In a hydraulic system with a dog clutch (23-25), a hydraulically operated dog clutch actuator is arranged to alternatively bring the dog clutch into a connect mode or a disconnect mode. The clutch actuator has a piston (27) reciprocally movable under hydraulic pressure between two end positions, corresponding to the two clutch modes. Pressurized hydraulic oil is supplied to the clutch actuator by a hydraulic power system comprising a pump (4) driven by an electric motor (3). Means are provided in the clutch actuator to decrease the hydraulic pressure acting on the piston (27) at the approaching by the piston of either of its end positions, so that a hydraulic signal is transmitted back to the hydraulic power system.

A hydraulic system including a hydraulically actuated clutch, a hydraulically actuated shifting piston, and a pressure source for actuating the clutch as well as the shifting piston. The movement of the shifting piston also controls a valve function which serves to open a connection from the pressure source to the clutch only when the shifting piston has reached one of its end positions.

An oil supply structure for a power unit includes a working oil pump, a lubrication oil pump, an oil storage section, a working oil pressure detection part and a lubrication hydraulic pressure detection part, the oil storage section including a lubrication oil storage chamber in which a suction section of the lubrication oil pump is opened, and a working oil storage chamber in which a suction section of the working oil pump is opened, and oil overflowed from the working oil storage chamber being stored in the lubrication oil storage chamber.

The invention relates to a clutch device for a drivetrain of a motor vehicle, including a pressure plate which is preferably displaceable in the axial direction of the clutch device, wherein the pressure plate, in a coupled position of the clutch device, presses a clutch disk against a counterpressure plate that can be connected to a crankshaft of an internal combustion engine, and including an actuating device which has a displaceable actuating piston. The displacement position of the actuating piston defines a position of the pressure plate and the actuating piston can be driven by a drive unit of the actuating device in order to displace the pressure plate between the coupled position and an uncoupled position. The drive unit has at least one pump, and the at least one pump is accommodated in a pump seat housing and the pump seat housing is connected to the counterpressure plate in such a way as to rotate therewith.

Disclosed is an exemplary hydraulic system including a first fluid circuit and a first pump fluidly connected to the first fluid circuit. The first pump configured to produce a fluid output at a first flow rate when operated at a selected speed. The hydraulic system further includes a second fluid circuit and a second pump selectively fluidly connectable to the first fluid circuit and the second fluid circuit. The second pump configured to produce a fluid output at a second flow rate when operated at the selected speed, with the second flow rate being greater than the first flow rate of the first pump. A first valve fluidly connects the second pump to the first fluid circuit when the first valve is arranged in an open position, and fluidly connects the second pump to second fluid circuit when the first valve is arranged in a closed position.

A hydraulic system for an automatic gearbox for a motor vehicle, includes a high-pressure circuit which includes a pressure accumulator, at least one clutch and actuators, and a low-pressure circuit for cooling the clutch, the high-pressure circuit and the low-pressure circuit each containing a hydraulic cooling pump and a hydraulic charging pump that can be driven by a shared electric motor; and a controller which, when it is detected that the pressure accumulator needs to be charged, controls the electric motor to run at a charging setpoint speed, and/or, when it is detected that cooling is needed or another need exists, controls the electric motor to run at a cooling setpoint speed or another setpoint speed. When the pressure accumulator does not need to be charged and there is no need for cooling and no other need, the controller reduces the setpoint speed to zero for a specified period. At the end of the period the controller controls the electric motor to run at least at the test speed.

The invention relates to a clutch device for a drivetrain of a motor vehicle, including a pressure plate which is preferably displaceable in the axial direction of the clutch device, wherein the pressure plate, in a coupled position of the clutch device, presses a clutch disk against a counterpressure plate that can be connected to a crankshaft of an internal combustion engine, and including an actuating device which has a displaceable actuating piston. The displacement position of the actuating piston defines a position of the pressure plate and the actuating piston can be driven by a drive unit of the actuating device in order to displace the pressure plate between the coupled position and an uncoupled position. The drive unit has at least one pump, and the at least one pump is accommodated in a pump seat housing and the pump seat housing is connected to the counterpressure plate in such a way as to rotate therewith.