A method of operating a rotary tool driven by a brushless motor comprising:
- a DC brushless motor for rotationally driving a rotary bit,
- a torque setting clutch mechanism provided in a shaft-coupling portion for coupling said rotary bit and an output shaft of said brushless motor,
- a drive switch for drive-controlling a drive control circuit of said brushless motor, and
- a control means configured so as to rotationally drive said brushless motor by an operation of said drive switch and so as to stop a rotational drive of said brushless motor by detecting clutch action of said clutch mechanism, wherein:
- first Hall elements for respectively detecting a lever operation and a push operation are respectively provided for a lever operation mechanism and a push operation mechanism both being said drive switch for said brushless motor, a second Hall element for detecting a clutch action is provided for said clutch mechanism, and a third Hall element for detecting forward/reverse switching operation is provided for a forward/reverse switching operation mechanism that performs forward/reverse switching operation of said blushless motor;
- said control means is configured so that, based on a drive switch operation signal provided by one of said first Hall elements, said drive control circuit of said brushless motor is drive-controlled so as to rotationally drive said brushless motor and so that, based on a clutch mechanism action signal provided by said second Hall element, said drive control circuit of said brushless motor is stop-controlled so as to stop the rotational drive of said brushless motor;
- and
- said brushless motor drive control circuit is comprised of:
- an AC/DC conversion means connected to a commercial power source for obtaining a power supply voltage for driving said brushless motor, an inverter circuit comprising a semiconductor bridge configuration that converts said power supply voltage into a brushless motor drive voltage, a drive circuit for ON/OFF-controlling a semiconductor that comprises said bridge configuration of said inverter circuit, and a position detection circuit for detecting a position of a rotor with respect to magnetizing windings in said brushless motor;
- wherein said method comprises the steps of
- interrupting, when stop-control of said drive control circuit of said brushless motor is performed by said control means, a drive power for said brushless motor based on said clutch mechanism action signal provided by said second Hall element, and control-operating said semiconductor, which comprises said bridge configuration of said inverter circuit provided in said drive control circuit of said brushless motor, so as to short-circuit said magnetizing windings of said brushless motor, thus braking said rotor of said brushless motor;
- control-operating, when a lever operation or push operation of said lever operation mechanism or push operation mechanism, both being said brushless motor drive switch, is suspended, said semiconductor, which comprises said bridge configuration of said inverter circuit provided in said drive control circuit of said brushless motor, so as to short-circuit said magnetizing windings of said brushless motor, thus braking said rotor of said brushless motor and stopping said brushless motor;
- and
- rotating forward or in reverse said brushless motor through said control means based on a forward/reverse switching operation signal provided by said third Hall element.