JPH0270567A - Anti-skid controller - Google Patents

Abstract

PURPOSE:To prevent the extension of a braking distance while the force of brake of carwheels against a road surface is maintained highly, and prevent the drastic reduction of a carwheel speed, by making longer the output time of a pulse depressurization control signal as it is presumed that oil pressure supplied to a hydraulic brake means at the time point of the pulse depressurization control signal being outputted, is becoming larger. CONSTITUTION:A pulse depressurization control signal is outputted, if, at a time t1, a carwheel speed is lower than a slip reference speed and also, a carwheel acceleration is lower than a depressurization reference acceleration G1 which becomes the output decision of the pulse depressurization control signal. As the number of output times of a pulse pressure increase control signal which has been outputted before this time t1, is less than four times which is the number of times that becomes a reference for adding a correction time to the pulse depressurization control signal, a correction time is not added to the output time T of this depressurization control signal. Next, in the case of the pulse pressure increase control signal being outputted six times before a time t3, a correction time DELTAT1 is added to the output time T of the normal pulse depressurization control signal, and an output is made to a hydraulic brake means.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an anti-skid control device for controlling the rotational speed of the wheels of an automobile during brake operation, and more specifically to a control device for reducing the hydraulic pressure of a hydraulic braking means. This is preferably carried out.

The anti-skid control device is a device that hydraulically controls the slip rate of the wheels using hydraulic braking means so that the frictional braking force generated between the wheels and the road surface when the brake is depressed is maximized. Here, if the traveling speed of the automobile is VS and the rotational speed of the wheels (hereinafter referred to as "r wheel speed") is VW, then the slip ratio S is defined by the first equation.

When the driver suddenly depresses the brake pedal, the braking oil pressure supplied to the hydraulic braking means for braking the rotation of the wheels rapidly increases. This sudden increase in braking oil pressure causes the rotational speed of the wheels to decrease, resulting in a locked state in which the wheel speeds become zero. This rock shape! When υ, the braking distance increases and steering performance is lost. Therefore, the anti-skid control device is designed to prevent the wheels from locking up.
When the wheel speed approaches the locked state, a pressure reduction operation is performed to reduce the braking oil pressure supplied to the hydraulic braking means. This pressure reduction operation restores the wheel speed, increases the braking force between the wheels and the road surface, and maintains steering performance. When the wheel speed has sufficiently recovered, pressure increase control is performed again to increase the braking oil pressure to the hydraulic braking means, and as described above, the wheel slip ratio S is set to the value that exerts the highest braking force. The hydraulic braking means is controlled by a combination of pressure increase control, holding control, and pressure reduction control so as to achieve the following.

Problems to be Solved by the Invention However, the above-mentioned conventional anti-skid system
The two-position system is uniform for changes in the friction coefficient between the wheels and the road surface due to changes in the road surface condition, for example, and changes in the friction coefficient between the wheels and the road surface due to changes in the traveling speed of the car. Therefore, it cannot be said that the anti-skid control is necessarily performed in an optimal state.

In other words, on a road with a high friction coefficient, the braking oil pressure that causes the wheels to lock is low friction 11! Since the coefficient road becomes higher than that of the coefficient road, it is necessary to increase the wheel cylinder pressure in order to maintain the same slip ratio S. The same thing happens when the traveling speed of the car decreases.

Figure 9 shows the coefficient of friction μ for changes in the traveling speed of the car.
This is a μS curve for explaining changes in the slip rate S. As the traveling speed of the car decreases from the high speed range to the low speed range, as shown in lines 111 to 113 of the 9th rl,
It is understood that the friction coefficient μ increases for the same slip ratio.

Therefore, as the traveling speed of the vehicle decreases, the friction coefficient μ between the wheels and the road surface increases, and therefore the braking oil pressure at which the wheels begin to lock increases. Therefore, the anti-skid control device needs to increase the braking oil pressure supplied to the hydraulic braking means in order to maintain the slip ratio S that provides the highest braking force.

However, as the wheel cylinder pressure supplied to the hydraulic braking device increases, the hysteresis of the hydraulic braking device also increases. FIG. 10 is a graph showing that this hysteresis increases, and is a graph for explaining the relationship between the wheel cylinder pressure and the braking torque generated by the hydraulic braking means.

That is, as the wheel cylinder pressure increases along line N14, the braking torque, that is, the torque applied in the opposite direction to the wheel rotation direction by the hydraulic braking means to reduce the rotation of the wheel, also increases. Even if the wheel cylinder pressure is reduced to P2 after the wheel cylinder pressure reaches Pl along line 114, for example, the braking torque remains at T1 and does not decrease in response to the reduction in the wheel cylinder pressure. In other words, even if the wheel cylinder pressure is reduced from pressure P1 to pressure P2, the operating point of the hydraulic braking means only moves on line Z15, and the braking torque does not decrease and T
Maintain 1. As the wheel cylinder pressure is further decreased from P2, the operating point moves along line 116 and the braking torque begins to decrease. In this way, there is a hysteresis phenomenon between wheel cylinder pressure and braking torque, and even if the same pressure reduction control is performed on the hydraulic braking means, the effect of pressure reduction will differ depending on the wheel cylinder pressure at the time of starting pressure reduction. Become.

Therefore, especially on roads with a high friction coefficient, there is a problem in that the pressure reduction operation for the hydraulic braking means is insufficient due to the above-mentioned hysteresis, resulting in a significant decrease in wheel speed and an increase in braking distance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an anti-skid control device that avoids the shortage of pressure reduction caused by the above-mentioned hysteresis, prevents an increase in braking distance, and prevents a significant decrease in wheel speed.

Means for Solving the Problems The present invention provides an anti-skid control device that increases or decreases the oil pressure of a hydraulic brake means for a wheel so that the coefficient of friction between the wheel and the road surface increases. This is an air pressure control device characterized by selecting a large amount of pressure reduction at the point in time when the pressure should be reduced.

Further, the present invention changes the hydraulic pressure of the hydraulic braking means by periodic pulses, and when the pressure is reduced after the pulse number of the pulse pressure increase continues to be a predetermined value, the pressure reduction duration of the pulse pressure reduction is the pulse pressure increase. The anti-skid control device is characterized in that the pressure reduction duration of the pulse pressure reduction is selected to be longer than the pressure reduction duration when the number of pulses is less than the predetermined value.

Furthermore, the present invention provides an anti-skid control device that increases or decreases the hydraulic pressure of the hydraulic braking means of the wheels to increase the vibration coefficient between the wheels and the road surface. This anti-skid control device is characterized in that the amount of pressure reduction is selected to be larger than the amount of pressure reduction that is selected when the vehicle speed is equal to or higher than a predetermined vehicle speed.

Function In the present invention, the anti-skid system (n device controls the hydraulic pressure supplied to the hydraulic braking means l\ which brakes the rotation of the wheels so that the coefficient of friction between the wheels and the road surface becomes large. Then, the pressure is reduced. The amount of pressure reduction is selected so as to increase as the hydraulic pressure supplied to the f-stage hydraulic brake increases at the time.

In addition, in the present invention, the hydraulic pressure supplied to the hydraulic braking means is controlled to increase by pulse pressure increase Q, /L, and when the number of pulse pressure increase pulses continues to exceed a predetermined value, a pressure reduction output is output in the pulse pressure reduction control of the brake. The time is selected to be longer than the depressurization duration of the pulse decompression when the predetermined value is not reached.

Furthermore, in the present invention, as the vehicle speed decreases,
A value larger than the pressure reduction amount selected when the pressure reduction amount of the hydraulic braking means at the time when the pressure should be reduced is equal to or higher than a predetermined vehicle speed is selected.

Actual example 10 is a block diagram of an anti-skid system (ear device) which is an embodiment of the present invention.An anti-skid control circuit 1 is provided, for example, in a vehicle interior or a rear trunk.Wheel speed sensor 2a -2d are sensors provided for each wheel to detect the wheel speed.The wheel speed sensors 2a-2d are formed with, for example, a large number of notches and protrusions equally spaced in the circumferential direction. A detection plate made of a ferromagnetic material is fixed to the wheel axle, and a signal with a frequency proportional to the wheel speed is detected by, for example, an electromagnetic connection and a pull-up provided near the circumference of the detection plate.Wheel speed sensors 2a to 2d The detected wheel speed signal is waveform shaped by Ii!83a.
Processing circuit 4a realized by a microcomputer or the like after waveform shaping into a pulse signal by ~3d
, 4b.

The switch 2e is, for example, a brake switch that sends out a signal indicating that the brake pedal has been depressed, and the output signal of the switch 2e is given to the level conversion circuit 3e, and the signal level is sent to the anti-skid control circuit 1'a.
is converted to a matching voltage level. The output of the level conversion circuit 3e is sent to processing circuits 4a and 4b.

The processing circuit 4a calculates the respective wheel speeds based on the wheel speed signals from the wheel speed sensor 2a provided on the right front wheel and the wheel speed sensor 2b provided on the left rear wheel, and then calculates the wheel speed of the larger wheel. The speed is transferred to the processing circuit 4b via the signal line s&1.

Similarly, the processing circuit 4b calculates the respective wheel speeds based on the wheel speed signals from the wheel speed sensor 2c provided on the left front wheel and the wheel speed sensor 2d provided on the right rear wheel, and then selects the larger one. The wheel speed is transferred to the processing circuit 4a via the signal line s12.

The processing circuits 4a and 4b use the transferred wheel speeds and the wheel speeds calculated in each processing circuit to estimate, for example, the larger wheel speed of these wheel speeds as TJ, the vehicle body speed and each Anti-skid calculation is performed based on the wheel speed, and wheel cylinder oil pressure is controlled.

The control signals output from the processing circuits 4a, 4b are power amplified by the solenoid drive circuits 5a to 5d, and then applied to the solenoid coils provided in the switching valves 6a to 6d. Processing circuit 4a.

The solenoid relay drive signal sent from the solenoid relay drive circuit 4b is given to the logic logic circuit 7, and its output is power amplified by the solenoid relay drive circuit 8, and then sent to the solenoid relay 9.
is applied to the relay coil 9a. When the contact 9b becomes conductive, the battery voltage of the battery 11 is applied to the other end of the solenoid coil incorporated in the switching valves 6a to 6d via the contact 9b and the connection point 10.

The motor 12a is a motor for driving a hydraulic pump,
When the motor relay 13 is turned on, power is supplied from the battery 11 and control hydraulic pressure is generated. Processing circuits 4a, 4
The motor drive signal from b is given to the OR circuit 14,
When either of the motor drive signals from the processing circuits 4a, 4b becomes high level, the motor relay drive circuit 15 is turned on, and the motor relay 13 is also turned on. When a lamp drive signal from the processing circuit 4a or 4b is applied to the lamp drive circuit 16, the alarm lamp 17 is turned on. Warning lamp 17
If some abnormality occurs in the anti-skid control device6
lights up to warn the driver.

The positive electrode of the battery 11 is connected to one power supply circuit via a power switch 18. One power supply circuit converts the battery voltage into a desired voltage, and then supplies the converted voltage to each circuit. Further, the negative electrode of the battery 11 is connected to the vehicle body, so that so-called body grounding is performed.

2nd [2I] is a block diagram for explaining the hydraulic path of the anti-skid control device which is one embodiment of the present invention. The hydraulic pressure generated in the master cylinder 21 by depressing the brake pedal 20 is transferred to the switching fp i'l+a
-6d to the wheel cylinders 22a-22d to reduce the rotational speed of the wheels 23a-23d.

During anti-skid control, the braking oil pressure generated by driving the motor 12a is supplied to the P valves 24b 24d. When a pressure increase control signal is sent from the anti-skid control circuit 1 to the switching valve 6a, the braking oil pressure generated by the oil pressure source 12 is supplied to the wheel cylinder 22a via the pipes 25a and 26a. Also, the pressure reduction control signal is applied to the switching valve 6a.
When the hydraulic pressure inside the wheel cylinder 22a is
The water is returned to the reservoir tank 28 via the pipe line 26=t and 273, thereby reducing the oil pressure in the wheel cylinder 22a. Furthermore, when the holding control signal is sent to the switching valve 6a, all of the pipes 25a, 26a, and 27 are cut off, and the oil pressure in the wheel cylinder 22a is maintained constant. The same applies to 6d.

The P valves 24b and 24d are the rear wheel cylinders 22.
This is a valve for restricting the slope of the braking oil pressure supplied to the cylinders b and 22d rising from a predetermined value or higher.

FIG. 3 is a functional block diagram for explaining the correction calculation of the pressure reduction time of the pulse pressure reduction control in the processing circuits 4a and 4b. As already mentioned, as the wheel cylinder pressure in the hydraulic braking means increases, the hysteresis increases. Therefore, in this embodiment, the number of outputs of the pulse pressure increase control signal or the total pressure increase time of the pulse pressure increase control signal is detected among the control signals output to the hydraulic braking means, and the detected value is used to determine the wheel cylinder pressure. It is possible to estimate P. Here, the "pulse pressure increase control signal" is a signal that performs one-pressure control only during the period when the pulse signal is output, and performs holding control for the rest of the time.

Furthermore, the "pulse pressure reduction control signal" is a signal that performs pressure reduction control only during the period when the pulse signal is output, and performs holding control during the rest of the time.

Therefore, in this embodiment, the hysteresis of the hydraulic braking means is applied to the pulse pressure reduction control signal that is output after the number of outputs of the pulse pressure increase control signal or the total pressure increase time of the pulse pressure increase control signal reaches a predetermined value or more. Add a correction time to offset this and lengthen the decompression duration of pulse decompression.

In FIG. 3, the control unit 31 includes wheel speed sensors 2a to 2.
The wheel speed calculated based on any wheel speed signal d and the wheel acceleration which is the time change rate of this wheel speed are introduced, and anti-skid calculation is performed. The pressure reduction time correction unit 32 is a part that determines whether a correction time should be added when the pulse pressure reduction control signal is output to the hydraulic braking means.
A control signal output from the controller 3 to the hydraulic braking means is inputted, and the number of outputs of the pulse pressure increase control signal or the total pressure increase time of the pulse pressure increase control signal is detected.

When the pressure reduction request signal is sent from the control section 31 to the pressure reduction time correction section 32, the pressure reduction time correction section 32 sends a pressure reduction +Mt3'll signal to the control section 31 if the detected value is equal to or greater than a predetermined value. A correction signal to which a correction time is added is output. In this way, the control unit 31 uses the correction time ff to cancel the hysteresis of the hydraulic braking means.
Pulse decompression control (outputs a signal).

FIG. 4 is a timing chart for explaining the operation of this embodiment. 4121 (1) shows the change in wheel speed, Fig. 4 (2) shows the change in wheel acceleration, Fig. 4 (3) shows the change in wheel cylinder pressure, and Fig. 4 (4) shows the output of the control signal. The shape is shown respectively.

In addition, in FIG. 4 (2), G means gravitational acceleration. In FIG. 4(1), a line 11 represents a change in wheel speed, a line 12 represents a change in vehicle speed calculated within the processing circuits 4a and 4b, and a line I! 3 represents a speed 10% lower than the vehicle speed (hereinafter referred to as "slip reference speed"), and is a speed that serves as the output reference of the control signal in anti-skid control calculation.

4 [, 1(1), the wheel speed is below the slip reference speed at time t1, and the wheel acceleration shown in FIG. When the pressure decreases below , a pulse depressurization control signal is output as shown in FIG. 4 (4). However, time t1
Since the number of outputs of the previously output pulse pressure increase control signal is less than 4 times, which is the reference number for adding correction time to the pulse pressure reduction control signal, the correction time is equal to the output time T of the pulse pressure reduction control signal. The same applies to the pulse decompression control signal output at time t2.

However, if the pulse pressure increase υ control signal has been output six times before time t3, the correction time ΔT1 is added to the output time T of the normal pulse pressure decrease control signal, and the signal is output to the hydraulic braking means.

In the embodiment described above, a correction time is added when the number of outputs of the pulse pressure increase control signal exceeds a predetermined number of times, but if the total pressure increase time of the pulse pressure increase control signal exceeds a predetermined time. In some cases, a correction time may be added.

FIG. 5 is a functional block diagram of another embodiment illustrating correction calculation of the pressure reduction time of the pulse pressure reduction control signal in the processing circuits 4a and 4b. A wheel speed and a wheel acceleration, which is a time change rate of the wheel speed, are introduced into the control unit 41 . Control unit 4
1 performs anti-skid control calculations based on wheel speed and wheel acceleration, and outputs a control signal to the hydraulic braking means. The control section 41 further sends the vehicle speed calculated within the control section 41 to the depressurization time correction section 42. Decompression time correction section 42
determines whether the vehicle speed is less than a predetermined speed,
If it is less than that, a correction signal is output to the control section 41. When the correction signal is input, the control section 41 adds the correction time to the pulse pressure reduction control signal and outputs the signal to the hydraulic braking means.

FIG. 6 is a schematic flowchart of anti-skid control in the processing circuits 4a and 4b of this embodiment. The processing of each step will be explained below.

Note that, in order to simplify the explanation, the control for the right front wheel 23a will be described below, but the control for the other wheels is exactly the same.

Anti-skid in the processing circuit 4a, till 11
When the anti-skid control is started, it is first determined in step S1 whether or not the anti-skid control is currently being executed. If the anti-skid control is currently being executed, there is no need to determine whether to start the anti-skid control, and the process proceeds to step s4 in 6 steps s1. If anti-skid control is not being performed in step s2, it is determined whether the conditions for starting anti-skid control are satisfied. The anti-skid control start condition is, for example, if the wheels are locked or if the car (1st gear is lower than the predetermined rotation speed and the wheel deceleration (negative wheel acceleration) is greater than the predetermined deceleration. If the conditions for opening the anti-skid control b are met, the process proceeds to step s3, and a predetermined memory area of the processing circuit 4a is stored with the pressure reduction information for causing the wheel cylinder to perform the pressure reduction operation fj. A flag is set.

In step s2, if it is determined in step 111 that the conditions for starting the anti-skid control are not satisfied, step s
19, the switching valve 6a is set to the pressure increasing position so that the hydraulic pressure generated in the master cylinder by depression of the brake pedal is directly transmitted to the wheel cylinder.

In step S4, the conditions for ending the anti-skid control are determined, and the anti-skid control is canceled, for example, when the foot is released from the brake pedal or when the vehicle speed becomes 5 km/h or less.

If the anti-skid control termination condition is not satisfied in step s4, the process proceeds to step s5, where a flag for controlling increase/decrease in wheel cylinder oil pressure is determined.

In step s5, the flag set in the memory area is determined, and the process is moved to each control of pressure reduction, holding, pressure increase, or pulse pressure increase. Further, in step s5, the total number of outputs of the pulse pressure increase control signal or the pressure increase time of the pulse pressure increase control signal is calculated, and the result is stored in the memory.

When the anti-skid control starts, since the pressure reduction flag is set in step S3, the process proceeds to step s6, and further proceeds to step s7, where the wheel cylinder 22
a is controlled by pulse reduction.

In step s6, when the pulse pressure reduction control is completed by 4%, that is, when the wheel acceleration exceeds the predetermined acceleration G2 and the wheel speed begins to show signs of recovery, the process proceeds to step s8. In step s8, a flag is set to keep the oil pressure of the wheel cylinder 22a constant. When the holding flag is set, the process proceeds from step S9 to step slo, where a holding control signal is output to the switching valve 6a and the wheel cylinder pressure is kept constant.

In step s9, when the wheel acceleration exceeds the acceleration G2 and then falls below the acceleration G2, the holding end condition is met. When the holding end condition is satisfied, the process proceeds from step S9 to step all, where a pressure increase flag for increasing the oil pressure of the wheel cylinder 22a is set. wheel cylinder 2
The output time of the control signal for increasing the pressure 2a is set by the value of the wheel acceleration after the pressure is decreased. And step s
12 to step s13, the wheel cylinder 22
The oil pressure in a is increased. When the pressure increase setting time ends, the process proceeds from step s12 to step s14, where a pulse pressure increase flag is set to gradually increase the pressure in the wheel cylinder 22a.

Then, the process proceeds from step s15 to step s16, where a pulse pressure increase control signal having a predetermined time width is sent from the processing circuit 4a to the solenoid drive circuit 5a, and the switching valve 6
A performs pressure increase control for a time corresponding to the pulse width given from the solenoid drive circuit 5a. In step s15, when the pulse pressure increase termination condition is met, that is, when the wheels start to lock or when the wheel speed falls below the slip reference speed and the wheel acceleration falls below the pressure reduction reference acceleration G, the process moves from step s15 to step s17. The advance depressurization flag is set.

When the pulse pressure reduction flag is set, the process proceeds to step s18, where a correction calculation for the output time of the pulse pressure reduction control signal, which will be described later, is performed. When the correction calculation of the pulse pressure reduction control signal is completed, the process proceeds to step S7, and the pulse pressure reduction control signal is output to the hydraulic braking means.

71 is a processing flowchart in the case of correcting the output time of the pulse pressure reduction control signal according to the same number of outputs of the pulse pressure increase control signal in this embodiment. In step m1, it is determined whether the counter C1 that counts the number of outputs of the pulse pressure increase control signal exceeds the pulse pressure increase number determination criterion Kl (for example, 9). If it exceeds, the process advances from step m1 to step rn2, and T1 is added to the first correction time in the memory M1 in which the pulse decompression control time is set. For example, the first correction time ΔT1 is 13
m5ec) is selected. Counter C1 at step m]
If the value does not exceed the first pulse pressure increase criterion number of times of 1, the process proceeds to Stella 11 mouth 3 and is compared with the second pulse pressure increase criterion number of times of 2 (for example, 4). If the value of the counter C1 exceeds the reference number of times by 2, the process advances to step m4 and the second correction time ΔT2 is stored in the memory M1.
is added. For example, 4 msec is selected as this second correction time ΔT2.

If the value of the counter C] does not exceed the Moeki reference number of times 1 or 2 in step rn3, proceed to step m5;
No correction calculation is performed on the memory M1 in which the output time of the pulse pressure reduction control signal is stored.

No. 8121 is a processing flowchart for correcting the output time of the pulse pressure reduction control signal according to the vehicle speed according to another embodiment of the present invention. In step n1, it is determined whether or not the vehicle speed exceeds the high speed determination speed KVI. T3 is subtracted from the correction time. For example, 8 m5ec is selected as the third correction time. If the vehicle speed does not exceed the high speed determination speed KVI in step n1, the process proceeds to step n3, and furthermore, the vehicle speed is determined to be low speed determination speed] (V 2
It is determined whether or not the value is below .

If the low speed judgment speed is below KV2, the process proceeds to step 14, and the fourth correction time ΔT4 is stored in the memory M2.
is added. For example, 4rnsecf)C is selected as the fourth correction time ΔT4.

In step n3, if the vehicle speed is not lower than the low speed judgment speed ■ (V2, that is, the vehicle speed is low speed I'11
If the speed is between the constant speed KV2 and the high speed determination speed KVI, the output time correction calculation for the pulse depressurization control signal is not performed in step rI5.

In the above-mentioned embodiment, two judgment criteria are provided to correct the output time of the pulse pressure reduction control signal, but more judgment criteria may be provided to perform the correction. Smoother control can be achieved by performing correction calculations in proportion to the number of signal outputs or the total pressure increase time.

Effects of the Invention As described above, according to the present invention, as it is estimated that the hydraulic pressure supplied to the hydraulic braking means increases at the time when the pulse pressure reduction control signal is output, the output time of the pulse pressure reduction control signal is lengthened. Therefore, it is possible to prevent an increase in braking distance while maintaining a high braking force of the wheels on the road surface, and to prevent a large drop in wheel speed.

[Brief explanation of the drawing]

The first I21 is a block diagram of an anti-skid control device which is an embodiment of the present invention, the second (2I is a block diagram for explaining the hydraulic path of this embodiment, and FIGS. 3 and 5 are a processing circuit 4a, 4b is a functional block diagram for explaining the correction calculation of the pressure reduction time of the pulse pressure reduction control signal in 4b.
FIG. 6 is a timing chart for explaining the operation of this embodiment, FIG. 6 is a schematic flowchart of anti-skid control in the processing circuits 4a and 4b of this embodiment, and FIG. 7 is a pulse boost control signal in this embodiment. FIG. 8 is a processing flowchart for correcting the output time of the pulse depressurization control signal according to the number of outputs of the pulse decompression control signal, and FIG. Fig. 9 is a μ-S curve for explaining the changes in the friction coefficient μ and slip rate S with respect to changes in the running speed of the vehicle. This is a graph for explaining the system. 1...Anti-skid control circuit, 2a-2d...Wheel speed sensor, 4a, 4b...Processing circuit, 5a-5d.
・Solenoid drive circuit, 6a to 6d... switching valve, 8,
... Solenoid relay drive circuit, 9... Solenoid relay 11... Battery, 12 - Hydraulic power source, 13...
・Motor relay, 15...Motor relay drive circuit, 1
1...Power supply circuit, 21...Master cylinder, 22a
~22d...-Wheel Cylinder Agent Patent Attorney Keishi Saikyo 1st Prisoner Figure Figure

Claims (3)

[Claims] (1) In an anti-skid control device that increases or decreases the oil pressure of the hydraulic braking means of the wheels to increase the coefficient of friction between the wheels and the road surface, the higher the oil pressure of the hydraulic braking means, the more the pressure decreases at the point when the pressure should be reduced. Anti-skid control device characterized by a large selection of quantities. (2) The hydraulic pressure change of the hydraulic braking means is changed by periodic pulses, and when the pressure is reduced after the number of pulses of this pulse pressure increase continues at a predetermined value, the pressure reduction duration of the pulse pressure reduction is the pulse pressure increase. 2. The anti-skid control device according to claim 1, wherein the pulse number is selected to be longer than the pressure reduction duration of the pulse reduction when the number of pulses is less than the predetermined value. (3) In an anti-skid control device that increases or decreases the oil pressure of the hydraulic braking means of the wheels to increase the coefficient of friction between the wheels and the road surface, the lower the vehicle speed, the more the amount of pressure reduction at the point in time is predetermined. An anti-skid control device characterized in that the amount of pressure reduction is selected to be larger than the amount of pressure reduction that is selected when the vehicle speed is equal to or higher than a predetermined vehicle speed.