Levitation system with permanent magnets and coils

• US 5,168,183 A
• Filed: 03/27/1991
• Issued: 12/01/1992
• Est. Priority Date: 03/27/1991
• Status: Expired due to Term

• Current Assignee: Levitation Arts, Inc., British Columbia Cancer Agency Branch (Province of British Columbia)
• Original Assignee: University of British Columbia
• Inventors: Whitehead, Lorne A. R.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): HASZKO, DENNIS
• Application Number:
  US07/676,066
• Time in Patent Office: 615 Days
• Field of Search: 310/12, 310/90.5, 310/13, 310/14, 104/284
• US Class Current: 310/12.09
• CPC Class Codes: F16C 32/044 Active magnetic bearings
• CPC Class Codes: H02N 15/00 Holding or levitation devices using magnetic attraction or repulsion, not otherwise provided for electric or magnetic devices for holding work on machine tools B23Q3/15 ; monorail vehicle propulsion or suspension B60L13/00; sliding or levitation devices for railway systems B61B13/08; material handling devices associated with conveyors incorporating devices with electrostatic or magnetic grippers B65G47/92; separating thin or filamentary articles from piles using magnetic force B65H3/16; delivering thin or filamentary articles from magnetic holders by air blast or suction B65H29/24; bearings using magnetic or electric supporting means F16C32/04; relieving bearing loads using magnetic means F16C39/06; magnets H01F7/00; dynamo-electric clutches or brakes H02K49/00 ; electric furnaces with simultaneous levitation and heating H05B6/32

Abstract

A levitation system for levitating a levitated magnetic element in a stable suspended position on one side of a separating plane using a magnetic arrangement on the opposite side of the separating plane. The magnetic arrangement provides a preselected static magnetic field configuration that interacts with a magnet in the levitated element so that the magnetic potential energy of this interaction increases for displacements of the element from its stable position in directions parallel to a stability plane and decreases for displacements of the element from the stable position perpendicular to the stability plane. Any movement perpendicular to the stability plane is sensed and used by a feedback control system to control a force applied to the levitated element to stabilize the element against displacement from the stable position in directions perpendicular to the stability plane.

Claims

1. A levitating system comprising a levitating device positioned on one side of a separating plane for maintaining a levitated element at a substantially stable position on the side of said separating plane remote from said one side and wherein said levitated element includes magnetic means defining a magnetic region, and said levitating device comprises a static magnetic means producing a preselected static magnetic field configuration such that said levitated element is levitated by said magnetic field configuration interacting with said magnetic region to cause magnetic potential energy of said interaction to increase for substantially all displacements of said levitated element from said stable position in directions parallel to a preselected stability plane and said magnetic potential energy to decrease for any displacement of said levitated element from said stable position in a direction perpendicular to said stability plane, a sensor means generating a signal dependent on displacement of said levitated element in said direction perpendicular to said stability plane, a non contacting controllable force means and a feedback control means, said feedback control means receiving said signal from said sensor means and controlling said controllable force means to stabilize said levitated element against displacement from said stable position in said direction perpendicular to said stability plane.

2. A levitating system as defined in claim 1 wherein said static magnetic means comprises a first magnetic means which stabilizes said levitated element against displacement from said stable position parallel to a first direction within said stability plane and a second magnetic means which stabilizes said levitated element against displacements parallel to a second direction within said stability plane and wherein said second direction is substantially perpendicular to said first direction.

3. A levitating system as defined in claim 1 wherein said magnetic means forming said magnetic region is formed by at least one magnet having a polarization substantially parallel to a preselected magnetic direction and wherein said magnetic region has a maximum dimension which is significantly less than the minimum distance between said at least one magnet and said static magnetic means.

4. A levitating system as defined in claim 1 wherein said stability plane is substantially parallel to a straight line between the center of said static magnetic means and the center of said magnetic region.

5. A levitating system as defined in claim 3 wherein said static magnetic means comprises a first magnetic means which stabilizes said levitated element against displacement from said stable position parallel to a first direction within said stability plane and a second magnetic means which stabilizes said levitated element against displacements parallel to a second direction within said stability plane and wherein said second direction is substantially perpendicular to said first direction.

6. A levitating system as defined in claim 4 wherein said static magnetic means comprises a first magnetic means which stabilizes said levitated element against displacement from said stable position parallel to a first direction within said stability plane and a second magnetic means which stabilizes said levitated element against displacements parallel to a second direction within said stability plane and wherein said second direction is substantially perpendicular to said first direction.

7. A levitating system as defined in claim 4 wherein said magnetic means forming said magnetic region is formed by at least one magnet having a polarization substantially parallel to a preselected magnetic direction and wherein said magnetic region has a maximum dimension which is significantly less than the minimum distance between said at least one magnet and said static magnetic means.

8. A levitating system as defined in claim 5 wherein said stability plane is substantially parallel to a straight line between the center of said static magnetic means and the center of said magnetic region.

9. A levitating system as defined in claim 2 wherein said first magnetic means comprises a pair of spaced bar magnets with their poles facing in a direction parallel to a straight line from the center of said pair of magnets to the center of said magnetic region of said levitated element and wherein said first magnetic means and said magnetic element have their opposite magnetic poles adjacent to each other.

10. A levitating system as defined in claim 6 wherein said first magnetic means comprises a pair of spaced bar magnets with their poles facing in a direction parallel to a straight line from the center of said pair of magnets to the center of said magnetic region of said levitated element and wherein said first magnetic means and said magnetic element have their opposite magnetic poles adjacent to each other.

11. A levitating system as defined in claim 8 wherein said first magnetic means comprises a pair of spaced bar magnets with their poles facing in a direction parallel to a straight line from the center of said magnets to the center of said magnetic region of said levitated element and wherein said first magnetic means and said magnetic element have their opposite magnetic poles adjacent to each other.

12. A levitating system as defined in claim 2 wherein said second magnetic means comprises a second pair of spaced bar magnets with poles facing substantially in the opposite direction as said poles of said first magnetic means.

13. A levitating system as defined in claim 10 wherein said second magnetic means comprises a second pair of spaced bar magnets with poles facing substantially in the opposite direction as said poles of said first magnetic means.

14. A levitating system as defined in claim 11 wherein said second magnetic means comprises a second pair of spaced bar magnets with poles facing substantially in the opposite direction as said poles of said first magnetic means.

15. A levitating system as defined in claim 2 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field, said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

16. A levitating system as defined in claim 4 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

17. A levitating system as defined in claim 6 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

18. A levitating system as defined in claim 7 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

19. A levitating system as defined in claim 8 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

20. A levitating system as defined in claim 9 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

21. A levitating system as defined in claim 10 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

22. A levitating system as defined in claim 11 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

23. A levitating system as defined in claim 12 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

24. A levitating system as defined in claim 13 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

25. A levitating system as defined in claim 14 wherein said controllable force means comprises an electromagnet formed by two coil sections arranged with a gap therebetween, said gap being symmetrically positioned relative to said stability plane, said gap providing a leakage magnetic field, said leakage magnetic field from said gap having a polarity opposite to the polarity of the magnetic field created by said electromagnet in the region surrounding said electromagnet and wherein said leakage field and said surrounding field substantially cancel each other at said stable position.

26. A levitating system as defined in claim in claim 1 wherein said static magnetic means comprises a main magnet having an annular groove formed in a face thereof facing said levitated element and wherein said main magnet and said magnetic means of said levitated element have their opposite magnetic poles adjacent to each other.

27. A levitating system as defined in claim in claim 3 wherein said static magnetic means comprises a main magnet having an annular groove formed in a face thereof facing said levitated element and wherein said main magnet and said magnetic means of said levitated element have their opposite magnetic poles adjacent to each other.

28. A levitating system as defined in claim 26 wherein said controllable force means comprises an electromagnet substantially positioned in and extending around said annular groove.

29. A levitating system as defined in claim 27 wherein said controllable force means comprises an electromagnet substantially positioned in and extending around said annular groove.