Rotor Assembly with Heat Pipe Cooling System

• US 20140368064A1
• Filed: 06/13/2013
• Published: 12/18/2014
• Est. Priority Date: 06/13/2013
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Pearce, Edwin Marcum Jr., Fedoseyev, Lev
• Granted Patent: US 9,331,552 B2
• Time in Patent Office: Days
• US Class Current: 310/54
• 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
• CPC Class Codes: H02K 9/225 Heat pipes

Abstract

An electric motor cooling system is provided in which at least one heat pipe is captured within at least one hollow region within the motor'"'"'s rotor shaft. An end of the heat pipe that extends out and away from the end of the rotor shaft is coupled to a heat exchanger, for example a heat sink in which the fins of the heat sink are shaped as fan blades. During motor operation, as the rotor heats up thermal energy is absorbed by the heat pipe within the rotor shaft and transferred to the heat sink for efficient removal.

Claims

1. An electric motor cooling system, comprising:

an electric motor rotor assembly comprised of a core assembly rigidly coupled to a rotor shaft, said rotor shaft comprising;

a first end of said rotor shaft, wherein said first end is closed;

a second end of said rotor shaft distal from said first end, wherein said second end of said rotor shaft includes at least one opening;

a least one hollow region within said rotor shaft and extending from said at least one opening in said second end towards said first end of said rotor shaft;

at least one heat pipe, wherein a first portion of said at least one heat pipe is captured within said at least one hollow region within said rotor shaft, wherein said first portion of said at least one heat pipe is thermally coupled to said rotor shaft, and wherein a second portion of said at least one heat pipe extends out of and beyond said at least one opening in said second end of said rotor shaft; and

a heat exchanger thermally coupled to said second portion of said at least one heat pipe.

2. The electric motor cooling system of claim 1, wherein a first centerline corresponding to said at least one hollow region is parallel to a second centerline corresponding to said rotor shaft.

3. The electric motor cooling system of claim 2, wherein said first and second centerlines are co-axial.

4. The electric motor cooling system of claim 1, wherein said at least one heat pipe is interference fit within said at least one hollow region of said rotor shaft.

5. The electric motor cooling system of claim 1, wherein said at least one heat pipe is bonded within said at least one hollow region of said rotor shaft.

6. The electric motor cooling system of claim 1, wherein said at least one heat pipe is brazed within said at least one hollow region of said rotor shaft.

7. The electric motor cooling system of claim 1, wherein said at least one heat pipe is soldered within said at least one hollow region of said rotor shaft.

8. The electric motor cooling system of claim 1, wherein said at least one hollow region is comprised of a single hollow region within said rotor shaft, wherein a first centerline corresponding to said single hollow region is co-axial with a second centerline corresponding to said rotor shaft, and wherein said at least one heat pipe is comprised of a single heat pipe captured within said single hollow region.

9. The electric motor cooling system of claim 1, wherein said at least one hollow region is comprised of a single hollow region within said rotor shaft, wherein a first centerline corresponding to said single hollow region is co-axial with a second centerline corresponding to said rotor shaft, and wherein said at least one heat pipe is comprised of a plurality of heat pipes captured within said single hollow region.

10. The electric motor cooling system of claim 9, wherein each of said plurality of heat pipes is partially flattened to form a plurality of elliptically-shaped heat pipes.

11. The electric motor cooling system of claim 1, wherein said at least one hollow region is comprised of a plurality of hollow regions within said rotor shaft, wherein each centerline corresponding to each of said plurality of hollow regions is parallel to and spaced apart from a rotor shaft centerline, and wherein said at least one heat pipe is comprised of a plurality of heat pipes corresponding to said plurality of hollow regions.

12. The electric motor cooling system of claim 1, wherein said heat exchanger is comprised of a heat sink attached to said second portion of said at least one heat pipe.

13. The electric motor cooling system of claim 12, wherein said heat sink is comprised of a plurality of fan blades.

14. The electric motor cooling system of claim 13, wherein said plurality of fan blades is comprised of a plurality of radial fan blades.

15. The electric motor cooling system of claim 13, wherein said plurality of fan blades is comprised of a plurality of forward curved fan blades.

16. The electric motor cooling system of claim 13, wherein said plurality of fan blades is comprised of a plurality of backward curved fan blades.

17. The electric motor cooling system of claim 13, wherein said plurality of fan blades is comprised of a plurality of axial fan blades.

18. The electric motor cooling system of claim 13, further comprising a fan shroud at least partially surrounding said plurality of fan blades.

19. The electric motor cooling system of claim 1, further comprising a liquid cooling system thermally coupled to said heat exchanger.

20. The electric motor cooling system of claim 1, wherein said at least one heat pipe is fabricated from a material selected from the group of materials consisting of copper, copper alloys, nickel, stainless steel, and aluminum, and wherein a working fluid contained within each of said at least one heat pipes is selected from the group of working fluids consisting of water, acetone, methanol, ammonia and combinations of at least some of water, acetone, methanol and ammonia.

21. The electric motor cooling system of claim 20, wherein each of said at least one heat pipes further comprise a wicking material.