Abstract: A rotational system can include a shaft assembly rotationally coupling a first rotor, a second rotor, and a fluid pump. A fluid circuit can include the fluid pump that can be configured to motivate a working fluid through the fluid circuit. A pressurizing valve can be disposed downstream of the fluid pump wherein the rotational system can be configured to rotationally decouple the first rotor from the second rotor by closing the pressurizing valve. The pressurizing valve can be actuated by a controller. A method can include raising a pressure differential across a fluid pump driven by a shaft assembly thereby applying an increased braking torque to the shaft assembly. The pressure differential can be raised by actuating a valve in hydraulic communication with the fluid pump. The shaft assembly can rotationally couple a first rotor with a second rotor, and increasing the braking torque can decouple the rotors.

Abstract: A manual valve is provided between a mechanical oil pump and a clutch of an automatic transmission device for connecting an engine with the automatic transmission device, a first check valve is provided in a passage connecting the mechanical oil pump with the manual valve, and an electric oil pump is provided in parallel with the mechanical oil pump, wherein the electric oil pump is operated during an idling stop of the engine and an output side of the electric oil pump is connected to the passage between the first check valve and the manual valve so that the working fluid from the electric oil pump is supplied to the clutch of the automatic transmission device through the manual valve. Accordingly, the electric oil pump can be made smaller and the supply of the working fluid from the electric oil pump to the clutch can be prevented when it is not necessary.

Abstract: A drive axle assembly for use in an all-wheel drive vehicle having a first hydraulic coupling operable to automatically transfer drive torque to a secondary driveline in response to slip of the primary driveline and a second hydraulic coupling operable to bias torque and limit slip between the wheels of the secondary driveline.

Abstract: A device for transmitting torque between two rotatable shaft members (2, 3) in a stationary housing (1) contains a number of alternate clutch discs (10, 11) engageable to counteract differential rotational speed between the two shaft members, to which they are connected, a hydraulic clutch piston (12) to engage the clutch discs and a hydraulic pump arrangement (13-22) driven by the speed differential between the two shaft members. An externally controllable pressure-reducing valve (25-27) is provided in the hydraulic connection from the clutch piston to the low pressure side of the pump arrangement, whose high pressure side is connected to the clutch piston.