Dynamic-static shaft seal

Claim 1

A sealing assembly comprising a shaft, a housing surrounding said shaft and formed with an inwardly open annular groove, and a seal received in said groove and surrounding said shaft, said seal being disposed in said housing between a high-pressure zone and a low-pressure zone formed therein, said seal comprising: a cup packing of asymmetrical section and formed with radially extending flange and with a frustoconical lip extending from one axial side of said flange toward said high-pressure zone and having an inner face resiliently engageable with the outer surface of said shaft; a supple pressure-distributing ring having an end surface bonded to said one side of said flange, an inner portion formed with a recess snugly receiving and bonded to the outer face of said lip, said recess having a frustoconical wall bonded to said outer face, a substantially cylindrical outer periphery resiliently engaging with and bottoming in the interior of said groove, and a substantially cylindrical inner periphery engaging said outer surface of said shaft, said lip having an inner face inclined inwardly toward said inner periphery and terminating flush therewith; and a nonresilient ring received in said packing at the other axial side thereof, said presssure-distributing ring retaining said packing out of engagement with the bottom of said groove and holding most of said lip out of engagement with said outer surface in the absence of a pressure differential across said zones.