Patent ID: 7370741

Claim:
A rotation-transmission unit with built-in roller clutch for starting an engine for transmitting power in a specified direction between a rotating member which rotates together with a crankshaft of an engine during use and the rotating shaft of the motor for starting the engine which is inserted into the center of the rotating member to rotate in the specified direction during use, the rotation-transmission unit comprising a pair of support bearings provided in a circular space between the inner peripheral surface of the rotating member and the outer peripheral surface of the rotating shaft and spaced apart from each other in the axial direction, a roller clutch provided between the support bearings in the circular space, the roller clutch becoming engaged when the rotating shaft rotates in the specified direction to transmit power from the rotating shaft to the rotating member, and becoming idling when the rotating member rotates faster than the rotating shaft in the specified direction so as not to transmit power from the rotating member to the rotating shaft, and seal rings being provided on the opposite ends of the support bearings, such that the seal ring on the outer side opposite to the roller clutch is of the contact type while the seal ring on the inner side near the roller clutch is of the non-contact type.