Shaft seal with helical pumping element

摘要

An oil or grease seal unit of the radially acting type which includes a relatively stiff mounting portion and a relatively flexible elastomeric sealing lip portion adapted to surround or be surrounded by a relatively movable machine member or element to prevent passage of fluid, such as oil or the like, axially along the shaft to the exterior of the region to be sealed. A novel form of pumping element is provided whereby a strong pumping or oil return action from the exterior of the sealed region to the interior thereof may be accomplished by the provision of generally helically disposed, rib-like pumping elements lying on one frusto-conical surface of the sealing lip. The pumping elements are disposed at an angle both to the direction of shaft rotation and to a shaft axis, and are arranged to blend into the intended area of contact between the seal lip and the shaft, that is, the static lip formed by the convergence of inner and outer frusto-conical surfaces. Pumping action remains relatively constant throughout the working life of the seal.