JPH07242168A - Fail-safe device in antiskid control device - Google Patents

Abstract

PURPOSE:To reduce the cost and lighten the weight of device while realizing a fail-safe function of an antiskid control device. CONSTITUTION:When antiskid control is repeatedly executed, a temperature of members rises in an output circuit or the like of an antiskid control device for driving an actuator 13. In a temperature detecting means 21, a temperature of the member is detected for whether increased or not to a specific value or higher. For instance, a temperature rise value of the member per one time action of antiskid control is left as predetermined, to detect a number of executing times of the antiskid control per specific time, in the temperature detecting means 21. In response to a detection result from the temperature detecting means, operation of a control means 6 is inhibited by a control inhibiting means 22. Accordingly, in the actuator 13, output circuit, etc., the member thereof having small heat capacity, that is, for instance, small rated current can be used, so that reducing the cost and lightening the weight can be attained by eliminating apprehension of erroneous operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fail-safe device in an anti-skid control device, and more particularly to a device for preventing malfunction due to repeated operation of the anti-skid control device.

[0002]

2. Description of the Related Art An anti-skid control device is a device for controlling a braking force so as to increase a friction coefficient between a wheel and a road surface on the basis of a wheel speed, a vehicle body speed, etc., and shortening a braking distance. .

That is, when the braking operation is performed by depressing the brake pedal, the braking hydraulic pressure rises, and the wheels start to lock and the slip ratio between the wheels and the road surface increases, the control means such as a microcomputer causes each wheel to move. The control circuit outputs a control signal to an output circuit such as a power transistor provided in a brake hydraulic pressure piping path to control the brake hydraulic pressure by an actuator such as an electromagnetic control valve. When the wheel speed is recovered by this pressure reduction control, the control means increases the braking hydraulic pressure again. By repeating such pressure reducing operation, pressure increasing operation, or holding operation, the braking force is controlled so that the slip ratio becomes optimum.

When the anti-skid control is continuously operated, a large current flows from the output circuit such as the power transistor to the solenoid valve, and the output circuit and the actuator generate heat. When the temperatures of the output circuit and the solenoid valve rise, the anti-skid control may malfunction, for example, the power transistor may remain conductive. Therefore, in the conventional anti-skid control device, assuming a continuous operation of the anti-skid control, the rated current value of the power transistor is selected to be large, and the heat capacity such as increasing the wire diameter of the solenoid valve is sufficiently large. We are designing to have it.

[0005]

Therefore, in the anti-skid control device of the prior art, since the control operation which is rarely performed has a sufficient margin as described above, the cost is increased and the cost is increased. The weight increases.

On the other hand, as a prior art of a fail-safe device against heat generation in an anti-skid control device, there is JP-A-62-120259. However, this prior art discloses in the publication that "the temperature of the brake device is high because the industrial application" on the first page and the "problem to be solved by the invention" on the second page. , The operation of the anti-skid system is stopped when the wheel rotation speed detection sensor may generate an erroneous signal. "

Therefore, while this prior art has a problem of increasing the temperature of the brake device, the present invention has a problem of increasing the temperature of the device relating to the operation itself of the anti-skid control such as the output circuit and the actuator, which is a fail safe. The symmetry of is completely different.

An object of the present invention is to provide a fail-safe device in an anti-skid control device, which can realize the fail-safe function of the anti-skid control device, while reducing the cost and weight of the device.

[0009]

According to the present invention, there is provided a fail-safe device in an anti-skid control device for controlling a braking hydraulic pressure of a wheel so that the wheel exerts a high friction braking force on a road surface. Temperature detection means provided for control and provided in association with a member whose temperature rises by executing anti-skid control, and the temperature of the member is predetermined in response to the detection result of the temperature detection means. A fail-safe device in an anti-skid control device, comprising: a control prohibiting means for prohibiting a control operation of the anti-skid control device when the temperature becomes equal to or higher than a temperature.

Further, the temperature detecting means of the present invention is characterized by detecting the number of executions of the anti-skid control per predetermined time.

Further, the member of the present invention is characterized in that it is an output circuit of an anti-skid control device for driving an actuator provided in a pipeline of a brake hydraulic pressure to each wheel.

[0012]

According to the present invention, the fail-safe device in the anti-skid control device includes the temperature detection means and the control prohibition means. The temperature detecting means is provided for the anti-skid control, and a member whose temperature rises by executing the anti-skid control, such as an electromagnetic control valve provided in a piping path for braking hydraulic pressure to each wheel. Provided in association with the output circuit that drives the actuator. The control prohibiting means prohibits the control operation of the anti-skid control device when the temperature of the member exceeds a predetermined temperature in response to the detection result of the temperature detecting means.

Therefore, if the temperature of the member rises and the malfunction of the anti-skid control may occur by repeatedly performing the anti-skid control, the anti-skid control operation is prohibited in advance. This prevents the occurrence of this malfunction. As a result, it is not necessary to unnecessarily have a large heat allowance in the output circuit or the like, and cost reduction and weight reduction can be achieved.

Further preferably, the temperature detecting means detects the number of times of execution of the anti-skid control per predetermined time. For example, the amount of temperature rise of the member per antiskid control is determined in advance,
How much the temperature of the member has risen is estimated from the product value of the number of executions of the anti-skid control detected by the temperature detecting means.

Therefore, it is not necessary to actually provide a temperature sensor or the like, and thereby, in order to realize the fail-safe function, new parts such as the sensor are not required, and a position relatively distant from the anti-skid control is not required. It is possible to further reduce the cost without routing the wire harness to a certain actuator or the like.

[0016]

1 is a functional block diagram showing the configuration of the present invention. The wheel speed sensor 1 detects the rotation speed of the wheel and inputs it to the control means 6. The vehicle body speed sensor 3 estimates the vehicle body speed from the detection result of the wheel speed sensor 1 and inputs it to the control means 6. Based on the input results from the wheel speed sensor 1, the vehicle body speed sensor 3, and the brake switch 7, the braking operation is performed by depressing the brake pedal, the braking hydraulic pressure rises, the wheels start to lock, and the slip between the wheels and the road surface occurs. When the ratio becomes large, the control means 6 drives and controls the actuator 13 to perform an anti-skid control operation for increasing, reducing or maintaining the braking hydraulic pressure.

By repeatedly executing the antiskid control, the temperature of members such as the output circuit of the antiskid control device for driving the actuator 13 rises. The temperature detecting means 21 detects whether or not the temperature of the member has become equal to or higher than a predetermined temperature. Specifically, for example, the amount of increase in the temperature of the member per the number of times of execution of the antiskid control is set in advance, and the temperature detecting means 21 detects the number of times of execution of the antiskid control per a predetermined time. When the detection result of the temperature detecting means 6 exceeds the predetermined temperature, the control prohibiting means 22 prohibits the control operation of the actuator 13 by the control means 6 as described above.

FIG. 2 is a block diagram showing the electrical construction of an anti-skid control device having a fail-safe function according to an embodiment of the present invention, and FIG. 3 is a piping route diagram of braking hydraulic pressure of the anti-skid control device. The wheel speed sensors 1a to 1d provided on the wheels 34a to 34d are
The rotation speeds of a to 34d are detected.

These wheel speed sensors 1a to 1d are, for example, in the circumferential direction of a ferromagnetic detection plate fixed to the wheel shaft.
A large number of notches and protrusions are provided at equal intervals, and a wheel speed signal having a frequency proportional to the rotation speed of the wheel is derived by an electromagnetic pickup or an optical sensor provided near the circumference of the detection plate. Has been done. The wheel speed signals from the wheel speed sensors 1a to 1d are given to the waveform shaping circuits 5a to 5d in the anti-skid control circuit 4, and after being waveform shaped into pulse signals, are sent to the control circuit 2 which is the control means 6. Is entered.

The control circuit 2 receives an input from the switch 7 which detects that the brake pedal 30 is depressed, after the level conversion circuit 8 converts the output to a voltage level suitable for the antiskid control circuit 4. To be done.
The voltage from the battery 11 input through the power switch 10 is stabilized by the power circuit 9 and then supplied to each circuit in the anti-skid control circuit 4.

The control circuit 2 controls the actuators 13a to 13d based on the input result input as described above.
Drive control and perform anti-skid control operation. The actuators 13a to 13d are electromagnetic control valves 32a to 32d.
And wheel cylinders 33a to 33d and the like. Therefore, the control circuit 2 controls the relay coil 1 of the relay 15 via the solenoid relay drive circuit 14.
5a is excited, whereby the relay switch 15b becomes conductive. A high level voltage is commonly applied to one input of each of the actuators 13a to 13d via the relay switch 15b. Control signals from the control circuit 2 are applied to the other inputs of the actuators 13a to 13d via the solenoid drive circuits 12a to 12d, respectively. As a result, the electromagnetic control valve 32
a to 32d control the braking hydraulic pressure to either a pressure-increasing state, a pressure-decreasing state, or a holding state.

The control circuit 2 also outputs the output to the relay coil 16a of the relay 16 via the motor relay drive circuit 18, and thereby the motor for generating the braking hydraulic pressure is connected to the relay switch 16b of the relay 16. 17
Are driven and controlled. Furthermore, the control circuit 2 turns on the warning lamp 19 via the lamp drive circuit 20 when an abnormality occurs in the anti-skid control.

The detection result of the temperature sensor 23 is also read into the control circuit 2 via the analog / digital converter 24. In the temperature sensor 23, the voltage derived from the connection point of the resistance and the temperature-sensitive resistor that are interposed in series between the high-level voltage Vcc and the ground line changes depending on the change in the resistance value of the temperature-sensitive resistor as the temperature changes. It takes advantage of changing.

On the other hand, the solenoid drive circuits 12a to 12d which are output circuits are realized by power transistors and the like. The temperature sensor 23 is provided in a member, such as the solenoid drive circuits 12a to 12d and the electromagnetic control valves 32a to 32d, whose temperature rises by executing antiskid control.

Referring to FIG. When the brake pedal 30 is stepped on, a braking hydraulic pressure is generated in the master cylinder 31, the braking hydraulic pressure is supplied to the electromagnetic control valves 32a to 32d via the pipelines P1 to P4, and further to the pipeline P5. P
8 is supplied to the wheel cylinders 33a to 33d. The wheel cylinders 33a to 33d drive a brake pad or the like (not shown) to be displaced, whereby the wheels 34
The a to 34d are braked and the vehicle speed is reduced. Further, the anti-skid control circuit 4 supplies the braking hydraulic pressure reduced during the anti-skid control by the motor 17 via a hydraulic pump and a pipe (not shown) to the master cylinder side pipe P1.
To P4, the electromagnetic control valves 32a to 32d are controlled to be in a pressure increasing, depressurizing, or holding state to control the braking hydraulic pressure of the wheel cylinders 33a to 33d.
As a result, the slip ratio of the wheels 34a to 34d is controlled to a value at which a high friction braking force acts on the road surface.

The relationship between the pressure increase / decrease of the electromagnetic control valve and the pipelines P1 to P8 will be described. Driver brake pedal 30
Even if you fully depress the
The pipelines P5 to P8 are cut off from the corresponding pipelines P1 to P4, respectively, and connected to a reservoir tank (not shown).
In this way, the braking hydraulic pressure in the wheel cylinders 33a to 33d and the pipelines P5 to P8 is reduced. On the other hand, during pressure increase control, the electromagnetic control valves 32a to 32d are connected to the pipes P1 to P1.
Each of the conduits P5 to P8 corresponding to P4 is electrically connected. As a result, the braking hydraulic pressure in the master cylinder 31 is supplied to the wheel cylinders 33a to 33d via the pipelines P1 to P4 and P5 to P8.

When the anti-skid control for increasing / decreasing the braking hydraulic pressure is repeated many times, the solenoid drive circuits 12a-12d and the electromagnetic control valves 32a-32d are used.
Temperature rises. Solenoid drive circuits 12a-12d
Serves as an output circuit of the antiskid controller for driving the actuators 13a to 13d. The control circuit 2 has a function as a control prohibiting unit that prohibits execution of the anti-skid control when the detection result of the temperature sensor 23 becomes equal to or higher than a predetermined temperature.

FIG. 4 is a flow chart showing the fail-safe operation in the anti-skid control device of the present invention. After initial setting is performed in step n1, timing adjustment is performed in step n2 so that the anti-skid control is entered at every predetermined cycle of 4 msec, for example. In step n3, the wheel speed is calculated, and in step n4
From the calculation result of the wheel speed, for example, the higher value of the wheel speeds of the driven wheels is selected and the vehicle speed is estimated.

At step n5, the detection result of the temperature sensor 23 is read. When it is determined in step n6 that the detection result is equal to or higher than the predetermined temperature, the control circuit 2 as the control prohibiting means turns on the warning lamp 19 via the lamp drive circuit 20 in step n7, n8
Disable anti-skid control with.

When it is determined in step n6 that the detection result is not equal to or higher than the predetermined temperature, in step n9 the wheels tend to lock based on the wheel speed calculation result and the estimated vehicle speed, and it is necessary to reduce the brake hydraulic pressure. It is determined whether or not the anti-skid control condition such as is satisfied. When it is determined that the antiskid control conditions are not satisfied, the process proceeds to step n8, and the control circuit 2 does not perform the antiskid control. When it is determined that the antiskid control conditions are satisfied, the process proceeds to step n10, and the control circuit 2 performs antiskid control.

FIG. 5 is a waveform diagram for explaining the operation of another embodiment of the present invention, and FIG. 6 is its flowchart. The amount of temperature rise of the solenoid drive circuits 12a to 12d per one antiskid control is determined in advance, and the control circuit 2 detects the number N of executions of the antiskid control per a predetermined time W1, for example, 30 minutes. . When the anti-skid control is repeatedly executed and the temperature of the solenoid drive circuits 12a to 12d or the like becomes equal to or higher than a predetermined temperature, that is, the number N of times of execution of the anti-skid control per predetermined time W1 is the solenoid drive circuits 12a to 12d. The control circuit 2 prohibits execution of the anti-skid control when the predetermined number of times N1 of the anti-skid control corresponding to the predetermined temperature is 1, for example, three times or more.

First, how the control circuit 2 detects the temperatures of the solenoid drive circuits 12a to 12d will be outlined with reference to FIG. When the anti-skid control is being performed, the flag F1 indicating that the control is being performed is set to 1 as shown in FIG. 5A, and when the control is not being performed, the flag F1 is set to 0. Each time the flag F1 becomes 1, the count value N of the counter indicating the number of times of anti-skid control is incremented by 1, as shown in FIG. 5 (2). The number of times of anti-skid control is counted per a predetermined time W1. Note that FIG.
T1 shown in (3) is a count value for counting the time W1.

In counting the time W1,
The flag F2 shown in FIG. 5 (4) is used. The flag F2 is set to 1 when the anti-skid control is started, and is reset when the time W1 has elapsed. When the count value N of the number of times of anti-skid control at the time W1 becomes equal to or more than the number of times of anti-skid control N1 corresponding to the temperature of the solenoid drive circuits 12a to 12d, the control circuit 2 performs the anti-skid control as shown in FIG.
The predetermined time W2 shown in (6) is prohibited. At this time, as shown in FIG. 5 (5), a control prohibition flag F3 indicating prohibition of the anti-skid control is set. T2 is a count value for counting the predetermined time W2.

Next, the fail-safe operation of the anti-skid controller of this embodiment will be described with reference to FIG.
As an example, the control circuit 2 includes the solenoid drive circuit 12a.
It is assumed that the temperature detection of ~ 12d is performed by counting the number of anti-skid controls.

At step m1, it is judged from the calculation results of the wheel speed and the estimated vehicle speed that the antiskid control conditions are satisfied. If it is judged that the anti-skid control conditions are not satisfied, step m
In 2, the flag F indicating whether or not the anti-skid control is currently performed
1 is reset to 0 and the process returns to step m1. When it is determined that the antiskid control condition is satisfied, it is determined in step m3 whether the flag F1 has already been set to 1. If it is determined that the flag F1 is set to 1, it means that the anti-skid control is being performed, and therefore the count value T1 of the time counter is incremented by 1 in step m4. The count value T1 is introduced to count a predetermined time W1. When it is determined that the flag F1 is not 1 even though the anti-skid control condition is satisfied, that is, when the anti-skid control is started each time, the flag F1 is set in step m5.
While 1 is set to 1, the count value N of the counter indicating the number of times of anti-skid control is incremented by 1 in step m6.

At step m7, it is judged if the flag F2 to be started during the predetermined time W1 is 1 or not. When it is determined that the flag F2 is 1, it is within the time W1 from the start time of the first control, and thus the count value T1 of the time counter is incremented by 1 in step m4. When it is determined that the flag F2 is not 1, that is, when the first control is started, the flag F2 is set from 0 to 1, and the count value T1 of the time counter is set to 0 in step m9.
Then, the system is reset to start counting the predetermined time W1.

In step m10, it is judged whether or not the count value N for counting the number of anti-skid controls is equal to or more than the number of controls N1 corresponding to the temperature rise of the solenoid drive circuits 12a to 12d. When it is determined that the count value N is the control count N1 or more, the solenoid drive circuit 12a
The temperature of ~ 12d has risen above the predetermined temperature,
Since the fail-safe operation for inhibiting the control should be performed, the control inhibition flag F3 indicating the inhibition of the anti-skid control is set from 0 to 1 in step m11, and the process proceeds to step m12. When it is determined in step m10 that the count value N is smaller than the control count N1, the process directly proceeds to step m12.

At step m12, it is judged if the count value T1 of the time counter is equal to or larger than the count value w1 corresponding to the predetermined time W1. When it is determined that the count value T1 is greater than or equal to the count value w1, the predetermined time W1 has been reached, so the flag F2 is reset from 1 to 0 in step m13, and the number of anti-skid control is counted in step m14. After the count value N is reset to 0 and the count value T1 of the time counter is reset to 0 in step m15, the process proceeds to step m16.

When it is determined in step m12 that the count value T1 is smaller than the count value w1, the process directly proceeds to step m16.

At step m16, the control prohibition flag F3
Is determined to be 1 or not. When it is determined that the control prohibition flag F3 is 1, the count value T2 for counting the predetermined time W2 is increased in step m17 to prohibit the anti-skid control for the predetermined time W2.
The anti-skid control is prohibited in step m18, and the process proceeds to step m21.

If it is determined in step m16 that the control prohibition flag F3 is not 1, it is not necessary to perform the fail-safe operation yet. Therefore, in step m19, the count value T2 is reset to 0, and in step m20, the antiskid operation is performed. Control is performed, and the process proceeds to step m21.

At step m21, it is judged if the count value T2 for counting the time for prohibiting the anti-skid control is greater than or equal to the count value w2 corresponding to the predetermined time W2. When it is determined that the count value T2 is equal to or greater than the count value w2, the anti-skid control has already been prohibited for the period of the time W2, so the control prohibition flag F3 is reset to 0 in step m22, and step m23 The count value T2 is reset to 0 with. Such an operation is performed in a predetermined cycle, for example, every 4 msec.

FIG. 7 is a waveform diagram for explaining the temperature detecting operation of still another embodiment of the present invention. During the anti-skid control period in which the flag F1 is set to 1 as shown from time t1 to t2 and t3 to t4 in FIG. 7 (1), the solenoid drive is performed as shown in FIG. 7 (2). The temperature of the circuits 12a to 12d and the like rises, and when the antiskid uncontrolled state is reached, the temperature falls. In this embodiment, the temperature K is estimated based on the equation 1 during the anti-skid control, and is estimated based on the equation 2 when the non-controlled state is reached. When the temperature K thus obtained becomes equal to or higher than the predetermined value K1, At time t5, the control prohibition flag F3 is set to 1 as shown in FIG.
Disable anti-skid control.

K = Ta + RQo + (To−Ta−RQo) e ^{−t / CR} (1) K = Ta + (To−Ta) e ^{−t / CR} (2) However, To is the time when the control state changes, For example, the estimated temperatures at the times t1, t2, t3, t4 ...
Is the elapsed time after such a change in the control state, Ta is the outside air temperature, and R is the solenoid drive circuit 12
a is a thermal resistance of 12d, Qo is the amount of heat generated from the solenoid drive circuits 12a to 12d, and C is its thermal capacity.

FIG. 8 is a flow chart for explaining the temperature detecting operation as described above, and this operation is performed as a part of the anti-skid control instead of step n5 in the embodiment shown in FIG. At step k1,
It is determined whether or not the flag F1 is 1, that is, whether or not the anti-skid control is being performed, and if so, the process proceeds to step k2, where the temperature K is estimated based on the equation 1, and if not, the step is performed. At k3, the temperature K is estimated based on the above equation 2. Step k
From 2, k3 to step k4, the estimated temperature K
Is greater than or equal to a predetermined value K1, and if so, the control prohibition flag F3 is set to 1 in step k5 to end the operation, and otherwise, the control prohibition flag F3 is set in step k6. It is reset to 0 and the operation ends.

FIG. 9 shows solenoid drive circuits 12a-12d.
FIG. 10 is an electric circuit diagram showing a specific configuration of FIG. 10, and FIG. 10 is a timing chart showing an operation of the solenoid drive circuits 12a to 12d at the time of anti-skid control for explaining another embodiment of the present invention. The solenoid drive circuits 12a to 12d include a power transistor 36 for switching and bypass diodes 37, 3 for absorbing surge.
And 8 are included.

From the anti-skid control circuit 2 to the base of the power transistor 36 at time t1 in FIG. 10 (1).
When a high-level drive output as shown between 1 to t12 and t13 to t14 is given, the power transistor 36 becomes conductive, and as shown by reference numeral Io, the solenoid 35 of the electromagnetic control valves 32a to 32d is operated. The load current indicated by 10 (2) is taken in. Thus, the electromagnetic control valves 32a-32
d is excited. This allows the power transistor 36
Collector voltage Vo decreases as shown in FIG. 10 (3).

On the other hand, when the output from the anti-skid control circuit 2 becomes low level, the power transistor 3
6 shuts off. At this time, the back electromotive force generated by the solenoid 35 raises the collector voltage Vo as shown in FIG. 10 (3), and the load current Io is transferred to the base of the power transistor 36 via the zener diode 37 and the diode 38. Inflow, a period during which the load current Io due to this counter electromotive force is flowing, that is, time t1.
During the period from 2 to t15 and t14 to t16, the power transistor 36 remains conductive, and the counter electromotive force is bypassed and removed.

Therefore, in such a case, the temperature K can be estimated by using Expression 3 instead of Expression 2 described above.

K = Ta + (To + Tk−Ta) e ^{−t / CR} (3) where Tk is the amount of heat generated by switching the solenoid 35 from the conductive state to the cutoff state.

In addition to the so-called four-channel type in which the pressure increasing / decreasing control is performed for each of the wheels 34a to 34d as described above, the anti-skid control device has a simple structure.
Various control channel configurations have been proposed, such as a three-channel type in which the rear wheels are commonly controlled, or a two-channel type in which each of the left and right sides is controlled. Therefore, the above-described temperature detection is performed. It may be configured to perform each of these channels.

In this way, when the temperature of the solenoid drive circuits 12a to 12d or the like rises abnormally due to the repetition of the antiskid control, the failsafe operation for prohibiting the antiskid control is performed to prevent the malfunction of the antiskid control. It can be prevented. Therefore, it is not necessary to select parts having a large heat capacity for the power transistor 35 of the solenoid drive circuits 12a to 12d, the coil 35 of the electromagnetic control valves 32a to 32d, etc., and thus cost reduction and weight reduction can be achieved. . In addition, in the embodiment shown in FIG.
~ It is not necessary to provide the temperature sensor 23 in the embodiment shown in Fig. 4, therefore, the temperature sensor can be omitted and the wire harness can be routed to the sensor.
Further cost reduction can be achieved.

[0053]

As described above, according to the present invention, malfunctions due to temperature rise of members such as the output circuit due to repeated operation of anti-skid control are prevented in advance, so that the members have an unnecessarily large heat capacity. You no longer have to design
The cost and weight can be reduced.

Further preferably, the temperature detecting means estimates the temperature rise of the member provided for anti-skid control by detecting the number of times of execution of anti-skid control per predetermined time. Therefore, it is not necessary to provide a new component such as a temperature sensor, and the cost can be further reduced.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of an anti-skid control device having a fail-safe function according to an embodiment of the present invention.

FIG. 3 is a piping path diagram of a braking hydraulic pressure of the anti-skid control device.

FIG. 4 is a flowchart showing a fail-safe operation in the anti-skid control device of the present invention.

FIG. 5 is a waveform diagram for explaining the operation of another embodiment of the present invention.

FIG. 6 is a flowchart of FIG.

FIG. 7 is a timing chart for explaining a temperature detecting operation of still another embodiment of the present invention.

8 is a flowchart of FIG. 7.

FIG. 9 is an electric circuit diagram showing a specific configuration of solenoid drive circuits 12a to 12d.

FIG. 10 is a solenoid drive circuit at the time of anti-skid control for explaining another embodiment of the present invention.
It is a timing chart which shows operation of 2d.

[Explanation of symbols]

 1, 1a-1d Wheel speed sensor 2 Control circuit 3 Body speed sensor 4 Anti-skid control circuit 6 Control means 7 Brake switch 12a-12d Solenoid drive circuit 13, 13a-13d Actuator 14 Solenoid relay drive circuit 21 Temperature detection means 22 Control prohibition Means 23 Temperature sensor 32a-32d Electromagnetic control valve 33a-33d Wheel cylinder 34a-34d Wheel

Claims (3)

[Claims] 1. A fail-safe device in an anti-skid control device for controlling a braking hydraulic pressure of the wheel so that the wheel exerts a high friction braking force on a road surface, the anti-skid control device being provided for the anti-skid control. The temperature detecting means provided in association with the member whose temperature rises by executing skid control, and the anti-skid when the temperature of the member exceeds a predetermined temperature in response to the detection result of the temperature detecting means. A fail safe device in an anti-skid control device, comprising: a control prohibiting means for prohibiting a control operation of the control device. 2. A fail-safe device in an anti-skid control device, wherein the temperature detecting means detects the number of times of execution of the anti-skid control per predetermined time. 3. The fail-safe device in an anti-skid control device, wherein the member is an output circuit of an anti-skid control device that drives an actuator provided in a brake hydraulic pressure piping path to each wheel.