Pressure control arrangement for vehicle braking system with antiskid control equipment

摘要

An antiskid control arrangement of a hydraulic vehicle braking system includes a master cylinder device and a throttling valve device arranged between the master cylinder device and the brake pedal. The throttling valve device is incorporated in a circulating circuit which includes a hydraulic pump operated exclusively during antiskid control operation. During normal braking operation without antiskid control action, the braking system operates in a static manner. During antiskid control braking operation, the drive of the hydraulic pump is energized while the throttling valve device remains closed until the dynamic pressure generated by the hydraulic pump has risen to the level to the static pressure then prevailing in the working compartments of the master cylinder device. Thereafter, the throttling valve device opens to relieve excess pressure. The pressurized hydraulic fluid from the auxiliary energy source is fed from the secondary side to the working side of the master piston to operate the wheel brake actuating cylinders in a dynamic manner during the antiskid control operation. An annular positioning piston is provided which becomes effective only during operation in the antiskid control mode as an abutment for the throttling valve so that the brake pedal is brought into a defined position during the antiskid control operation. A shutoff valve which is controlled in response to the movement of the positioning piston is interposed in the return conduit and prevents escape of hydraulic fluid from the master cylinder device when the hydraulic pump is out of operation.