| 摘要 |
The purpose of the present invention is to provide an impact tool capable of performing high torque fastening operation by driving a motor efficiently while limiting temperature increase. An impact tool with a control means for controlling the driving power supplied to a motor using semiconductor switching elements and an impact mechanism for continuously or intermittently driving a tip tool using the rotational force of the motor, wherein during a single operation (period t0 - t9) from when an operator pulls a trigger until release of same, the control means varies the PWM drive signal for driving the semiconductor switching elements to perform control so as to intermittently manifest high duty impacts (62a, 63a ...) resulting from high duty ratio (100%) control between low duty impacts (62b, 62c, 63b, 63c ...) resulting from low duty ratio (80%) control. The control means monitors the motor electric current (80) and when a threshold (11) is exceeded, makes the duty ratio 100% and when a threshold (I2) is subsequently exceeded two times, switches the duty ratio to (80%). |
