Abstract: A device for transmitting torque between two rotatable, coaxial shaft members (1, 2) in a stationary housing (4) has a clutch (11, 12) engageable to counteract differential rotational speed between the shaft members. A hydraulic clutch piston (14) is arranged to engage the clutch, and a hydraulic pump arrangement (1', 18-21, 11", 14-17), driven by the speed differential between the two shaft members, creates a hydraulic pressure on the clutch piston. The hydraulic pump arrangement includes a supply piston (18) and the clutch piston. Rollers (17, 21) are rotatable with one of the shaft members (2) and engage the other of the shaft members (1) via cams (1', 11"), which are angularly offset in relation to each other, so as to impart to the pistons a reciprocating movement at the differential rotational speed between the shaft members.

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 (15-24) driven by the speed differential between the two shaft members. An annular control piston (15) is axially movably arranged in the housing and is in contact with control pins (17), which are rotatable together with one of the shaft members (3) and cooperate with a cam curve (20) in the other shaft member (2) in such a way that the control pins and thus the control piston are imparted an oscillating movement with a frequency directly proportional to the rotational speed differential between the two shaft members.

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.