Electric machine having offset rotor sections

• US 9,641,033 B2
• Filed: 09/06/2013
• Issued: 05/02/2017
• Est. Priority Date: 09/06/2013
• Status: Active Grant

• Current Assignee: Westinghouse Air Brake Technologies Corporation
• Original Assignee: General Electric Company
• Inventors: Papini, Francesco, Fiseni, Alexander Felix, Osama, Mohamed
• Primary Examiner(s): Kenerly, Terrance
• Application Number:
  US14/019,630
• Publication Number:
  US 20150069863A1
• Time in Patent Office: 1,334 Days
• Field of Search: 31015653, 31015609, 310216121, 310216122, 310216123
• CPC Class Codes: H02K 1/2766 having a flux concentration effect
• 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 15/02 of stator or rotor bodies
• CPC Class Codes: H02K 2201/06 Magnetic cores, or permanent magnets characterised by their skew
• CPC Class Codes: H02K 7/003 Couplings; Details of shafts means for mounting rotors on shafts H02K1/28
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine
• CPC Class Codes: Y10T 29/49012 Rotor

Abstract

A motor rotor assembly that includes multiple motor rotor sections and a rotor bar that extends through the motor rotor sections, such that the rotor bar and the motor rotor sections are configured such that the rotor sections are step-skewed, or continuously skewed, from each other. The assembly may be used in an IPM or Synchronous Reluctance motor; and, the motor rotor sections may be of solid core or laminations. Various assembly components, IPM and Synchronous Reluctance motors, and methods of construction/assembly are also disclosed. The present invention has been described in terms of specific embodiment(s), and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.

Claims

1. A rotor shaft component comprising:

a longitudinal axle having a plurality of keybars extending outward from a surface of the longitudinal axle, wherein each of the plurality of keybars are disposed axially along and circumferentially around the longitudinal axle, further wherein an axis of the plurality of keybars is parallel to the longitudinal axle, wherein a portion each of the plurality of keybars overlap an adjacent keybar in a circumferential direction, wherein each of the plurality of keybars are configured to receive a corresponding key on a corresponding rotor section of a plurality of rotor sections, thereby defining a stacked rotor assembly having a step-skewed configuration.

2. The component of claim 1, wherein the plurality of keybars has a helical profile.

3. The component of claim 1, wherein each of the plurality of keybars are straight.

4. The component of claim 1, wherein each of the plurality of rotor sections comprises a plurality of rotor laminations.

5. The component of claim 1, wherein each of the plurality of rotor sections comprises a solid core section.

6. The component of claim 1, wherein the stacked rotor assembly is configured for use in one of an interior permanent magnet (IPM) machine and a Synchronous Reluctance motor.

7. The component of claim 1, wherein the plurality of keybars are disposed circumferentially around the longitudinal axis, wherein a skew angle, θ

_seat, is an angle between adjacent rotor sections.

8. The component of claim 7, wherein the skew angle, θ

_seat, is selected to provide a shift in a torque vs. rotor position profile of the plurality of rotor sections, thereby reducing torque ripple.

9. The component of claim 7, wherein an offset θ

_key between adjacent keybars comprises θ

_sect+θ

₀, wherein θ

₀ comprises an additional mechanical offset for clearance for adjacent rotor sections.

10. The component of claim 1, wherein the plurality of keybars comprises a first set of keybars, the component further comprising a second set of keybars, wherein each of the keybars of the second set of keybars is located circumferentially opposite a keybar of the first set of keybars.

11. An assembly comprising:

a plurality of motor rotor sections, wherein each of the plurality of motor rotor sections comprise a solid core rotor core section, and wherein each of the plurality of motor rotor section has a key; and

a rotor bar extending through the plurality of motor rotor sections, the rotor bar including a longitudinal axle having a plurality of keybars extending outward from a surface of the longitudinal axle, wherein each of the plurality of keybars are disposed axially along and circumferentially around the longitudinal axle, further wherein an axis of the plurality of keybars is parallel to the longitudinal axle, and wherein a portion each of the plurality of keybars overlap an adjacent keybar in a circumferential direction,

wherein each of the plurality of keybars are configured to receive a corresponding key on a corresponding motor rotor section of the plurality of motor rotor sections, thereby defining a stacked rotor assembly having a step-skewed configuration.

12. The assembly of claim 11, further comprising a plurality of end plates having the plurality of motor rotor sections located therebetween.

13. The assembly of claim 11, further comprising a plurality of magnets located within the motor rotor sections.

14. An interior permanent magnet (IPM) machine comprising the assembly of claim 13, and, a stator surrounding the assembly.

15. The IPM machine of claim 14, wherein the assembly is configured to reduce torque ripple in the IPM machine.

16. The assembly of claim 13, wherein the plurality of magnets comprise a material of at least one of ferrite, alnico, and a rare earth metal.

17. A Synchronous Reluctance motor comprising the assembly of claim 11, and, a stator surrounding the assembly.

18. The Synchronous Reluctance motor of claim 17, wherein the assembly is configured to reduce torque ripple in the Synchronous Reluctance motor.

19. An Interior Permanent Magnet (IPM) machine rotor comprising:

a rotor shaft component including a longitudinal axle having a plurality of keybars extending outward from a surface of the longitudinal axle, wherein each of the plurality of keybars are disposed axially along and circumferentially around the longitudinal axle, further wherein an axis of the plurality of keybars is parallel to the longitudinal axle, wherein a portion each of the plurality of keybars overlap an adjacent keybar in a circumferential direction; and

a plurality of motor rotor sections, each of the plurality of motor rotor section having a key,

wherein each of the plurality of keybars are configured to receive a corresponding key on a corresponding motor rotor section of the plurality of motor rotor sections, thereby defining a stacked rotor assembly of an Interior Permanent Magnet (IPM) machine rotor having a step-skewed configuration, and

wherein the plurality of motor rotor sections are solid core.

20. The IPM machine rotor of claim 19, wherein the plurality of motor rotor sections are laminated.

21. A Synchronous Reluctance motor rotor comprising:

a rotor shaft component including a longitudinal axle having a plurality of keybars extending outward from a surface of the longitudinal axle, wherein each of the plurality of keybars are disposed axially along and circumferentially around the longitudinal axle, further wherein an axis of the plurality of keybars is parallel to the longitudinal axle, wherein a portion each of the plurality of keybars overlap an adjacent keybar in a circumferential direction; and

a plurality of motor rotor sections assembled along the rotor shaft component and defining a rotor stack assembly, each of the plurality of motor rotor section having a key,

wherein each of the plurality of keybars are configured to receive a corresponding key on a corresponding motor rotor section of the plurality of motor rotor sections, thereby defining a stacked rotor assembly of a Synchronous Reluctance motor rotor having a step-skewed configuration with a skew angle, θ

_sect, defined by the following equation;

θ

_sect=θ

_skew /(N_sect−

1),

where

θ

_skew is a rotor skew angle between end sections of the rotor stack assembly; and

N_sect is a number of the plurality of motor rotor sections.

22. The Synchronous Reluctance motor rotor of claim 21, wherein the plurality of motor rotor sections are laminated.

23. The Synchronous Reluctance motor rotor of claim 21, wherein the plurality of motor rotor sections are solid core.