Electric tool
AssigneeKoki Holdings 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.
Claims11
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 in a state where the reverse rotation is set by the changeover switch,
- the controller controls a duty ratio of the PWM control of the semiconductor switching element according to an operating amount of the trigger to drive the motor in a case that the operating amount of the trigger is less than a predetermined amount, and
- the controller controls the semiconductor switching element at a high duty ratio to drive the motor in a case that the operating amount of the trigger is the predetermined amount or larger, and thereafter the controller restricts the duty ratio of the PWM control of the semiconductor switching element when the controller detects a predetermined state.
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 power transmission mechanism configured to rotate a tip tool by the motor;
- a controller configured to control rotation of the motor;
- and
- a current detector configured to detect a current value flowing through the motor or the semiconductor switching element,
- wherein the controller controls the semiconductor switching element at a first duty ratio to drive the motor after the trigger is pulled, thereafter the controller changes from the first duty ratio to a second duty ratio, which is lower than the first duty ratio, to drive the motor in a case that the current value detected by the current detector exceeds a first threshold, and thereafter the controller changes from the second duty ratio to a third duty ratio, which is lower than the second duty ratio, to drive the motor in a case that the current value exceeds a second threshold which is larger than the first threshold.
Dependencies are inferred from the claim text.