Patent US2790475A successfully refreshed from Google Patents.
US4473259A
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Linear magnetic bearings
Assignee: National Aeronautics and Space Administration
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Filing: 1982-09-08
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Granted: 1984-09-25
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Expires: 2002-09-08
Abstract
Abstract A magnetic bearing for supporting in suspension a linear armature member (20) includes an elongated cylindrical housing (18) having two sets of U-shaped stationary electromagnets (10 1 , 12 1 , 14 1 , 16 1 and 10 2 , 12 2 , 14 2 , 16 2 ) and position sensors (48 1 , 50 1 and 48 2 , 50 2 ) respectively located at each end of the housing (18). Each set of electromagnets preferably consists of four electromagnet assemblies (10, 12, 14, 16) located 90° apart around the periphery of the housing (18) and are operable to generate four orthogonal magnetic fields (30) within the housing (18). Each set of position sensors (48, 50) are aligned with the electromagnets (10 and 12) to define two orthogonal horizontal (X) and vertical (Y) axes from which signals proportional to orthogonal shaft displacement are provided. These signals are fed to four separate circuit means (126, 132, 138, 140, 150), two for each X and Y axis which are adapted to provide signals proportional to shaft positional displacement and velocity within the housing which are utilized to generate respective control signals of the proper amplitude and direction to energize the coil windings (32 1 , 34 1 , 36 1 , 38 1 and 32 2 , 34 2 , 36 2 , 38 2 ) for radially centering the shaft (20) within the housing (18) while maintaining a predetermined stiffness and dampening characteristic. The armature 20 is composed of a magnetic material, at least in the vicinity of the two sets of electromagnets and sufficiently beyond, so as to provide support for the armature throughout its distance of linear, axial travel. The remainder of the armature may be reduced in diameter or of lightweight material. A bumper magnet assembly (106), comprising an axially magnetized magnet (108) situated between a pair of magnets (112, 114), is included for positioning, axially moving or dampening axial displacement of the armature member (20).
Inventors
- 👤 Michael P. Goldowsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:01
CPC Classifications
F; F16; F16C; F16C29/00; F16C32/00; F16C32/04; F16C32/0406; F16C32/044; F16C32/0472
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
326 words
An active magnetic bearing for supporting a linear member (20) which is magnetic at least in the region (86) of being supported, comprising the combination of: elongated housing means (18) having at least one nonmagnetic region (39 1 ) along its length located in the vicinity of said linear member (20) which includes said region (86) of being supported; at least one set of stationary electromagnets (10 1 , 12 1 , 14 1 , 16 1 ) equidistantly positioned around said housing means (18) at said nonmagnetic region (39 1 ), each electromagnet being comprised of a coil winding (32 1 , 34 1 , 36 1 , 38 1 ) wound on a bifurcated pole piece (22 1 , 24 1 , 26 1 , 28 1 ) having an optionally tapered region (90 and 92) adjoining each pole face of a pair of pole faces (94 and 96), said pole faces having a contour substantially corresponding to the cross sectional configuration of said housing means (18) and directed inwardly towards said linear member (20) to provide a localized magnetic field (30) of increased flux density which is coupled to said linear member to provide a suspension force for said linear member; position sensor means (48 1 and 50 1 ) selectively positioned on said housing means (18) adjacent said set of electromagnets and being operable to detect any displacement of said linear member (20) from a predetermined position within said housing means (18) and providing an output indicative of said displacement; and drive circuit means (126, 132, 138, 140, 150), coupled to said position sensor means (48 1 and 50 1 ) and being responsive to said output therefrom to provide a control signal, said control signal being coupled to predetermined coil windings (32 1 , 36 1 and 34 1 , 38 1 ) of said set of electromagnets for selective energization thereof to center said linear member at said nonmagnetic region.
Claim 2
Dependent Claim
326 words
An active magnetic bearing for supporting a linear member (20) which is magnetic at least in the region (86) of being supported, comprising the combination of: elongated housing means (18) having at least one nonmagnetic region (39 1 ) along its length located in the vicinity of said linear member (20) which includes said region (86) of being supported; at least one set of stationary electromagnets (10 1 , 12 1 , 14 1 , 16 1 ) equidistantly positioned around said housing means (18) at said nonmagnetic region (39 1 ), each electromagnet being comprised of a coil winding (32 1 , 34 1 , 36 1 , 38 1 ) wound on a bifurcated pole piece (22 1 , 24 1 , 26 1 , 28 1 ) having an optionally tapered region (90 and 92) adjoining each pole face of a pair of pole faces (94 and 96), said pole faces having a contour substantially corresponding to the cross sectional configuration of said housing means (18) and directed inwardly towards said linear member (20) to provide a localized magnetic field (30) of increased flux density which is coupled to said linear member to provide a suspension force for said linear member; position sensor means (48 1 and 50 1 ) selectively positioned on said housing means (18) adjacent said set of electromagnets and being operable to detect any displacement of said linear member (20) from a predetermined position within said housing means (18) and providing an output indicative of said displacement; and drive circuit means (126, 132, 138, 140, 150), coupled to said position sensor means (48 1 and 50 1 ) and being responsive to said output therefrom to provide a control signal, said control signal being coupled to predetermined coil windings (32 1 , 36 1 and 34 1 , 38 1 ) of said set of electromagnets for selective energization thereof to center said linear member at said nonmagnetic region.
Claim 3
Dependent Claim
179 words
The magnetic bearing as defined by claim 1 wherein said set of stationary electromagnets (10 1 , 12 1 , 14 1 , 16 1 ) comprises a set of four electromagnets equidistantly positioned around said housing means (18) such that two electromagnets (10 1 , 14 1 and 12 1 , 16 1 ) each comprise mutually opposing pairs of electromagnets on opposite sides of said housing means (18) and respectively located along a common axis of two orthogonal axes (X, Y), wherein said position sensor means comprises two sensor means (48 1 and 50 1 ) each of which is aligned with a respective axis (X and Y) of said orthogonal axes, and wherein said drive circuit means comprises first and second drive circuits (126, 132, 138, 140, 150) respectively coupled to said sensor means (48 1 and 50 1 ) and operative to drive respective coil windings (32 1 , 36 1 and 34 1 , 38 1 ) of said pairs of electromagnets (10 1 , 14 1 and 12 1 , 16 1 ).
Claim 4
Dependent Claim
321 words
The magnetic bearing as defined by claim 1 wherein said housing means includes another nonmagnetic region (39 2 ) in spaced apart relationship with said at least one nonmagnetic region (39 1 ), and additionally including: a second set of stationary electromagnets (10 2 , 12 2 , 14 2 , 16 2 ) equidistantly positioned around said housing means (18) at said another nonmagnetic region (39 2 ), each electromagnet of said second set also being comprised of a coil winding (32 2 , 34 2 , 36 2 38 2 ) wound on a bifurcated pole piece (22 2 , 24 2 , 26 2 , 28 2 ) having a tapered region (90 and 92) adjoining each pole face of a pair of pole faces (94 and 96), said pole faces having a contour corresponding to the cross sectional configuration of said housing means and directed inwardly towards said linear member to provide a localized field (30) as aforesaid; second position sensor means (48 2 and 50 2 ) selectively positioned on said housing means (18) adjacent said second set of electromagnets (10 2 , 12 2 , 14 2 , 16 2 ) and being operable to detect any displacement of said linear member (20) from a predetermined position in said housing means (18) at said another nonmagnetic region (39 2 ) and providing a respective output indicative of said displacement thereat; and second drive circuit means (126, 132, 138, 140, 150) coupled to said second sensor means and being responsive to said output therefrom to provide another control signal, said another control signal being coupled to predetermined coil windings (32 2 , 36 2 and 34 2 , 38 2 ) of said second set of electromagnets (10 2 , 12 2 , 14 2 , 16 2 ) for selective energization thereof to center said linear member at said another nonmagnetic region (39 2 ).
Claim 5
Dependent Claim
223 words
The magnetic bearing as defined by claim 3 wherein both sets of electromagnets (10 1 , 12 1 . . . 14 2 , 16 2 ) are mounted in mutually opposing pairs (10 1 , 14 1 . . . 12 2 , 16 2 ) around said housing means (18) along two mutually perpendicular axes (X, Y) transversely through said housing means at said nonmagnetic regions (39 1 and 39 2 ), wherein both sets of position sensor means (48 1 , 50 1 and 48 2 , 50 2 ) include a respective pair of position transducers substantially aligned with said electromagnets (10 1 , 12 1 and 10 2 , 12 2 ) so as to detect any displacement of said linear member from said predetermined position along said axes (X and Y), and wherein both said drive circuit means comprises pairs of drive circuits (126, 134, 138, 140, 150) coupled to respective pairs of position transducers (48 1 , 50 1 and 48 2 , 50 2 ) for energizing respective pairs of electromagnets (10 1 , 14 1 . . . 12 2 , 16 2 ) which are thereby adapted to position said linear member along said perpendicular axes (X, Y) at both said nonmagnetic regions (39 1 and 39 2 ) of said housing means.
Claim 6
Dependent Claim
19 words
The magnetic bearing as defined by claim 4 wherein said elongated housing means (18) is generally cylindrical in shape.
Claim 7
Dependent Claim
56 words
The magnetic bearing as defined by claim 4 wherein said housing means (18) is generally circular in cross section and wherein said linear member (20) comprises an elongated armature shaft having a generally rounded outer surface (43) at least in the proximity of said nonmagnetic regions (39 1 and 39 2 ) of said housing means.
Claim 8
Dependent Claim
46 words
The magnetic bearing as defined by claim 6 wherein said bifurcated pole pieces (22 1 , 24 1 . . . 26 2 , 28 2 ) have generally concave pole faces (94, 96) substantially matching the rounded outer surface (43) of said armature shaft (20).
Claim 9
Dependent Claim
30 words
The magnetic bearing as defined by claim 5 wherein said linear member (20) comprises a shaft generally cylindrical in shape (43) in the region of said generally cylindrical housing (18).
Claim 10
Dependent Claim
41 words
The magnetic bearing as defined by claim 5 wherein said linear member (20) comprises a shaft having a cross section including a region (86, 88) of magnetic material coincident with said region (96 1 , 96 2 ) of being supported.
Claim 11
Dependent Claim
59 words
The magnetic bearing as defined by claim 5 wherein said linear member (20) comprises an elongated shaft having an annular cross section of varying dimensions (86, 88) along its length and wherein the cross sectional area is greater in said region of being supported at said nonmagnetic regions (96 1 , 96 2 ) of said housing means (18).
Claim 12
Dependent Claim
47 words
The magnetic bearing as defined by claim 5 wherein said linear member (20) comprises a shaft (20') having a sleeve (98, 100) of magnetic material located in said regions of being supported at said nonmagnetic regions (96 1 , 96 2 ) of said housing means (18).
Claim 13
Dependent Claim
56 words
The magnetic bearing as defined by claim 5 wherein said linear member (20) comprises a shaft (20") of nonmagnetic material including an axial bore within which is located respective magnetic bodies (102 and 104) situated at the region of being supported at said nonmagnetic regions (96 1 , 96 2 ) of said housing means (18).
Claim 14
Dependent Claim
48 words
The magnetic bearing as defined by claim 4 and additionally including magnetic shield means (72 and 74) located intermediate said electromagnets (10 1 , 12 1 . . . 14 2 , 16 2 ) and said position sensor means (48 1 . . . 50 2 )
Claim 15
Dependent Claim
74 words
The magnetic bearing as defined by claim 4 and additionally including flange means (58 and 60) located on the exterior of said housing means (18) for attaching said electromagnets thereto, and wherein said flange means include radially extending shield members (72 and 74) located intermediate said electromagnets (10 1 , 12 1 . . . 14 2 , 16 2 ) and said position sensor means (48 1 . . . 50 2 ).
Claim 16
Dependent Claim
26 words
The magnetic bearing as defined by claim 4 wherein said position sensor means (48 1 . . . 50 2 ) comprises eddy current sensor means.
Claim 17
Dependent Claim
62 words
The magnetic bearing as defined by claim 1 wherein said drive circuit means (126, 132, 138, 140, 150) includes means providing respective signals proportional to displacement and velocity of said linear member from a central position in said housing means (18) from which is generated a composite control signal of a predetermined gain for providing a desired bearing stiffness and dampening characteristic.
Claim 18
Dependent Claim
25 words
The magnetic bearing as defined by claim 1 and additionally including means (106) connected to said linear member (20) for dampening undesired axial displacement thereof.
Claim 19
Dependent Claim
43 words
The magnetic bearing as defined by claim 17 wherein said dampening means (106) comprises a bumper magnet assembly including a magnet (108), coupled to said linear member (20), located adjacent at least one stationary magnet (112) and being poled to be repulsed thereby.
Claim 20
Dependent Claim
56 words
The magnetic bearing as defined by claim 17 wherein said dampening means (106) comprises a bumper magnet assembly including a magnet (108) coupled to one end of said linear member (20), located intermediate a pair of stationary magnets (112 and 114), said magnets being poled so that the intermediate magnet is repulsed by both stationary magnets.
Claim 21
Dependent Claim
21 words
The magnetic bearing as defined by claim 19 wherein the magnets (108, 112 and 114) are comprised of axially magnetized magnets.
Claim 22
Dependent Claim
58 words
The magnetic bearing as defined by claim 20 wherein said axially magnetized magnets (108, 112 and 114) are permanent magnets and additionally including means (118) located in proximity to said intermediate magnet (108) for applying an AC axial magnetic field thereto thereby causing said intermediate magnet (108) to oscillate between said pair of stationary magnets (112 and 114).
Claim 23
Dependent Claim
47 words
The magnetic bearing as defined by claim 21 wherein said permanent magnets (108, 112 and 114) are located in a housing (116) adjacent said elongated housing means (18) and wherein said means for applying said AC magnetic field comprises a coil (118) located around said housing (116).
Claim 24
Dependent Claim
39 words
The magnetic bearing as defined by claim 19 wherein one of said stationary magnets (112) includes an aperture, and additionally including a connecting link (110) passing through said aperture connecting said intermediate magnet (108) to said linear member (20).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-25 | 1988-03-26 | 1988-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-25 | 1992-03-26 | 1992-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-25 | 1996-03-26 | 1996-09-25 | $7700.00 | Window Closed / Lapsed |