| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology for accurately and quickly discriminating a no-load state from a load state of a motor to suppress noise and vibration in the no-load state and improving the responsiveness of motor rotation speed when switched from the no-load state to the load state in an electric tool.SOLUTION: An electric tool includes a motor; a tool driven by the motor; and a torque estimating means for estimating load torque acting on the motor from a workpiece through the tool. The torque estimating means estimates load torque reflecting at least driving torque corresponding to a current flowing through the motor and also reflecting inertial torque corresponding to the moment of the inertia of the motor. The electric tool can be selectively switched between a no-load mode and a load mode according to the load torque estimated by the torque estimating means. In the electric tool, the rotation speed of the motor in the no-load mode is lower than the rotation speed of the motor in the load mode. |
