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:
Nov. 24, 1992
Filed:
Feb. 12, 1992
Akihiko Koba, Kitakyushu, JP;
Nok Corporation, Tokyo, JP;
Abstract
A magnetic fluid seal apparatus adapted to prevent a magnetic fluid from being displaced along a shaft or housing during linear motion of the shaft. In the apparatus of the bore mounted type, a pole piece is hermetically fixed within a bore of the housing, while an associated inner ring is fitted over the shaft so as to form an annular magnetic gap in which the magnetic fluid is magnetically retained. The inner ring has an axial length smaller than that of the pole piece. Thus, a portion of the magnetic fluid is retained along the outer face of the inner ring, while the remainder of the fluid is retained along the inner face of the pole piece to form a film of magnetic fluid. The pole piece has an axial length equal to or greater than the travel of linear motion of the shaft so that the portion of magnetic fluid retained along the inner ring is in continuous, integrated fluid-to-fluid engagement with the film of magnetic fluid throughout the travel of the shaft. Various other embodiments, including a magnetic fluid seal apparatus of the shaft mounted type, are also disclosed.