Actuator and lubricant supply for a motor vehicle

An actuator for hydraulically actuating a functional part of a motor vehicle, comprising:

• a working piston that is movable in a pressure cylinder of a piston-cylinder unit, which can be acted upon by a hydraulic pressure of a pressure supply and can be moved reciprocally within the pressure cylinder between a first extreme position and a second extreme position;
• wherein two chambers separated from each other by the working piston are provided in the pressure cylinder and a first chamber is formed as a first working chamber with a first pressure inlet,
• wherein a hydraulic pressure applied to the first pressure inlet urges the working piston in a first direction towards the first extreme position in order to enlarge the first working chamber, and
• wherein, for forming an at least unistable working piston, which is automatically attracted in one of the extreme positions when approaching the one of the extreme positions and is held there until a sufficient release force occurs, at least one holding means is provided in the pressure cylinder for automatically fixing the working piston in the one of the extreme positions when reaching this extreme position even without hydraulic pressure being applied.

A hydraulic actuating and lubricant supply system for a motor vehicle for the combined, mechanical actuation of a functional part of the motor vehicle by driving movement of a power transmission element connected directly or indirectly to the functional part and driven by the working piston, and for conveying coolants and/or lubricants for lubricating or cooling components of the motor vehicle, comprising:

• an actuator for hydraulically actuating a functional part of a motor vehicle that includes a working piston that is movable in a pressure cylinder of a piston-cylinder unit, which can be acted upon by a hydraulic pressure of a pressure supply and can be moved reciprocally within the pressure cylinder between a first extreme position and a second extreme position;
• wherein two chambers separated from each other by the working piston are provided in the pressure cylinder and a first chamber is formed as a first working chamber with a first pressure inlet, wherein a hydraulic pressure applied to the first pressure inlet urges the working piston in a first direction towards the first extreme position in order to enlarge the first working chamber, and wherein, for forming an at least unistable working piston, which is automatically attracted in one of the extreme positions when approaching the one of the extreme positions and is held there until a sufficient release force occurs, at least one holding means is provided in the pressure cylinder for automatically fixing the working piston in the one of the extreme positions when reaching this extreme position even without hydraulic pressure being applied;
• and
• a valve, actuatable by a control unit and between the hydraulic fluid outlet and the pressure supply, wherein the valve is controllable such that a switching pressure can be generated in the pressure cylinder by the pressure supply when the valve is closed in order to transfer the working piston into a first position, and the hydraulic fluid outlet is released by opening the valve as soon as the working piston is transferred into the first position.