Abstract: A differential apparatus is disclosed for controlling differential between left- and right-hand axles of a vehicle. A differential mechanism of planetary gear type is received within a differential case. The differential case is provided with a ring gear of the differential mechanism. A first hub is provided with a sun gear of the differential mechanism, and is fixed to one of the axles. A second hub is so provided as to be capable of being rotatable with respect to the first hub, and is fixed to the other axle. The carrier is movable axially relative to the second hub of the differential mechanism and is integrally rotatable together with the second hub of the differential mechanism. A first friction clutch for limiting differential between the carrier and the first hub is engaged by a cam mechanism controlled by a second friction clutch.

Abstract: A power transmission apparatus comprises a device for transmitting power by frictional force between first and second rotary members rotated relative to each other; a device for pressing the power transmitting device in a direction of increasing frictional force; a drive device for driving the pressing device in the direction of increasing frictional force; and a stopper for restricting the movement of the drive device.