| 摘要 |
<P>PROBLEM TO BE SOLVED: To transmit fixed turning force without abrasion of parts in simple structure for applying the rotational driving force larger in loosening a screw than that in thread fastening to a driver bit in a turning force transmitting means of a motor-driven screw driver. <P>SOLUTION: This motor-driven screw driver includes: a rotary input member 106 driven to rotate by a driving motor; a driving roller 108 to which the rotational driving force is transmitted; a rotary output member 10 connected to a bit holder to be driven to rotate; and a driven ball 112 held on the rotary output shaft and engaged with the driving roller 108 to transmit the rotational driving force to the rotary output shaft. The driving roller 108 is displaced to a rotary input member 106 depending on the normal rotation of the rotary driven input member round the central axis of rotation and the reversion, and engaged with the driven ball 112 at different points, thereby varying the rotational driving force transmitted from the rotary input member 106 through the driving roller, and the driven roller to the rotary output member 110. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
