Over mold with integrated insert to enhance heat transfer from an electric machine end winding

• US 10,008,907 B2
• Filed: 03/17/2016
• Issued: 06/26/2018
• Est. Priority Date: 03/17/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Hanumalagutti, Prasad Dev, Degner, Michael W.
• Primary Examiner(s): Andrews, Michael
• Application Number:
  US15/072,676
• Publication Number:
  US 20170271954A1
• Time in Patent Office: 831 Days
• Field of Search: 310 54, 310 58, 310 59, 310 60 R, 310 60 A
• CPC Class Codes: H02K 3/24 with channels or ducts for cooling medium between the conductors
• CPC Class Codes: H02K 5/02 Casings or enclosures characterised by the material thereof
• CPC Class Codes: H02K 5/18 with ribs or fins for improving heat transfer
• CPC Class Codes: H02K 5/203 specially adapted for liquids, e.g. cooling jackets
• CPC Class Codes: H02K 9/197 in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator

Abstract

An electric machine includes a stator. The stator has a plurality of slots defined between a plurality of laminated protrusions. A plurality of wire windings is disposed in the slots. The wire windings form end windings at respective ends of the stator. A cover is disposed about the end windings. A coolant chamber is defined between an inner surface of the cover and the stator. The cover includes a plurality of flow disruption members extending from the inner surface into the coolant chamber.

Claims

1. An electric machine comprising:

a stator defining a plurality of slots;

a plurality of wire windings disposed in the slots and forming end windings extending out of the slots; and

a cover fully encapsulating the end windings, defining a coolant chamber between an inner surface of the cover and the stator, and including a plurality of flow disruption members integrally formed with the cover to extend from the inner surface into the coolant chamber.

2. The electric machine of claim 1, further comprising:

a plurality of coolant passages extending through the cover and being in fluid communication with the coolant chamber; and

a coolant supply duct coupled to at least one of the coolant passages and configured to provide a coolant fluid to the coolant chamber.

3. The electric machine of claim 2, wherein the coolant fluid includes a hydrocarbon lubricant.

4. The electric machine of claim 1, wherein the cover is generally shaped as an annular ring having a first circumferential portion and a second circumferential portion, the first circumferential portion having the plurality of flow disruption members extending from the inner surface, the second circumferential portion having no flow disruption members extending from the inner surface.

5. The electric machine of claim 1, wherein the cover includes an outer shell and an intermediate shell, the inner surface being an inner surface of the intermediate shell, the intermediate shell further having an intermediate shell outer surface, the outer shell having an outer shell inner surface, a second coolant chamber being defined between the outer shell inner surface and the intermediate shell outer surface, the second coolant chamber being in fluid communication with the coolant chamber.

6. The electric machine of claim 1, wherein the cover comprises an epoxy material.

7. A method of cooling an electric machine, comprising:

providing an electric machine, including a stator with slots defined therein and wire windings disposed in the slots and forming end windings; and

disposing a cover about the end windings to fully encapsulate the end windings and to define a coolant chamber between an inner surface of the cover and the stator, the cover including a plurality of flow disruption members extending from the inner surface into the coolant chamber.

8. The method of claim 7, further comprising providing a coolant fluid to the coolant chamber.

9. The method of claim 8, wherein the cover includes a plurality of coolant passages extending through the cover and being in fluid communication with the coolant chamber and a coolant supply duct coupled to at least one of the coolant passages, and wherein providing a coolant fluid comprises providing a coolant fluid via the coolant supply duct.

10. An electric motor, comprising:

a stator having a first end, a second end, and a central portion extending from the first end to the second end, the central portion having projections extending therefrom, defining slots between the projections;

a plurality of wire windings disposed in the slots;

end windings proximate both the first end and the second end of the stator; and

a first end cover fully encapsulating the end windings proximate the first end; and

a second end cover fully encapsulating the end windings proximate the second end,

wherein each of the first end cover and the second end cover has an inner surface, a coolant cavity defined between the inner surface and the stator, and a plurality of turbulence generation members extending from the inner surface into the coolant cavity.

11. The electric motor of claim 10, further comprising:

a plurality of coolant passages extending each of the first end cover and the second end cover for fluid communication with a respective coolant cavity; and

a coolant supply duct coupled to at least one of the coolant passages and configured to provide a coolant fluid to the respective coolant cavity.

12. The electric motor of claim 11, wherein the coolant fluid includes a hydrocarbon lubricant.

13. The electric motor of claim 10, wherein each of the first end cover and the second end cover is generally shaped as an annular ring having a first circumferential portion and a second circumferential portion, the first circumferential portion having the plurality of turbulence generation members extending from the inner surface, the second circumferential portion having no turbulence generation members extending from the inner surface.

14. The electric motor of claim 10, wherein the each of the first end cover and the second end cover includes an outer shell and an intermediate shell, the inner surface being an inner surface of the intermediate shell, the intermediate shell further having an intermediate shell outer surface, the outer shell having an outer shell inner surface, a second coolant cavity being defined between the outer shell inner surface and the intermediate shell outer surface, the second coolant cavity being in fluid communication with the coolant cavity.

15. The electric motor of claim 10, wherein each of the first end cover and the second end cover comprises an epoxy material.

16. The electric motor of claim 10, wherein the plurality of turbulence generation members form an integral unit with a respective first end cover or second end cover.