Patent ID: 7520132

Claim:
A cup seal received in a concavity and allowing a slidable member to pass therethrough, said cup seal comprising: an annular base portion extending radially, an annular inner lip extending axially from an inner peripheral side end of the base portion such that the slidable member is slidably inserted through the annular inner lip, and an annular outer lip extending axially from an outer peripheral side end of the base portion to contact with a bottom wall of said concavity such that the outer lip can be spaced apart from the bottom wall, wherein the cup seal has a laterally-facing U-shaped section, wherein the base portion includes base side fluid passage grooves extending radially to allow communication between an outer peripheral side and an inner peripheral side of said base portion, the inner lip includes lip side fluid passage grooves extending radially to completely penetrate therethrough to open at a front end of said inner lip, and the annular inner lip is longer than the annular outer lip in an axial direction of the cup seal.