Linear magnetic motor/generator

• US 4,315,197 A
• Filed: 02/07/1980
• Issued: 02/09/1982
• Est. Priority Date: 02/07/1980
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Studer, Philip A.
• Primary Examiner(s): Dobeck, B.
• Application Number:
  US06/119,336
• Time in Patent Office: 733 Days
• Field of Search: 310/12, 310/15, 335/266, 335/229, 335/236, 318/135
• US Class Current: 318/135
• CPC Class Codes: H02K 33/16 with polarised armatures moving in alternate directions by reversal or energisation of a single coil system
• CPC Class Codes: H02K 35/06 with moving flux distributors, and both coil systems and magnets stationary

Abstract

A linear magnetic motor/generator (10) is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator (10) includes an axially movable actuator mechanism (12). A permanent magnet mechanism (14) defines a first magnetic flux path (16) which passes through a first end portion (18) of actuator mechanism (12). Another permanent magnet mechanism (20) defines a second magnetic flux path (22) which passes through a second end portion (24) of actuator mechanism (12). A drive coil (26) defines a third magnetic flux path (28) passing through a third central portion (30) of actuator mechanism (12). Drive coil (26) selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux paths (16) and (22), respectively, for supplying an axial force to the actuator mechanism (12).

Claims

1. A linear magnetic motor/generator, comprising:

axially moveable actuator means having three portions;

permanent magnet means including a plurality of pairs of transverse and symmetrical magnets substantially aligned radially and transversely with a common axis and equidistantly spaced around and separated from a first portion of said actuator means, thereby defining a first magnetic flux path passing through said first portion of said axially moveable actuator means;

another permanent magnet means including another plurality of pairs of transverse and symmetrical magnets substantially aligned radially and transversely with said common axis and equidistantly spaced around and separated from a second portion of said actuator means thereby defining a second magnetic flux path passing through said second portion of said axially moveable actuator means;

a plurality of magnetically soft end pieces arranged in a plurality of arrays defining a gap between said end pieces and said actuator whereby facing pairs of said end pieces in adjacent arrays are coupled across opposite ends of said pluralities of permanent magnets; and

coil means defining a third magnetic path passing through a third portion of said axially moveable actuator means and selectively modulating magnetic flux flowing in said first and second magnetic flux paths for supplying an axial force to said axially moveable actuator means.

2. The linear magnetic motor/generator of claim 1 wherein said actuator means moves bidirectionally.

3. The linear magnetic motor/generator of claim 1 wherein said first and second flux paths within said gap between said end pieces and said actuator means are normal to the axis of movement of said actuator means.

4. The linear magnetic motor/generator of claim 1 wherein said magnetic flux modulated by said coil means is along sections of said first and second flux paths normal to the axis of movement of said actuator means.

5. The linear magnetic motor/generator of claim 1 wherein said permanent magnet means and

said end pieces are disposed outside the area of axial movement of said three portions of said actuator means thereby defining an open bore gap permitting unobstructed axial movement of said three portions.

6. The linear magnetic motor/generator of claim 5 further including:

a plurality of magnetically soft rings coupled to the peripheries of said end pieces opposite to said magnets.

7. The linear magnetic motor/generator of claim 6 further including a magnetic bridge means coupling said permanent magnet means with said other permanent magnet means.

8. The linear magnetic motor/generator of claim 7 wherein said magnetic bridge means includes a magnetically soft bridge coupled between axially opposed other magnetically soft end pieces of said permanent magnet means and said other permanent magnet means.

9. The linear magnetic motor/generator of claim 8 wherein said first flux path extends from each of said magnets in said plurality of pairs of magnets of said permanent magnet means through said end pieces, radially across said gap, axially through said first portion of said actuator means, radially across said gap, and through said end pieces.

10. The linear magnetic motor/generator of claim 9 wherein said second flux path extends from each of said magnets in said plurality of pairs of magnets of said other permanent magnet means through said end pieces, radially across said gap, axially through said second portion of said actuator means, radially across said gap, and through the opposite of said end pieces.

11. The linear magnetic motor/generator of claim 10 wherein said coil means surrounds said third portion of said actuator means.

12. The linear magnetic motor/generator of claim 11 further including means for axially moving said actuator means, said axial movement causing magnetic flux to flow through said third flux path which induces a current to flow in said coil means.

13. The linear magentic motor/generator of claim 11 wherein said third magnetic flux path extends axially through said third portion of said actuator means, selectively through one of said first portion or said second portion of actuator means, radially across said gap, through said other end pieces, through said magnetically soft bridges, through axially opposed end pieces, radially across said gap, and selectively through one of said second portion or said first portion of said actuator means.

14. The linear magnetic motor/generator of claim 13 further including:

means for inducing current to flow through said coil means, said current causing magnetic flux to pass through said third magnetic flux path causing an axial force to be applied to said actuator means for axial movement of said actuator means; and

means responsive to said axial movement for monitoring the magnitude of said axial movement of said actuator means.

15. The linear magnetic/generator of claim 14 further including:

means for sensing a change in gap distance between each of said end pieces and said actuator means; and

means responsive to said sensing means for varying the magnitude of magnetic flux flowing in said gap thereby maintaining said actuator means substantially centrally suspended between said plurality of magnets.

16. The linear magnetic motor/generator of claim 15 wherein said monitoring means and said sensing means include an actuator position sensing circuit coaxially disposed with said actuator means within said gap.

17. The linear magnetic motor/generator of claim 16 wherein said actuator position sensing circuit includes:

a cylindrical substrate;

a plurality of electrodes coupled to said cylindrical substrate, said electrodes including pairs of electrodes wherein said electrodes in each of said pairs of electrodes are radially opposed; and

a plurality of other electrodes coupled to said cylindrical substrate, said other electrodes including pairs of electrodes wherein said other electrodes in each of said pairs of electrodes are radially opposed.

18. The linear magnetic motor/generator of claim 17 wherein said varying means includes a plurality of suspension coils coupled to said rings.

19. The linear magnetic motor/generator of claim 18 wherein said sensing circuit selectively varies the current flowing in said suspension coils for varying the magnetic flux flowing in said gap.

20. The linear magnetic motor/generator of claim 19 wherein each of said suspension coils are would around said rings between adjacent and pieces.

21. The linear magnetic motor/generator of claim 19 wherein each of said suspension coils are wound around said rings between adjacent end pieces thereby coupling said rings together through said suspension coils.

22. The linear magnetic motor/generator of claim 1 wherein said plurality of magnets of said permanent magnet means and said other permanent magnet means are disposed in axially spaced pairs and each of said axially spaced pairs of magnets are coupled together by a magnetic bridge.

23. The linear magnetic motor/generator of claim 22 wherein said first flux path extends from said magnets of said pair, radially across said gap, axially through said first portion of said actuator means, radially across said gap, through said magnets of said other pair, and through said magnetic bridge.

24. The linear magnetic motor/generator of claim 23 wherein said second flux path extends from said magnets of said pair, radially across said gap, axially through said second portion of said actuator means, radially across said gap, through said magnets of said other pair, and through said magnetic bridge.

25. The linear magnetic motor/generator of claim 24 further including a plurality of magnetic bridges coupling said permanent magnet means and said other permanent magnet means together.

26. The linear magnetic motor/generator of claim 25 wherein said coil means surrounds said third portion of said actuator means.

27. The linear magnetic motor/generator of claim 26 wherein said third flux path extends axially through said third portion of said actuator means, selectively through said first portion or second portion of said actuator means, radially across said gap, through said magnetic bridges, radially across said gap and selectively through said second portion or said first portion of said actuator means.

28. The linear magnetic motor/generator of claim 27 further including means for axially moving said actuator means, said axial movement causing magnetic flux to flow through said third flux path, and said magnetic flux inducing a current to flow in said coil means.

29. The linear magnetic motor/generator of claim 27 further including:

means for inducing current to flow through said coil means, said current causing magnetic flux to pass through said third magnetic flux path, and said magnetic flux causing an axial force to be applied to said actuator means for axial movement of said actuator means; and

means responsive to said axial movement for monitoring the magnitude of said axial movement of said actuator means.

30. The linear magnetic motor/generator of claim 29 further including:

means for sensing a change in gap distance between said plurality of magnets of said permanent magnet means and said actuator means and between said other permanent magnet means and said actuator means; and

means responsive to said sensing means for varying the magnitude of magnetic flux flowing in said gap for maintaining said actuator means substantially centrally suspended between said plurality of magnets.

31. The linear magnetic motor/generator of claim 30 wherein said varying means includes a plurality of suspension coils magnetically coupled through said permanent magnet mechanism and said other permanent magnet mechanism to said first and second portions of said actuator means.

32. The linear magnetic motor/generator of claim 31 wherein said suspension coils selectively vary the current flowing therein for varying the magnetic flux flowing in said gap.