Patent ID: 8002100

Claim:
A device for actuating a clutch ( 2 ) in a vehicle via one of a pneumatic actuator and a hydraulic actuator, the device comprising: an actuator ( 24 ) having an actuation chamber ( 25 ) and communicating with a diaphragm spring ( 8 ) of the clutch ( 2 ) for actuating the clutch ( 2 ), the diaphragm spring ( 8 ) providing the clutch ( 8 ) with a releasing force (F) that varies over a length of a release stroke (a) wherein the releasing force (F), plotted over the release stroke (a), is a nonlinear curve (k); and a controller ( 40 ) located upstream of the actuator ( 24 ) is connected to the actuator ( 24 ) such that a controller output ( 42 ) generated by the controller ( 40 ) in response to a controller input ( 44 ) the controller ( 40 ) representing a desired displacement of the actuator ( 24 ) displaces the actuator against the releasing force (F) of the diaphragm spring ( 8 ) and a characteristic curve of the controller output ( 42 ), with respect to the controller input ( 44 ), at least approximately overlaps the nonlinear curve of the release force (F) of the diaphragm spring ( 8 ); the controller ( 40 ) includes an inlet valve arrangement ( 26 ) which has at least first and second independently actuatable valves ( 30 , 32 ) of different orifice diameters operating in parallel to provide an actuating pressure to the actuating chamber ( 25 ) of the actuator ( 24 ) and an outlet valve arrangement ( 28 ) includes at least first and second independently actuatable valves ( 34 , 36 ) of different orifice diameters operating in parallel for releasing the actuating pressure from the actuating chamber ( 25 ) of the actuator ( 24 ), and the at least first and the second independently actuatable valves ( 30 , 32 , 34 36 ) of the input valve arrangement ( 26 ) and the output valve arrangement ( 28 ) are actuatable so that a travel amplification resulting therefrom does not change at a switchover point in the nonlinear curve of the release force (F) of the diaphragm spring 8 .