US5036235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless DC motor having a stable hydrodynamic bearing system
Assignee: Xerox Corp
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Filing: 1990-07-25
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Granted: 1991-07-30
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Expires: 2010-07-25
Abstract
Abstract A brushless DC motor having a hydrodynamic bearing system includes a stator core having windings arranged thereabout, the stator core rotating about a first center line. The motor further includes a rotor having permanent magnets positioned about an inner diameter thereof, said rotor being rotatable about a second center line. The first center line of the stator core is eccentric to and parallel to the second center line of the rotor such that the magnets exert forces on the stator core which eliminate whirl instability in the rotor.
Inventors
- 👤 Robert J. Kleckner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:56
CPC Classifications
H; H02; H02K; H02K7/00; H02K7/08; H02K7/09; F; F16; F16C; F16C25/00; F16C25/06; F16C25/08; F16C25/086; F16C33/00; F16C33/02; F16C33/04; F16C33/06; F16C33/10; F16C33/1025; F16C33/103; F16C33/1035; F16C39/00; F16C39/06; F16C39/063; H02K5/00; H02K5/04; H02K5/16; H02K5/163
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
92 words
A brushless DC motor comprising: a stator comprising a core positioned about a first center line, said core having windings arranged thereabout; a rotor having an inner diameter being rotatable about a second center line; a shaft supporting said rotor at one end thereof and having an axis collinear with said second center line; magnet means positioned about the inner diameter of said rotor for exerting radial and axial magnetic load forces on said stator; said first center line of said stator being eccentric to said second center line of said rotor.
Claim 2
Dependent Claim
92 words
A brushless DC motor comprising: a stator comprising a core positioned about a first center line, said core having windings arranged thereabout; a rotor having an inner diameter being rotatable about a second center line; a shaft supporting said rotor at one end thereof and having an axis collinear with said second center line; magnet means positioned about the inner diameter of said rotor for exerting radial and axial magnetic load forces on said stator; said first center line of said stator being eccentric to said second center line of said rotor.
Claim 3
Dependent Claim
28 words
The motor as recited in claim 1, wherein: said first center line of said stator is eccentric to and parallel to said second center line of said rotor.
Claim 4
Dependent Claim
17 words
The motor as recited in claim 1, wherein: said magnet means comprise a plurality of permanent magnets.
Claim 5
Dependent Claim
21 words
The motor as recited in claim 3, wherein: said permanent magnets are equally spaced around the inner diameter of said rotor.
Claim 6
Dependent Claim
26 words
The motor as recited in claim 2, wherein said first center line is eccentric to said second center line by a distance of about 0.010 inch.
Claim 7
Dependent Claim
21 words
The motor as recited in claim further comprising: a motor housing, and bearing means for supporting said shaft within said housing.
Claim 8
Dependent Claim
20 words
The motor as recited in claim 6, wherein: a lubricant is provided in said housing for lubricating said bearing means.
Claim 9
Dependent Claim
13 words
The motor as recited in claim 7, wherein: said lubricant is a ferrofluid.
Claim 10
Dependent Claim
21 words
The motor as recited in claim 7, wherein: said housing includes a magnetic seal which seals the lubricant within said housing.
Claim 11
Dependent Claim
30 words
The motor as recited in claim 1, wherein: said bearing means includes a pair of journal surfaces which support the radial load forces, the journal surfaces extending around said shaft.
Claim 12
Dependent Claim
33 words
The motor as recited in claim 1, wherein said bearing means includes a thrust bearing which supports the axial load force, the thrust bearing being located adjacent to an end of said shaft.
Claim 13
Dependent Claim
19 words
The motor as recited in claim 11, wherein: said thrust bearing is a six-pad stepped sector hydrodynamic thrust bearing.
Claim 14
Dependent Claim
20 words
The motor as recited in claim 11, wherein: said thrust bearing is provided on an end cap of said housing.
Claim 15
Dependent Claim
15 words
The motor as recited in claim 13, wherein: said end cap is flat and disk-shaped.
Claim 16
Dependent Claim
17 words
The motor as recited in claim 1, further comprising: said rotor supporting at least one reflective surface.
Claim 17
Dependent Claim
99 words
A brushless DC motor for use in a laser scanner comprising: a stator comprising a core positioned about a first center line, said core having windings arranged thereabout; a rotor having an inner diameter and being rotatable about a second center line; a shaft supporting said rotor at one end thereof and having an axis collinear with said second center line; magnet means positioned about the inner diameter of said rotor for exerting radial and axial magnetic load forces on said stator; said first center line of said stator being eccentric to said second center line of said rotor.
Claim 18
Dependent Claim
99 words
A brushless DC motor for use in a laser scanner comprising: a stator comprising a core positioned about a first center line, said core having windings arranged thereabout; a rotor having an inner diameter and being rotatable about a second center line; a shaft supporting said rotor at one end thereof and having an axis collinear with said second center line; magnet means positioned about the inner diameter of said rotor for exerting radial and axial magnetic load forces on said stator; said first center line of said stator being eccentric to said second center line of said rotor.
Claim 19
Dependent Claim
26 words
The motor as recited in claim 16, wherein: said center line of said stator is eccentric to and parallel to said center line of said rotor.
Claim 20
Dependent Claim
17 words
The motor as recited in claim 16, wherein: said magnet means comprise a plurality of permanent magnets.
Claim 21
Dependent Claim
21 words
The motor as recited in claim 18, wherein: said permanent magnets are equally spaced around the inner diameter of said rotor.
Claim 22
Dependent Claim
26 words
The motor as recited in claim 17, wherein: said stator center line is eccentric to said rotor center line by a distance of about 0.010 inch.
Claim 23
Dependent Claim
22 words
The motor as recited in claim 16, further comprising: a motor housing, and bearing means for supporting said shaft within said housing.
Claim 24
Dependent Claim
20 words
The motor as recited in claim 21, wherein: a lubricant is provided in said housing for lubricating said bearing means.
Claim 25
Dependent Claim
13 words
The motor as recited in claim 22, wherein: said lubricant is a ferrofluid.
Claim 26
Dependent Claim
21 words
The motor as recited in claim 22, wherein: said housing includes a magnetic seal which seals the lubricant within said housing.
Claim 27
Dependent Claim
30 words
The motor as recited in claim 16, wherein: said bearing means includes a pair of journal surfaces which support the radial load forces, the journal surfaces extending around said shaft.
Claim 28
Dependent Claim
33 words
The motor as recited in claim 16, wherein said bearing means includes a thrust bearing which supports the axial load force, the thrust bearing being located adjacent to an end of said shaft.
Claim 29
Dependent Claim
16 words
The motor as recited in claim 26, wherein: said thrust bearing is a hydrodynamic thrust bearing.
Claim 30
Dependent Claim
20 words
The motor as recited in claim 26, wherein: said thrust bearing is provided on an end cap of said housing.
Claim 31
Dependent Claim
15 words
The motor as recited in claim 28, wherein: said end cap is flat and disk-shaped.
Claim 32
Dependent Claim
17 words
The motor as recited in claim 16, further comprising: said rotor supporting at least one reflective surface.
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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) | 1994-07-29 | 1995-01-28 | 1995-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-29 | 1999-01-28 | 1999-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-29 | 2003-01-28 | 2003-07-30 | $7700.00 | Window Closed / Lapsed |