficient of friction or a low μ road surface having a low braking friction coefficient. In some cases, the rear wheel may continue to lock, in which case the directional stability of the vehicle becomes extremely poor. Also, one rear wheel may continue to lock on a high μ road surface with a high braking friction coefficient, in which case the tire will be in a flat spot state (uneven wear state), and in the worst case, it may burst (burst). There is.

[Problems to be solved by the invention]

The present invention prevents the flat spot state and burst of the diamond while reducing the size, weight, and cost of the device, and allows locking of one rear wheel only under special conditions, so that the maneuverability of the vehicle is improved. An object of the present invention is to provide an anti-skid brake control method for a vehicle that can sufficiently secure directional stability and control force.

[Means for solving the problem]

An object of the present invention is to provide an anti-skid brake control method in which a brake system hydraulic pipe to the front and rear wheels arranged on a diagonal line is provided as one system and provided with two systems of X pipes. , A controller that outputs a valve control signal in accordance with an output signal from the wheel speed detector, and an anti-skid provided in each system and operated by a valve control signal from the controller Control hydraulic pressure control valve, the controller forms a brake control signal according to the rotation state of the wheel for each individual wheel based on the output signal from each wheel speed detector, in each system When the brake control signal from the front wheel is used as the valve control signal in preference to the brake control signal from the rear wheel, and when the brake control signal is generated for the front wheel, The signal is used as a valve control signal to activate the anti-skid control hydraulic pressure control valve in the system to which the front wheel belongs, to determine whether the vehicle body deceleration is equal to or greater than a predetermined deceleration reference value, and whether the vehicle is traveling straight. And whether the slip of the rear wheel is equal to or greater than a first slip reference value, and when the brake control signal is generated in one of the two rear wheels,
If the vehicle body deceleration is equal to or greater than the predetermined deceleration reference value and the vehicle is running straight, the vehicle body deceleration is not equal to or greater than the predetermined deceleration reference value, and the other rear wheel slips. When the vehicle deceleration is equal to or greater than the first slip reference value, and when the vehicle body deceleration is equal to or greater than the predetermined deceleration reference value, the vehicle is not traveling straight, and the slip of the other rear wheel is equal to or less than the first slip reference value.
When the slip reference value is equal to or more than the reference value, the brake control signal from the rear wheel is used as a valve control signal to operate the anti-skid control hydraulic pressure control valve in the system to which the rear wheel belongs. This is achieved by an anti-skid brake control method.

[Action]

Since only two hydraulic pressure control valves (two channels) are used and the pressure selecting means is omitted, the size and weight of the apparatus can be reduced, and the cost can be reduced.

In addition, since the brake control signals from both front wheels are used as valve control signals in preference to the brake control signals from both rear wheels, locking of both front wheels can be prevented. It can be fully demonstrated, the control distance can be shortened, and the steering performance can be sufficiently secured.

If a brake control signal is generated from the rear wheels during straight-ahead braking when it is determined that the vehicle is traveling on a high μ road surface by detecting the vehicle deceleration, the signal is used as a valve control signal, and the system to which the rear wheels belong is used. Since the hydraulic pressure control valve in the pipe is operated to control the brake hydraulic pressure of the system, locking of the rear wheels can be prevented, and a flat spot or burst of the tire can be prevented.

Except during braking while traveling straight on a high μ road surface, if the slip of the other rear wheel is smaller than the first slip reference value even if the brake control signal is generated for one of the rear wheels, Locking of the wheels is allowed, so that the maximum braking force can be exerted on both front wheels, and the directional stability of the vehicle can be secured by the other rear wheel. Therefore, during braking while turning on a high μ road surface, no brake control signal is generated from both front wheels, a brake control signal is generated from one rear wheel (inner rear wheel), and the other rear wheel (outer rear wheel). If the slip of (1) is smaller than the first slip reference value, the brake control signal from the one rear wheel is not used as a valve control signal, so that the locking of the one rear wheel is permitted.
Since there is no control of the brake pressure of the outer front wheel which can exert the most braking force with the most load, the braking force of the front wheel is not lost.

When a brake control signal is generated for one rear wheel and the slip of the other rear wheel is equal to or greater than the first slip reference value,
That is, when there is a risk of locking both rear wheels, the brake control signal for the one rear wheel is used as a valve control signal, so that both rear wheels do not lock together and the directional stability of the vehicle is ensured. Can be secured.

〔Example〕

Next, a hydraulic pressure control device for an anti-skid device according to a first embodiment of the present invention will be described with reference to the drawings.

First, the piping and wiring system of the entire apparatus of this embodiment will be described with reference to FIG.

In FIG. 1, the master cylinder (1) is a pedal (2).
And one of the hydraulic pressure generating chambers is connected to the right front wheel (6a) via a line (3), a three-position solenoid valve (4a) and a line (5).
Wheel cylinder (7a). The line (5) is further connected to the left rear wheel (11) through the line (13) and the pressure reducing valve (32b).
b) is connected to the wheel cylinder (12b).

The other hydraulic pressure generation chamber of the master cylinder (1) is connected to the pipeline (1
6) Connected to the wheel cylinder (7b) of the left front wheel (6b) via the 3-position electromagnetic switching valve (4b) and the conduit (17). The pipe (17) is further connected to the wheel cylinder (12a) of the right rear wheel (11a) via the pipe (15) and the pressure reducing valve (32a). The outlets of the switching valves (4a) and (4b) are pipes (60a) (60b)
Are connected to the reservoirs (25a) and (25b). The reservoirs (25a) (25b) consist of pistons (27a) (27b) and weak springs (26a) (26b) slidably fitted to the body.
This reservoir chamber is connected to the suction ports of the hydraulic pumps (20a) (20b). The hydraulic pumps (20a) and (20b) are shown in a schematic diagram, and include a body for accommodating a piston in a slidable manner, a motor (22) for reciprocating the piston, and a check valve as is well known, and a discharge port thereof is a pipe. It is connected to roads (3) and (16).

Wheel speed detectors (28a) (28b) (29a) (29b) are disposed on the wheels (6a) (6b) (11a) (11b), respectively.
From these detectors, a pulse signal having a frequency proportional to the rotation speed of the wheels (6a) (b) (11a) (11b) is obtained and applied as an input to the controller (31) according to the present invention.
The controller (31) controls the control signals Sa and Sb and the motor drive signal Qo
Occurs. Control signals Sa and Sb are 3-position electromagnetic switching valves (4a)
It is supplied to the solenoid (30a) (30b) of (4b). The three-position solenoid operated directional control valves (4a) and (4b) have their solenoids (30a) (3
It is configured to take one of three positions A, B, and C according to the magnitude of the current of the control signals Sa and Sb supplied to 0b). That is, when the currents of the control signals Sa and Sb are 0, the first position A is set as the braking position. In this position, the master cylinder (1) side and the wheel cylinders (7a) (7b) are in communication. Control signal Sa, S
When the current b is at a low level (hereinafter "1/2" is used for convenience), that is, when a brake holding signal is generated, the second position B is taken as the brake holding position. In this position, the communication between the master cylinder (1) and the brake cylinders (7a) (7b) and the communication between the wheel cylinders (7a) (7b) and the reservoirs (25a) (25b) are cut off. I will be in a state to do. When the currents of the control signals Sa and Sb are at a high level (hereinafter, for convenience, the signal "1" is used), that is, when the brake release signal is generated, the third position C is set as the brake release position. . In this position, the master cylinder (1) side and the wheel cylinders (7a) (7b) side are shut off, but the wheel cylinders (7a) (7b) side and the reservoirs (25a) (25b)
And the wheel cylinder (7
a) The brake pressure fluid of (7b) is discharged to the reservoirs (25a) (25b) through the pipes (60a) (60b). Drive signal Q generated when either control signal Sa or Sb becomes "1"
o is supplied to an electric motor (22) as a hydraulic pump driving means.

Next, the details of the controller (31) will be described with reference to FIG.

Output signals from the wheel speed detectors (28a) (28b) (29a) (29b) provided on the front wheels (6a) (6b) and rear wheels (11a) (11b) are sent to the brake control signal generation circuit (40). An output signal supplied from each of the circuits and an output terminal of the circuit (40) is supplied to a valve control signal generation circuit (41). The brake control signal generation circuit (40) has a well-known configuration, and forms a wheel speed signal from the output signals of the wheel speed detectors (28a) (28b) (29a) (29b). A signal, an acceleration signal, a slip signal, and the like are formed. Due to the logical combination of these signals, control signals EV _VR , AV _VR , EV _RL , AV based on the respective wheel speeds are output from this circuit (40).
_RL , EV _VL , AV _VL , EV _RR , and a brake pressure constant holding signal and a brake pressure reduction control signal for AV _RR are generated. Here, EV and AV mean hold constant brake pressure and brake pressure decrease, respectively.
The suffixes VR, VL, RR, and RL mean the right front wheel, left front wheel, right rear wheel, and left rear wheel, respectively. Further, based on the wheel speed signal, an approximate vehicle speed signal F _REF and a vehicle deceleration signal a ^FZ are generated. These signals are supplied to a valve control signal generation circuit (41), which determines whether to release the brake, to maintain the brake constant, or to increase the pressure by a logical combination of the above signals shown in the flowchart of FIG. Indicating valve control signal AV ₁ ,
Generating a EV _1, QV ₁ and AV _2, EV ₂ QV _2. In this embodiment, the current level of the brake pressure increase control signals QV ₁ and QV ₂ is “0”. The outputs as these valve control signals are supplied to amplifiers (42a) and (42b), where they are amplified to amplify the current, and the solenoids (30a) of the hydraulic control valves (4a) and (4b) are used.
a) Supplied to (30b). By controlling the current at each of these levels, the hydraulic pressure control valves (4a) and (4b) take any one of three positions A, B, and C so as to increase the brake pressure, hold it constant, or reduce the pressure. In FIG. 1, the signal S
a, Sb is made from the respective output AV _1, EV _1, QV ₁ and _{AV 2, EV 2, QV 2} . The controller (31) includes a motor drive circuit, and generates a connection signal Qo during the anti-skid control when any of the outputs AV ₁ and AV ₂ occurs.

Next, a program incorporated in the valve control signal generation circuit (41) in FIG. 2 will be described with reference to FIG.

This embodiment is applied to an FF vehicle, that is, a front engine vehicle and a front drive vehicle. What kind of brake control signal and what approximate vehicle body signal F _REF and vehicle body deceleration signal a ^FZ are generated for the front and rear wheels of this one system is described. And a logic for determining what kind of valve control should be performed. First, the front and rear wheel speed detectors (28a) (28b) (29a) (29
The output signal from b) is received by the brake control signal generation circuit (40) in the upper stage, whereby the brake holding signal E
_VVR , brake pressure reduction signal _AVVR, etc. are formed, and the following programs are executed by these brake control signals.

First, in step a, it is determined whether or not the brake pressure reduction signal AV is generated on the front wheels. (Note suffix to describe only one system will be omitted.) Has occurred, that is, so as to generate an output AV ₁ in the decompression signal or a second view at the stage R if Yes. This releases the brakes in this system. (Note that the suffix "1" is added as the valve control signal to represent the system of the hydraulic pressure control valve (4a).) If No, the next step b, that is, whether the pressure reduction signal AV is present at the rear wheel is determined. Is done. If Yes, it is determined in step c whether the vehicle deceleration a ^FZ is more than 0.6 g. If Yes, in the next step d, the difference between the approximate vehicle speed F _REF and the wheel speed V _{FRONT of the} front wheel on the same side as the rear wheel where the pressure reduction signal AV is generated is calculated, and this is 5 km / h or less. It is determined whether or not, and if Yes, in the next step e, it is determined whether or not the slip ratio of the rear wheel of the other system is smaller than 1.5%. If No generating a vacuum signal AV ₁ to the line in step R. If yes, next step g
Make a judgment. It is determined that the vehicle is traveling straight now by YES at step d and NO at step e. Also, if YES at step d, if YES at step e, it is determined that the vehicle is curved.

If the vehicle deceleration a ^FZ is smaller than 0.6 g, that is, if No in step c, it is determined in the next step f whether the rear wheel slip ratio of the other system is 15% or more.
If Yes generates a vacuum signal AV _1. This prevents both rear wheels from locking. If No, the process proceeds to the next step g.

At this stage g, it is determined whether or not the brake holding signal EV is generated at the front wheels of this system. If Yes is adapted to generate a holding signal EV ₁ at the stage H in the system. That is, the braking force is kept constant. No
Then, in the next step h, it is determined whether or not the brake holding signal EV is generated at the rear wheel of this system. Guided by pressure increasing signal generating step Q if No, thereby the solenoid portion (30a) and a signal QV ₁ level "0" is added.
That is, the pressure is increased. If it is determined in step h that the rear wheel is generating EV, the vehicle deceleration is performed in the next step i.
a It is determined whether or not ^FZ is equal to or greater than 0.6 g.If Yes, in the next step j, the approximate vehicle speed F _REF and the wheel speed V _{FRONT of the} front wheel that is on the same side as the rear wheel where EV is now generated are obtained. Difference of 5km / h
The following whether Isuzu determination, If No-wheel slip ratio after the next step l ie other system is either Isuzu determined whether 15% or more, to generate a brake holding signal EV ₁ If Yes Like that. And so as to generate a pressure increasing signal QV ₁ if No.

If Yes in the above step j, it is determined in the next step k whether or not the slip ratio of the rear wheel of the other system is smaller than 1.%. If No, the braking force is kept constant and Yes. to generate a pressure increase signal QV ₁ if. Step j is Yes, Step k
Is No, it is determined that the vehicle is traveling straight.

As described above, what kind of brake control signal is generated for the front and rear wheels of each system, whether the vehicle body deceleration is larger or smaller than a predetermined value, the approximate vehicle speed and the front wheel speed V _FRONT of the other system. Is greater than or less than a predetermined value,
Alternatively, the slip ratio of the rear wheel of the other system is the first and the second.
The brake fluid pressure of the system is increased, decreased, or kept constant, depending on whether it is smaller or larger than a predetermined rate. The brake control signal for the front wheel is preferentially used, and under specific conditions, the hydraulic pressure control valve is also controlled by the brake control signal for the rear wheel.

Since the brake pressure is controlled as described above, maneuverability is stable, there is no shortage of braking force, there is no need to extend the braking distance, and flat tires and bursts on the rear wheels as in the past. Does not occur.

FIG. 4 shows a program in a controller in the anti-skid brake fluid pressure control device for a vehicle according to the second embodiment of the present invention, which is applied to a four-wheel drive vehicle according to the present embodiment. Therefore, it is slightly different from the first embodiment, and in particular, the judgment as to whether the vehicle is going straight ahead is different.

That is, in FIG. 4, the brake control signals for the front and rear wheels of one system in this embodiment will be described.
First, in a first step m, it is determined whether or not AV is occurring in the front wheels. If Yes, a pressure reduction signal is generated in step R. If No, the rear wheel
It is determined whether the generating AV, If No next hold signal EV at step r to the front wheels is determined whether occurring, generates a hold signal EV ₁ at the stage H if I occurred.
If No, it is determined in the next step s whether or not EV has occurred in the rear wheel.
Generate ₁ Also, if EV is generated on the rear wheels, at the next stage t, it is determined whether or not the vehicle deceleration is 0.6 g or more.
If it is greater than or equal to g, is the difference between the approximate vehicle speed F _REF in the next stage u and the wheel speed V _{FRONT of the} front wheel on the same side as the rear wheel where the brake holding signal is now generated less than 5 km / h? it is determined whether to generate a hold signal EV ₁ if less, if the large-wheel slip ratio after the next step v other system in it is judged whether or not more than 15%, if 15% or more and so as to generate a pressure increasing signal QV ₁ if holding signal EV ₁ is small to generate. If the rear wheels generate AV in the above-mentioned step n, it is determined in the next step o whether or not the vehicle deceleration a ^FZ ≧ 0.6 g, and if Yes, F _REF −V in the next step p.
_FRONT ≦ 5km / h at whether Isuzu is determined, generating a vacuum signal AV ₁ to this system, if Yes. And, if No next step q the other wheel slip rate after the system is determined whether more than 15%, generating a reduced pressure signal AV ₁ If Yes, the follows the above If No Guided to step r.

That is, in this embodiment, since the vehicle is a four-wheel drive vehicle, it is determined whether the vehicle is traveling straight ahead when the difference between the approximate vehicle speed and the wheel speed V _{FRONT of the} front wheel on the same side as the rear wheel in question is 5 km / h or less. Judgment is based solely on the existence. That is, in the rear wheels, for example, the rotational force of the rear wheel having the higher rotational speed is transmitted to the other rear wheel by the LSD mechanism, so that the slip amount is made substantially the same. Others are almost the same as the first embodiment.

According to this embodiment, insufficient braking force can be avoided, and tire flat spots and bursts of the rear wheels, which occur conventionally, can be prevented.

The embodiments of the present invention have been described above.
The present invention is not limited to these, and various modifications can be made based on the technical idea of the present invention.

For example, each set value in the above embodiment is not limited to the numerical values described in the above embodiment. For example, whether or not the road surface is Highμ is determined based on whether or not the vehicle deceleration is greater than 0.6 g.
6g may be raised or lowered further. Also, to determine whether the vehicle is traveling straight or on a curve, the difference between the approximate vehicle speed and the vehicle speed of the front wheels on the same side as the rear wheel in question is 5 km / h or less, or Although it is determined whether the slip ratio of the rear wheel of the other system is smaller than a predetermined value, the value of 5 km / h may be further increased or decreased. The slip ratio of the first embodiment is 1.5% and 1
The same applies to 5%. Further, a slip amount may be used instead of the slip ratio.

In the above embodiment, it is detected that the vehicle is traveling straight when the difference between the rotational speed of the rear wheel on which the brake control signal is generated and the front wheel on the same side of the vehicle and the vehicle speed are within a predetermined value. However, the following method may be used instead.

That is, by detecting that the rotational speed difference between the two front wheels is within a predetermined value.

This is because the rotational speed difference between the two rear wheels is within a predetermined value.

This is because the slip of both rear wheels is larger than a predetermined slip reference value.

Both front wheels detect that the difference between the rotational speed of the wheels and the vehicle speed is within a predetermined value.

This is based on detecting that the difference between the rotational speed of the rear wheel not generating the brake control signal and the rotational speed of the front wheel on the diagonal line and the vehicle speed is within a predetermined value.

This is based on detecting that the rotational speed difference between the rear wheel having the smaller slip and the front wheel on the diagonal line is within a predetermined value.

This is based on detecting that the rotational speed difference between the front and rear wheels on each diagonal is within a predetermined value.

The vehicle straight traveling may be detected by combining at least two of the vehicle straight traveling detecting methods described in the above-mentioned and the embodiments.

It should be noted that, when the conditions for judging vehicle straight ahead detection described in the above embodiments or are satisfied, it is naturally judged that the vehicle is going straight ahead. A filter circuit or a limiting circuit for setting that the time is still straight ahead may be provided. By providing such a circuit, it is possible to prevent erroneous curve traveling detection due to a slight change in road surface condition.

In addition, for detecting the straight traveling of the vehicle, the output signal of an external, for example, a steering angle sensor (a steering angle sensor) is used instead of the output signal in the controller to detect that the steering angle is within a predetermined value. May be performed.

Further, the brake control signal may be composed of only the brake pressure reduction control signal, or may be composed of the brake pressure reduction control signal, the brake pressure constant holding signal, and / or the brake pressure reduction control signal.

The vehicle speed may be detected by a ground speed sensor using the Doppler effect or the like. Further, the detection of the vehicle body deceleration may be detected by using, for example, a G sensor having a mercury switch.

Further, in the above embodiments, the FF vehicle and the four-wheel drive vehicle have been described, but the invention is also applicable to a rear wheel drive vehicle.

In the above embodiment, QV ₁ ,
QV ₂ is connected to the solenoids (30a) (30) of the switching valves (4a) (4b).
In b), a current of level “0” is continuously applied, thereby continuously increasing the brake fluid pressure. However, “0”, “1/2”, and “0” are pulsed. ",“ 1/2 ”……
.., And in this case, the brake fluid pressure is increased stepwise.

〔The invention's effect〕

As described above, according to the anti-skid brake control method of the present invention, the size and weight of the device can be reduced and the cost thereof can be reduced. The brake fluid pressure of both front wheels is controlled by the front wheel brake control signal. In addition, both front wheels are not locked, steering performance can be sufficiently secured, and flat spots and bursts of tires, which have conventionally occurred, can be reliably prevented. Furthermore, since locking of one rear wheel is permitted only under special conditions, the directional stability and braking force of the vehicle can be sufficiently ensured under normal conditions. Since the fluid pressure is controlled, sufficient directional stability and braking force of the vehicle can be ensured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a piping system diagram and electric wiring of an anti-skid brake control device of the present invention, FIG. 2 is a block diagram of a controller in FIG. 1, and FIG. 3 is a circuit diagram of a valve control signal generating circuit in FIG. FIG. 4 is a control flowchart of the first embodiment, and FIG. 4 is a control flowchart of the valve control signal generating circuit in FIG. 2 according to the second embodiment. In the figure, (31) ... Controller

Claims (14)

(57) [Claims] An anti-skid brake control method comprising two lines of X-system piping, wherein a hydraulic system hydraulic piping for front and rear wheels arranged on a diagonal line is provided as one system, and provided for each wheel. A wheel speed detector for detecting a speed, a controller for outputting a valve control signal in response to an output signal from the wheel speed detector, and anti-control devices provided in each system and operated by a valve control signal from the controller. A hydraulic pressure control valve for skid control, wherein the controller forms a brake control signal for each individual wheel based on the output signal from each of the wheel speed detectors according to the rotation state of the wheel. In the above, the brake control signal from the front wheel is used as the valve control signal in preference to the brake control signal from the rear wheel, and when the brake control signal is generated on the front wheel, The signal is used as a valve control signal to activate the anti-skid control hydraulic pressure control valve in the system to which the front wheel belongs, to determine whether the vehicle body deceleration is equal to or greater than a predetermined deceleration reference value, and whether the vehicle is traveling straight. And whether the slip of the rear wheel is equal to or greater than a first slip reference value, and when the brake control signal is generated in one of the two rear wheels,
If the vehicle body deceleration is equal to or greater than the predetermined deceleration reference value and the vehicle is running straight, the vehicle body deceleration is not equal to or greater than the predetermined deceleration reference value, and the other rear wheel slips. When the vehicle deceleration is equal to or greater than the first slip reference value, and when the vehicle body deceleration is equal to or greater than the predetermined deceleration reference value, the vehicle is not traveling straight, and the slip of the other rear wheel is equal to or less than the first slip reference value.
When the slip reference value is equal to or more than the reference value, the brake control signal from the rear wheel is used as a valve control signal to operate the anti-skid control hydraulic pressure control valve in the system to which the rear wheel belongs. Anti-skid brake control method. 2. The straight traveling detection of the vehicle is performed by detecting that a difference between a rotation speed of a front wheel on the same side as a rear wheel generating a brake control signal and a vehicle speed is within a predetermined value. The anti-skid brake control method according to claim 1. 3. The vehicle according to claim 1, wherein the difference between the rotation speed of the front wheel on the same side as the rear wheel generating the brake control signal and the vehicle speed is within a predetermined value, and the other rear wheel is detected. The anti-skid brake control method according to claim 1, wherein the slip is detected by detecting that the slip is equal to or more than a second slip reference value smaller than the first slip reference value. 4. The anti-skid brake control method according to claim 1, wherein the detection of the straight traveling of the vehicle is performed by detecting that a difference between the rotational speeds of both front wheels is within a predetermined value. 5. The anti-skid brake control method according to claim 1, wherein the detection of straight traveling of the vehicle is performed by detecting that a difference between the rotational speeds of both rear wheels is within a predetermined value. 6. The anti-skid brake control method according to claim 1, wherein the straight-ahead detection of the vehicle is performed by detecting that the slip of both rear wheels is greater than a predetermined slip reference value. 7. The anti-skid brake according to claim 1, wherein the detection of straight traveling of the vehicle is performed by detecting that a difference between a rotational speed of the vehicle wheels and a vehicle speed of both front wheels is within a predetermined value. Control method. 8. The straight traveling detection of the vehicle is performed by detecting that a difference between a rotation speed of a front wheel diagonally from a rear wheel not generating a brake control signal and a vehicle speed is within a predetermined value. The anti-skid brake control method according to claim 1, which is performed. 9. The straight traveling detection of the vehicle is performed by detecting that a rotational speed difference between a rear wheel having a smaller slip between the two rear wheels and a diagonally located front wheel is within a predetermined value. The anti-skid brake control method according to item (1). 10. The anti-skid brake control method according to claim 1, wherein the straight-ahead detection of the vehicle is performed by detecting that a rotational speed difference between front and rear wheels on each diagonal is within a predetermined value. . 11. The anti-skid brake control method according to claim 1, wherein the detection of straight traveling of the vehicle is performed by combining at least two of the above-mentioned claims (2) to (10). 12. A filter circuit or a dimensional circuit for setting that the vehicle is still traveling straight for a predetermined time period immediately after the condition for detecting the straight traveling of the vehicle is no longer satisfied. An anti-skid brake control method according to 11). 13. The anti-skid brake control method according to claim 1, wherein the straight traveling of the vehicle is detected by detecting that the steering angle is within a predetermined value using an output signal of a steering angle sensor. . 14. The anti-skid brake control method according to claim 1, wherein said brake control signal includes at least a brake pressure reduction control signal.