BRUSHLESS PM MACHINE CONSTRUCTION ENABLING LOW COERCIVITY MAGNETS

US 20120217834A1
Filed: 02/28/2012
Published: 08/30/2012
Est. Priority Date: 02/28/2011
Status: Active Grant

First Claim

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1. A brushless permanent magnet machine comprising:

a rotor that is essentially circular shaped;

a pair of magnets arranged in the rotor, the pair of magnets each being U-shaped and having a thickness direction extending along a contour of the corresponding magnet between the opposite poles of the corresponding magnet, respectively,wherein the pair of magnets are each composed of a non-rare earth material having a lower coercivity than a rare earth material, andwherein a direction of magnetization of each of the pair of magnets is parallel to the thickness direction of the corresponding magnet.

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Abstract

The present disclosure provides a brushless permanent magnet machine which includes an essentially circular shaped rotor, and a pair of magnets arranged in the rotor. The magnets are each U-shaped and have a thickness direction extending along a contour of the corresponding magnet between the opposite poles of the corresponding magnet, respectively. The magnets are each composed of a non-rare earth material having a lower coercivity than a rare earth material. A direction of magnetization of each of the pair of magnets is parallel to the thickness direction of the corresponding magnet. The present disclosure also provides a method of manufacturing such a brushless permanent magnet machine.

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22 Claims

1. A brushless permanent magnet machine comprising:
- a rotor that is essentially circular shaped;
  
  a pair of magnets arranged in the rotor, the pair of magnets each being U-shaped and having a thickness direction extending along a contour of the corresponding magnet between the opposite poles of the corresponding magnet, respectively,wherein the pair of magnets are each composed of a non-rare earth material having a lower coercivity than a rare earth material, andwherein a direction of magnetization of each of the pair of magnets is parallel to the thickness direction of the corresponding magnet.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- - 2. The brushless permanent magnet machine according to claim 1,wherein the pair of magnets are adjacent to each other in the rotor and have opposite polarities such that sides of the pair of magnets immediately adjacent to each other have the same polarity, andwherein the direction of magnetization of each of the pair of magnets is toward the sides of the magnets which are immediately adjacent to each other.
  - 3. The brushless permanent magnet machine according to claim 1, wherein the non-rare earth material having a lower coercivity than a rare earth material is one of Aluminum Nickel Cobalt (AlNiCo) and Iron Cobalt Tungsten (FeCoW).
  - 4. The brushless permanent magnet machine according to claim 1, wherein the pair of magnets are surrounded by a material having low permeability and low resistivity.
  - 5. The brushless permanent magnet machine according to claim 4, wherein the material having low permeability and low resistivity has low conductivity and is non-ferromagnetic.
  - 6. The brushless permanent magnet machine according to claim 5, wherein the material having low permeability and low resistivity is selected from the group consisting of plastics, epoxies, polymers, fiberglass, and carbon fiber.
  - 7. The brushless permanent magnet machine according to claim 1, wherein the pole faces of the magnets in the pair are connected by a soft magnetic material in the rotor.
  - 8. The brushless permanent magnet machine according to claim 7, wherein the soft magnetic material is constituted by a material selected from the group consisting of iron, silicon-steel, and nickel-iron.
  - 9. The brushless permanent magnet machine according to claim 1, comprising:
    - a plurality of retainers respectively arranged in a corresponding one of each concave portion of the U-shaped magnets to secure the pair of magnets in the rotor.
  - 10. The brushless permanent magnet machine according to claim 9, wherein the retainers are non-magnetic.
  - 11. The brushless permanent magnet machine according to claim 1, comprising:
    - an extension component in one of the magnets of the pair and a mating receiving component in the other one of the magnets of the pair to receive the extension component of the one of the magnets.
  - 12. The brushless permanent magnet machine according to claim 1, comprising:
    - a plurality of retaining rods provided in a corresponding one of a concave portion of the U-shaped pair of magnets; and
      
      a cap having receiving components corresponding to the retaining rods,wherein the cap is configured to be secured with the retaining rods to secure the rotor.
  - 13. The brushless permanent magnet machine according to claim 1, wherein the rotor has a non-uniform diameter at a portion of the rotor in which the pair of magnets interface.
  - 14. The brushless permanent magnet machine according to claim 1, wherein at least one of the magnets in the pair is constituted by a continuous structure between opposite poles of the at least one magnet.
  - 15. The brushless permanent magnet machine according to claim 1, wherein at least one of the magnets in the pair is segmented into at least two separate pieces.

16. A method of manufacturing a brushless permanent magnet machine, comprising:
- arranging a pair of a magnets in a rotor that is essentially circular shaped;
  
  forming each of the pair of magnets to be a U-shape with a thickness direction extending along a contour of the corresponding magnet between the opposite poles of the magnet, respectively; and
  
  forming each of the pair of magnets to be composed of a non-rare earth material having a lower coercivity than a rare earth material, such that a direction of magnetization of each of the pair of U-shaped magnets is parallel to the thickness direction of the corresponding magnet.
- View Dependent Claims (17, 18, 19, 20, 21, 22)
- - 17. The method of manufacturing a brushless permanent magnet machine according to claim 16, comprising:
    - arranging the pair of magnets to be adjacent to each other in the rotor and have opposite polarities such that sides of the pair of magnet immediately adjacent to each other have the same polarity and the direction of magnetization is toward the sides of the magnets which are immediately adjacent to each other.
  - 18. The method of manufacturing a brushless permanent magnet machine according to claim 16, wherein the non-rare earth materials having a lower coercivity than a rare earth material is one of Aluminum Nickel Cobalt (AlNiCo) and Iron Cobalt Tungsten (FeCoW).
  - 19. The method of manufacturing a brushless permanent magnet machine according to claim 16, comprising:
    - surrounding the pair of magnets in the rotor by a material having low permeability and low resistivity.
  - 20. The method of manufacturing a brushless permanent magnet machine according to claim 16, comprising:
    - connecting the pole faces of each of the pair of magnets by a soft magnetic material in the rotor.
  - 21. The method of manufacturing a brushless permanent magnet machine according to claim 16, comprising:
    - arranging a plurality of retainers respectively in a corresponding one of each concave portion of the U-shaped magnets to secure pair of magnets in the rotor.
  - 22. The method of manufacturing a brushless permanent magnet machine according to claim 16, comprising:
    - arranging a plurality of retaining rods in a corresponding one of a concave portion of the U-shaped pair of magnets; and
      
      securing a cap having receiving components corresponding to the retaining rods to the retaining rods.

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Current Assignee
Danfoss Power Solutions (US) Company (Danfoss A/S)
Original Assignee
UQM Technologies, Inc. (Danfoss A/S)
Inventors
LEY, Josh, LUTZ, Jon

Granted Patent

US 8,928,198 B2
Time in Patent Office

Days
Field of Search
US Class Current

310/156.39
CPC Class Codes

H02K 1/2753   the rotor consisting of mag...

H02K 1/2766   having a flux concentration...

Y02T 10/64   Electric machine technologi...

Y10T 29/49012   Rotor

BRUSHLESS PM MACHINE CONSTRUCTION ENABLING LOW COERCIVITY MAGNETS

First Claim

3 Assignments

0 Petitions

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Abstract

24 Citations

22 Claims

Specification

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BRUSHLESS PM MACHINE CONSTRUCTION ENABLING LOW COERCIVITY MAGNETS

First Claim

3 Assignments

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0 Petitions

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Accused Products

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Abstract

24 Citations

22 Claims

Specification

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Solutions

Use Cases

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