US5152539A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferrofluid seal apparatus
Assignee: Koyo Seiko Co Ltd
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Filing: 1990-09-21
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Granted: 1992-10-06
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Expires: 2010-09-21
Abstract
Abstract A ferrofluid seal apparatus comprises magnetic fluid holding or positing means for storing or retaining a magnetic fluid in a sealing arrangement wherein inner and outer elements are relatively rotated. The magnetic fluid holding means includes an arrangement for retaining the magnetic fluid which flows out from its original position.
Inventors
- 👤 Hirokazu Takii
- 👤 Tetsuo Oda
- 👤 Shinji Abe
- 👤 Kazuya Suzuki
- 👤 Hirotsugu Kusano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 20:08
CPC Classifications
H; H02; H02K; H02K5/00; F; F16; F16C; F16C33/00; F16C33/72; F16C33/76; F16C33/762; F16C33/763; F16C33/765; F16J; F16J15/00; F16J15/16; F16J15/40; F16J15/43; G; G11; G11B; G11B19/00; G11B19/20; G11B19/2009; F16C2370/00; F16C2370/12; Y; Y10; Y10S; Y10S277/00; Y10S277/919
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
277 words
In a sealing apparatus for sealing two rings made of a magnetic material coaxially and relatively rotated through a plurality of rolling members in which a magnetic fluid holding means for storing a magnetic fluid is provided, said magnetic fluid holding means being attached to one of said two rings to form a fine annular clearance, so that the magnetic fluid is positioned within the fine annular clearance, said magnetic fluid holding means comprising: an annular magnetic piece positioned in a member made of a non-magnetic material, said member including an annular portion engaged with said one of said two rings and a radial flange portion extended from an end of said annular portion toward the other of said rings to form said fine annular clearance; said annular magnetic piece having a free end and being fixed to an annular step provided by said annular portion and said radial flange portion of said member, and axially magnetized to provide a magnetic circuit via said fine annular clearance adjacent the other of said two rings made of the magnetic material, so that said magnetic circuit retains the magnetic fluid; a non-magnetic metal plate fixed to an axial side of said magnetic piece opposed to said radial flange portion of said member, an end of said non-magnetic metal plate extending toward the other of said two rings to form an additional fine annular clearance with the surface of the other of said two rings; and a recess, formed at a circumferential portion of said free end of said magnetic piece adjacent said non-magnetic metal plate for preventing the magnetic fluid from flowing away from said magnetic fluid holding means.
Claim 2
Dependent Claim
277 words
In a sealing apparatus for sealing two rings made of a magnetic material coaxially and relatively rotated through a plurality of rolling members in which a magnetic fluid holding means for storing a magnetic fluid is provided, said magnetic fluid holding means being attached to one of said two rings to form a fine annular clearance, so that the magnetic fluid is positioned within the fine annular clearance, said magnetic fluid holding means comprising: an annular magnetic piece positioned in a member made of a non-magnetic material, said member including an annular portion engaged with said one of said two rings and a radial flange portion extended from an end of said annular portion toward the other of said rings to form said fine annular clearance; said annular magnetic piece having a free end and being fixed to an annular step provided by said annular portion and said radial flange portion of said member, and axially magnetized to provide a magnetic circuit via said fine annular clearance adjacent the other of said two rings made of the magnetic material, so that said magnetic circuit retains the magnetic fluid; a non-magnetic metal plate fixed to an axial side of said magnetic piece opposed to said radial flange portion of said member, an end of said non-magnetic metal plate extending toward the other of said two rings to form an additional fine annular clearance with the surface of the other of said two rings; and a recess, formed at a circumferential portion of said free end of said magnetic piece adjacent said non-magnetic metal plate for preventing the magnetic fluid from flowing away from said magnetic fluid holding means.
Claim 3
Dependent Claim
38 words
The sealing apparatus as set forth in claim 1, wherein said magnetic piece comprises an annular permanent magnet and an annular pole piece made of a magnetic material fixed to an axial side of the annular permanent magnet.
Claim 4
Dependent Claim
87 words
The sealing apparatus as set forth in claim 1, wherein there is provided a circumferential step in an axial end of the other of said rings to form said fine annular clearance between the annular circumference of the circumferential step and said magnetic fluid holding means, and a labyrinth seal lip extending axially toward a free end of said radial flange portion of said member made of the non-magnetic material to form an additional fine annular clearance with the remaining circumference of said one of said rings.
Claim 5
Dependent Claim
281 words
In a sealing apparatus for sealing two rings made of a magnetic material coaxially and relatively rotated through a plurality of rolling members in which a magnetic fluid holding means for storing a magnetic fluid is provided, said magnetic fluid holding means being attached to one of said two rings to form a fine annular clearance, so that the magnetic fluid is positioned within the fine annular clearance, said magnetic fluid holding means comprising: an annular magnetic piece positioned in a member made of a body made of a resin and a plate made of non-magnetic metal, said body including an annular portion engaged with said one of said two rings and a radial flange portion extended from an end of said annular portion toward the other of said rings to form said fine annular clearance, said non-magnetic metal plate is integrally provided in said body to form a radial section of an annular step provided by said annular portion and said radial flange portion of said member, an end of said non-magnetic metal plate extending toward the other of said rings to form the fine annular clearance with the surface of the other of said rings, said annular magnetic piece having a free end and being fixed to said annular step, and axially magnetized to provide a magnetic circuit via said fine annular clearance adjacent the other of said rings made of the magnetic material, so that said magnetic circuit retains the magnetic fluid; and a recess located in said annular magnetic piece at a circumferential portion of said free end of said annular magnetic piece, for preventing the magnetic fluid from flowing away from said magnetic fluid holding means.
Claim 6
Dependent Claim
281 words
In a sealing apparatus for sealing two rings made of a magnetic material coaxially and relatively rotated through a plurality of rolling members in which a magnetic fluid holding means for storing a magnetic fluid is provided, said magnetic fluid holding means being attached to one of said two rings to form a fine annular clearance, so that the magnetic fluid is positioned within the fine annular clearance, said magnetic fluid holding means comprising: an annular magnetic piece positioned in a member made of a body made of a resin and a plate made of non-magnetic metal, said body including an annular portion engaged with said one of said two rings and a radial flange portion extended from an end of said annular portion toward the other of said rings to form said fine annular clearance, said non-magnetic metal plate is integrally provided in said body to form a radial section of an annular step provided by said annular portion and said radial flange portion of said member, an end of said non-magnetic metal plate extending toward the other of said rings to form the fine annular clearance with the surface of the other of said rings, said annular magnetic piece having a free end and being fixed to said annular step, and axially magnetized to provide a magnetic circuit via said fine annular clearance adjacent the other of said rings made of the magnetic material, so that said magnetic circuit retains the magnetic fluid; and a recess located in said annular magnetic piece at a circumferential portion of said free end of said annular magnetic piece, for preventing the magnetic fluid from flowing away from said magnetic fluid holding means.
Claim 7
Dependent Claim
279 words
In a sealing apparatus for sealing two rings made of a magnetic material coaxially and relatively rotated through a plurality of rolling members in which a magnetic fluid holding means for storing a magnetic fluid is provided, said magnetic fluid holding means being attached to one of said two rings to form a fine annular clearance, so that the magnetic fluid is positioned within the fine annular clearance, said magnetic fluid holding means comprising: an annular magnetic piece positioned in a member of a body made of rubber and a plate made of non-magnetic metal, said body including an annular portion engaged with said one of said two rings and a radial flange portion extended from an end of said annular portion toward the other of said rings to form said fine annular clearance, said non-magnetic metal plate is integrally provided in said body to form a radial section of an annular step provided by said annular portion and said radial flange portion of said member, an end of said non-magnetic metal plate extending toward the other of said rings to form the fine annular clearance with the surface of the other of said rings, said annular magnetic piece having a free end and being fixed to said annular step, and axially magnetized to provide a magnetic circuit via said fine annular clearance adjacent the other of said rings made of the magnetic material, so that said magnetic circuit retains the magnetic fluid; and a recess located in said annular magnetic piece at a circumferential portion of said free end of said annular magnetic piece, for preventing the magnetic fluid from flowing away from said magnetic fluid holding means.
Claim 8
Dependent Claim
279 words
In a sealing apparatus for sealing two rings made of a magnetic material coaxially and relatively rotated through a plurality of rolling members in which a magnetic fluid holding means for storing a magnetic fluid is provided, said magnetic fluid holding means being attached to one of said two rings to form a fine annular clearance, so that the magnetic fluid is positioned within the fine annular clearance, said magnetic fluid holding means comprising: an annular magnetic piece positioned in a member of a body made of rubber and a plate made of non-magnetic metal, said body including an annular portion engaged with said one of said two rings and a radial flange portion extended from an end of said annular portion toward the other of said rings to form said fine annular clearance, said non-magnetic metal plate is integrally provided in said body to form a radial section of an annular step provided by said annular portion and said radial flange portion of said member, an end of said non-magnetic metal plate extending toward the other of said rings to form the fine annular clearance with the surface of the other of said rings, said annular magnetic piece having a free end and being fixed to said annular step, and axially magnetized to provide a magnetic circuit via said fine annular clearance adjacent the other of said rings made of the magnetic material, so that said magnetic circuit retains the magnetic fluid; and a recess located in said annular magnetic piece at a circumferential portion of said free end of said annular magnetic piece, for preventing the magnetic fluid from flowing away from said magnetic fluid holding means.
Claim 9
Dependent Claim
19 words
The sealing apparatus as set forth in claim 5, wherein said annular magnetic piece comprises an annular permanent magnet.
Claim 10
Dependent Claim
39 words
The sealing apparatus as set forth in claim 5, wherein said annular magnetic piece comprises an annular permanent magnet and an annular pole piece made of a magnetic material fixed to an axial side of the annular permanent magnetic.
Claim 11
Dependent Claim
82 words
The sealing apparatus as set forth in claim 5, wherein there is provided a circumferential step in an axial end of said other of said rings to form said fine annular clearance between an annular surface of the circumferential step and said magnetic fluid holding means, and a labyrinth seal lip extending axially from said radial flange portion of said body made of a rubber to form an additional fine annular clearance with the remaining circumference of said one of said rings.
Claim 12
Dependent Claim
65 words
The seal apparatus as set forth in claim 5, wherein there is an additional non-magnetic metal plate fixed to an axial side of said magnetic piece opposed to said radial flange portion of said member, an end of said non-magnetic metal plate extending toward said other of said rings to form an additional fine annular clearance with the surface of the other of said rings.
Claim 13
Dependent Claim
43 words
The seal apparatus as set forth in claim 9, wherein said additional fine annular clearance between said non-magnetic metal plate and the other of said rings is narrower than said fine annular clearance between said magnetic piece and the other of said rings.
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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) | 1995-10-06 | 1996-04-06 | 1996-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-06 | 2000-04-06 | 2000-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-06 | 2004-04-06 | 2004-10-06 | $7700.00 | Window Closed / Lapsed |