Arrangement for controlling the pressure in brake actuating cylinders of

Abstract

An arrangement for controlling the pressure in brake actuating cylinders incorporated in a hydraulic vehicle braking system which is supplied with auxiliary energy includes a master cylinder device having at least one master piston accommodated in a bore communicating with a replenishment chamber. A brake pedal actuated control valve device is arranged between the master cylinder device and the brake pedal and controls the supply of auxiliary energy from an auxiliary energy supply source through a hydraulic conduit to the replenishment chamber. Electromagnetically actuatable control valves are included in the braking circuit and locking of the wheels by controlling the operation of the wheel brake actuating cylinders. Furthermore, there is provided a return conduit to a hydraulic reservoir which incorporates a normally open hydraulic shutoff valve which closes when the pressure of the auxiliary energy drops below a predetermined threshold value. An electromagnetically actuatable normally closed valve is interposed in the hydraulic conduit, being opened when there is a need for antiskid control action. Another valve connects the replenishment chamber with the reservoir when the brake pedal is in its rest position, while discontinuing such communication during the antiskid control action. Thus, pressure in the replenishment chamber is relieved during normal braking operation and rises up to that of the auxiliary pressure source during antiskid control operation. All of the valves which are hydraulically actuatable in dependence on the pressure of the auxiliary energy can be structurally incorporated in a valve unit.