Patent US2035761A successfully refreshed from Google Patents.
US4988906A
Expired / Lapsed
US
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Magnetic bearing assembly
Assignee: Dow Chemical Co
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Filing: 1989-09-20
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Granted: 1991-01-29
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Expires: 2009-09-20
Abstract
Abstract A passive magnetic bearing assembly for a rotating shaft including: a. a journal subassembly suitable for mounting to the shaft so as to rotate with the shaft, the journal subassembly comprising a housing forming a chamber containing a journal magnetic material, a flexible fluid-filled hollow member which compensates for changes in the unoccupied volume within the chamber due to thermal expansion and changes in internal pressure, and a damping fluid in the chamber; and b. a bearing subassembly annularly and concentrically disposed around the journal subassembly such that a clearance is formed between the bearing and journal subassemblies, the bearing subassembly comprising a housing forming a chamber containing a bearing magnetic material, a flexible hollow fluid-filled member which compensates for changes in the unoccupied volume within the chamber due to thermal expansion and changes in internal pressure, and a damping fluid in the chamber.
Inventors
- 👤 David E. Littlefield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:41
CPC Classifications
F; F16; F16C; F16C39/00; F16C39/06; F16C39/063
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
144 words
A passive magnetic bearing assembly for a rotating shaft comprising: a. a journal subassembly suitable for mounting to the shaft so as to rotate with the shaft, the journal subassembly comprising a housing forming a chamber containing a journal magnetic material, a flexible fluid-filled hollow member which compensates for changes in the unoccupied volume within the chamber due to thermal expansion and changes in internal pressure, and a damping fluid in the chamber; and b. a bearing subassembly annularly and concentrically disposed around the journal subassembly such that a clearance is formed between the bearing and journal subassemblies, the bearing subassembly comprising a housing forming a chamber containing a bearing magnetic material, a flexible hollow fluid-filled member which compensates for changes in the unoccupied volume within the chamber due to thermal expansion and changes in internal pressure, and a damping fluid in the chamber.
Claim 2
Dependent Claim
144 words
A passive magnetic bearing assembly for a rotating shaft comprising: a. a journal subassembly suitable for mounting to the shaft so as to rotate with the shaft, the journal subassembly comprising a housing forming a chamber containing a journal magnetic material, a flexible fluid-filled hollow member which compensates for changes in the unoccupied volume within the chamber due to thermal expansion and changes in internal pressure, and a damping fluid in the chamber; and b. a bearing subassembly annularly and concentrically disposed around the journal subassembly such that a clearance is formed between the bearing and journal subassemblies, the bearing subassembly comprising a housing forming a chamber containing a bearing magnetic material, a flexible hollow fluid-filled member which compensates for changes in the unoccupied volume within the chamber due to thermal expansion and changes in internal pressure, and a damping fluid in the chamber.
Claim 3
Dependent Claim
27 words
The passive magnetic bearing assembly of claim 1 wherein the housing comprises an inner and outer cylindrical shell concentrically arranged with side walls for forming an enclosure.
Claim 4
Dependent Claim
17 words
The passive magnetic bearing assembly of claim 2 wherein the housing is made of a non-magnetic material.
Claim 5
Dependent Claim
18 words
The passive magnetic bearing assembly of claim 1 wherein the flexible fluid-filled hollow member is a tubular member.
Claim 6
Dependent Claim
18 words
The passive magnetic bearing assembly of claim 4 wherein the tubular member is made of a vinyl compound.
Claim 7
Dependent Claim
16 words
The passive magnetic bearing assembly of claim 4 wherein the tubular member is a flexible bellows.
Claim 8
Dependent Claim
20 words
The passive magnetic bearing assembly of claim 1 wherein the flexible fluid-filled hollow member is filled with an inert gas.
Claim 9
Dependent Claim
22 words
The passive magnetic bearing assembly of claim 6 wherein the inert gas is selected from the group comprising nitrogen, argon and helium.
Claim 10
Dependent Claim
26 words
The passive magnetic bearing assembly of claim 1 wherein the dampening fluid is selected from the group comprising glycerine, mineral oil, oil polyglycol and silicon-based fluid.
Claim 11
Dependent Claim
25 words
The passive magnetic bearing assembly of claim 1 wherein the magnetic material is selected from the group comprising a rare earth/iron alloy and a ceramic.
References Cited (Backward Citations)
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US3746407A
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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) | 1994-01-28 | 1994-07-30 | 1995-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-28 | 1998-07-30 | 1999-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-28 | 2002-07-30 | 2003-01-29 | $7700.00 | Window Closed / Lapsed |