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US 4,598,914 AGranted
Sealing and bearing means by use of ferrofluid
AssigneeNippon Seiko Kabushiki Kaisha
InventorsKyozaburo Furumura, Hiromi Sugi, Yasuo Murakami, Hiromitsu Asai
Life of this patent
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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.
Claims7
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.
Dependencies are inferred from the claim text.