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US 6,672,592 B1Granted
Magnetic fluid seal
AssigneeNok Corporation
InventorHiroshi Anzai
Life of this patent
Estimating the term…
Abstract
A magnetic fluid seal with an excellent quality for reduction of leak of magnetic fluid. Among the projections of the pole pieces, the projections, that are nearest to the permanent magnet, are placed at positions intruding into the permanent magnet sides to hold the magnetic fluid in a space between the projections and the surface of the shaft.
Claims11
A magnetic fluid seal for sealing a circular space between a shaft and a housing, comprising:
- a magnetic force generating member that is arranged so that one end thereof corresponds to a north pole and the other end thereof corresponds to a south pole in a shaft extending direction;
- a pair of magnetic pole members that are respectively provided on both sides of said magnetic force generating member so that the magnetic force generating member is sandwiched therebetween,
- each of said pair of magnetic pole members includes a plurality of holding projections that extend toward a surface of said shaft and hold a magnetic fluid in a space between the holding projections and the shaft surface,
- a distance between the holding projections, which are nearest to the magnetic force generating member among the holding projections of the pair of magnetic pole members, is shorter than a length of the magnetic force generating member in the shaft extending direction, and
- an intercepting seal for intercepting a space between said magnetic force generating member and the shaft surface being provided between the holding projections that are nearest to said magnetic force generating member.
2 more elements
A magnetic fluid seal for sealing a circular space between a shaft and a housing, comprising:
- a magnetic force generating member that is arranged so that one end thereof corresponds to a north pole and the other end thereof corresponds to a south pole in a shaft extending direction;
- and
- a pair of magnetic pole members that are respectively provided on both sides of said magnetic force generating member so that the magnetic force generating member is sandwiched therebetween,
- each of said pair of magnetic pole members includes a plurality of holding projections that extend toward a surface of said housing and hold a magnetic fluid in a space between the holding projections and the housing surface, and a distance between the holding projections, which are nearest to the magnetic force generating member among the holding projections of the pair of magnetic pole members, is shorter than a length of the magnetic force generating member in the shaft extending direction.
1 more element
A magnetic fluid seal for sealing a circular space between a shaft and a housing, comprising:
- a magnetic force generating member that is arranged so that one end thereof corresponds to a north pole and the other end thereof corresponds to a south pole in a shaft extending direction;
- a pair of magnetic pole members that are respectively provided on both sides of said magnetic force generating member so that the magnetic force generating member is sandwiched therebetween,
- each of said pair of magnetic pole members includes a plurality of holding projections that extend toward a surface of said shaft and hold a magnetic fluid in a space between the holding projections and the shaft surface,
- a distance between the holding projections, which are nearest to the magnetic force generating member among the holding projections of the pair of magnetic pole members, is shorter than a length of the magnetic force generating member in the shaft extending direction, and
- the holding projections, which are farthest from the magnetic force generating member among the holding projections of said magnetic pole members, being provided at positions that are placed inward from end surfaces in the shaft extending direction of main bodies of the magnetic pole members, and a distance between the shaft surface and wall surfaces, which oppose the shaft surface and exist at positions placed outward from the holding projections that are farthest from the magnetic force generating member, being longer than a distance from tips of the holding projections to the shaft surface and being shorter than heights of the holding projections.
2 more elements
Dependencies are inferred from the claim text.