Servo brake unit operated by pressure difference

摘要

The servo brake unit has a casing, a diaphragm device dividing the casing cavity into a constant pressure chamber (9) and a variable pressure chamber (11). A valve body (13) passes through the diaphragm device and contains a valve mechanism including a plunger (22) connected to an input rod (27). There is a reaction fitting between the plunger and an output rod (34). The valve mechanism is operable to create a pressure difference across the diaphragm device to transmit its motion to the output rod. Some of the reaction force is transmitted back to the input rod (27) via the reaction fitting and the plunger.