Spoke-type PM machine with bridge

Patent metadata

Field	Value
Publication number	US-9692266-B2
Application number	US-201414337833-A
Country	US
Kind code	B2
Filing date	Jul 22, 2014
Priority date	Jul 22, 2014
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A rotor of a permanent magnet synchronous machine includes a rotor core structure. A first set of apertures are formed in a first radial layer of the rotor core structure having a first set of permanent magnets disposed therein forming respective poles. A second set of apertures formed in a second radial layer of the rotor core structure of each pole. A third set of apertures is formed in a third radial layer of the rotor core structure. A second set of permanent magnets is inserted within the third set of apertures. A plurality of bridges each extends across a respective side of each of the third set of apertures in the third radial layer. The plurality of bridges provides structural support of the rotor core structure when operating. The plurality of bridges are integrally formed as single-piece laminations.

First claim

What is claimed is:

1. A rotor of a permanent magnet synchronous machine comprising:
a rotor core structure including a plurality of stacked laminations;
a first set of apertures formed in a first radial layer of the rotor core structure;
a first set of permanent magnets inserted within the first set of apertures forming respective poles within the rotor core structure;
wherein the first set of apertures includes a demagnetization structure formed on an outermost wall of the first set of apertures, wherein the demagnetization structure forms air gaps between the outermost wall of the first set of apertures and the first set of permanent magnets disposed therein;
a second set of apertures formed in a second radial layer of the rotor core structure, each pole including an aperture from the second set of apertures, the second set of apertures formed radially inward from the first set of apertures;
a third set of apertures formed in a third radial layer of the rotor core structure, the third set of apertures is formed radially outward from the first set of apertures;
a second set of permanent magnets inserted within the third set of apertures, wherein a respective pair of permanent magnets within a pole cooperatively generates a magnetic field in a same direction within the pole, and wherein the magnetic field generated by a pair permanent magnets in a respective pole is opposite to a magnetic field generated by permanent magnets in an adjacent pole; and
a plurality of bridges each extending across a respective side of each of the third set of apertures in the third radial layer, the plurality of bridges providing structural support of the rotor core structure when operating, the plurality of bridges being integrally formed as single-piece laminations.

2. The rotor of claim 1 wherein the plurality of bridges include top bridges, wherein the top bridges are disposed between the third set of apertures and the outer circumferential edge and extend across an outermost side of each of the third set of apertures.

3. The rotor of claim 2 wherein the wherein the third set of apertures are an extension of the first set of apertures, wherein an air gap is disposed between the first permanent magnet of each respective pole and the second permanent magnet of each respective pole.

4. The rotor of claim 2 wherein the top bridge reduces mechanical stress at speeds in excess of 15000 rpm.

5. The rotor of claim 2 wherein the top bridge reduces torque ripple during rotor operation.

6. The rotor of claim 2 wherein a width of the top bridge is substantially 2 mm or less.

7. The rotor of claim 1 wherein the plurality of bridges include internal bridges, wherein the internal bridges extend across an innermost side of each of the third set of apertures.

8. The rotor of claim 7 further comprising an open air gap formed on an uppermost side of each of the third set of apertures, the air gap extending from the uppermost side of each of the third set of apertures to an outer circumference wall of the rotor structure.

9. The rotor of claim 8 wherein the open air gap extends to an air gap separating the rotor structure and a stator.

10. The rotor of claim 8 wherein the open air gap extends perpendicular from the outermost wall of the third set of apertures and the outer circumference wall.

11. The rotor of claim 8 wherein the internal bridge reduces mechanical stress at speeds in excess of 15000 rpm.

12. The rotor of claim 8 wherein the internal bridge reduces torque ripple during rotor operation.

13. The rotor of claim 1 wherein the first set of apertures includes a demagnetization structure formed on an innermost wall of the first set of apertures, wherein the demagnetization structure forms air gaps between the innermost wall of the first set of apertures and the first set of permanent magnets disposed therein.

14. The rotor of claim 1 further comprising a third set of permanent magnets inserted within the second set of apertures in the second radial layer.

15. The rotor of claim 14 wherein each of the permanent magnets within the pole cooperatively generates a magnetic field in the same direction within the pole, and wherein the magnetic field generated by the permanent magnets in the respective pole is opposite to the magnetic field generated by permanent magnets in the adjacent pole.

16. The rotor of claim 15 wherein the first set of apertures includes a first demagnetization structure and a second demagnetization structure, wherein the first demagnetization structure is formed on an outermost wall of the first set of apertures, wherein the first demagnetization structure forms air gaps between the outermost wall of the first set of apertures and the first set of permanent magnets disposed therein, wherein the second demagnetization structure is formed on an innermost wall of the first set of apertures, wherein the second demagnetization structure forms air gaps between the innermost wall of the first set of apertures and the first set of permanent magnets disposed therein.

17. The rotor of claim 15 wherein each respective aperture in the second radial layer of the rotor core structure are radially aligned with a respective aperture in the first radial layer of the rotor core structure.

18. The rotor of claim 15 wherein each respective aperture in the first radial layer of the rotor core structure are radially aligned with a respective aperture in the third radial layer of the rotor core structure.

19. The rotor of claim 1 further comprising a fourth set of apertures in the rotor core structure, the fourth set of apertures disposed between each respective pole, the fourth set of apertures reducing the weight of the rotor core structure.

20. The rotor of claim 1 wherein the plurality of permanent magnets in the first radial layer have a residual flux density and coercive force higher than the plurality of permanent magnets in the third radial layer.

21. The rotor of claim 1 wherein the rotor core structure includes a plurality of single piece spoke-type stacked laminations.

22. The rotor of claim 21 wherein each lamination includes a plurality of spokes, each spoke is formed between each juxtaposed pair of apertures of the second set of apertures, the spoke including a main body portion that is substantially rectangular.

23. The rotor of claim 22 wherein the main body portion of each spoke is of a respective length to saturate the spoke for minimizing the amount of magnetic flux to pass through, and wherein the main body portion of each spoke is of a respective width for minimizing mechanical stress exerted on each respective stacked lamination.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Nehl Thomas W
• Hao Lei
• Vyas Rajeev
• Namuduri Chandra S
• Reynolds Michael G

Classifications

• H02K1/2766

  having a flux concentration effect · CPC title

• H02K1/2773 Primary

  consisting of tangentially magnetized radial magnets · CPC title

• H02K1/246

  Variable reluctance rotors · CPC title

• H02K1/276

  Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] · CPC title