Anti-skid brake control system for vehicles including a hydraulic braking circuit and anti-skid actuator driven by pump powered hydraulic pressure for controlling the braking pressure in response to an electric signal indicating a wheel rotational condition. The actuator includes a cut off valve for ON-OFF controlling of the braking circuit, a hydraulic pressure reducing piston operatively connected to the cut off valve for reducing the hydraulic brake pressure of the circuit, and an electro-magnetic valve which is actuated to change over the pump powered hydraulic pressure in response to the skid sensing signal whereby, the actuator includes a further electro-magnetic valve which is to be actuated as a safety valve in case the skid sensing signal is generated for an extended period of time such that the normal braking operation might be in danger of a no-braking condition.
An anti-skid brake control system includes an actuator device having cut-off valve means provided in braking circuits between a master cylinder and wheel brake cylinders. A normally closed leak oil flow-preventing valve assembly is disposed between a reservoir and a spool valve type control device for controlling the hydraulic pressure applied to the actuator device. By said valve assembly, the pressure oil leaked from the control valve device during non-braking operation is prevented from flowing into the reservoir. During a braking operation, the leak oil flow-preventing valve assembly is opened due to the booster pressure or the braking pressure transmitted from the master cylinder. As a result, communication between the control valve device and the reservoir is rendered effective.
A vehicular skid control system for relieving the brake pressure when an incipient skid condition is sensed. A regulator is provided in a circuit connecting a source of ancillary fluid with an expansion chamber, positioned between a check and bleed valve and wheel brakes, for maintaining at least a predetermined pressure in the circuit. The pressure maintained by the regulator is dependent upon the pressure in the brake circuit.
A vehicular skid control system for relieving the brake pressure when an incipient skid condition is sensed. The system includes a combined check and bleed valve between the master cylinder and rear wheel brakes, a modulator assembly actuable by a ancillary source of fluid pressure, a fal safe bypass valve for communicating unmodulated master cylinder pressure directly to the rear brakes upon failure of the ancillary pressure source, and a regulator provided in the circuit connecting the source of ancillary fluid with the expansion chamber for maintaining at least a predetermind pressure in the circuit. Certain of the elements of the system may be automatically cycled each time the vehicle engine is started and stopped.
