Elastomeric seal

In combination, a seal and a rotatable shaft of predetermined diameter located within a housing, said seal comprising a ring of imperforate elastomeric material having a generally cylindrical inner surface engaging the shaft and a generally cylindrical outer surface frictionally engaging the interior surface of the housing, means in said housing limiting axial movement of said seal, said seal ring having one end abutting said movement limiting means and an opposite free end provided with a pair of concentric annular inner and outer lips separated by an annular generally V-shaped groove defining the lips, said groove and lips being exposed to pressure in said housing causing inward and outward movement of said lips in a generally radial direction to engage said shaft and housing, respectively, axially spaced annular rings on the cylindrical inner surface engaging the shaft and separated by a pair of concave recesses, said annular rings and annular lips all having rounded surfaces in contact with said shaft and housing, and one end of said seal having a cut-away counterbore on the cylindrical inner surface adjacent said movement limiting means to prevent extrusion of said elastomeric material between said movement limiting means and said shaft.