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US 4,486,026 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
This invention relates to 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.
Claims9
Sealing and bearing means for use of ferrofluid comprising:
- a thrust support disc for preventing a thrust movement of a rotary shaft;
- a magnet disc opposing to the thrust support disc, the magnet disc being made of a normal magnet or a plastic-contained magnet;
- either one of the thrust support disc and the magnet disc being fixed with the rotary shaft, the both discs enclosing the rotary shaft concentrically;
- a ferrofluid being retained in a gap formed between opposing surfaces of the thrust support disc and the magnet disc;
- and
- either one of the thrust support disc and the magnet disc being, at its surface sliding with the other one, provided with grooves for dynamic pressure of the ferrofluid.
3 more elements
Dependencies are inferred from the claim text.