Patent ID: 9387577
Filing Date: 2016-07-12
CPC Classification: B25B,B25F,F16H

Claim Text:
1. A power tool comprising: a prime mover that is capable of driving a tool bit, and a planetary gear speed reducing mechanism that transmits torque of the prime mover, wherein: the planetary gear speed reducing mechanism includes a driving member which is rotationally driven by the prime mover, a driven member which is rotatably and coaxially disposed with the driving member and to which the tool bit is capable of being coupled, and an intervening member that is disposed between the driving member and the driven member, the intervening member has a contact surface in contact with the driving member and the intervening member is configured as a planetary member and at least caused to rotate by frictional force acting on the contact surface in contact with the driving member when the driving member is rotationally driven, so that torque of the driving member is transmitted to the driven member at reduced speed, a tapered surface of at least one of the driving member or the driven member is inclined with respect to a rotation axis of the driving member, the intervening member is held in frictional contact with the tapered surface, and a pressing force is applied between the intervening member and the tapered surface under loaded conditions, under unloaded conditions, a predetermined preload is constantly applied between the intervening member and the tapered surface, and when the driving member and the driven member are rotationally driven, in addition to the predetermined preload, a pressing force is further applied between the intervening member and the tapered surface.