Electric tool
AssigneeHitachi Koki Co., Ltd.
InventorsNobuhiro Takano, Kazutaka Iwata
Life of this patent
Estimating the term…
Abstract
An electric tool includes: a motor configured to be driven by PWM controlling a semiconductor switching element; a trigger configured to adjust startup and rotation of the motor; a changeover switch configured to switch a rotation direction of the motor between a forward rotation and a reverse rotation; a power transmission mechanism configured to rotate a tip tool by the motor, and a controller configured to control rotation of the motor. When the reverse rotation is set by the changeover switch, the controller PWM controls the semiconductor switching element at a high duty ratio after the trigger is pulled to drive the motor, and thereafter drives the motor at a state where the high duty ratio is changed to a low duty ratio.
Claims15
An electric tool comprising:
- a motor configured to be driven by PWM controlling a semiconductor switching element;
- a trigger configured to adjust startup and rotation of the motor;
- a changeover switch configured to switch a rotation direction of the motor between a forward rotation and a reverse rotation;
- a power transmission mechanism configured to rotate a tip tool by the motor, and
- a controller configured to control rotation of the motor,
- wherein the controller PWM controls the semiconductor switching element at a high duty ratio after the trigger is pulled to drive the motor, and thereafter drives the motor at a state where the high duty ratio is changed to a low duty ratio.
An electric tool comprising:
- a motor configured to be driven by PWM controlling a semiconductor switching element;
- a trigger configured to adjust startup and rotation of the motor;
- a changeover switch configured to switch a rotation direction of the motor between a forward rotation and a reverse rotation;
- a power transmission mechanism configured to rotate a tip tool by the motor, and
- a controller configured to control rotation of the motor,
- wherein the controller PWM controls the semiconductor switching element at a duty ratio higher than a duty ratio when the forward rotation is set, thereby rotating the motor in the reverse rotation.
An electric tool comprising:
- a motor;
- a trigger configured to adjust startup and rotation of the motor;
- a changeover switch configured to switch a rotation direction of the motor between a forward rotation and a reverse rotation;
- a power transmission mechanism configured to rotate a tip tool by the motor, and
- a controller configured to control rotation of the motor,
- wherein the controller drives the motor at a high-speed mode after the trigger is pulled and thereafter drives the motor at a state where a rotating property of the motor is switched from the high-speed mode to a low-speed mode.
An electric tool comprising:
- a motor;
- a trigger configured to adjust startup and rotation of the motor;
- a changeover switch configured to switch a rotation direction of the motor between a forward rotation and a reverse rotation;
- a power transmission mechanism configured to rotate a tip tool by the motor;
- and
- a controller configured to control rotation of the motor,
- wherein the controller rotates the motor in a reverse direction, and lowers a duty ratio of PWM control of the motor or switches a rotating property of the motor from a high-speed mode to a low-speed mode during the reverse rotation.
Dependencies are inferred from the claim text.