| 摘要 |
The purpose of the present invention is to use a motor with as high an output as possible to complete tightening operations at a high speed while limiting continuous drive output. In a power tool having a plurality of impact operation modes, the motor thereof is controlled at a 100% duty cycle so as to rotate at a high speed in the period between pulling of a trigger and starting of an impact operation (71a-71b), and the duty cycle is changed to a low duty cycle matching the appropriate operation mode after an impact by an impact mechanism is started and a predetermined stroke is performed so that the motor is driven at the low duty cycle until the trigger is returned (arrow 71c-71d). The switching of the duty cycle is performed when the current flowing to the motor exceeds a threshold (I1). |
