| 摘要 |
PROBLEM TO BE SOLVED: To provide a thread fastening device capable of achieving a highly accurate thread fastening using a stepping motor.SOLUTION: A thread fastening device includes a bit 10 for being fitted to a screw, a stepping motor 11 for imparting power to rotate the bit 10, a driving circuit 12 for driving the stepping motor 11 by an input PWM (Pulse Width Modulation) signal, and a control circuit 14 for calculating torque of the stepping motor 11 from a current value detected in the driving circuit 12, determining a thread fastening state using the calculated torque and continuing or interrupting the input of the PWM signal into the driving circuit 12 according to the determined state. |
