Brushless Motor for a Power Tool

Patent metadata

Field	Value
Publication number	US-2016149463-A1
Application number	US-201514951667-A
Country	US
Kind code	A1
Filing date	Nov 25, 2015
Priority date	Nov 25, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A power tool is provided including a housing and an electric brushless DC (BLDG) motor housed inside the housing. The motor includes a stator, a rotor pivotably arranged inside the stator, and a motor end cap arranged at an end of the stator. At least one of the motor end cap or the stator includes flexible posts that engage a surface of the other one of the motor end cap or the stator to absorb tolerances associated with the stator and the end cap.

First claim

1 . A power tool comprising:
a housing; and an electric brushless DC (BLDG) motor housed inside the housing and including a stator, a rotor pivotably arranged inside the stator, and a motor end cap arranged at an end of the stator, wherein at least one of the motor end cap or the stator includes a plurality of flexible posts that engage a surface of the other one of the motor end cap or the stator to absorb tolerances associated with the stator and the end cap.

2 . The power tool of claim 1 , wherein the flexible posts comprise elastic material.

3 . The power tool of claim 1 , wherein the flexible posts are arranged on the surface of the motor end cap facing the stator.

4 . The power tool of claim 3 , wherein tips of the flexible posts engage corresponding post pockets recessed in the surface of the stator facing the end cap.

5 . The power tool of claim 3 , wherein the stator includes a lamination stack having a plurality of laminations, and at least one end insulator secured to an end of the lamination stack, wherein the post pockets are formed in an outer surface of the end insulator.

6 . The power tool of claim 3 , wherein the flexible posts are located proximate an outer periphery of the motor end cap.

7 . The power tool of claim 3 , wherein the flexible posts are received within cylindrical pockets on the surface of the end cap facing the stator.

8 . The power tool of claim 1 , further comprising a motor housing arranged to house at least a portion of the stator, the end cap being secured via a plurality of fasteners to the motor housing.

9 . An electric brushless DC (BLDC) motor comprising:
a stator; a rotor pivotably arranged inside the stator; and a motor end cap arranged at an end of the stator, wherein at least one of the motor end cap or the stator includes a plurality of flexible posts that engage a surface of the other one of the motor end cap or the stator to absorb tolerances associated with the stator and the end cap.

10 . The electric motor of claim 9 , wherein the flexible posts are arranged on the surface of the motor end cap facing the stator, further comprising a motor housing arranged to house at least a portion of the stator, the end cap being secured via a plurality of fasteners to the motor housing.

11 . A power tool comprising:
a housing; and an electric brushless DC (BLDC) motor housed inside the housing and including: a stator including a lamination stack having a plurality of laminations and an end insulator disposed at the end of the lamination stack; a rotor pivotably arranged inside the stator; and a motor end cap arranged at an end of the stator facing the end insulator, wherein the end cap comprises a plurality of axial posts facing the end insulator, and the end insulator comprises a plurality of peripheral recessed portions and a plurality of radial deflect portions arranged within the peripheral recessed portions, wherein the axial posts of the end cap engage the radial deflect portions, the radial deflect portions applying a springing force against the axial posts in the axial direction to absorb tolerances associated with the stator and the end cap.

12 . The power tool of claim 11 , wherein the radial deflect portions project outwardly toward a periphery of the end insulator from inner portions of the peripheral recessed portions.

13 . The power tool of claim 11 , wherein a width of the radial deflect portions is smaller than a width of the end insulator.

14 . The power tool of claim 11 , wherein the lamination stack and the radial deflect portions define a gap therebetween.

15 . The power tool of claim 11 , further comprising a motor housing arranged to house at least a portion of the stator, the end cap being secured via a plurality of fasteners to the motor housing.

Assignees

• Black & Decker Inc

Inventors

• Smith David J
• Gillespie David E
• Tennison Merritt J

Classifications

• H02K11/215

  Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements · CPC title

• H02K7/145

  Hand-held machine tool · CPC title

• H02K2213/12

  Machines characterised by the modularity of some components · CPC title

• H02K1/276

  Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] · CPC title

• H02K5/24

  specially adapted for suppression or reduction of noise or vibrations · CPC title