摘要 |
<p>A hydraulic actuation system for an automated transmission system including, a hydraulic clutch actuator (22) for controlling engagement of a clutch (14), a gear engagement actuator (114,115) for controlling engagement of a gear, said gear engagement actuator (114,115) being in the form of a double acting ram having first and second working chambers (118,119) acting on opposite sides of a piston (116,117), a main control valve (120), the main control valve (120) selectively connecting the clutch actuator (22) and/or the gear engagement actuator (114,115) to an accumulator (275) or to a reservoir (278); a gear engagement control valve (144,146) selectively connecting the first and second working chambers (118,119) of the gear engagement actuator (114,115) to the main control valve (120) or to the reservoir (278); an electrically driven pump (223) being provided to charge the accumulator, the pressure of fluid supplied by the pump being controlled by variation of the current driving the pump (223).</p> |