Power tool

Patent metadata

Field	Value
Publication number	US-10903718-B2
Application number	US-201815919615-A
Country	US
Kind code	B2
Filing date	Mar 13, 2018
Priority date	Sep 11, 2013
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A power tool (1; 90) includes a motor (17) having a stator (18) and a rotor (19). The stator (18) includes front and rear insulators (21, 22) respectively disposed forward and rearward of a stator core (20) in an axial direction thereof. At least six coils (23) are respectively wound on the stator (18) such that the coils (23) are wound through the front and rear insulators (21, 22). Winding wires (23a) respectively electrically connect circumferentially-adjacent pairs of the coils (23). A short circuiting device (25) short circuits respective pairs of windings (23a) that are located diagonally or diametrically across from one another.

First claim

We claim:

1. A power tool comprising:
a brushless motor having a stator and a rotor, the stator including front and rear insulators respectively disposed forward and rearward of a stator core in an axial direction thereof,
a plurality of coils respectively wound on the stator such that the coils are wound on the front and rear insulators, and
an integral tubular housing that houses the brushless motor and that has a front and a rear,
wherein the stator is provided with at least one notch having a radially outwardly facing opening,
a rear part of the integral tubular housing is located at the rear of the tubular housing, and
a projection extends from the rear part axially into an interior of the integral tubular housing and engages the at least one notch.

2. The power tool according to claim 1 , wherein:
a sensor circuit board is located in the integral tubular housing between the rear part and the stator core.

3. The power tool according to claim 1 , wherein:
short circuit elements are provided on the stator between the rear part and the stator core.

4. The power tool according to claim 1 , wherein:
the integral tubular housing has longitudinal ribs, and
the longitudinal ribs make contact with a surface of the stator.

5. The power tool according to claim 1 , wherein the rear part of the housing includes a recessed part holding a bearing that rotatably supports the rotor.

6. A power tool comprising:
a brushless motor having a stator and a rotor, the stator including first and second insulators respectively disposed first end and second end of a stator core in an axial direction thereof,
a plurality of coils respectively wound on the stator such that the coils are wound on the first and second insulators,
an integral tubular housing that houses the brushless motor, the tubular housing having air suction ports defined therein, a recessed part holding a bearing that rotatably supports the rotor, and a rotation stopping rib that engages the stator and blocks rotation of the stator relative to the tubular housing, and
a threaded fastener extending through a plate having a center opening and into an axial opening in the housing such that the plate presses against the stator in the axial direction,
wherein at least a portion of the plate extends into a notch in the front insulator or in the rear insulator.

7. The power tool according to claim 6 , further comprising:
short circuiting elements that short circuit respective pairs of the plurality of coils,
wherein the short circuiting elements are fixed to the first insulator, and
the first insulator is disposed closer to the recessed part than the second insulator.

8. The power tool according to claim 6 , wherein:
the threaded fastener is a screw,
the plate is a washer, and
the washer is configured to prevent movement of the stator in the axial direction.

9. The power tool according to claim 8 , further comprising:
short circuiting elements that short circuit respective pairs of the plurality of coils,
wherein the short circuiting elements are fixed to the first insulator, and
the first insulator is disposed closer to the recessed part than the second insulator.

10. The power tool according to claim 9 , wherein:
the integral tubular housing has a front and a rear and a rear part located at the rear of the tubular housing,
a sensor circuit board is located in the integral tubular housing between the rear part and the stator core, and
the short circuiting elements are provided on the stator between the rear part and the stator core.

11. The power tool according to claim 10 , wherein:
a projection extends from the integral tubular housing; and
at least one notch is defined in the stator and has a radially outwardly facing opening that engages with the projection.

12. The power tool according to claim 11 , wherein the at least one notch comprises:
a first notch on the first insulator or on the second insulator, and
a second notch on the sensor circuit board.

13. The power tool according to claim 6 , wherein:
a projection extends from the integral tubular housing; and
at least one notch is defined in the stator and has a radially outwardly facing opening that engages with the projection.

14. The power tool according to claim 6 , wherein:
the integral tubular housing has a longitudinal axis, and
the integral tubular housing is configured to allow insertion of the brushless motor into the integral tubular housing in a direction of the longitudinal axis.

15. A power tool comprising:
a brushless motor having a stator and a rotor, the stator including front and rear insulators respectively disposed forward and rearward of a stator core in an axial direction thereof,
a plurality of coils respectively wound on the stator and the front and rear insulators,
an integral tubular housing that houses the brushless motor and that has a front, a rear, a front opening at the front, a rear part at the rear, and a plurality of longitudinal ribs in contact with the stator,
at least one plate having a center opening, and
a threaded fastener extending through the at least one plate and into an axially extending threaded opening in the housing, the threaded fastener pressing the at least one plate against the stator in the axial direction,
wherein:
the front opening and the longitudinal ribs of the integral tubular housing are configured to allow insertion of the brushless motor into the integral tubular housing in a direction from the front of the housing to the rear of the housing,
the rear part of the integral tubular housing includes air suction ports, a recessed part holding a bearing that rotatably supports the rotor and a projection extending axially from the rear part toward the front,
the rear insulator includes a notch having a radially outwardly facing opening, the projection on the rear part of the integral tubular engaging the notch of the rear insulator, and
at least a portion of the at least one plate extends into a notch in the front insulator.

16. The power tool according to claim 15 , wherein the at least one plate comprises at least one washer.

Assignees

• Makita Corp

Inventors

• Nagahama Tatsuya
• INUZUKA Junya
• Momose Takashi

Classifications

• H02K2203/09

  Machines characterised by wiring elements other than wires, e.g. bus rings, for connecting the winding terminations · CPC title

• H02K29/08

  using magnetic effect devices, e.g. Hall-plates, magneto-resistors (H02K29/12 takes precedence) · CPC title

• B25F5/02

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

• H02K5/225

  Terminal boxes or connection arrangements (specially adapted for submersible motors H02K5/132) · CPC title

• H02K7/116

  with gears · CPC title