Rotor assembly for an electric machine with thermal management features

• US 10,523,079 B2
• Filed: 09/06/2013
• Issued: 12/31/2019
• Est. Priority Date: 09/06/2013
• Status: Active Grant

• Current Assignee: GE Aviation Systems LLC (GE Aerospace)
• Original Assignee: GE Aviation Systems LLC (GE Aerospace)
• Inventors: Huang, Hao, Jia, Xiaochuan, Wirsch, Jr., Paul James
• Primary Examiner(s): Lian, Mang Tin Bik
• Assistant Examiner(s): Almawri, Maged M
• Application Number:
  US14/916,700
• Publication Number:
  US 20160204663A1
• Time in Patent Office: 2,307 Days
• Field of Search: 310262, 310216051, 310261086, 310269, 3102611-266, 310216001-216091, 310 52- 64
• CPC Class Codes: H02K 1/02 characterised by the magnetic material
• CPC Class Codes: H02K 1/24 Rotor cores with salient poles ; Variable reluctance rotors
• CPC Class Codes: H02K 1/26 Rotor cores with slots for windings
• CPC Class Codes: H02K 1/265 Shape, form or location of the slots
• CPC Class Codes: H02K 1/28 Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium
• CPC Class Codes: H02K 1/325 between salient poles
• CPC Class Codes: H02K 19/02 Synchronous motors
• CPC Class Codes: H02K 19/16 Synchronous generators
• CPC Class Codes: H02K 19/38 Structural association of synchronous generators with exciting machines
• CPC Class Codes: H02K 3/18 Windings for salient poles
• CPC Class Codes: H02K 3/52 Fastening salient pole windings or connections thereto
• CPC Class Codes: H02K 3/527 applicable to rotors only
• CPC Class Codes: H02K 9/02 by ambient air flowing through the machine
• 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 9/223 Heat bridges
• CPC Class Codes: H02K 9/227 Heat sinks

Abstract

A rotor assembly (40) for an electric machine including a core (42) having at least one post (44) about which a winding may be wound, and a cap (52) coupled to the post (44) and having a portion overlying a winding (46), wherein the cap (52) comprises a plurality of laminations and the core (42) does not comprise a plurality of laminations.

Claims

1. A rotor assembly for an electric machine comprising:

a non-lamination structure defining a core comprising a unitary body with a hollow center and having at least one post comprising;

a base portion formed at the core proximate the hollow center, and

a branched portion having at least two branches extending radially from the base portion toward an outer surface, defining a recess extending radially inward from the outer surface, and at least partially defining a winding seat;

a cap comprising a plurality of laminations, at least one projection received within the at least one recess, and having a portion overlying the winding to collectively define an axially extending winding slot with the core;

a winding wound about the branched portion of the post, overlying the projection, and received by the winding seat to define a pole for the electric machine; and

a coolant path defined at least in part by the base portion of the post;

wherein the cap is made of material that is less electrically conductive than the core.

2. The rotor assembly of claim 1 wherein the core comprises a body formed from additive manufacturing.

3. The rotor assembly of claim 1 wherein the core further comprises:

at least one radial coolant passage, the at least one radial coolant passage extending radially outward from a center of the core;

at least one cooling channel adjacent at least a portion of the winding slot, the at least one cooling channel extending radially outward from the radial coolant passage; and

a layer between the at least one cooling channel and the at least a portion of the winding slot,

wherein the layer is electrically isolating, and

wherein the layer is thermally conductive.

4. The rotor assembly of claim 1 wherein the winding seat is rotationally offset relative to the at least one post.

5. The rotor assembly of claim 1 wherein the core is made from material that is thermally more conductive than the cap.

6. The rotor assembly of claim 5 wherein in the cap is made from cobalt and the core is made from steel.

7. The rotor assembly of claim 1 wherein the core further comprises a thermal conductor provided on the winding seat.

8. The rotor assembly of claim 7 wherein the thermal conductor is a coating applied to the winding seat.

9. The rotor assembly of claim 1 further comprising:

at least one wedge biasing the winding into the winding seat; and

at least one radial element comprising a recess, the at least one radial element mechanically coupled to the core, the recess receiving a projection radially extending from the core and mechanically coupling the at least one radial element to the core,

wherein the at least one wedge is disposed between the at least one radial element and the core.

10. The rotor assembly of claim 9 wherein the at least one wedge comprises a biasing element.

11. The rotor assembly of claim 1 wherein the cap is removably coupled to the core.

12. The rotor assembly of claim 11 wherein one of the cap and the core comprises a projection, the other of the cap and the core comprises a recess, and the projection is received within the recess to removably couple the cap to the core.

13. The rotor assembly of claim 12 wherein the projection and recess have complementary cross sections.

14. The rotor assembly of claim 13 wherein the complementary cross sections are at least one of:

at least partially circular or at least partially trapezoidal.

15. A rotor assembly for an electric machine comprising:

a core having a plurality of poles, the plurality of poles spaced about the assembly, each pole of the plurality of poles comprising;

at least one post having a base portion formed at the core and a branched portion having at least two branches extending radially from the base portion toward an outer surface, defining a recess extending radially inward from the outer surface, and at least partially defining a winding seat;

at least one cap comprising a plurality of laminations, at least one projection received within the at least one recess and having a portion overlying the at least one winding to collectively define an axially extending winding slot with the core;

a plurality of radial elements spaced about the assembly such that each radial element of the plurality of radial elements alternates about the assembly with poles of the plurality of poles;

a winding wound about the branched portion of the post, overlying the projection, and received by the winding seat to define a pole for the electric machine; and

a coolant path defined at least in part by the base portion of the post,

wherein the at least one cap is less electrically conductive than the core-and the core does not comprise a plurality of laminations.

16. The rotor assembly of claim 15, wherein a plurality of second projections extends radially outward from the core and a plurality of second recesses are disposed within the plurality of radial elements receive the plurality of second projections, and

wherein the plurality of second projections and the plurality of second recesses mechanically couple the plurality of radial elements to the core.

17. The rotor assembly of claim 16 further comprising:

a central coolant passage extending axially along an interior of the core;

at least one radial coolant passage fluidly coupling the central coolant passage to the at least one radial coolant passage; and

a plurality of coolant passage holes spaced around the interior of the core;

wherein each coolant passage hole of the plurality of coolant passage holes aligns with one of the at least one radial coolant passage.

18. A rotor assembly for an electric machine comprising:

a non-lamination structure defining a core having at least one post about which a winding is wound to define a pole for the electric machine, with the at least one post comprising a base portion formed at the core, and a branched portion having at least two branches extending radially from the base portion toward an outer surface, defining a recess extending radially inward from the outer surface, and at least partially defining a winding seat in which the winding is received; and

a lamination structure defining a cap having at least one projection coupled to the post when the at least one projection is received within the recess and having a portion overlying the winding to collectively define an axial extending winding slot with the core, the cap comprising at least one corner finger engaged to a complementary portion of the core and spaced from the winding, the at least one corner finger comprising a trapezoidal cross section; and

a coolant path defined at least in part by the base portion of the post,

wherein the winding is wound about the branched portion of the post and overlies the projection, and

wherein the lamination structure defining a cap is less electrically conductive than the non-lamination structure defining the core.

19. The rotor assembly of claim 18, wherein a cross-section of the winding comprises a rectangular shape, the rotor assembly further comprising:

an axially extending wedge abutting the winding on a first side of the winding;

an axially extending internal coolant passage abutting the winding on a radially inward second side of the winding; and

a radially extending coolant passage abutting the winding on a third side of the winding;

wherein the cap abuts the winding on a radially outward fourth side of the winding.

20. The rotor assembly of claim 18 further comprising at least one internal coolant passage, the at least one internal coolant passage extending axially, the at least one internal coolant passage adjacent to the at least one post;

and

at least one radial coolant passage fluidly coupled to the at least one internal coolant passage at a radially outward end of the at least one radial coolant passage;

wherein the at least one internal coolant passage comprises coolant.