JPS588450A - Fail safe device of anti-skid control system - Google Patents

Abstract

PURPOSE:To improve safety and reliability of a system, by returning control to normal brake operation through a fail safe circuit, when an anti-skid control system causes a fault, and interposing and inspection device in said fail safe circuit. CONSTITUTION:If abnormality in a system is detected, a fault detector circuit 4 opens a relay contact 5 to perform return operation to a normal brake. An inspection device A is interposed in a system 12, and for its inspection, if a relay contact 5 is in a fault when a switch 7 is closed, the contact 5 is left as closed, and an EX-OR10 generates output of an H level when a transistor Tr5 is turned off through transistors Tr6, Tr4, after a prescribed time, a control circuit 11 sets a RS-FF12 to turn on a transistor Tr7 with output of Q=H level and turn on a fault lamp 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention makes it possible to know in advance whether or not the operation of the fail-safe circuit is normal or not, when an abnormality in the system is detected, the hydraulic actuator is stopped from operating and the fail-safe circuit is returned to the normal braking system. This article relates to the failure mechanism of the anti-skid control system.

Conventionally, in this type of anti-skid control system, for example, as shown in FIG. A circuit 4 is provided, and when a system failure is detected, the transistor T
The power supply to the drive circuit of the hydraulic actuator equipped with the solenoids 3a to 3c driven by ri to Tr3 is cut off by opening the relay image point 50 to prohibit the operation of the hydraulic actuator and return to normal braking. A failsafe is implemented.

Therefore, even if a failure occurs in any of the sensors 1 to lc or if the anti-skid control circuit 2 fails to output a pressure reduction signal, the brakes will automatically return to normal braking, ensuring sufficient safety. gender is ensured.

By the way, in the above device, as a means of prohibiting the operation of the hydraulic actuator in the event of a failure, the relay coil is energized to open (relay contact 5 as a normally closed contact). The relay coil connected to the failure detection circuit 4Ke is energized by power supply such as when the ignition switch is turned on, and the relay coil is closed.

Therefore, during long-term use of K, if the relay coil is disconnected or short-circuited, the relay contact 5 will not close and remain open even when the ignition switch is turned on, causing the hydraulic pressure to drop during braking. 9 or the actuator did not operate.

It is conceivable that the transistor for energizing the relay coil may be short-circuited, and even if a failure is detected, the relay contact 5 will not open and the brake will not return to normal braking mode.

Therefore, during periodic inspection, the operation of relay contact 5 should be
ll! ! It is necessary to thoroughly check that the relay contact 5 is opened and closed reliably.

However, in the unlikely event that a relay contact malfunctions during use, it is unclear whether the relay contact is working properly or not, and the relay contact remains open even if there is no abnormality in the system.

9. Anti-skid control is not performed and normal braking is applied. Furthermore, if the relay contact remains closed, there is a risk that the brake will not return to normal braking even if an abnormality in the system is detected and an alarm is output.

The present invention has been made in view of the above, and includes a fail-safe device that prevents the hydraulic actuator from operating and returns the brake system to the normal brake system when a system failure is detected. In order to be able to know in advance whether or not the hydraulic actuator is normal, the above-mentioned device is activated in response to an inspection command to detect the operation of the power cutoff switch of the hydraulic actuator, and to issue an alarm in the event of an abnormality.

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

@2 Figure 7 shows an actual example of the present invention, and 7 is a circuit block diagram.

First, to explain the configuration, 18 to lb are sensors that detect wheel speed, and wheel speed signals from 2Fi sensors 1a to 1b, for example, a hydraulic control signal that allows maximum braking efficiency to be obtained based on the angular velocity signal during braking. Solenoids for solenoid valves of hydraulic actuators are energized by power transistors Tri to Tr3, which are turned on and off by hydraulic control signals 3a to 36, respectively.

A failure detection circuit that detects and outputs abnormalities in the 4-way system, such as sensor disconnection and depressurization signals, outputs voltage +V from the 5-wire battery to solenoid 3 when the system is normal.
It is a relay contact and a 6Fi fuse that applies voltage to a to 30.

At the output of the failure detection circuit 4, a large transistor Tr5 is provided, the collector of which is a relay coil 9 for which a transistor Tr5 opens and closes a relay contact, and when the system is normal,
The output of failure detection M4 is at H level, turning on transistor Tr5, and energizing relay coil 9 to close relay contact 5.

On the other hand, as a means for opening and closing the relay contact 5 for inspection,
It is activated by a trigger pulse caused by switching on the switch 7, which is turned on by the ignition switch, driving operation, handbrake release operation, etc., and the differentiator circuit consisting of the resistor R1 and the capacitor C3, and outputs a pulse with a constant pulse width. A circuit consisting of a monostable multi 8 and a transistor Tr4 which is turned on by the output of the monostable multi 8 and turns off the transistor Tr 15 is provided.

In addition, as a means for checking whether the relay contact 5 is opened or closed by turning on the switch 70, the relay contact 5
Exclusive OR (hereinafter referred to as 1'
(referred to as -EX-ORJ) 10. A j54H path is provided which has a transistor Trγ that causes the H level output of FiX-ORIO to connect to the relay contact 5 and light up the alarm lamp 13. Next, manufacture is carried out! When the system performing 2#4 is normal, the output of the failure detection circuit 4 is H.
level, the relay coil 9 is energized by turning on the transistor Tri, the relay contact 5 is closed, and the hydraulic actuator solenoids 3a to 3c [battery voltage +vl
and is ready for skid control at any time.

On the other hand, when a system abnormality is detected, the failure detection circuit 4
When the output becomes L level, the transistor Tr5 is turned off, the relay coil 9 is deenergized, and the relay contact st is opened to cut off the electric wires to the solenoids 3a to 3c and return to normal braking.

Next, the inspection operation of the relay contacts will be explained.

Switch 7 is activated in conjunction with the operation force of the ignition switch.
When closed, the monostable multi 8 outputs a pulse with a predetermined time width, turns on the transistor Tr4, grounds the pace of the transistor Tr5 and turns it off, and deenergizes the relay coil 9, which remains closed until then. Open relay contact 5. Monostable! When the pulse signal from multi-channel 8 disappears, relay contact 5 closes again.

If this rounding and relay contact 5 are normal, switch 70
When turned on, relay contact 5 changes from (closed) → (II) → (closed)
It works.

In this way, when the relay contact 5 operates, the changes in the collector potentials of the transistors Tri and Tr6 are (L) → (H) → CL), respectively, in terms of logic levels, and in either state, the change in the collector potential of the transistors Tri and Tr6 is as follows: Since the input is (HlH) or (L, L), the output of EX-ORIO is at L level and the failure lamp 1lti does not light up.

On the other hand, if the 17-relay contact 5 is out of order due to damage to the relay contact 5, disconnection or short circuit of the relay coil 9, etc.
Even if the switch 7 is closed, the relay contact 5 remains closed, so the collector output of the transistor Tr6 is L level tt, and when the transistor Tr4 is turned on and the transistor Tr5 is turned off, the input of EX-ORIO is becomes (H, L) and produces an H level output, and the time limit circuit 11 sets R8-FF12 after a predetermined time to memorize the failure, and turns on the transistor Tr7 with the Q=H level output of R8-FF12. , the failure lamp 13 is lit to warn the driver of malfunction of the relay contact.

3atJFi This shows another embodiment of the circuit section A in the embodiment shown in FIG. .

In other words, the integral 11 is made up of the resistor Re and capacitor C3, which are charged at a predetermined time constant when the circuit power is turned on.
When the charging voltage of the capacitor Ct exceeds the reference voltage Vr, the comparator 14 generates an H level output, and the AND gate 15 receives an H level output (normally) from the failure detection circuit 4. The relay coil 9 is energized by turning on the transistor 71'r5 by setting the transistor 71'r5 to a permissible state.

Its action is such that the relay coil 9 is not energized and the relay contact 5 is opened from the time the power is turned on until the comparator 14 produces an H level output. If so,
Figure 4 shows another embodiment of the circuit A shown in the embodiment of Figure 2, in which a fault lamp is turned on to notify the user of the fault. 7 starts the oscillator 16, and at the same time starts the monostable multi 17 to output an oscillation pulse with a predetermined time width, and inputs the output of the monostable multi 17 inverted to the anti-gear 18 for fault detection. While inhibiting the H level signal from the circuit 4, the controller 191 is allowed, and the transistor TrS is turned on by the oscillation pulse from the oscillator 16.
When the relay coil 9 is activated, the relay contact 50 is repeatedly turned on and off to check whether it is operating normally.

According to this embodiment, the relay contact is opened or closed at t
In addition to checking for failures such as tK, it is also possible to check whether or not the relay contacts open and close following the oscillation pulse.

FIG. 5 is a circuit pull diagram showing another embodiment of the present invention. This embodiment is characterized by being able to easily determine the movement of relay contacts that open and close according to inspection commands. 1. That is, battery voltage + Vm'f: Solenoid 31
A switching contact 20 is provided as a relay contact for applying voltage to 3C, and a lamp 13' is connected to the contact side of the switching contact 20 so as to be grounded.Transistors Tr6 and EX- used in the embodiment of FIG. At the time of OR10, lli#li path 11, R8-FFI 2, and transistor Tr7 are removed. Since the other configurations are the same as those of the embodiment shown in FIG. 2, the description thereof will be omitted by adding a -1 symbol.

The operation of this embodiment is such that when a check is commanded by closing the switch 7, the relay coil 9 is deenergized and the switching contact 20, which was closed at a@, switches to bliil, and the battery voltage increases.
While Vl is applied to the lamp 13' through the switching contact 20 and the monostable multi 8 is output, the 2 lamp 1 lights up.

Therefore, if the lamp 13' lights up during the check, turn it off.
If the system operates normally at point 20Fi, a fail-safe operation is confirmed in which when a system failure is detected, the operation of the 1 hydraulic actuator is prohibited and the brake is returned to normal braking.

In this embodiment, if the lamp 13' does not light up even if the switching contact 20 operates normally, it can also be checked that the fuse 6 is disconnected or the power terminal is disconnected.

FIG. 6 shows another embodiment of the circuit section B in FIG.
The lamp 13' is connected by applying one voltage +E to the power line @ to the solenoids 38 to 3c.

In this embodiment, as in the embodiment shown in FIG. 5, when the switching contact 20 switches b@<<, the lamp 1g lights up, indicating that the switching contact 20 is operating normally.

FIG. 7 shows another embodiment of the circuit section B in FIG. 5, in which a relay contact 5 is used instead of the switching contact, and when the relay contact 5 is closed, the battery voltage +Vl is applied to the transistor. When Tr8 is turned on, the transistor Tr
When the relay contact 5 fails to open, the transistor Tr8 is turned off and the transistor Tr9 is turned on, thereby turning on the lamp 13'. This l! Similarly to the embodiment shown in FIG. 5, this embodiment also includes a solenoid 3 in addition to the relay contact 5.
It is possible to check for breakage of the power line or fuse 6 at 1 to 3cj, or disconnection of the power terminal.

In each of the embodiments described above, when a system failure is detected by the failure detection circuit 4, the failure lamp 13 or the lamp 13' is turned on by opening the relay contact 5 or switching the switching contact 20 to the b side. will light up, so
The fault lamp 13 or lamp 13 can be worn as a system fault indicator light.

As explained above, according to this book, the configuration is such that when a system failure is detected, the hydraulic attuator is prevented from operating and the system is restored to the normal brake system by issuing an inspection command. In order to activate the above-mentioned device and to issue a warning when the system does not return to normal during play, the relay contact of the power supply line, which is designed to prohibit the operation of the hydraulic actuator, closes or closes. Since it is possible to detect a failure of the fail-safe circuit such as 11 being opened and notify the driver before braking, it is possible to take sufficient countermeasures and improve the safety of the system. The effect is that the reliability can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of an anti-skid control system equipped with a conventional fill-safe device; the second factor is a circuit block diagram showing an embodiment of the present invention; FIGS. 3 and 4 #i! 2 is a circuit diagram showing another embodiment of the circuit section A, and FIG. 5 is another embodiment of the present invention. FIG. 6.7 is a circuit block diagram showing another embodiment of the circuit section B in the iris diagram. 1a-1c...Sensor 2...Anti-skid control circuit 31-3c...Solenoid 4...Failure detection circuit 5...Relay contact 6...Fuse 7.
・Switch 8.17 ・Monostable multi 9・
・・Relay coil 10・・Exclusive OR (EX-OR) 11・
...Time limit circuit 12...B5-FF13...Failure lamp 1...Lamp 14...Comparator 15, 18, 19...Angel) 16...Oscillator 20...Switching contact patent Applicant Nissan Motor Co., Ltd.

Claims (1)

[Claims] When a failure of the anti-skid control system is detected,
In a fail-safe device that prevents the hydraulic actuator from operating and returns it to the normal brake system, an output means outputs an operating signal to the above-mentioned device when an inspection command is issued, and an operating signal output from the # output means. An anti-skid control system, characterized in that it has an alarm means for detecting operation of a power cutoff switch of a hydraulic actuator by activating the electric generator, and issuing a K11P alarm in the event of an abnormality.