US4857781A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-speed non-contact linear motor with magnetic levitation
Assignee: Eastman Kodak Co
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Filing: 1988-07-13
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Granted: 1989-08-15
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Expires: 2008-07-13
Abstract
Abstract A linear brushless DC motor is provided with a stationary member and a movable member each having opposing pole faces. A first magnetic device operates to displace the movable member translationally with respect to the stationary member. A second magnetic device which has electromagnet windings wound around each of the pole faces operates to levitate the movable member by magnetic attractive force with respect to the stationary member. A control system is used for maintaining a certain air gap between the movable member and the stationary member.
Inventors
- 👤 Liang Shih
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:19
CPC Classifications
H; H02; H02K; H02K7/00; H02K7/08; H02K7/09; H02K41/00; H02K41/02; H02K41/035; H02K41/0352; H02K41/0354; H02K41/0356
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
189 words
A linear motor comprising: a first member having a substantially rectangular cross section and an elongated shape; a second member, having an upper portion formed from a magnetic material, a lower portion formed from a magnetic material and a pair of side portions formed from non-magnetic material for rigidly holding said upper portion and said lower portion in a spaced configuration to define a substantially rectangular opening for receiving said first member; a first permanent magnet affixed to said upper portion of said second member; a second permanent magnet affixed to said lower portion of said second member; a motor winding affixed to said first member for generating a magnetic field for inducing relative motion between said first and said second members along the elongated axis of said first member in response to a position signal; sensing means for sensing the spacing of said first member within the defined opening of said second member and for providing a signal indicative of the sensed spacing; and magnetic means responsive to the signal provided by said sensing means for maintaining a desired spacing between said first member and said second member.
Claim 2
Dependent Claim
189 words
A linear motor comprising: a first member having a substantially rectangular cross section and an elongated shape; a second member, having an upper portion formed from a magnetic material, a lower portion formed from a magnetic material and a pair of side portions formed from non-magnetic material for rigidly holding said upper portion and said lower portion in a spaced configuration to define a substantially rectangular opening for receiving said first member; a first permanent magnet affixed to said upper portion of said second member; a second permanent magnet affixed to said lower portion of said second member; a motor winding affixed to said first member for generating a magnetic field for inducing relative motion between said first and said second members along the elongated axis of said first member in response to a position signal; sensing means for sensing the spacing of said first member within the defined opening of said second member and for providing a signal indicative of the sensed spacing; and magnetic means responsive to the signal provided by said sensing means for maintaining a desired spacing between said first member and said second member.
Claim 3
Dependent Claim
43 words
The linear motor according to claim 1 wherein said first member is configured with a centrally open portion through which is mounted a bar of ferrous material for providing a path for the return of the magnetic field generated by said motor winding.
Claim 4
Dependent Claim
62 words
The linear motor according to claim 1 wherein said first member is comprised of: an elongated central member; first and second elongated outer members; and first and second end plates affixed to first and second ends of said central member and said first and said second outer members to rigidly maintain said outer members parallel on opposite sides of said central member.
Claim 5
Dependent Claim
34 words
The linear motor according to claim 3 wherein said sensing means is affixed to said first and said second elongated outer members, and wherein said motor winding is wound around said elongated central member.
Claim 6
Dependent Claim
154 words
A high-speed linear brushless DC motor comprising: a first member comprising: a pair of spaced-apart levitating electromagnets, a frame member rigidly maintaining said pair of electromagnets a spaced distance apart, and a first and a second motor coil wound onto said frame member and insulated from said levitating electromagnets; a second member comprising: pole faces proximately positioned to said electromagnets for levitating said first member, permanent magnets proximately positioned to said first and said second motor coil for causing a linear motor action between said first and said second member; servomechanism means coupled to said pair of levitating electromagnets for providing a current for maintaining the distance between said first and said second member at a fixed distance thereby levitating said first member; and pairs of electromagnets positioned on said first and said second member to restrict the movement of said first member with respect to said second member to a desired linear axis.
Claim 7
Dependent Claim
154 words
A high-speed linear brushless DC motor comprising: a first member comprising: a pair of spaced-apart levitating electromagnets, a frame member rigidly maintaining said pair of electromagnets a spaced distance apart, and a first and a second motor coil wound onto said frame member and insulated from said levitating electromagnets; a second member comprising: pole faces proximately positioned to said electromagnets for levitating said first member, permanent magnets proximately positioned to said first and said second motor coil for causing a linear motor action between said first and said second member; servomechanism means coupled to said pair of levitating electromagnets for providing a current for maintaining the distance between said first and said second member at a fixed distance thereby levitating said first member; and pairs of electromagnets positioned on said first and said second member to restrict the movement of said first member with respect to said second member to a desired linear axis.
Claim 8
Dependent Claim
173 words
A high-speed linear brushless DC motor comprising: a first member comprising: a pair of spaced-apart levitating electromagnets, a frame member rigidly maintaining said pair of electromagnets a spaced distance apart, and a first and a second motor coil wound onto said frame member and insulated from said levitating electromagnets; a second member comprising: pole faces proximately positioned to said electromagnets for levitating said first member, permanent magnets proximately positioned to said first and said second motor coil for causing a linear motor action between said first and said second member; servomechanism means coupled to said pair of levitating electromagnets for providing a current for maintaining the distance between said first and said second member at a fixed distance thereby levitating said first member; wherein said second member is comprised of: a central, elongated, ferro-magnetic body having first permanent magnets affixed to opposite edges and second permanent magnets mounted to the opposite edges in a spaced-apart relationship; and bars of ferrous material within the space between the first and second pairs of permanent magnets.
Claim 9
Dependent Claim
173 words
A high-speed linear brushless DC motor comprising: a first member comprising: a pair of spaced-apart levitating electromagnets, a frame member rigidly maintaining said pair of electromagnets a spaced distance apart, and a first and a second motor coil wound onto said frame member and insulated from said levitating electromagnets; a second member comprising: pole faces proximately positioned to said electromagnets for levitating said first member, permanent magnets proximately positioned to said first and said second motor coil for causing a linear motor action between said first and said second member; servomechanism means coupled to said pair of levitating electromagnets for providing a current for maintaining the distance between said first and said second member at a fixed distance thereby levitating said first member; wherein said second member is comprised of: a central, elongated, ferro-magnetic body having first permanent magnets affixed to opposite edges and second permanent magnets mounted to the opposite edges in a spaced-apart relationship; and bars of ferrous material within the space between the first and second pairs of permanent magnets.
Claim 10
Dependent Claim
48 words
A high-speed linear brushless DC motor according to claim 6 wherein said first and said second motor coils are each wound with an open center and wherein at least one bar of ferrous material is positioned within the open center of a respective one of said motor coils.
Claim 11
Dependent Claim
50 words
A high-speed linear brushless DC motor according to claim 5 and further comprising: lens means affixed to said first member for focusing on an image plane; and means for adjusting the levitation of said first member on said second member as a function of the focus of said lens means.
References Cited (Backward Citations)
US4156548A
Cited
US4334207A
Cited
JPS5841449A
Cited
JPS5856237A
Cited
JPS6085446A
Cited
US4689529A
Cited
JPS61142537A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-14 | 1993-02-13 | 1993-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-14 | 1997-02-13 | 1997-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-14 | 2001-02-13 | 2001-08-15 | $7700.00 | Window Closed / Lapsed |