US4598914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sealing and bearing means by use of ferrofluid
Assignee: NSK Ltd
•
Filing: 1984-06-27
•
Granted: 1986-07-08
•
Expires: 2004-06-27
Abstract
Abstract 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 00:56
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: 8
Claim 1
Independent Claim
88 words
A sealing a bearing assembly for a rotating shaft, which comprises: a cylindrically-shaped magnetic member concentrically-disposed about said shaft and formed of a magnetic material, said cylindrically-shaped magnetic member having a cylindrically-shaped surface in siding contact with said shaft, said cylindrically-shaped surface of said cylindrically-shaped magnetic member formed with grooves; and a ferrofluid disposed between said surface of said cylindrically-shaped magnetic member and said shaft whereby said groove generates dynamic pressure of said ferrofluid by rotation of said shaft within said cylindrically-shaped surface of said cylindrically-shaped magnetic member.
Claim 2
Dependent Claim
88 words
A sealing a bearing assembly for a rotating shaft, which comprises: a cylindrically-shaped magnetic member concentrically-disposed about said shaft and formed of a magnetic material, said cylindrically-shaped magnetic member having a cylindrically-shaped surface in siding contact with said shaft, said cylindrically-shaped surface of said cylindrically-shaped magnetic member formed with grooves; and a ferrofluid disposed between said surface of said cylindrically-shaped magnetic member and said shaft whereby said groove generates dynamic pressure of said ferrofluid by rotation of said shaft within said cylindrically-shaped surface of said cylindrically-shaped magnetic member.
Claim 3
Dependent Claim
28 words
The sealing and bearing assembly as claimed in claim 1 wherein said cylindrically-shaped magnetic member is made of a mixture of a magnetic substance and a synthetic resin.
Claim 4
Dependent Claim
29 words
The sealing and bearing assembly as claim in claim 1 wherein said cylindrically-shaped magnetic member is comprised of a cylindrically-shaped magnetic body on which is coated a plastic layer.
Claim 5
Dependent Claim
48 words
The sealing and bearing assembly as claimed in claim 1 wherein said cylindrically-shaped magnetic member is comprised of a pair of magnets joined to each other, each of said magnets formed with grooves on said surface, said grooves of each of said magnets forming a herringbone figuration therebetween.
Claim 6
Dependent Claim
37 words
The sealing and bearing assembly as claimed in claim 1 wherein said cylindrically-shaped body is comprised of from 10 to 70 weight % of magnetic powder, said sealing and bearing assembly being used as a radial bearing.
Claim 7
Dependent Claim
47 words
The sealing and bearing assembly as claimed in claim 1 wherein said cylindrically-shaped member is comprised of magnetic powder, 10 to 60 weight % of reinforced fiber and a filler, the total quantity of magnetic powder, reinforced fiber and filler being no more than 95 weight %.
Claim 8
Dependent Claim
25 words
The sealing and bearing assembly as claimed in claim 1 wherein said cylindrically-shaped member is comprised of 70 to 95 weight % of magnetic powder.
References Cited (Backward Citations)
US3746407A
Cited
US3834775A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-07 | 1990-01-06 | 1990-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-07 | 1994-01-06 | 1994-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-07 | 1998-01-06 | 1998-07-08 | $7700.00 | Window Closed / Lapsed |