A power transmission device includes a pulley (4) and a hub (11) that are arranged on the same rotation axis, and a connecting member (13) that connects these rotation bodies. The power transmission device includes a first connecting structure (14) that co...

There is provided a compact one-way clutch unit that can perform connection and disconnection of power in two systems. An end portion on a side of a deep groove ball bearing portion 65 of a second one-way clutch 2 is disposed in an annular recess 67, which...

There is provided a one-way clutch unit that is simple in structure and compact. An annular recess 67 is provided in an inner periphery of a side of a deep groove ball bearing portion 55 of a first inner ring 7 of a first one-way clutch 1, and an end porti...