Pneumatic brake booster with relay valve in the booster-cylinder-end

摘要

A pneumatic-hydraulic booster for vehicles includes a master cylinder part; a pneumatic cylinder part combined with the master cylinder part including a power piston slidably fitted to a cylindrical casing and an output rod fixed to the power piston, extending to the master cylinder part; a partition wall body fitted to the cylindrical casing; and a relay valve part being arranged at the opposite side of the partition wall body to the power piston in the cylindrical casing. The relay valve supplies compressed air into an air pressure chamber formed between the partition wall body and the power piston and discharges the compressed air from the air pressure chamber to the atmosphere. When compressed air is supplied into the air pressure chamber through the relay valve part, the power piston and the output rod are moved forwards to generate hydraulic pressure in the master cylinder part. The hydraulic pressure is applied to a wheel cylinder.