Electric motor assemblies including stator and/or rotor cooling

• US 8,963,384 B2
• Filed: 06/21/2011
• Issued: 02/24/2015
• Est. Priority Date: 06/21/2010
• Status: Active Grant

• Current Assignee: Nidec Motor Corporation (Nidec Corporation)
• Original Assignee: Nidec Motor Corporation (Nidec Corporation)
• Inventors: Kirkley, Thomas E. Jr., Wittman, Lawrence J., Poag, Andrew F., Randall, Steven P.
• Primary Examiner(s): Andrews, Michael
• Application Number:
  US13/164,876
• Publication Number:
  US 20110309697A1
• Time in Patent Office: 1,344 Days
• Field of Search: 310/54, 310/58, 310/59
• US Class Current: 310/58
• CPC Class Codes: H02K 1/2766 having a flux concentration effect
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 3/24 with channels or ducts for cooling medium between the conductors
• CPC Class Codes: H02K 5/203 specially adapted for liquids, e.g. cooling jackets
• CPC Class Codes: H02K 7/083 radially supporting the rotary shaft at both ends of the rotor H02K7/086, H02K7/09 take precedence
• CPC Class Codes: H02K 9/19 for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil

Abstract

An electric motor assembly including a stator having a stator core and windings around the stator core is disclosed. The stator core has opposing ends and an outer surface extending between the opposing ends. The electric motor assembly also includes a housing having an inner surface enclosing at least a portion of the stator, and at least one fluid passage between the outer surface of the stator core and the inner surface of the housing. The fluid passage permits a coolant in the fluid passage to contact one or more portions of the outer surface of the stator core to remove heat from the stator core during operation of the electric motor assembly. Additional motor assemblies including stator and/or rotor cooling features are disclosed.

Claims

1. An electric motor assembly comprising:

a stator including a stator core and windings around the stator core, the stator core having opposing ends spaced from one another along an axis and an outer surface extending between the opposing ends;

a housing having an inner surface enclosing at least a portion of the stator; and

at least one fluid passage between the outer surface of the stator core and the inner surface of the housing, the fluid passage having a substantially S-shaped configuration,

said fluid passage including—

a plurality of generally axially extending passage sections defined between a passage inlet and a passage outlet, and

a plurality of turns each interconnecting an adjacent pair of first and second passage sections such that fluid flows along the passage in the first passage section in an at least substantially opposite direction than in the second passage section,

said fluid passage extending generally circumferentially about at least a portion of the stator such that the inlet and outlet are generally diametrically opposed,

said inlet and said outlet being spaced at least substantially the same distance from one of the opposing ends of the stator,

said fluid passage permitting a coolant in the fluid passage to remove heat from the stator core during operation of the electric motor assembly,

said inlet and said outlet being spaced at least substantially equally between the opposing ends of the stator.

2. The assembly of claim 1 wherein the fluid passage includes at least one flow disruptor to generate turbulence in the coolant as the coolant flows through the fluid passage.

3. The assembly of claim 1 wherein the fluid passage permits the coolant in the fluid passage to contact one or more portions of the outer surface of the stator core for removing heat from the stator core during operation of the electric motor assembly.

4. The assembly of claim 3 wherein the housing inner surface has a recessed channel extending therein, the outer surface of the stator core and the recessed channel of the housing inner surface define the at least one fluid passage, and the housing inner surface engages the outer surface of the stator core at a plurality of locations about the circumference of the stator along an entire axial length of the stator core, the stator core axial length extending between its opposing ends.

5. The assembly of claim 4 wherein the recessed channel presents a maximum axial dimension,

said axial dimension of the channel being less than the axial length of the stator core.

6. The assembly of claim 1 wherein the housing includes a fluid collection area adjacent the passage outlet,

said fluid collection area and said outlet positioned below the stator.

7. The assembly of claim 1 wherein the fluid passage extends along a central portion of the stator core such that the passage sections are positioned at least substantially centrally between the opposing ends of the stator.

8. The assembly of claim 7,

each of said passage sections being spaced axially equidistantly from the opposing ends of the stator core.

9. The assembly of claim 1 wherein the assembly comprises two of said fluid passages, said fluid passages extending generally circumferentially around opposite sides of the stator core.

10. The assembly of claim 1 wherein the stator windings include end turns, the assembly further comprising at least one orifice for spraying coolant on the end turns during operation of the electric motor assembly.

11. The assembly of claim 1 further comprising a rotor having at least one fluid passage extending along or through the rotor, the rotor fluid passage permitting a coolant therein to contact one or more portions of the rotor for removing heat from the rotor during operation of the electric motor assembly.

12. The assembly of claim 11 further comprising an end plate coupled to an end of the rotor, the end plate including at least one fluid port in fluid communication with the rotor fluid passage, and an impeller for drawing coolant into the fluid port and through the rotor fluid passage when the rotor and the end plate are rotated during operation of the electric motor assembly.

13. The assembly of claim 1,

said turns being configured such that fluid flow at least substantially reverses direction in each turn.

14. The assembly of claim 13,

said turns being at least substantially U-shaped.

15. The assembly of claim 1,

each of said passage sections being sloped slightly toward the outlet such that fluid in each passage section flows toward the outlet.