Rotational apparatus including a passive magnetic bearing

• US 20080042504A1
• Filed: 08/20/2007
• Published: 02/21/2008
• Est. Priority Date: 08/18/2006
• Status: Active Grant

• Current Assignee: Maglev Technologies, LLC
• Original Assignee: Maglev Technologies, LLC
• Inventors: Williams, Christopher, Irvin, Daniel, Thibodeau, Robert
• Granted Patent: US 7,902,706 B2
• Time in Patent Office: Days
• US Class Current: 310/90.5
• CPC Class Codes: F16C 32/0436 with a conductor on one part movable with respect to a magnetic field, e.g. a body of copper on one part and a permanent magnet on the other part
• CPC Class Codes: F16C 39/063 Permanent magnets
• CPC Class Codes: H01F 7/0236 Magnetic suspension or levitation for vehicles B60L13/04; magnetic bearings F16C39/063
• CPC Class Codes: H02K 7/09 with magnetic bearings

Abstract

A rotational apparatus with one or more passive magnetic bearing(s) is described. The rotational apparatus includes a rotor with a tapered magnetic ring and a stator with a tapered array of shorted conducting circuits. A repulsive force between the tapered magnetic ring and the tapered array of shorted conducting circuits acts a passive magnetic bearing that centers the rotor radially in a stator cavity and that repels the rotor axially away from an end of the stator cavity.

Claims

1. A rotational apparatus with a passive magnetic bearing, the rotational apparatus comprising:

a stator assembly comprising;

a stator body having a cavity with a first cavity end and a central cavity axis passing through a center of the first cavity end; and

a tapered array of shorted conducting circuits supported by the stator body, the tapered array of shorted conducting circuits having an inner profile that defines a tapered shape extending toward the first cavity end; and

a rotor assembly comprising

a rotor body having a first body end and a central body axis passing through the center of first body end, the rotor body including a first tapered portion extending along the central body axis and tapering toward the first body end, wherein a shape of the tapered portion of the rotor body is complementary to the tapered shape of the inner profile of the tapered array of shorted conducting circuits; and

a tapered magnetic ring disposed at the first tapered portion of the rotor body, the tapered magnetic ring having a plurality of magnetic arrays;

wherein the rotor assembly is disposed in the cavity of the stator assembly.

2. The rotational apparatus of claim 1, wherein the plurality of magnetic arrays produces a magnetic field with a substantial component directed at a normal to a surface of the first tapered portion of the rotor body.

3. The rotational apparatus of claim 1, wherein a magnetic field produced by the plurality of magnetic arrays measured at a surface of the first tapered portion of the rotor body has a substantial component directed tangentially with respect to the central body axis and with respect to the surface.

4. The rotational apparatus of claim 1, wherein rotation of the tapered magnetic ring about the central body axis induces current in the tapered array of shorted circuits causing a magnetic force on the tapered magnetic ring directed away from the tapered array of shorted conducting circuits;

and wherein the magnetic force on the tapered magnetic ring has both an inward radial component with respect to the central cavity axis and an axial component relative to the central cavity axis.

5. The rotational apparatus of claim 4, wherein the magnetic force acts to center the rotor assembly with respect to the central cavity axis.

6. The rotational apparatus of claim 1, wherein the plurality of magnetic arrays comprises a plurality of magnetic Halbach arrays, wherein each of the plurality of magnetic Halbach arrays is oriented and positioned to minimize a magnitude of a magnetic field directed into the rotor body.

7. The rotational apparatus of claim 6, wherein each of the plurality of magnetic Halbach arrays comprises five magnetic segments.

8. The rotational apparatus of claim 7, wherein a first end magnetic segment and a last end segment are smaller than middle segments of each array of five segments.

9. The rotational apparatus of claim 1, wherein the tapered magnetic ring of the rotor assembly is opposed to the magnetic array of shorted conducing circuits of the stator assembly when the rotor assembly is rotating.

10. The rotational apparatus of claim 1, wherein the plurality of magnetic arrays of the tapered magnetic ring form a single continuous repeating magnetic array.

11. The rotational apparatus of claim 1, wherein the plurality of arrays of the tapered magnetic ring do not form a non-continuous repeating magnetic array.

12. The rotational apparatus of claim 1, wherein a plurality of shorted conducting circuits in the tapered array of conducting circuits are substantially coplanar with the central cavity axis.

13. The rotational apparatus of claim 1, wherein a shorted conducting circuit in the tapered array of shorted conducting circuits comprises:

an inner conducting segment forming a portion of the inner profile of the tapered array;

an outer conducting segment parallel to the inner conducting segment;

a top conducting segment perpendicular to the inner conducting segment; and

a bottom conducting segment perpendicular to the inner conducting segment.

14. The rotational apparatus of claim 1, wherein the tapered array of shorted conducting circuits is a tapered array of stamped shorted coils.

15. The rotational apparatus of claim 1, wherein a plurality of shorted conducting circuits in the tapered array of conducting circuits are substantially parallel to a first tapered body surface when the rotor assembly is positioned for rotation.

16. The rotational apparatus of claim 1, wherein the plurality of shorted conducting circuits comprises a tapered conducting ring having a plurality of slots formed therethrough.

17. The rotational apparatus of claim 1, wherein the plurality of shorted conducting circuits comprises a plurality of tapered conducting rings, each tapered conducting ring having a plurality of slots formed therethrough.

18. The rotational apparatus of claim 1, wherein the first tapered body surface has a conical shape.

19. The rotational apparatus of claim 1, wherein the first tapered body surface has a spherical shape.

20. The rotational apparatus of claim 1, wherein a profile of the first tapered portion of the rotor body is arcuate.

21. The rotational apparatus of claim 1, wherein the stator assembly further comprises an array of non-shorted conducting circuits.

22. The rotational apparatus of claim 21, wherein the non-shorted conducting circuits are positioned and oriented to exert magnetic torque on the rotor assembly when the non-shorted conducting circuits are supplied with alternating current.

23. The rotational apparatus of claim 21, wherein the non-shorted conducting circuits are positioned and oriented for current to be induced in the non-shorted conducting circuits when the rotor assembly is rotating.

24. The rotational apparatus of claim 21, wherein the rotational apparatus is an electric motor, an electric generator or both.

25. The rotational apparatus of claim 1, wherein the rotor body further comprises an impeller.

26. The rotational apparatus of claim 1, wherein the rotor body further comprises a plurality of rotor blades.

27. The rotational apparatus of claim 1, wherein the stator assembly further comprises a fluid inlet connected with the first end of the cavity and a fluid outlet connected with the second end of the cavity.

28. The rotational apparatus of claim 1, wherein the rotor body further comprises a helical turbine blade.

29. The rotational apparatus bearing of claim 1,

wherein the rotor body has a second body end opposite the first body end and the rotor body includes a second tapered portion extending along the central body axis and tapering toward the second body end;

wherein the tapered magnetic ring tapers toward the first body and and tapers toward the second body end;

wherein the stator body has a second cavity end opposite the first cavity end;

wherein the stator assembly further comprises a second tapered array of shorted conducting circuits supported by the stator body; and

wherein the second tapered array of shorted conducting circuits has an inner profile defining a second tapered shape that is complementary to a second tapered portion of the rotor body.

30. A rotational apparatus with a passive magnetic bearing, the rotational apparatus comprising:

a stator comprising;

an axle portion having a first axle end, a second axle end and a central stator axis passing through the center of the first axle end and the second axle end; and

a first flared array of shorted conducting circuits supported by the axle portion;

wherein an outer profile of the flared array increases toward the first axle end; and

a rotor body having a central channel with a first channel end and a second channel end and a central rotor axis passing through a center of the rotor body, the rotor body having a flared channel surface flaring toward the first channel end, the rotor body comprising;

a magnetic ring comprising a plurality of magnetic arrays;

the magnetic ring disposed at the first channel end and encircling the central channel.

31. The rotational apparatus of claim 30,

wherein a magnetic field produced by the plurality of magnetic arrays measured at the flared surface has a substantial component directed tangentially with respect to a central channel axis and with respect to the flared channel surface, and has a substantial component directed along a normal to the flared channel surface.

32. A rotational apparatus comprising:

a stator assembly comprising;

a stator body having a cavity with a first cavity end, a second end; and

a central cavity axis passing through a center of the first cavity end and a center of the second cavity end;

a first tapered stator bearing array supported by the stator, disposed at the first cavity end, and tapering toward the first cavity end; and

an array of non-shorted conducting circuits supported by the stator body; and

a rotor assembly comprising;

a rotor body having a first rotor end, a second rotor end; and

a central rotor axis passing through a center of the first rotor end and a center of the second rotor end; and

a tapered magnetic ring tapering toward a first rotor end, encircling the central rotor axis and disposed at a radial periphery of the rotor body.

33. The rotational apparatus of claim 32, wherein the tapered magnetic ring and the first tapered stator bearing array form a magnetic bearing that exerts a radial magnetic force on the tapered magnetic ring to center the rotor assembly with respect to the central cavity axis, and that exerts an axial magnetic force on the tapered magnetic ring to prevent the tapered rotor assembly from contacting the tapered stator bearing array.

34. The rotational apparatus of claim 32, wherein the tapered magnetic ring and the array of non-shorted conducting circuits convert between rotational energy and electrical energy.

35. The rotational apparatus of claim 32, wherein the rotational apparatus is an electric generator.

36. The rotational apparatus of claim 32, wherein the rotational apparatus is an electrical motor.

37. The rotational apparatus of claim 32, further comprising a second stator bearing array supported by the stator, disposed at the second cavity end, and tapering toward the second cavity end;

wherein the magnetic rotor array and the second stator bearing array form a second magnetic bearing.

38. The rotational apparatus of claim 32, wherein rotor assembly forms a fluid flow turbine.

39. The rotational apparatus of claim 38, wherein the apparatus is a fluid flow generator.

40. The rotational apparatus of claim 32, wherein the rotor body further comprises at least one rotor blade.

41. The rotational apparatus of claim 40, wherein the tapered magnetic ring is integral with the at least one rotor blade.

42. The rotational apparatus of claim 41, wherein the tapered magnetic ring is formed in one piece with the at least one rotor blade.

43. The rotational apparatus of claim 32, wherein the stator assembly further comprises a fluid inlet connected with the first end of the cavity and a fluid outlet connected with the second end of the cavity.

44. A rotational apparatus comprising:

a stator assembly comprising;

a stator body having an axle portion including a first axle end, a second axle end and a central stator axis passing through the center of the first axle end and the second axle end;

a flared stator bearing array disposed at the first axle end and flaring toward the first axle end; and

an array of non-shorted conducting circuits supported by the stator body; and

a rotor assembly comprising;

a rotor body having a central channel with a first channel end, a second channel end and a central rotor axis passing through a center of the rotor body, the rotor body having a flared channel surface flaring toward the first channel end; and

a first flared magnetic ring including a plurality of magnetic array, the first flared magnetic ring disposed at the first channel end of the rotor body, encircling the central channel, and flared in a direction of the first channel end.

45. The rotational apparatus of claim 44, wherein the flared magnetic ring and the flared stator bearing array form a magnetic bearing that exerts a radial magnetic force on the flared magnetic ring to center the rotor assembly with respect to the central cavity axis, and that exerts an axial force on the flared magnetic ring to prevent the rotor assembly from contacting the flared stator bearing array.

46. The rotational apparatus of claim 44, wherein the flared magnetic ring and the array of non-shorted conducting coils convert between rotational energy and electrical energy.