Patent US4486026A successfully refreshed from Google Patents.
US4486026A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sealing and bearing means by use of ferrofluid
Assignee: NSK Ltd
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Filing: 1983-02-03
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Granted: 1984-12-04
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Expires: 2003-02-03
Abstract
Abstract This invention relates to sealing and bearing means by use of ferrofluid, in which a magnet is utilized effectively in cooperation with grooves engraved on one surface thereof, the grooves having the function for generating the dynamic pressure of the ferrofluid. The ferrofluid is retained in a gap between a rotary shaft and a magnet of cylindrical or disc type enclosing the rotary shaft concentrically. The magnet performs excellent two functions of bearing and sealing respectively.
Inventors
- 👤 Kyozaburo Furumura
- 👤 Hiromi Sugi
- 👤 Yasuo Murakami
- 👤 Hiromitsu Asai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:32
CPC Classifications
G; G11; G11B; G11B19/00; G11B19/20; G11B19/2009; F; F16; F16C; F16C17/00; F16C17/10; F16C17/102; F16C17/107; F16C33/00; F16C33/02; F16C33/04; F16C33/06; F16C33/10; F16C33/1025; F16C33/103; F16C33/1035; F16C33/72; F16C33/74; F16C33/741; F16C33/743; F16C33/746; F16J; F16J15/00; F16J15/16; F16J15/40; F16J15/43; F16C2210/00; F16C2210/02; F16C2210/06; F16C2370/00; F16C2370/12; Y; Y10; Y10S; Y10S277/00; Y10S277/935; Y10S277/936; Y10S277/939
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
119 words
Sealing and bearing means for use of ferrofluid comprising: a thrust support disc for preventing a thrust movement of a rotary shaft; a magnet disc opposing to the thrust support disc, the magnet disc being made of a normal magnet or a plastic-contained magnet; either one of the thrust support disc and the magnet disc being fixed with the rotary shaft, the both discs enclosing the rotary shaft concentrically; a ferrofluid being retained in a gap formed between opposing surfaces of the thrust support disc and the magnet disc; and either one of the thrust support disc and the magnet disc being, at its surface sliding with the other one, provided with grooves for dynamic pressure of the ferrofluid.
Claim 2
Dependent Claim
119 words
Sealing and bearing means for use of ferrofluid comprising: a thrust support disc for preventing a thrust movement of a rotary shaft; a magnet disc opposing to the thrust support disc, the magnet disc being made of a normal magnet or a plastic-contained magnet; either one of the thrust support disc and the magnet disc being fixed with the rotary shaft, the both discs enclosing the rotary shaft concentrically; a ferrofluid being retained in a gap formed between opposing surfaces of the thrust support disc and the magnet disc; and either one of the thrust support disc and the magnet disc being, at its surface sliding with the other one, provided with grooves for dynamic pressure of the ferrofluid.
Claim 3
Dependent Claim
30 words
The sealing and bearing means as claimed in claim 1, wherein reserving grooves for reserving the ferrofluid are formed adjacent the grooves for generating the dynamic pressure of the ferrofluid.
Claim 4
Dependent Claim
30 words
The sealing and bearing means as claimed in claim 1, wherein the magnet disc comprises 10 to 70 weight % of magnetic powder and is used for a thrust bearing.
Claim 5
Dependent Claim
65 words
The sealing and bearing means as claimed in claim 1, wherein the magnet disc comprises a magnetic powder, 10 to 60 weight % of reinforced fiber such as carbon fiber, glass fiber or the like and a filler such as polytetrafluoroethylene, graphite or the like, the total quantity of the magnetic powder, the reinforced fiber and the filler being no more than 95 weight %.
Claim 6
Dependent Claim
29 words
The sealing and bearing means as claimed in claim 1, wherein the magnet disc comprises 90 to 95 weight % of magnetic powder and is used for sealing purposes.
Claim 7
Dependent Claim
85 words
The sealing and bearing means as claimed in claim 1, wherein the thrust support disc is engaged with the rotary shaft and pressed resiliently in a thrust direction, while the magnet disc is opposing to the thrust support disc, the ferrofluid being retained between two sliding and opposing surfaces of the thrust support disc and the magnet disc respectively, and the grooves for generating the dynamic pressure of the ferrofluid being formed on either sliding surface of the thrust support disc and the magnet disc.
Claim 8
Dependent Claim
35 words
The sealing and bearing means as claimed in claim 6, wherein the thrust support disc is made of a normal magnet or a plastic-contained magnet, while the magnet disc is replaced with a non-magnetic disc.
Claim 9
Dependent Claim
53 words
The sealing and bearing means as claimed in claim 6, wherein the magnet disc is, at either one of the outer periphery and inner periphery thereof, provided with grooves for preventing any liquid to be sealed so that it is not penetrated into the grooves for generating the dynamic pressure of the ferrofluid.
Claim 10
Dependent Claim
85 words
The sealing and bearing means as claimed in claim 1, wherein the thrust support disc is engaged with the rotary shaft, while two magnet discs spaced from the rotary shaft are opposing to two surfaces of the thrust support disc, the ferrofluid being retained between respective sliding and opposing surfaces of the thrust support disc and the two magnets, and the grooves for generating the dynamic pressure of the ferrofluid being formed on either sliding surface of the thrust support disc and two magnet discs.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |