Abstract: A seal having an exterior seal casing which includes a mounting surface and a seal lip body bonded to a portion of the casing, with the seal lip body comprising annular surfaces defining the air and oil side portions of a primary lip which meet along a generally cylindrical locus of measurable axial extent to provide a primary seal band with a plurality of spaced apart hydrodynamic pumping elements located on this seal band. An auxiliary lip is defined by a pair of frusto-conical surfaces meeting along a generally circular locus to provide an auxiliary or excluder lip portion. Said primary and secondary lips are spaced apart by an annular region of generally V-shaped cross-section, and the primary lip dimension or the pumping elements serve to maintain the primary lip seal band spaced just apart from an associated shaft, at least in the regions of the elements. Said auxiliary lip is of reduced diameter in relation to said seal band dimension in the relaxed condition of the seal.

Abstract: An oil or like fluid seal having a rigid exterior casing, a primary lip and an auxillary lip, with the primary or axially inner lip having a primary seal band surface which is generally cylindrical in its relaxed condition and which includes at least one hydrodynamic pumping element on its shaft contact surface, with the auxillary lip, in its relaxed condition, being of greater inside diameter than the primary lip, with the primary and secondary lips being spaced apart so as to define an intermediate annular groove of generally V-shaped cross-sections between them, with the pumping element acting to space portions of the primary lip apart from the associated shaft so as to provide initial venting of gas and vapors from the sealed cavity into the intermediate region and beneath the auxillary lip as cavity pressure increases so as avoid excessive pressure build up in the sealed region or sudden or erratic venting of such pressure.

Abstract: The invention relates to a fluid seal unit which vents gas pressure from a sealed region. The seal includes vents extending axially along its inside or outside mounting surface diameter, preferably communicating with an annular manifold lying adjacent one face of the seal. The manifold in turn is sealed by a flexible diaphragm which provides a valve or vent control action in use. The mounting surface containing the vent may be a metal surface, forming a part of the seal casing or a rubber surface where the seal has a rubber covered mounting flange.