To provide a power transmission device capable of obtaining a secure self-lock function at 1 or near of speed reducing ratio, and to provide a winch using the same.

An input shaft 8 and an output shaft 9 are pivotally supported by a case 7 freely to rotate on the same axis, and a bearing hole 19 provided at the center of a swing body 18 is pivotally fitted on an eccentric shaft 11 provided in the output shaft 9. A plurality of engagement holes 22 are provided in one side surface of the swing body 18, and pins 21 to be engaged with each of the engagement holes 22 are provided in the inner surface of an end wall of the case 7 opposite to the engagement holes 22. An eccentric cam 28 is provided in the inner end surface of the input shaft 5, and a bearing hole 23, in which the eccentric cam 28 is to be pivotally fitted, is provided in the other side surface of the swing body 18 opposite to the eccentric cam 28. Sliding resistance between the input shaft 8 and the swing body 18 when relatively rotating is thereby formed larger than sliding resistance between the swing body 18 and the output shaft 9 when relatively rotating.

COPYRIGHT: (C)2006,JPO&NCIPI