The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 30, 2011
Filed:
Jun. 24, 2004
Akira Yamamura, Tokyo, JP;
Heiichi Unozawa, Nosaka-machi, JP;
Akira Yamamura, Tokyo, JP;
Heiichi Unozawa, Nosaka-machi, JP;
Ferrotec Corporation, Tokyo, JP;
Abstract
A magnetic fluid is held by a magnetic field in a stationary state and by a centrifugal force during rotation, leaking and splashing of the magnetic fluid caused by the instability of the pumping of a dynamic pressure bearing are prevented without using a magnetic fluid with a high saturation magnetization value, and the service life of the dynamic pressure bearing is extended. For this purpose, a sleevehaving a protruding tubular section is fitted and fixed to the outer periphery of the shafthaving a thrust plateformed in an axial vicinity so as to be rotatable relatively to the shaft, an annular coveris formed outwardly from the thrust platein an axial direction, the radially inward end of the annular coverserves as an opening, at least two clearance sections serve as a reservoirfor reserving the magnetic fluid, and a magnetomotive force memberis provided for concentrating the magnetic flux lines on the radially outer side of the end portionof the magnetic fluid