Rotation transmission device

摘要

A mechanical device to be mounted on a four-wheel drive vehicle capable of transmitting driving force to the rear wheels while the vehicle is being accelerated and cutting off the transmission of driving force to the rear wheels while being braked. This device has an inner member to be coupled in series with a differential or a limited slip differential device, and an outer ring. On the opposite surfaces of the inner member and the outer ring are formed a cylindrical surface and a plurality of cam surfaces, between which are defined wedge-shaped spaces. A retainer is provided between the inner member and the outer ring. It is formed with pockets to receive rollers as engaging elements. A turning effort imparting device is coupled to the retainer through a one-way clutch. A torsion coil spring for producing turning effort is mounted between the retainer and the inner member. When the one-way clutch is switched on or off, the direction of turning effort applied to the retainer changes, so that the direction in which the rotation of the retainer delays with respect to the inner member is reversed. The rollers are thus kept in one of the two opposite engageable positions when the inner member is rotating in either direction.