Abstract: An electromagnetic actuator is provided at the outer periphery of and out of contact with a casing of a transmission joint for transmitting torque between two shafts. The electromagnetic actuator produces an electromagnetic field within the joint main body when an exciting current is supplied to a solenoid coil of the actuator. A movable magnetic ring is provided in the casing so as to be movable in the axial direction. The ring is moved in the axial direction by receiving an electromagnetic force induced by the field produced by the electromagnetic actuator. A relief valve connected to the ring is moved over an orifice of a pump, and a spring biasing the relief valve is compressed due to such movement, thereby establishing a relief pressure.

Abstract: The rotational speed of a motor is reduced by a worm gear and a worm wheel and the reduced rotation is transferred to a first pinion gear. A first moving plate is moved along a pair of shafts. A second moving plate is provided for the first moving plate by inserting to the same pair of shafts. A first coil spring is interposed between a retaining portion of a shaft inserting hole of the first moving plate of one of the shafts and a retaining portion of a shaft inserting hole of the second moving plate. The first coil spring is compressed by the movement of the first moving plate upon switching to the 4-wheel drive, thereby accumulating the force. A second coil spring is interposed between a retaining portion of the shaft inserting hole of the first moving plate of the other shaft and a retaining portion of the shaft inserting hole of the second moving plate. The second coil spring is compressed by the movement of the first moving plate upon switching to the 2-wheel drive, thereby accumulating the force.