Ferrofluid seal apparatus
AssigneeKoyo Seiko Co., Ltd.
InventorsHirokazu Takii, Tetsuo Oda, Shinji Abe, Kazuya Suzuki, Hirotsugu Kusano
Life of this patent
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Abstract
A ferrofluid seal apparatus comprises magnetic fluid holding means for storing a magnetic fluid with one of an inner and an outer elements which are relatively rotated. The magnetic fluid holding means has a storage section for storing a part of the magnetic fluid which flows out of said magnetic fluid holding means.
Claims22
A sealing apparatus for sealing coaxial and relatively rotated inner and outer elements made of a magnetic material in which a magnetically permeable fluid holding means for positioning a magnetic fluid is provided, said magnetic fluid holding means being attached to the outer element to form a fine annular clearance between the fluid holding means and the inner element, so that the magnetic fluid is positioned within said fine annular clearance, said magnetic fluid holding means comprising:
- a holder made of a non-magnetic material and having a cylindrical portion, said holder being secured to said outer element by adhesive material, said holder having an extension portion extending from said cylindrical portion toward said inner element and providing a fine clearance with said inner element;
- said extension portion having an annular projection located thereon and extending parallel to said cylindrical portion;
- and
- an annular magnetic piece located in an annular space between said cylindrical portion of said holder and said extension portion of said holder and having a fine clearance with said cylindrical portion and being positioned by engagement with said annular projection on said extension portion to be coaxially arranged with said holder, said annular magnetic piece being secured by adhesive material filled within said fine clearance of said holder and being magnetized axially to form a magnetic circuit through the fine clearance with the inner element, so that said magnetic fluid is retained within said magnetic circuit.
The sealing apparatus for sealing inner and outer rings made of a magnetically permeable material and coaxially and relatively rotated through a plurality of rolling members lubricated with a grease in which a magnetic fluid holding means for storing a magnetic fluid is provided, said magnetic fluid holding means being attached to said outer ring to form a fine annular clearance with said inner ring, so that the magnetic fluid is positioned within the fine clearance, said magnetic fluid holding means comprising:
- a holder made of a non-magnetic material and having a cylindrical portion, said holder being secured to said outer ring via an adhesive, said holder also having an extension portion extending toward said inner ring and providing a fine clearance with said inner ring;
- said extension portion having an annular projection located thereon and extending parallel to said cylindrical portion;
- and
- an annular magnetic piece located in an annular space between said cylindrical portion of said holder and said extension portion of said holder and having a fine clearance with said cylindrical portion and being positioned by engagement with said annular projection on said extension portion to be coaxially arranged with said holder, said annular magnetic piece being secured by adhesive material filled within said fine clearance with said holder and being magnetized axially to form a magnetic circuit through the fine clearance with the inner ring, so that said magnetic fluid is retained within said magnetic circuit.
A rolling bearing having a sealing apparatus for sealing inner and outer rings made of a magnetically permeable material and coaxially and relatively rotated through a plurality of rolling members lubricated with a grease, said sealing apparatus comprising:
- a magnetic fluid holding means for storing a magnetic fluid, said magnetic fluid holding means being attached to said outer ring to form a fine clearance with the outer surface of said inner ring;
- a magnetic fluid being positioned within said fine clearance by said magnetic fluid holding means;
- an annular seal element having first and second ends, made of an elastic material and reinforced with a metal core, said annular seal element being provided between said magnetic fluid holding means and said rolling members,
- said first end of said annular seal element being fixed in an annular groove formed in said outer ring and said second end of said annular seal element being loosely engaged in an annular groove formed in said inner ring,
- said magnetic fluid holding means comprises:
- a holder made a non-magnetic material and having a cylindrical portion, said holder being secured to said outer ring via an adhesive, said holder also having an extension portion extending toward said inner ring and providing a fine clearance with said inner ring, said extension portion having an annular projection located and extending parallel to said cylindrical portion;
- and
- an annular magnetic piece located in an annular space between said cylindrical portion of said holder and said extension portion of aid holder and having a fine clearance with said cylindrical portion and being positioned by engagement with said annular projection on said extension portion to be coaxially arranged with said holder, said annular magnetic piece being secured by adhesive material filled within said fine clearance with said holder and being magnetized axially to form a magnetic circuit through the fine clearance with the inner ring, so that said magnetic fluid is retained within said magnetic circuit.
Dependencies are inferred from the claim text.