Electric motor commutator

• US 8,053,945 B2
• Filed: 10/24/2008
• Issued: 11/08/2011
• Est. Priority Date: 10/26/2007
• Status: Expired due to Fees

• Current Assignee: Johnson Electric International AG (Johnson Electric Holdings Limited)
• Original Assignee: Johnson Electric SA (Johnson Electric Holdings Limited)
• Inventors: Ma, Hai Bo, Qin, Rui Feng, Guan, Xin Hui
• Primary Examiner(s): Nguyen; Tran
• Application Number:
  US12/258,015
• Publication Number:
  US 20090108698A1
• Time in Patent Office: 1,110 Days
• Field of Search: 310/234, 310/236, 310/237
• US Class Current: 310/234
• CPC Class Codes: H01R 39/32 Connections of conductor to commutator segment
• CPC Class Codes: H01R 4/024 comprising preapplied solder
• CPC Class Codes: H01R 4/187 combined with soldering or welding
• CPC Class Codes: H01R 4/625 Soldered or welded connections
• CPC Class Codes: H02K 13/04 Connections between commutator segments and windings

Abstract

A commutator 10 for an electric motor comprises a plurality of commutator segments supported by a base. The segments have an electrically conductive body portion 14 and at least one electrically conductive foldable tang 16 provided on the body portion 14 for engaging a winding lead wire 44 of an electric motor. The foldable tang 16 has a proximal end 18 on or adjacent to the body portion 14, and a distal end 22 remote from the proximal end 18. A wire-accommodating portion 30 is provided on or adjacent to the foldable tang 16, so that, when the tang 16 is folded, the wire-accommodating portion provides a predetermined gap 56 for the winding lead wire 44.

Claims

1. A commutator for an electric motor, comprising a plurality of commutator segments supported by an electrically non-conductive base, the commutator segments comprising:

an electrically conductive body portion and at least one tang provided on the body portion for engaging a winding lead wire of the electric motor;

the tang being electrically conductive and foldable and having a proximal end on or adjacent to the body portion, and a distal end remote from the proximal end; and

a preformed wire-accommodating portion on or adjacent to the tang, so that, when the tang is folded, the distal end contacts a brush contacting surface of the body portion, and the wire-accommodating portion provides a predetermined interior gap for accommodating the winding lead wire without damaging the lead wire, and a layer of an electrically conductive ductile material formed on a surface of the tang that contacts the winding lead wire;

wherein the winding lead wire and the tang are made of different material and the electrically conductive ductile material provides a protective layer between the tang and the lead wire to reduce galvanic corrosion.

2. The commutator of claim 1, wherein the electrically conductive ductile material is tin.

3. The commutator of claim 1, wherein the electrically conductive ductile material is solder.

4. The commutator of claim 3, wherein the solder is arranged to flow over and cover a contact portion of the winding lead wire during attachment.

5. The commutator of claim 1, wherein the wire-accommodating portion is one of a step and a ramp.

6. The commutator of claim 5, wherein the said step or ramp is provided on at least one of the tang spaced from the body portion and on the body portion.

7. The commutator of claim 1, wherein the tang is hooked shaped.

8. The commutator of claim 1, wherein, when the tang is folded and contacting the brush-contacting surface, an interior surface of the tang is spaced from the brush-contacting surface and defines the predetermined interior gap.

9. The commutator of claim 1, wherein the tang includes a longitudinal interior edge which extends from the proximal end to the distal end, the longitudinal interior edge including a chamfer or rounded portion.

10. An electric motor comprising a stator, a rotor having a shaft and a rotor core mounted on the shaft, electrically conductive windings wound on the rotor core, the commutator of claim 1, and brush gear in contact with the body portion, with the tang in a folded condition, at least one of the lead wires or the winding passing through the predetermined gap formed by the wire-accommodating portion.

11. The electric motor of claim 10, wherein the winding lead wires include aluminum, and the tang is made of copper.

12. The electric motor of claim 10, wherein the ductile material coats a portion of the lead wire and fills the predetermined internal gap.

13. The commutator of claim 1, wherein the proximal end of the tang is offset in a radial direction from the brush contacting surface of the body portion.

14. The commutator of claim 1, wherein the lead wire includes aluminum and the tang is copper.