Electric motor with field assemblies having core pieces with mating features

• US 7,233,091 B2
• Filed: 09/03/2004
• Issued: 06/19/2007
• Est. Priority Date: 09/05/2003
• Status: Active Grant

• Current Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Black & Decker Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Du, Hung T., Verbrugge, Brandon L., Smith, David J., Zemlok, Michael A., Ortt, Earl M., Kusmierski, Robert G., Agnes, Michael J.
• Primary Examiner(s): NGUYEN, TRAN N
• Application Number:
  US10/934,104
• Publication Number:
  US 20050099087A1
• Time in Patent Office: 1,019 Days
• Field of Search: 310216-218, 310/254
• US Class Current: 310/216.091
• CPC Class Codes: H02K 1/148 Sectional cores H02K1/141 takes precedence
• CPC Class Codes: H02K 1/18 Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures
• CPC Class Codes: H02K 15/0435 Wound windings
• CPC Class Codes: H02K 15/10 Applying solid insulation to windings, stators or rotors
• CPC Class Codes: H02K 15/12 Impregnating, heating or drying of windings, stators, rotors or machines
• CPC Class Codes: H02K 3/325 for windings on salient poles, such as claw-shaped poles
• CPC Class Codes: H02K 3/522 for generally annular cores with salient poles
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine
• CPC Class Codes: Y10T 29/49012 Rotor
• CPC Class Codes: Y10T 29/49071 by winding or coiling
• CPC Class Codes: Y10T 29/49073 by assembling coil and core
• CPC Class Codes: Y10T 29/53143 Motor or generator

Abstract

An electric motor has a field assembly, such as a stator, has field coils that are wound to a net shape. Lead wires are brought out from the ends of each field coil. The field coils are insulated. The field coils are assembled with stator core pieces, such as pole pieces and return path pieces, into the stator. The stator core pieces are formed prior to being assembled with the field coils. In an aspect of the invention, the pole pieces and return path pieces are separately formed and then assembled together with the field coils, which have also been separately formed. The pole pieces and return path pieces are formed with mating features that are mated to hold the pole pieces and return path pieces together.

Claims

1. An electric motor, comprising:

a. a multi-piece stator having a plurality of pole pieces with a plurality of return path pieces mated to each of the pole pieces and a plurality of field coils;

i. each return path piece having opposed ends with a projection extending from each end;

ii. each pole piece having a neck with opposed receiving pockets therein between opposed outer fingers of a radial outer end of the neck and opposite sides of a radially outer section of a pole tip section of the pole piece, each opposed receiving pocket having one of the projections of one of the return oath pieces received therein, each pole piece secured to the return path pieces mated to the pole piece by deformation of the opposed outer fingers of the radial outer end of the neck of the pole piece against the projections of those return oath pieces, the fingers of the radial outer end of the neck of each pole piece having radially inwardly extending projections and the projections of the return path pieces have recesses that are distally spaced from junctions of the projections of the return path pieces and the ends of the return path pieces, the radially inwardly extending projections of the fingers of the radial outer end of the neck of each pole piece received in the recesses of the return path pieces when the fingers are deformed against the projections of the return path pieces received in the opposed receiving pockets of the pole pieces to form mating detects that mechanically lock the pole piece and the return path pieces together, the mating detents distally spaced from the junctions of the ends of the return path pieces and the projections of the return oath pieces to increase a critical length of the pole piece and return path pieces mated to the pole piece;

iii. at least one of the field coils disposed around each pole piece between the pole tip section of the pole piece and the return path pieces mated to the pole piece; and

b. an armature received in the stator.

2. The electric motor of claim 1 wherein each return path piece is also welded to each pole piece to which it is mated.

3. An electric motor, comprising:

a. a multi-piece stator having a plurality of pole pieces with a plurality of return path pieces mated to each of the pole pieces and a plurality of field coils;

i. each return oath piece having opposed ends with a projection extending from each end;

ii. each pole piece having a neck with opposed receiving pockets therein between opposed outer fingers of a radial outer end of the neck and opposite sides of a radially outer section of a pole tip section of the pole piece, each opposed receiving pocket having one of the projections of one of the return path pieces received therein, each pole piece secured to the return oath pieces mated to the pole piece by deformation of the opposed outer fingers of the radial outer end of the neck of the pole piece against the projections of those return path pieces;

iii. at least one of the field coils disposed around each pole piece between the pole tip section of the pole piece and the return path pieces mated to the pole piece;

iv. the opposite sides of the radially outer section of the pole tip section of each pole piece having circumferentially and radially outer edges that are recessed and have a radius to facilitate placement of the field coils on the pole and

b. an armature received in the stator.

4. The electric motor of claim 3 wherein the circumferentially and radially outer edges of the pole tip section of each pole piece project outward to provide lips that provide retention of the field coils disposed on the pole pieces.

5. An electric motor, comprising:

a. a multi-piece stator having a plurality of pole pieces with a plurality of return path pieces mated to each of the pole pieces and a plurality of field coils;

i. each return path piece having opposed ends with a projection extending from each end;

ii. each pole piece having a neck with opposed receiving pockets therein and a pole tip section extending radially inwardly from the neck, each opposed receiving pocket having one of the projections of one of the return path pieces received therein;

iii. each pole path piece secured to the return path pieces mated to the pole piece by welding;

iv. at least one of the field coils disposed around each pole piece between the pole tip section of the pole piece and the return path pieces mated to the pole piece;

v. each pole tip section having circumferentially and radially outer edges that are recessed and have a radius to facilitate placement of the filed coils on the pole pieces; and

b. an armature received in the stator.

6. A hand-held power tool, comprising:

a. a housing surrounding an electric motor, the electric motor including;

a multi-piece stator having a plurality of pole pieces with a plurality of return path pieces mated to each of the pole pieces and a plurality of field coils;

each return path piece having opposed ends with a projection extending from each end;

each pole piece having a neck with opposed receiving pockets therein between opposed outer fingers of a radial outer end of the neck and opposite sides of a radially outer section of a pole tip section of the cole piece, each opposed receiving pocket having one of the projections of one of the return path pieces received therein, each pole piece secured to the return path pieces mated to the pole piece by deformation of the opposed outer fingers of the radial outer end of the neck of the pole piece against the projections of those return path pieces, the fingers of the radial outer end of the neck of each pole piece having radially inwardly extending projections and the projections of the return path pieces have recesses that are distally spaced from junctions of the projections of the return path pieces and the ends of the return path pieces, the radially inwardly extending projections of the fingers of the radial outer end of the neck of each pole piece received in the recesses of the return path pieces when the fingers are deformed against the projections of the return path pieces received in the opposed receiving pockets of the pole pieces to form mating detents that mechanically lock the pole piece and the return path pieces together, the mating detents distally spaced from the junctions of the ends of the return path pieces and the projections of the return path pieces to increase a critical length of the pole piece and return path pieces mated to the pole piece;

at least one of the field coils disposed around each pole piece between the pole tip section of the pole piece and the return path pieces mated to the pole piece;

ii. an armature received in the stator; and

b. a drive train coupled to the motor.

7. The power tool of claim 6 wherein each return path piece is also welded to each pole piece mated to the return path piece.

8. A hand-held power tool, comprising:

a. a housing surrounding an electric motor, the electric motor including;

a multi-piece stator having a plurality of pole pieces with a plurality of return path pieces mated to each of the pole pieces and a plurality of field coils;

each return path piece having opposed ends with a projection extending from each end;

each pole piece having a neck with opposed receiving pockets therein between opposed outer fingers of a radial outer end of the neck and opposite sides of a radially outer section of a pole tip section of the pole piece, each opposed receiving pocket having one of the projections of one of the return path pieces received therein, each pole piece secured to the return oath pieces mated to the pole piece by deformation of the opposed outer fingers of the radial outer end of the neck of the pole piece against the projections of those return path pieces;

at least one of the field coils disposed around each pole piece between the pole tip section of the pole piece and the return path pieces mated to the pole piece;

the opposite sides of the radially outer section of the pole tip section of each pole piece having circumferentially and radially outer edges that are recessed and have a radius to facilitate placement of the field coils on the pole pieces;

ii. an armature received in the stator; and

b. a drive train coupled to the motor.

9. A power tool, comprising

a. a housing surrounding an electric motor, the electric motor including:

i. a multi-piece stator having a plurality of pole pieces, a plurality of field coils and a plurality of return path pieces, a plurality of the return path pieces mated to each of the pole pieces;

each pole piece having a neck with opposed receiving pockets therein and a pole tip section extending radially inwardly from the neck, each opposed receiving pocket having one of the projections of one of the return path pieces received therein;

each pole oath piece secured to the return path pieces mated to the pole piece by welding;

at least one of the field coils disposed around each pole piece between the pole tip section of the pole piece and the return path pieces mated to the pole piece;

each pole tip section having circumferentially and radially outer edges that are recessed and have a radius to facilitate placement of the filed coils on the pole pieces by allowing the field coils to slide more freely onto the pole pieces when placed onto the pole pieces;

ii. an armature received in the stator; and

b. a drive train coupled to the motor.