Vacuum limiting valve for motor vehicle's brake servo system breaks connection between servo unit and vacuum pump if set underpressure is achieved, with set underpressure acting upon piston against opening force of spring

摘要

The vacuum limiting valve is installed in the connection between a brake servo unit and vacuum pump, or between the brake servo unit and suction pipe. The vacuum limiting valve breaks the connection if the predetermined underpressure is achieved. The predetermined underpressure acts upon a piston (9) against the opening force of a spring (37). The piston is supported on a membrane (15). The piston has a conical shape and the piston seat represents a flat or conical surface (7) on a support (3) so that a line form seal is created between the piston and seat.