| 摘要 |
[Technical Problem] Provided is a motor-driven screwdriver configured such that the upper limit value of transmittable rotational driving force differs between forward and backward rotation. [Solution to Problem] The motor-driven screwdriver has a bit holder (22) and a rotational driving force transmission device (24) for transmitting rotational driving force to the bit holder. The rotational driving force transmission device has a driving member (30), a driven member (40) having through-holes (42), power transmission members (50) held in the through-holes, respectively, and an urging member (60) urging the power transmission members inward. Each through-hole (42) is provided such that a through-hole center axis (46) passing through a center between a forward rotation guide surface (42-1) and backward rotation guide surface (42-2) of the through-hole does not intersect a rotation center axis (32), whereby the force with which the power transmission member is pushed radially outward is made to differ between forward and backward rotation. |
