Stator assembly for a brushless motor in a power tool

Patent metadata

Field	Value
Publication number	US-2022014066-A1
Application number	US-202117484595-A
Country	US
Kind code	A1
Filing date	Sep 24, 2021
Priority date	Jun 14, 2010
Publication date	Jan 13, 2022
Grant date	—

Abstract

A stator assembly for a BLDC motor includes a stator core, at least one magnet wire wound on poles of the stator core, an end insulator mounted on an end surface of the stator core, a non-conductive mount member mounted on the outer circumferential surface of the stator core, and conductive terminals mounted on the non-conductive mount member. Each conductive terminal includes: a main portion mounted on the non-conductive mount, a tang portion extending from a first longitudinal end adjacent the end insulator and folded over the main portion, and a connection tab extending angularly from a second longitudinal end. A contact portion of the magnet wire is wrapped around the tang portion and fused to make an electric connection to the conductive terminal.

First claim

1 . A power tool comprising:
a housing; a motor housed inside the housing, the motor having a stator assembly and a rotor rotatably arranged inside the stator, the stator assembly comprising:
a stator core having a substantially cylindrical body formed around a longitudinal axis of the motor, the cylindrical body having an outer circumferential surface, and a plurality of poles radially extending from an inner surface of the body;
at least one magnet wire wound on the plurality of poles forming a plurality of phases;
an end insulator mounted on an end surface of the stator core along a radial plane to electrically insulate the end surface of the stator core from the at least one magnet wire, the end insulator including a plurality of guide features for routing the at least one magnet wire between the plurality of poles along an end surface of the end insulator facing away from the stator core;
a non-conductive mount member mounted on the outer circumferential surface of the stator core in contact therewith; and
a plurality of conductive terminals mounted on the non-conductive mount member arranged to supply electric power to the plurality of phases;
wherein each conductive terminal includes: a main portion mounted on the non-conductive mount, a tang portion extending from a first longitudinal end of the main portion adjacent the end insulator and folded over the main portion, and a connection tab extending angularly from a second longitudinal end of the main portion opposite the first longitudinal end, wherein at least a contact portion of the at least one magnet wire is wrapped around the tang portion and fused to make an electric connection to the conductive terminal, and the connection tab is arranged to make electric contact with a wire supplying electric power to the motor.

2 . The power tool of claim 1 , wherein the end insulator comprises an extension portion extending longitudinally over an outer surface of the stator core to retain the non-conductive mount member on the outer circumferential surface of the lamination stack.

3 . The power tool of claim 1 , wherein the end insulator comprises two retaining walls protruding longitudinally along the outer surface of the stator core on two sides of the non-conductive mount member to retain the non-conductive mount member on the outer circumferential surface of the lamination stack.

4 . The power tool of claim 1 , further comprising a second end insulator arranged at a second end surface of the stator core, the two end insulators having retaining features that mate to retain the non-conductive mount member on the outer circumferential surface of the lamination stack.

5 . The power tool of claim 4 , wherein the connection tab of each of the plurality of terminals is provided adjacent the second end insulator.

6 . The power tool of claim 1 , wherein the conductive terminals are arranged at close proximity to one another in parallel, and the non-conductive mount member electrically isolates the plurality of conductive terminals from one another.

7 . The power tool of claim 1 , wherein the main portion of at least one of the plurality of conductive terminals is oriented substantially parallel to the longitudinal axis of the motor.

8 . The power tool of claim 1 , wherein the wire supplying electric power to the motor is soldered to the connection tab.

9 . The power tool of claim 1 , wherein the tang portion is pressed over a portion of the contact portion of the at least one magnet wire.

10 . The power tool of claim 1 , wherein two ends of the at least one magnet wire are configured to terminate around the tang portion of one of the plurality of terminals.

11 . The power tool of claim 1 , wherein the plurality of conductive terminals comprises three terminals, wherein a middle one of the three terminals is radially aligned with one of the plurality of poles of the stator core.

12 . A brushless direct-current (BLDC) motor having a stator assembly and a rotor rotatably arranged inside the stator, the stator assembly comprising:
a stator core having a substantially cylindrical body formed around a longitudinal axis of the motor, the cylindrical body having an outer circumferential surface, and a plurality of poles radially extending from an inner surface of the body; at least one magnet wire wound on the plurality of poles forming a plurality of phases; an end insulator mounted on an end surface of the stator core along a radial plane to electrically insulate the end surface of the stator core from the at least one magnet wire, the end insulator including a plurality of guide features for routing the at least one magnet wire between the plurality of poles along an end surface of the end insulator facing away from the stator core; a non-conductive mount member mounted on the outer circumferential surface of the stator core in contact therewith; and a plurality of conductive terminals mounted on the non-conductive mount member arranged to supply electric power to the plurality of phases; wherein each conductive terminal includes: a main portion mounted on the non-conductive mount, a tang portion extending from a first longitudinal end of the main portion adjacent the end insulator and folded over the main portion, and a connection tab extending angularly from a second longitudinal end of the main portion opposite the first longitudinal end, wherein at least a contact portion of the at least one magnet wire is wrapped around the tang portion and fused to make an electric connection to the conductive terminal, and the connection tab is arranged to make electric contact with a wire supplying electric power to the motor.

13 . The BLDC motor of claim 12 , wherein the end insulator comprises an extension portion extending longitudinally over an outer surface of the stator core to retain the non-conductive mount member on the outer circumferential surface of the lamination stack.

14 . The BLDC motor of claim 12 , wherein the end insulator comprises two retaining walls protruding longitudinally along the outer surface of the stator core on two sides of the non-conductive mount member to retain the non-conductive mount member on the outer circumferential surface of the lamination stack.

15 . The BLDC motor of claim 12 , further comprising a second end insulator arranged at a second end surface of the stator core, the two end insulators having retaining features that mate to retain the non-conductive mount member on the outer circumferential surface of the lamination stack.

16 . The BLDC motor of claim 15 , wherein the connection tab of each of the plurality of terminals is provided adjacent the second end insulator.

17 . The BLDC motor of claim 12 , wherein the conductive terminals are arranged at close proximity to one another in parallel, and the non-conductive mount member electrically isolates the plurality of conductive terminals from one another.

18 . The BLDC motor of claim 12 , wherein the main portion of at least one of the plurality of conductive terminals is oriented substantially parallel to the longitudinal axis of the motor.

19 . The BLDC motor of claim 12 , wherein the wire supplying electric power to the motor is soldered to the connection tab.

20 . The BLDC motor of claim 12 , wherein the tang portion is pressed over a portion of the contact portion of the at least one magnet wire.

21 . The BLDC motor of claim 12 , wherein two ends of the at least one magnet wire is configured to terminate around the tang portion of

Assignees

• Black & Decker Inc

Inventors

• Smith David J
• Ayers Justin H
• Gillespie David E
• Hatfield Eric E
• Ortt Earl M
• Osborne Stephen
• Friedman Brian
• Dunston Jarrett A

Classifications

• H02K7/145 Primary

  Hand-held machine tool · CPC title

• H02K3/522

  for generally annular cores with salient poles · CPC title

• H02K2203/06

  Machines characterised by the wiring leads, i.e. conducting wires for connecting the winding terminations · CPC title

• H02K3/521 Primary

  applicable to stators only · CPC title

• H02K3/345 Primary

  between conductor and core, e.g. slot insulation · CPC title