Brake pressure limiting valve - has front brake circuit monitoring piston which is coupled to pressure limiting piston and maintains pressure to rear brake circuit

摘要

The brake pressure limiting valve housing has an inlet (1) and an outlet (2) union for connection to the rear brake circuit and an inlet (3) to connect to the front brake circuit. The housing contains a sprung sliding piston (4) with a stepped axial bore that forms a shoulder (8) to serve as a valve seat for a spring-loaded ball (9). The latter can be pushed away from the seat by a pressure monitoring piston (22). The two brake inlets (1, 3) are subjected to main cylinder pressure, the monitoring piston (22) moving the pressure limiting piston (4) by means of push rod (18). A pressure increase (1) reverses the limiting piston causing the ball valve (9) to open. Should the front brake pressure fail, the valve is held continuously open to maintain full pressure to the rear brake circuit.