Rotary fluid seals with floating sealing rings

Claim 1

A rotary fluid seal, for preventing leakage of fluid between two coaxial relatively rotatable members, comprising a pair of axially opposed relatively rotatable counterface members, a circular flexible sealing ring freely located to float substantially coaxially between the conterface members, the sealing ring having a pair of radially outwardly divergent, oppositely axially directed, annular sealing lips to bear resiliently against the counterfaces respectively of the counterface members, so that the sealing ring is frictionally driven into rotation by one or the other of the counterface members on relative rotation thereof, the sealing lips each presenting to the respective counterface a frusto-conical contact face defined by radially inner and outer peripheral edges and the counterfaces being radially outwardly divergent and frusto-conical over an area provided for face contact by the sealing lip contact faces, the sealing ring being substantially coaxially located by seating between the counterfaces, and the effect of centrifugal force, due to rotation of the sealing ring, being to cause the sealing lips to tend to flex angularly outwardly towards a radial plane and thereby to reduce the bearing load of the contact faces on the counterfaces.