Electric motor stator housing interference gap reducing method and apparatus

• US 9,246,370 B2
• Filed: 01/17/2013
• Issued: 01/26/2016
• Est. Priority Date: 01/17/2013
• Status: Active Grant

• Current Assignee: BorgWarner Incorporated
• Original Assignee: Remy Technologies LLC (BorgWarner Incorporated)
• Inventors: Hossain, Noman, Chamberlin, Bradley D.
• Primary Examiner(s): LE, DANG D
• Application Number:
  US13/744,147
• Publication Number:
  US 20140197701A1
• Time in Patent Office: 1,104 Days
• Field of Search: 310/43, 310/64, 310/89
• US Class Current: 1/1
• CPC Class Codes: H02K 1/185 to outer stators
• CPC Class Codes: H02K 5/203 specially adapted for liquids, e.g. cooling jackets
• CPC Class Codes: H02K 9/19 for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil
• CPC Class Codes: H02K 9/223 Heat bridges
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A cooling system of an electric machine includes a stator core, a housing, and a thermal interfacial material interposed between complementary mating surfaces of the stator core and the housing for substantially eliminating air gaps therebetween. A method of cooling an electric machine having a housing and a stator includes placing a thermal interfacial material onto a heat transfer interface between the stator and the housing, whereby the thermal interfacial material reduces contact resistance at the heat transfer interface. A method of cooling a stator of an electric machine includes heating a housing having a radially inner surface, coating a radially outer surface of the stator and/or the radially inner surface of the housing with a thermal interfacial material, and inserting the stator into the heated housing, whereby the thermal interfacial material is interposed between the inner surface of the housing and the outer surface of the stator.

Claims

1. A cooling system of an electric machine, comprising

a stator core;

a housing including a cooling jacket wall;

a thermal interfacial material interposed between complementary mating surfaces of the stator core and the housing cooling jacket wall for substantially eliminating air gaps therebetween; and

seals at axial ends of the thermal interfacial material for enclosing the material between the complementary mating surfaces.

2. The cooling system of claim 1, wherein the seals include epoxy.

3. The cooling system of claim 1, wherein the enclosed thermal interfacial material comprises liquid.

4. The cooling system of claim 1, wherein the complementary mating surfaces have an interference fit.

5. The cooling system of claim 1, wherein the thermal interfacial material has a nominal thickness between 0.02 mm and 0.5 mm.

6. The cooling system of claim 1, wherein the thermal interfacial material is substantially uncurable thermal grease.

7. The cooling system of claim 1, wherein the respective mating surfaces of the stator core and the housing are substantially annular.