Power tool

Patent metadata

Field	Value
Publication number	US-9954418-B2
Application number	US-201514631317-A
Country	US
Kind code	B2
Filing date	Feb 25, 2015
Priority date	Mar 17, 2014
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A power tool includes a brushless motor having a stator and a rotor, which includes a rotary shaft extending in a front-rear direction of the power tool. The rotary shaft rotates a spindle that extends in an up-down direction of the power tool. A fan is fixedly coupled to the rotary shaft and rotates therewith. A switch is disposed rearward of the brushless motor and a controller is disposed rearward of the switch in the front-rear direction. A battery pack is disposed rearward of the controller. A main-body housing houses the brushless motor, the switch and the controller. The main-body housing includes a first tubular part, which houses the brushless motor, and a second tubular part, which houses the switch. The diameter of the second tubular part is smaller than the diameter of the first tubular part.

First claim

We claim:

1. A power tool, comprising:
a brushless motor comprising a stator and a rotor, the rotor comprising a rotary shaft extending in a front-rear direction of the power tool;
a spindle configured to be rotated by the rotary shaft and extending in an up-down direction of the power tool that is at least substantially perpendicular to the front-rear direction;
a fan fixedly coupled to the rotary shaft so as to rotate therewith;
a switch disposed rearward of the brushless motor in the front-rear direction, the switch being a push-button switch having a button that is movable in the front-rear direction;
a controller disposed rearward of the push-button switch in the front-rear direction and being configured to control the operation of the brushless motor;
a battery pack disposed rearward of the controller in the front-rear direction; and
a main-body housing that houses the brushless motor, the switch, and the controller;
wherein the main-body housing comprises a first tubular part, which houses the brushless motor, and a second tubular part, which houses the push-button switch, the second tubular part having a diameter that is smaller than a diameter of the first tubular part; and
an operating member is provided on an outside surface of the first tubular part, the operating member being configured to turn the push-button switch ON and OFF by sliding in the front-rear direction of the power tool.

2. The power tool according to claim 1 , wherein the operating member comprises a switch knob that is operably coupled to the push-button switch.

3. The power tool according to claim 2 , further comprising:
a slide plate operably coupled between the push-button switch and the switch knob, the slide plate being slidably guided in a guide groove defined on an inner surface of the main-body housing and extending in the front-rear direction.

4. The power tool according to claim 1 , wherein the main-body housing comprises:
a pair of left and right half housings joined by screws; and
receiving plates projecting from respective inner surfaces of the half housings;
wherein a bearing that rotatably supports the rotary shaft is held by the receiving plates; and
signal lines electrically connecting the stator to the controller pass between the screws joining the pair of left and right half housings and the receiving plates.

5. The power tool according to claim 1 , further comprising:
a retaining rib disposed on the second tubular part and holding the push-button switch,
wherein a wiring space is defined between an inner surface of the main-body housing and the retaining rib in the up-down direction, and
a power-supply line or a signal line connected to the stator passes through the wiring space.

6. The power tool according to claim 5 , further comprising:
a rear insulator provided on a rear end surface of a core of the stator; and
a sensor circuit board attached to the rear insulator;
wherein the signal line is led out from the sensor circuit board, passes through the second tubular part and electrically connects to the controller.

7. The power tool according to claim 1 , further comprising a disk operably coupled to the spindle, wherein the power tool is a grinder.

8. The power tool according to claim 1 , wherein:
the fan is configured to draw in outside air, when the rotary shaft rotates, into an interior of the main-body housing through at least one air-suction port defined in the main-body housing and to cause the outside air to pass through the brushless motor;
the controller is disposed adjacent to a terminal block that is provided on a battery-mount part of the main-body housing, the terminal block being electrically connected to the battery pack; and
the at least one air-suction port overlaps a gap between the controller and the terminal block in the front-rear direction of the power tool.

9. The power tool according to claim 8 , further comprising:
a display configured to display a remaining battery capacity of the battery pack and provided on the battery-mount part.

10. The power tool according to claim 1 , wherein
a battery-mount part is defined at a rear end of the main-body housing in the front-rear direction, the battery pack is detachably attachable to the battery-mount part;
the battery-mount part of the main-body housing also houses the controller,
at least one air-suction port is provided in the battery-mount part; and
the controller is disposed in the battery-mount part such that air, which is sucked in through the at least one air-suction port as the fan rotates, is directed towards the controller and cools the controller.

11. The power tool according to claim 10 , further comprising at least one air-suction-port cover detachably attached to the main-body housing and covering an outer side of the at least one air-suction port, the at least one air-suction-port cover comprising a wire mesh or a filter material.

12. The power tool according to claim 10 , further comprising a terminal block electrically connectable to the battery pack and provided rearward of the controller in the front-rear direction, the terminal block being disposed in the battery-mount part such that air, which is sucked in from the at least one air-suction port as the fan rotates, is directed towards the terminal block and cools the terminal block.

13. The power tool according to claim 12 , wherein the battery-mount part of the main-body housing constitutes a third tubular part of the main-body housing, the second tubular part having a diameter that is smaller than the diameter of the third tubular part.

14. The power tool according to claim 10 , further comprising:
a gear housing that houses the spindle and protrudes downward from a forward portion of the main-body housing; and
at least one air-exhaust port defined in the gear housing and being configured to exhaust air sucked in from the at least one air-suction port.

15. The power tool according to claim 10 , further comprising:
a sensor circuit board configured to detect the rotational position of the rotor, the sensor circuit board being fixed to a rear part of the stator via at least one screw; and
at least one signal line configured to output a detection signal from the sensor board, the at least one signal line extending out from an upper part of the sensor circuit board, through the second tubular part and electrically connecting to the controller.

16. The power tool according to claim 1 , further comprising:
a rear insulator provided on a rear end surface of a core of the stator; and
a sensor circuit board attached to the rear insulator;
wherein the signal line is led out from the sensor circuit board, passes through the second tubular part and electrically connects to the controller.

17. The power tool according to claim 1 , further comprising:
a slide plate slidably guided in a guide groove defined on an inner surface of the main-body housing and extending in the front-rear direction, the slide plate having:
a first end that is fixedly coupled to the operating member so as to slide together with the operating member and
a second end operably coupled with the push-button switch to turn the push-button switch ON and OFF when the operating member and slide plate are slid forward and rearward, respectively.

18. A power tool, comprising:
a housing comprising first and second half housings joined by screws, the joined first and second half housings defining a first tubular section connected to a second tubular section, and a third tubular section connected to the second t

Assignees

• Makita Corp

Inventors

• Kawakami Takahiro
• Nakahama Masatoshi

Classifications

• B24B23/02

  with rotating grinding tools; Accessories therefor · CPC title

• H02K29/06

  with position sensing devices (H02K29/03 takes precedence) · CPC title

• B25F5/008

  Cooling means · CPC title

• B25F5/02

  Construction of casings, bodies or handles {(B25F5/006, B25F5/008 take precedence)} · CPC title

• H02K11/27

  Devices for sensing current, or actuated thereby (overcurrent protection responsive to temperature of the machines or parts thereof, e.g. windings, H02K11/25) · CPC title