Integrated stator-axle for in-wheel motor of an electric vehicle

• US 7,256,526 B1
• Filed: 04/28/2005
• Issued: 08/14/2007
• Est. Priority Date: 11/13/2003
• Status: Expired due to Fees

• Current Assignee: BluWav Systems LLC (Magna International Incorporated)
• Original Assignee: BluWav Systems LLC (Magna International Incorporated)
• Inventors: Perkins, William P., Palazzolo, Joseph, Benson, Mark A., Peyghaleh, Mansour
• Primary Examiner(s): Schuberg; Darren
• Assistant Examiner(s): NGUYEN, HANH N
• Application Number:
  US11/116,228
• Time in Patent Office: 838 Days
• Field of Search: 310/218, 310/67.A, 310/67.R, 310/254, 310/52, 310/54, 310/64
• US Class Current: 310/216.102
• CPC Class Codes: B60K 2001/003 with means for cooling the electrical propulsion units
• CPC Class Codes: B60K 2007/0038 the motor moving together with the wheel axle
• CPC Class Codes: B60K 2007/0092 the motor axle being coaxial to the wheel axle
• CPC Class Codes: B60K 7/0007 the motor being electric
• CPC Class Codes: B60L 2220/44 Wheel Hub motors, i.e. integrated in the wheel hub
• CPC Class Codes: B60L 2220/50 Structural details of electrical machines
• CPC Class Codes: H02K 11/33 Drive circuits, e.g. power electronics H02K11/38 takes precedence
• CPC Class Codes: H02K 21/222 Flywheel magnetos
• CPC Class Codes: H02K 5/1732 radially supporting the rotary shaft at both ends of the rotor H02K5/1737 takes precedence
• CPC Class Codes: H02K 7/14 Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility

Abstract

One or more wheels of an electrically powered vehicle contains a motor rotor and a motor stator that is mounted on an integrated structure having a motor stator mounting element portion and wheel axle portion on each side thereof. The structure is fabricated from a unitary non-ferromagnetic substance. A rotor housing is journalled to the axle portion on both sides of the motor stator mounting element via bearings. A wheel assembly is mounted on the rotor housing thereby to be driven by the rotor. Forced-air cooling is provided through a hollow central passage. A plug separates the passage into two distinct sections, the inlet and the outlet. A plurality of cavities, provided with heat exchanger surfaces, are contained within the stator mounting element portion. Channels at each end of each cavity extend in the radial direction into the central passage. Cooling air enters from one end of the central passage, is directed through the inlet channels, the cavities and outlet channels before exiting through the opposite end of the central passage. Additional channels provide wire access to the motor stator.

Claims

1. An electric motor apparatus comprising:

a hollow shaft having a shaft wall defining a first central passage extending from one end of the hollow shaft to a central wall and a separate second central passage extending from the other end of the hollow shaft to the central wall, the shaft wall of the first central passage defining a first port and the shaft wall of the second central passage defining a second port, the first central passage in communication with the second central passage through the first and second ports;

a stator support structure secured to said hollow shaft;

a stator structure secured to said support structure;

a rotor rotationally supported by said hollow shaft, said rotor comprising a plurality of permanent magnets; and

wherein said rotor and said stator are separated by an air gap.

2. An electric motor apparatus as recited in claim 1, wherein the hollow shaft comprises at least one cavity that extends in a radial direction from the first central passage to the stator support structure.

3. An electric motor apparatus comprising:

a hollow shaft having a central passage extending from one end of the hollow shaft to the other end of the hollow shaft, wherein said hollow shaft comprises at least one cavity that extends in a radial direction from the central passage to said stator support structure;

a stator support structure secured to said hollow shaft, wherein an interior portion of the stator support structure includes a cavity extending between two locations in the axial direction, the cavity further extending radially from said two locations to the central passage of the hollow shaft;

a stator structure secured to said stator support structure;

a rotor rotationally supported by said hollow shaft, said rotor comprising a plurality of permanent magnets; and

wherein said rotor and said stator are separated by an air gap.

4. An electric motor apparatus as recited in claim 3, wherein said stator support structure is formed from a unitary material.

5. An electric motor apparatus as recited in claim 3, wherein said stator support structure is non-ferromagnetic.

6. An electric motor apparatus as recited in claim 3, wherein said stator support structure has a cylindrical shape about an axis.

7. An electric motor apparatus as recited in claim 3, wherein said stator support structure axis is collinear with the axis of said hollow shaft.

8. An electric motor apparatus as recited in claim 3, wherein said stator support structure has a perimeter diameter that is greater than its length in the direction of the axis.

9. An electric motor apparatus as recited in claim 3, wherein said hollow shaft has an outside diameter at said one end that is greater than the outside diameter at said other end.

10. An electric motor apparatus as recited in claim 3, wherein said cavity extends in a direction parallel to the axis at a fixed radial distance from the hollow shaft.

11. An electric motor apparatus as recited in claim 3, further comprising a heat exchanger that is in thermal communication with said cavity.

12. An electric motor apparatus as recited in claim 3, wherein the cavity is in thermal communication with the air gap.

13. An electric motor apparatus as recited in claim 3, wherein said hollow shaft comprises a plug positioned in the axial direction between said two locations, wherein coolant is directed through the cavity from a first axial side of the plug to a second axial side of the plug.

14. An electric motor apparatus as recited in claim 13 wherein said plug directs at least some portion of coolant through said cavity from a first side of said plug to a second side of said plug.

15. An electric motor apparatus as recited in claim 13, wherein the hollow shaft and stator support structure are configured to direct coolant incoming to the central passage through said cavity and past said heat exchanger and out to the central passage.

16. An electric motor apparatus as recited in claim 3, the hollow shaft comprises a plurality of openings for securing the hollow shaft to a frame.

17. An electric motor apparatus as recited in claim 3, wherein said hollow shaft is secured to a machine.

18. An electric motor apparatus as recited in claim 17, wherein said machine is a vehicle.

19. An electric motor apparatus as recited in claim 3, wherein a wheel is secured to the rotor.

20. An electric motor apparatus as recited in claim 3, further comprising a bearing arrangement coupling the rotor to the hollow shaft axially adjacent each side of the stator.

21. An electric motor apparatus as recited in claim 3, wherein the rotor is configured in the shape of annular ring.

22. An electric motor apparatus as recited in claim 3, further comprising coolant means for directing coolant through the central passage of the hollow shaft during motor operation.

23. An electric motor apparatus as recited in claim 3, wherein the stator comprises a plurality of elements ferromagnetically isolated from each other.

24. An electric motor apparatus as recited in claim 3, further comprising means to supply power to the stator.

25. An electric motor apparatus as recited in claim 3, further comprising a control unit connected to the stator.

26. An electric motor apparatus as recited in claim 3 wherein said rotor further comprises a back iron.

27. An electric motor apparatus as recited in claim 3 wherein said one or more cavities are formed along an arc at a fixed radial distance from the hollow shaft in a direction parallel to the axis.

28. An electric motor apparatus as recited in claim 3 wherein said cavity is in thermal communication with said air gap that separates said rotor from said stator.

29. An electric motor apparatus as recited in claim 3 wherein said cable apertures extend through said stator support structure to allow at least one cable to extend from said stator to a position external to said hollow shaft.

30. An electric motor apparatus comprising:

a hollow shaft having a central passage extending from one end of the hollow shaft to the other end of the hollow shaft;

wherein said hollow shaft comprises at least one cavity that extends in a radial direction from the central passage to said stator support structure;

at least one heat exchanger in thermal communication with the at least one cavity;

a stator support structure secured to said hollow shaft, wherein an interior portion of the stator support structure comprises a cavity extending between two locations in the axial direction, the cavity further extending radially from said two locations to the central passage of the hollow shaft;

a stator structure secured to said stator support structure;

a rotor rotationally supported by said hollow shaft, said rotor comprising a plurality of permanent magnets; and

wherein said rotor and said stator are separated by air gap.

31. An electric motor apparatus as recited in claim 30, wherein said cavity is in thermal communication with said air gap.

32. An electric motor apparatus as recited in claim 31, wherein said hollow shaft comprises a plurality of cable apertures.

33. An electric motor apparatus as recited in claim 31, wherein said stator support structure comprises apertures aligned with the cable apertures of the hollow shaft, whereby at least one cable can extend from the stator to a position external to the hollow shaft.

34. An electric motor apparatus as recited in claim 30, wherein the hollow shaft and stator support structure are configured to direct coolant incoming to the central passage through said cavity and past said heat exchanger and out to the central passage.