Magnetic sealing device for use between first and second magnetic members which rotate relative to each other

摘要

Installed between a housing and a shaft concentrically disposed with a space having a predetermined radial length therebetween so as to move relative to one another is a sealing device which comprises a ferrofluid seal device comprising a permanent magnet and a pair of pole pieces for supporting the magnet interposed therebetween, so that a ferrofluid is retained between the pole pieces at one end thereof and the shaft and that a radially outer air gap is provided at least one of the pole pieces at the other end thereof and the housing, whereby the magnetic flux path extending between the pole pieces at the other end thereof and the housing is eliminated.