Field assemblies having pole pieces with dovetail features for attaching to a back iron piece(s) and methods of making same

• US 20050189844A1
• Filed: 02/18/2005
• Published: 09/01/2005
• Est. Priority Date: 09/05/2003
• Status: Abandoned Application

• 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., McCormick, Garrett P., Ortt, Earl M.
• Application Number:
  US11/062,344
• Publication Number:
  US 20050189844A1
• Time in Patent Office: Days
• US Class Current: 310/433
• 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

Abstract

An electric motor, power tool using the electric motor, and method of making the electric motor includes making a stator that includes pole portions that have dovetail features that are received in corresponding recesses of the back iron portion.

Claims

1. An electric motor, comprising:

a. a stator having a back iron portion and at least two pole portions on which field coils are disposed, each pole portion having a dovetail feature at a radial outer end of a neck that is received in a corresponding recess in the back iron portion; and

b. an armature disposed in the stator.

2. The electric motor of claim 1 wherein each pole portion has an axial length shorter than an axial length of the back iron portion.

3. The electric motor of claim 2 wherein each pole portion has opposed axial ends that gradually decrease in width.

4. The electric motor of claim 1 wherein each pole portion has opposed axial ends that decrease in width.

5. A power tool, comprising:

a. a housing;

b. a motor disposed in the housing, the motor including;

i. a stator having a back iron portion and at least two pole portions on which field coils are disposed, each pole portion having a dovetail feature at a radial outer end of a neck that is received in a corresponding recess in the back iron portion; and

ii. an armature disposed in the stator.

6. The power tool of claim 5 wherein each pole portion has an axial length shorter than an axial length of the back iron portion.

7. The power tool of claim 6 wherein each pole portion has opposed axial ends that gradually decrease in width.

8. The power tool of claim 5 wherein each pole portion has opposed axial ends that gradually decrease in width.

9. A method of making an electric motor, comprising:

a. separately forming a back iron portion, at least two pole portions, and a field coil for each pole portion wherein each pole portion is formed to have a dovetail feature at a radial outer end of a neck and the back iron portion is formed to have recesses for receiving the dovetail features of the pole portions;

b. disposing the field coils on the necks of the pole portions and then inserting the dovetail features of the pole portions into the corresponding recesses in the back iron portion; and

c. then securing the pole portions to the back iron portion.

10. The method of claim 9 including forming each pole portion to have an axial length shorter than an axial length of the back iron portion.

11. The method of claim 10 including forming each pole portion to have opposed axial ends that gradually decrease in width.

12. The method of claim 9 including forming each pole portion to have opposed axial ends that gradually decrease in width.