JPS63159172A - Antiskid device for automobile - Google Patents

Abstract

PURPOSE:To improve safety of an antiskid device, by a method wherein when it is decided by a control unit that abnormality occurs, the circuit on the power source side and the circuit on the earth side of a fail safe relay are simultaneously disconnected, and the relay contact of the relay is switched into an OFF-state to hold it. CONSTITUTION:When abnormality occurs, both the power source side A and the earth side B of a coil 11 of a fail safe relay 1 are simultaneously disconnected to accurately bring a relay contact 12 of the relay 1 into an OFF-state. Through the stop of an antiskid control, a brake is reliably switched to an ordinary state where a brake liquid pressure is fed from a master cylinder directly to a brake device for each wheel. Simultaneously, by turning OFF a circuit F on the earth side of a coil 21 of a motor relay 2 with the aid of a control unit 3, a circuit E on the power source side and a circuit F on the earth side of the coil 21 of the motor relay 2 are both disconnected, a relay contact 22 of the motor relay 2 is reliably held in an OFF-state, and a motor 4 is prevented from being left running.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an anti-skid device for a motor vehicle.

Conventional technology In a hydraulic brake system for automobiles, when braking is performed by depressing the brake pedal and hydraulic pressure is supplied from the master cylinder to the brake system of each wheel, the brake system detects the rate and amount of decrease in wheel speed relative to the vehicle body speed. The brake fluid pressure supplied to the device is alternately reduced and increased by operating various solenoid valves and actuators such as electric motors to prevent wheels from locking and provide effective braking. Various types of anti-skid devices have been developed in the past, and have been disclosed, for example, in Japanese Unexamined Patent Publication No. 128053/1983.

In the above-mentioned anti-skid device, for example, there is an abnormality such as a short circuit or disconnection in the wheel speed sensor that detects the wheel speed and inputs the wheel speed signal to the control unit, or in various circuits connected to the control unit. The above control unit has a self-diagnosis function that can detect when an abnormality occurs, and when it self-diagnoses that an abnormality has occurred, it turns off the fail-safe relay and motor relay, stops anti-skid control, and activates the anti-skid device. It is necessary to equip a general braking system which does not have a fail-safe device, that is, a system in which braking fluid pressure is directly supplied from a master cylinder to a wheel braking device.

Problems to be Solved by the Invention However, the fail-safe device installed in the conventional anti-skid device is equipped with a switching element in the ground side circuit of each coil of the fail-safe relay and motor relay, and when self-diagnosing an abnormality, Since it is common practice to turn off the switching element and turn off each relay contact of the fail-safe relay and motor relay, the coils of the fail-safe relay and motor relay reach their respective switching elements. If there is a short circuit in the circuit between them, the power to the coil will not be cut off even if the switching element is turned off, and the relay load will not be bypassed even if a protective circuit such as a fuse is installed upstream of the relay. In such a case, the power will continue to be supplied to the relay coil without disconnection, and the relay contact will remain made, making it impossible to stop the anti-skid control or causing the motor to stop spinning. There is no other option than for the driver to turn off the ignition key switch, but if the driver is late in noticing such an accident, the motor may burn out, which is extremely inconvenient.

The present invention aims to address the problems of the conventional devices as described above.

Means for Solving the Problems The present invention provides an anti-skid device for an automobile equipped with a fail-safe device consisting of a fail-safe relay and a motor relay. The side circuit and the ground side circuit are simultaneously disconnected, and the relay contact of the fail-safe relay is switched and held in the OFF state,
The coil of the motor relay is connected to the power supply via the relay contact of the fail-safe relay, and is also connected to ground via a switch that is controlled on and off by the control unit, and the control unit malfunctions as described above. The present invention is characterized in that the switch means is turned off and the relay contact of the motor relay is held in the off state when it is determined that the motor relay has occurred.

As a result of the above, when an abnormality occurs, the coil of the fail-safe relay is disconnected on both the power supply side and the ground side at the same time, turning off the relay contact of the fail-safe relay accurately, stopping the anti-skid control, and restarting the master. At the same time, the control unit turns off the ground side circuit of the motor relay coil, thereby ensuring that the brake fluid pressure is directly supplied from the cylinder to the brake equipment of each wheel. Both the power supply side circuit and the ground side circuit are disconnected, and the relay contact of the motor relay is reliably held in the OFF state, thereby preventing an accident in which the motor does not rotate.

Example Embodiments of the present invention will be described below with reference to both figures.

In the figure, 1 is a fail-safe relay, 2 is a motor relay, and 3 is an anti-skid control unit. In the 1J, M control unit 3, when the brake pedal is depressed, braking fluid pressure is supplied from the master cylinder to the brake equipment of each wheel. During braking, the operation is started by a signal from a brake pedal switch that detects the depression of the brake pedal, and a signal is sent to a modulator (not shown) from the wheel speed signal of the wheel speed sensor 5, and when the wheel speed decreases to a certain extent, the brake system starts operating. A solenoid valve (not shown) (pressurizing and depressurizing It controls the energization of the anti-skid motor 4 and the anti-skid motor 4. Since these anti-skid controls are the same as those conventionally known, illustration and detailed explanation beyond the above will be omitted.

The control unit 3 that performs anti-skid control as described above has a self-diagnosis function that checks for abnormalities such as disconnections or short circuits in various devices and connected circuits of the anti-skid device (this self-diagnosis function also has a conventional self-diagnosis function). Since this is well known, detailed explanation will be omitted), when a disconnection or short circuit occurs, the power supply to the coil 11 of the fail-safe relay 1 is cut off, the relay contact 12 is turned off, and the power supply circuit of the modulator is cut off. , the power supply to the coil 21 of the motor relay 2 is cut off, the relay contact 22 of the motor relay 2 is turned off, and the power supply circuit of the motor 4 is cut off, thereby stopping the anti-skid control and applying the brakes to each axle directly from the master cylinder. A state is set in which brake fluid pressure is supplied to the device (hereinafter referred to as a normal brake state).

In the above, in the present invention, when the control unit 3 determines that there is an abnormality in the self-diagnosis, the control unit 3 switches the energization circuit of the coil 11 of the fail-safe relay 1 to both the power supply side circuit A and the earth side circuit B. At the same time, the energizing circuit of the coil 21 of the motor relay 2 is configured so that its ground side circuit F is disconnected by the control unit 3, and the power supply side circuit E of the coil 22 of the motor relay 2 is configured to be disconnected. The relay contact 12 of the fail-safe relay 1 is connected to a power source e through a circuit C.

That is, when the anti-skid device is normal, the energizing circuit of the coil 11 of the fail-safe relay 1 is conductive on both the power supply side A and the earth side B, the relay contact 12 is kept on, and the circuit C and relay are connected from the power supply e. Contact point 12. The circuit that passes through the circuit and reaches the modulator is closed, and as mentioned above, the solenoid valves for pressurization and pressure reduction operate in the correct order according to the signal from the control unit 3, and the circuit from the power supply e to the circuit c and the fail-safe relay 1
Relay contact 12, circuit E, coil 2 of motor relay 2
1゜The circuit for energizing the coil 21 of the motor relay 2 that passes through the circuit F and connects to the ground is controlled to turn on and off the ground side circuit F by the control unit 3, and is connected to the circuit H from the power supply e.
, relay contact 22 of motor relay 2. The circuit that passes through the motor 4 and connects to the ground is controlled on and off, and the braking fluid pressure of the brake device is repeatedly controlled to be reduced and increased in pressure as described above.

When the control unit 3 determines that there is an abnormality based on its self-diagnosis function, the energizing circuit of the coil 11 of the fail-safe relay 1 is cut off on both the power supply side A and the earth side B, and the relay contact 12 of the fail-safe relay 1 is switched and maintained in the OFF state. At the same time, the ground side F of the current-carrying circuit of the coil 21 of the motor relay 2 is turned off, and the relay contact 22 of the motor relay 2 is held in the OFF state, thereby switching the braking system to the normal braking state.

In this case, the power supply side A and the ground side B of the coil 11 of the fail-safe relay 1 are both disconnected, so even if any part of the energizing circuit to the coil 11 is short-circuited, the coil 11 is completely energized. , the contact 12 of the fail-safe relay 1 is reliably switched and maintained in the OFF state, and the anti-skid control is stopped and the switching to the normal braking state is accurately performed. is reliably held in the OFF state, the energizing circuit of the coil 21 of the motor relay 2 is connected to the power supply side E.
The power supply to the coil 21 is completely cut off no matter where the power is grounded, and the relay contact 22 of the motor relay 2 is reliably held in the OFF state, and the motor 4 Accidents that cause the car to spin will no longer occur.

Effects of the Invention As described above, according to the present invention, in a fail-safe device for an anti-skid device, an abnormality such as a disconnection or short circuit can be prevented in the anti-skid control system by using only an extremely simple circuit configuration without adding a new relay or the like. When an abnormality occurs, it is possible to reliably stop anti-skid control and accurately switch to the normal braking state, which not only improves the safety of the anti-skid device, but also allows the ignition key switch to be turned off without having to turn off the ignition key switch when an abnormality occurs. The ability to run continuously and the fact that there is no power consumption when an abnormality occurs and the battery can be prevented from running out of power can bring great practical benefits.

[Brief explanation of the drawing]

Both figures are circuit explanatory diagrams showing one embodiment of the present invention. l... Fail safe relay, 2... Motor relay, 3... Control unit, 4... Motor. that's all

Claims (1)

[Claims] When an abnormality such as a disconnection or short circuit occurs in the anti-skid control system, the control unit turns off the fail-safe relay and the motor relay to stop anti-skid control, and directly supplies brake fluid from the master cylinder to the brake equipment of each wheel. In the anti-skid device of a car equipped with a fail-safe device that switches and maintains the state in which pressure is supplied, the circuit that energizes the coil of the fail-safe relay is switched between the power supply side circuit and the ground side circuit when the control unit determines that an abnormality has occurred. The coil of the motor relay is connected to the power supply via the relay contact of the fail-safe relay, and the control unit switches the relay contact of the fail-safe relay to the OFF state. The motor relay is connected to ground through a switch means that is controlled to turn on and off, and when the control unit determines that an abnormality has occurred, the switch means is turned off and the relay contact of the motor relay is held in the off state. Automobile anti-skid device.