Hydraulic actuator for friction clutch - has pressure relief control and valves with pneumatic pressure store to facilitate gradual clutch engagement

摘要

The hydraulic actuator is for a friction clutch (19) and has a control valve (1) including a passage (10) controlled by a pressure relief valve (32) and by a pneumatic pressure store (15). Both absorb undue pressure peaks and facilitate gradual engagement of the clutch. The store returns excess flow to the circuit and the pressure control valve returns excess flow to a tank (18). A single pressure store may be provided for two clutch circuits (11,12) and a two-way valve (13) is provided to close the circuit when not in use.