AUTOMATIC TRANSMISSION FOR POWER TOOLS

摘要

An automatic gearshift device for a power tool (11) includes a speed reduction mechanism (18) that decelerates and transmits a rotary power of a motor (16), a ring gear (24) that slides and moves to switch a speed reduction ratio, a cam member (45) that moves the ring gear (24), a rotation body (44) rotated in cooperation with the cam member (45), a position detector (43) that detects the position of the ring gear (24), and a controller (46) that controls the driving of the gearshift motor (27) based on the value generated by the position detector (43). An adjustment gear (42) forming the rotation body (44) includes a slot (42a) used as a positioning mark at a predetermined location in the rotating direction. When the slot (42a) of the adjustment gear (42) is aligned with a predetermined device side positioning reference, the rotation body (44) is positioned in an initial position in a relative positional relationship with the ring gear (24).