Simple action actuator with a hydraulic fast-opening valve for controlling a clutch

An actuator for the control of a friction clutch in the drive train of a motor vehicle, the actuator comprising:

• a cylinder/piston unit generating a contact pressure for the friction clutch;
• a reversible electric motor/pump unit (3) selectively providing a pressure medium;
• and
• a self-regulating valve unit (2) fluidly coupling the cylinder/piston unit and the reversible electric motor/pump unit such that the friction clutch is controlled by actuating the motor/pump unit (3), the self-regulating valve unit (2) having
• a dump valve (8;8′;28;38) having a sleeve (10;10′) and a slide (12;12′;32) disposed within the sleeve, the sleeve having a first opening (11,11′) and the slide having a second opening, the slide (12;12′;32) being movable between a first position exposing the first opening (11;11′) and permitting pressure medium from the cylinder/piston unit (1) to flow to a sump and a second position aligning the first opening (11;11′) and the second opening and permitting pressure medium from the reversible electric motor/pump to flow to the cylinder/piston unit, the slide being spring biased in to the first position to permit the flow of pressure medium from the cylinder/piston unit to the sump when the reversible electric motor/pump unit is deactivated, the slide being positionable in the second position in response to positive pressure of the pressure medium from the reversible electric motor/pump unit and positionable in the first position in response to negative pressure of the pressure medium from the reversible electric motor/pump unit;
• and
• a nonreturn valve (9;29) disposed within the slide and fluidly coupling the cylinder/piston unit and the reversible electric motor/pump unit, the nonreturn valve being movable between a closed position and an opened position, the nonreturn valve being biased in the closed position, the nonreturn valve permitting flow of pressure medium therethrough only from the reversible electric motor/pump unit (3) to the cylinder/piston unit (1) via the first opening and the second opening in the opened position.

A friction clutch in the drive train of a motor vehicle, the friction clutch comprising:

• a clutch plate;
• and
• an actuator having:
• a cylinder/piston unit generating a contact pressure against the clutch plate;
• a reversible electric motor/pump unit (3) selectively providing a pressure medium;
• and
• a self-regulating valve unit (2) coupling the cylinder/piston unit and the reversible electric motor/pump unit such that the friction clutch is controlled by actuating the motor/pump unit (3), the self-regulating valve unit (2) having
• a dump valve (8;8′;28;38) having a sleeve (10;10′) and a spring-assisted slide (12;12′;32) disposed within the sleeve, the dump valve further having a first opening (11,11′), through which pressure medium from the cylinder/piston unit (1) can flow to a sump, the spring-assisted slide (12;12′;32) being movable between a first position, in which it exposes the opening (11;11′), and a second position, in which it conceals the opening (11;11′), the spring-assisted slide being spring biased in to the first position to permit the flow of pressure medium from the cylinder/piston unit to the sump when the reversible electric motor/pump unit is deactivated, the spring-assisted slide being positionable in the second position in response to positive pressure of the pressure medium from the reversible electric motor/pump unit and positionable in the first position in response to negative pressure of the pressure medium from the reversible electric motor/pump unit;
• and
• a nonreturn valve (9;29) disposed between the reversible electric motor/pump unit (3) and cylinder/piston unit (1), the nonreturn valve permitting a fluid flow to take place only in the direction from the reversible electric motor/pump unit (3) to the cylinder/piston unit (1).