JPH0159936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an apparatus for checking whether the system is normal or not by not operating a pressure reducing hydraulic actuator in order to prevent a no-brake situation when an inspection command is given. The present invention relates to an operation confirmation device for an anti-skid control system that allows one to easily determine whether or not a solenoid drive circuit for a hydraulic actuator is operating normally.

Conventionally, this type of anti-skid control system uses a signal from a wheel speed sensor that detects the wheel speed of the wheel to be skid-controlled to generate a control signal that provides a slip ratio (approximately 0.15 to 0.2) that provides maximum braking efficiency. This control signal is generated by the anti-skid control circuit, and this control signal activates the hydraulic actuator to repeatedly increase and decrease the brake hydraulic pressure applied to the brake system, thereby achieving maximum braking efficiency while maintaining vehicle stability during sudden braking. This allows for close braking.

On the other hand, in such an anti-skid control system, if the anti-skid control circuit fails, the correct control signal will not be output, but if you know in advance that a failure has occurred, you can be careful in operating the brakes. can.

Therefore, conventionally, in order to check whether the anti-skid control circuit operates normally, an operation check circuit has been provided. A pseudo signal of the wheel speed that changes as shown in FIG. (Tokuko Showa 48
-37953, 50-32380, etc.)

By the way, the above operation check is generally performed with the vehicle stopped and the handbrake pulled, but for example, when the vehicle is stopped on a slope with the footbrake pressed without pulling the handbrake,
When the operation is confirmed, the hydraulic actuator is actuated by the pressure reduction signal from the anti-skid control circuit as a result of the operation confirmation, and the brake hydraulic pressure applied to the brake equipment of each wheel is reduced. However, the brakes may be loosened and the vehicle may start moving.

Therefore, in order to prevent the brake hydraulic pressure from decreasing even if the operation is checked when the vehicle is stopped on a slope with the foot brake depressed, the hydraulic actuator is turned off while the operation is being checked. We are proposing a device that cuts off the power supply to the brake and maintains the normal brake hydraulic path.

That is, as shown in FIG. 1, when the operation confirmation signal is output from the operation confirmation circuit 1 to the anti-skid control circuit 2, the power relay contact 4 is opened to cut off the power to the solenoids 3a to 3d of the hydraulic actuator. Even if a pressure reduction signal from the anti-skid control circuit 2 is applied to the power transistors T _r1 to _{T r4} for driving the solenoids, the solenoids 3 a to 3 d are not energized.
In addition, each of 5a to 5d is a wheel speed sensor provided for each wheel to be skid controlled, and the AND gate 6
When all the pressure reduction signals are output, the lamp 7 is turned on to notify that the system is normal.

According to the device shown in Fig. 1, the solenoids 3a to 3d of the hydraulic actuator are not energized even when the operation is checked, so the operation is checked when the foot brake is depressed and the vehicle is stopped on a slope. Even when the brakes are worn out, loosening of the brakes can be reliably prevented.

By the way, failures that may occur in the anti-skid control system shown in FIG. 1 include failures in the anti-skid control circuit 2, as well as failures in the power transistors that drive the solenoids 3a to 3d of the hydraulic actuators.
It is possible that any of the power transistors T _r1 to T _r4 may deteriorate and malfunction after being used for a long time, and if the power transistors T _r1 to _{T r4} do not operate normally, the anti-skid control circuit 2 Even if the signal is output normally, anti-skid control will not be performed properly.

In particular, in the system shown in Figure 1, when checking the operation, the power relay contact 4 is opened and the power transistor T _{r1 is}
~ Since the operation of T _r4 is prohibited, the operation of the power transistor is not checked, and if the power transistor were to fail, it would not be possible to check the operation of the power transistor until braking near the maximum braking efficiency was performed during anti-skid control. There is a problem of noticing a system abnormality caused by a power transistor failure.

The present invention has been made in view of the above, and includes an operation confirmation device that prevents the hydraulic actuator from operating in order to prevent a decrease in brake oil pressure when inspecting a control system for an abnormality. In order to easily know whether it is normal or not, when an inspection command is given, a current smaller than the minimum current value that can drive the hydraulic actuator is supplied to the drive element of the hydraulic actuator. an actuator operation detection means for detecting whether or not a drive element of the hydraulic actuator is actuated by the current supplied from the current supply means; The apparatus further includes an alarm means for issuing an alarm when the actuator operation detection means detects that the drive element of the hydraulic actuator is not operated.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 is a circuit block diagram showing an embodiment of the present invention.

First, to explain the configuration, 10a to 10d are wheel speed sensors (hereinafter referred to as "sensors") provided for each wheel to be skid controlled, and 11 is a sensor 10a to 10d.
T r1 is an anti-skid control circuit that obtains a wheel speed signal from an alternating current signal or a pulse signal with a frequency proportional to the rotational speed of the wheels, and outputs a hydraulic control signal such that maximum braking efficiency can be obtained based on this wheel speed signal _. ~T _r4 is a power transistor forming a drive circuit for a hydraulic actuator that is turned on and off by a hydraulic control signal, 12a to 12d are solenoids of electromagnetic valves provided in the hydraulic actuator, and each solenoid 12a to 12d is a surge An absorption diode D is connected in parallel.

As operation confirmation means for such an anti-skid control system, an operation confirmation circuit 13 is provided which applies a pseudo wheel speed signal for operation confirmation to each channel of the anti-skid control circuit 11 to which the sensors 10a to 10d are connected. For example, an AC signal of a predetermined frequency is applied from an oscillator to each channel in conjunction with the on/off operation of an ignition switch when starting the engine. In addition, a power supply relay contact 14 is provided in the power supply line from the battery to the solenoids 12a to 12d, which opens for a certain period of time after an inspection command is issued by the operation confirmation circuit 13 to cut off the power supply. This prevents the hydraulic actuator from operating even if a hydraulic control signal is output from the anti-skid control circuit 11.

Furthermore, in order to confirm the operation of the power transistors T _r1 to _{T r4} , a power supply voltage +E is applied to the collectors of each of the power transistors T _r1 to _{T r4} via current limiting resistors 15a to 15d.
The collectors of T _r1 to _{T r4} are input to the NOR gate 16, and the output of the NOR gate 16 is connected to the transistor T _r5.
is provided, and is turned on by the H level output of the NOR gate 16 to light up the indicator lamp 17 to notify that the system is normal.

Each of the current limiting resistors 15a to 15d has a resistance value that allows the minimum amount of current to be supplied to check whether the power transistors T _r1 to _{T r4} operate normally, and the current limiting resistors 15 a to 15 d are connected to The flowing current has a sufficiently small value compared to the drive current of the solenoids 12a to 12d.

Next, the operation will be explained.

When the ignition switch is operated or the driver operates the inspection switch, the operation confirmation circuit 13 is activated and a pseudo wheel speed signal corresponding to anti-skid control is applied to each channel of the anti-skid control circuit 11. . If the anti-skid control circuit 11 is normal, the power transistor
A hydraulic control signal (pressure reduction signal) is output to each of T _r1 to T _r4 . At the same time, power relay contact 14 opens to cut off battery power to solenoids 12a-12d.

Power transistor with hydraulic control signal applied
Each of T _r1 to _{T r4} is a current limiting resistor 15a to 15
Since power is supplied by d, it can operate even if the power relay 14 is opened, and if all of the power transistors T _r1 to _{T r4} are turned on normally,
All the inputs of the NOR gate 16 become L level, and the output of the NOR gate 16 becomes H level, turning on the transistor T _r5 and lighting the indicator lamp 17 to inform that the system is normal.

On the other hand, if any of the power transistors T _r1 to T _r4 is malfunctioning, the NOR gate 1 is connected from the malfunctioning power transistor.
The input to 6 remains at H level and the indicator lamp 17 no longer lights up, indicating a system failure.

FIG. 3 shows another embodiment of the present invention,
A portion corresponding to the solenoid drive unit in the embodiment of FIG. 2 is extracted and shown.

This embodiment uses power transistors T _r1 to _{T r4}
This method focuses on the fact that the hydraulic control signal applied to the power transistors T _r1 to _{T r4} does not necessarily cause the power transistors T _r1 to _{T r4} to operate in saturation. 18a to 18d and compare it with the reference voltage _Vr , and when the collector voltage becomes less than the reference voltage _Vr , the L level output of the comparators 18a to 18d is taken out by the NOR gate 16 to inform that the system is normal. This is how it was done.

FIG. 4 shows relays 19a to 19d instead of power transistors T _r1 to _{T r4} in the embodiment of FIG. 3.
This figure shows another embodiment of the present invention using the system, and the operation of the system can be confirmed in this embodiment in the same manner as the embodiment shown in FIG.

FIG. 5 shows another embodiment of the present invention,
The operation confirmation circuit 13 and a circuit section for determining the state of the system are shown in detail, and in this embodiment, a failure in the system is detected and an indicator lamp 17 is turned on.

First, the operation confirmation circuit 13 operates the operation confirmation switch 2 which is linked to the on/off of the ignition switch.
0, an oscillator 21 that starts when the operation confirmation switch 20 is turned on and applies an AC signal or pulse signal of a predetermined frequency to each channel of the anti-skid control circuit 11 via a diode D;
0 is closed, the monostable multi 22 is activated by turning on the transistor T _r6 and produces an L level output for a certain period of time _T1 , and is deenergized by turning off the transistor T _r7 due to the L level output of the monostable multi 22, and the power is turned off. Relay coil 14 opening relay contact 14
Consists of a.

Incidentally, the setting time _T1 of the monostable multi-function switch 22 is set to be sufficiently longer than the ON time of the operation confirmation switch 20. Furthermore, the monostable multifunction device 22 may be activated at the timing when the operation confirmation switch 20 is switched from on to off.

On the other hand, the circuit section for determining the state of the system includes a differentiating circuit 23 consisting of a transistor T _r8 that produces a negative trigger synchronized with the turning off of the operation check switch 20, a capacitor C ₁ , and a resistor R ₁ ; A monostable multi 24 that is activated by a trigger and produces an L level output for a set time _T2 is provided, and the collectors of the power transistors T _r1 to _{T r4} are taken out by an OR gate 25, and the monostable multi 24
It is input to the exclusive OR 26 together with the output of . A timer 27 is provided at the output of the exclusive OR 26, and when the H level output of the exclusive OR 26 continues for a certain period of time _Td , it generates an H level output, sets the RS-FF 28, and sets the RS-FF.
Transistor with H level output by setting 28
T _r5 is turned on and the indicator lamp 17 lights up to notify of a system failure.

Next, refer to the time chart in Figure 6 and proceed to step 5.
The operation of the illustrated embodiment will be explained.

Assuming that the ignition switch is now turned on and off to start the engine, the operation confirmation switch 20 will interlock with the ignition switch and check the time t _1.
It turns on at time t2 and turns off at time _t2 . When the operation check switch 20 is turned on, the oscillator 21 is activated and sends an oscillation signal to each channel of the anti-skid control circuit 11 (sensors 10a to 10) via the diode D.
d), and this oscillation signal is converted by the anti-skid control circuit 11 into a wheel speed signal with a voltage proportional to the oscillation _frequency .
When the output of 1 stops, it creates the same state as the change in wheel speed in actual anti-skid control,
A decompression signal that is lower than the pseudo vehicle speed _Vc by a predetermined value is sent to the power transistor _Tr1 at time _t3 .
A decompression signal is output for T _r4 until time _t4 , when the pseudo vehicle speed _Vc becomes zero.

On the other hand, the time when the operation confirmation switch 20 is turned on
At t ₁ , the transistor T _r6 is also turned on and the monostable multi 22 is activated. L level output by starting the monostable multi 22 is performed for a set time _T1 ,
During this time, the transistor T _r7 is turned off to restore the relay coil 14a, and the power relay contact 14 is opened to cut off the battery power to the solenoid section 12 of the hydraulic actuator, so that the pressure reduction signal does not operate the hydraulic actuator.

Next, to explain the operation when the system works normally, power transistors T _r1 to _{T r4} are turned on by the output of the pressure reduction signal at time t ₃ , all inputs of the OR gate 25 become L level, and the inputs to the exclusive OR 26 are turned on. The output of the OR gate 25 becomes L level.

On the other hand, the monostable multi 24 is activated by the negative trigger pulse of the differentiating circuit ₂₃ generated when the operation confirmation switch 20 is turned off at time _t2 , and the output to the exclusive OR 26 is kept at L level for a set time T2.

Therefore, the input to the exclusive OR 26 becomes (L, L), so its output remains at the L level, and the indicator lamp 17 does not light up, indicating that the system is working normally.

Next, if an abnormality has occurred in the system due to malfunction of any of the power transistors T _r1 to T _r4 , one of the inputs of the OR gate 25 becomes H level, and therefore the input of the exclusive OR 26 becomes (L, H). ), producing an H level output.

Assuming that the output of the exclusive OR 26 continues for more than the set time _Tb of the timer 27, the output of the timer 27 becomes H level after time Tb, and the RS
-FF28 is set and latches the H level output of the timer 27, and when the Q=H level output of RS-FF28 turns on the transistor T _r5 , the display lamp 1
By lighting up 7, a system abnormality is notified.

The above operation is performed using the setting time T ₁ of the monostable multi 22.
and if T ₁ hour passes from time t ₁ ,
The output of the monostable multi 22 returns to H level, and the relay coil 14a is energized to close the power supply relay contact 14 and return to the initial state.

FIG. 7 is a circuit block diagram showing another embodiment of the present invention, in which a current limiting resistor 15 is connected in parallel with the power relay contact 14, and when the power relay contact 14 is opened by an inspection command, the current limiting resistor 15 is connected in parallel with the power relay contact 14. 15 and solenoids 12a to 12d, power is supplied to the power transistors T _r1 to T _r4 for operation confirmation, so that even if the power transistors T _r1 to T _r4 are turned on, the solenoids 12a to 12a are turned on.
The current flowing through 12d is suppressed by the current limiting resistor 15 to below the driving current of the hydraulic actuator.

Note that the same circuit as shown in the embodiment of FIG. 5 is used as the operation check circuit ₁₃ , and the _third
Similar to the embodiment shown in the figure, the comparators 18a to 18d are used to output the discrimination.

FIG. 8 shows another embodiment of the present invention,
The feature is that a current limiting resistor 15 is connected in parallel with the power relay contact 14, and the operation check circuit 13 and system status are determined and the indicator lamp 1 is activated in the event of a failure.
The circuit for lighting 7 is the same as the embodiment shown in _{FIG .} The difference is that the Q output is used.

Next, referring to the time chart in Figure 9,
The operation of the illustrated embodiment will be explained.

First, the operation from time _t1 to _t2 by the operation confirmation switch 20 in conjunction with the on/off of the ignition switch is the same as the operation of the embodiment shown in FIG.

Therefore, if the system operates normally,
When the power transistors T _r1 to T _r4 are turned on by the pressure reduction signal output from time _t3 , the comparators 18a to 18 are turned on.
All outputs of d become L level, and the NOR gate 16
The output becomes H level. At this time, the Q output of the monostable multi 24 is at H level, so the input of the exclusive OR 26 becomes (H, H), giving an L level output to the timer 27, the indicator lamp 17 does not light up, and the system is found to be normal. In addition, between time _t3 and time _t4 , the input of the exclusive OR 26 becomes (H, L) and the timer 27
However, since the time from T ₃ to _{T 4} is less than the set time T ₁ of the timer 27, the timer 27 does not produce an H level output.

Next, if there is an abnormality in the system, the output of the NOR gate 16 remains at the L level, and therefore, from time _t2 , the input to the exclusive OR 26 becomes (H, L), giving an H level output to the timer 27, and setting When time T _b has passed, timer 27 generates an H level output and sets RS-FF 28,
By turning on the transistor T _r5 and lighting up the indicator lamp 17, a system abnormality is notified.

In addition, the embodiment shown in FIGS. 7 and 8 uses power transistors T _r1 to _{T r4} as driving elements of the hydraulic actuator.
However, as shown in the embodiment of FIG. 4, the power transistor T _r1
It is exactly the same even if relays 19a to 19d are used instead of ~T _r4 .

As explained above, according to the present invention, when a command to inspect the system is given, the hydraulic actuator is not operated to prevent no braking, and the system is inspected to see if it is normal. a current supply means for supplying a current smaller than a minimum current value capable of driving the hydraulic actuator to a drive element of the hydraulic actuator when an inspection command is given; actuator operation detection means for detecting whether or not the drive element of the hydraulic actuator is actuated by a current applied from the means; Since we have provided an alarm means that issues an alarm when it is detected that the drive element of the hydraulic actuator has not operated, the hydraulic control signal ( This solves the problem of the hydraulic actuator being activated by the pressure reduction signal and the brakes becoming ineffective, and it is also possible to check the operation of the entire system, including not only the anti-skid control circuit, but also the hydraulic actuator drive circuit. The effect is that the reliability and safety of the system can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a circuit block diagram showing a device already proposed by the inventors of the present invention, Fig. 2 is a circuit block diagram showing an embodiment of the present invention, and Fig. 3 is a comparison for determining the operation of a power transistor. 4 is a circuit diagram showing another embodiment of the present invention using a relay instead of a power transistor, and FIG. 5 is a circuit diagram showing another embodiment of the present invention using a relay in place of a power transistor. A circuit block diagram showing another embodiment of the present invention in which an indicator lamp is lit, FIG. 6 is an operation time chart of the embodiment of FIG. 5, and FIGS. 7 and 8 are other embodiments of the present invention. A circuit block diagram showing an example, and FIG. 9 is an operation time chart of the embodiment of FIG. 8. 1, 13...Operation confirmation circuit, 2, 11...Anti-skid control circuit, 3a-3d, 12a-12
d... Solenoid, 12... Solenoid part, 4,
14...Power relay contact, 5a~5d, 10a~
10d...Wheel speed sensor, 6...And gate,
7, 17...Display lamp, 15, 15a to 15d
...Current limiting resistor, 16...Nor gate, 18a
~18d... Comparator, 19a-19d... Relay, 20... Operation check switch, 21... Oscillator, 22, 24... Monostable multi, 23... Differentiating circuit, 25... OR gate, 26... Exclusive OR, 27...Timer, 28...RS-
FF, T _r1 ~ T _r4 ... power transistor.

Claims (1)

[Claims] 1. When an inspection command is given, the anti-skid control device stops supplying drive current to the pressure reducing hydraulic actuator to check whether the system is normal. Current supply means for supplying a current smaller than a minimum current value capable of driving the hydraulic actuator to the drive element of the actuator, and the drive element of the hydraulic actuator is actuated by the current supplied from the current supply means. an actuator operation detection means for detecting whether the hydraulic actuator is not operated; and an alarm when the actuator operation detection means detects that the drive element of the hydraulic actuator does not operate even if current is applied by the current supply means. 1. An operation confirmation device for an anti-skid control system, characterized in that it is provided with an alarm means for emitting an alarm.