Method of operating a rotary tool

• US 20110030981A1
• Filed: 10/08/2010
• Published: 02/10/2011
• Est. Priority Date: 07/23/2004
• Status: Active Grant

• Current Assignee: Katsuyuki Totsu
• Original Assignee: Katsuyuki Totsu
• Inventors: Totsu, Katsuyuki
• Granted Patent: US 8,636,079 B2
• Time in Patent Office: Days
• US Class Current: 173/1
• CPC Class Codes: B25B 21/00 Portable power-driven screw or nut setting or loosening tools; details or components, e.g. casings, bodies, of portable power-driven tools not particularly related to the operation performed B25F5/00; for mounting or dismounting wheels B60B29/006; Attachments for drilling apparatus serving the same purpose machines B23P19/06
• CPC Class Codes: B25B 23/14 Arrangement of torque limiters or torque indicators in wrenches or screwdrivers couplings for transmitting rotation or clutches F16D; devices for measuring torque per se G01L
• CPC Class Codes: B25B 23/147 specially adapted for electrically operated wrenches or screwdrivers
• CPC Class Codes: H02P 6/22 in a selected direction of rotation
• CPC Class Codes: H02P 6/24 Arrangements for stopping

Abstract

To provide a rotary tool driven by a brushless motor with which constant torque tightening work for screws or the like can always be performed properly and efficiently, in which overall downsizing and improved torque control precision enhancement can easily be achieved, and with which it is possible to eliminate occurrences of switch contact-induced sparking and wear and of the damage imparted to the peripheral electronic equipment and electronic circuitry as occurred in drive switches or torque detection mechanisms that use a conventional mechanical switch mechanism, so that the constituting parts are able to have a reduced size and an extended life.

First Hall elements 31a and 31b for respectively detecting operations of the respective lever operation mechanism 20 and push operation mechanism 18, both being the drive switch, are provided, and a second Hall element 32 for detecting clutch actions is also provided; and a control means 50 is configured so that a DC brushless motor 12 is rotationally driven based on an operation signal provided by the first Hall elements 31a and 31b and is stopped based on an action signal provided by the second Hall element 32.

Claims

1-10. -10. (canceled)

11. 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.

12. A method of operating a rotary tool driven by a brushless motor comprising:

a DC brushless motor for rotationally driving a rotary bit,

a load current detection means for detecting a load current 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 when a load current detected by said load current detection means exceeds a predetermined set value, 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, 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 respective 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, when a load current detected by said load current detection means exceeds a set value, 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 if a load current that is detected by said load current detection means exceeds a set value, 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.