Lip Seal With Inversion Prevention Feature

Abstract

A dynamic shaft seal assembly is provided including a dynamic seal for engaging a rotary shaft. The dynamic seal includes a mounting portion that is mounted within a casing and has an axially extending barrel portion extending from a radially inner end of the mounting portion. The axially extending barrel portion terminates in a radially extending leg portion which extends inwardly from an end of the axially extending portion. A generally conically shaped seal portion extends from an end of the radially extending portion and the seal portion includes a radially inner face engaging the shaft and a radially outer face having a stiffening bead integrally formed thereon. The mounting portion defines a bumper spaced from the axially extending barrel portion by a gap distance that is designed to prevent the seal lip from inverting under sustained high pressure or pressure spikes.

What is claimed is: 
     
         1 . A dynamic seal, comprising:
 an annular mounting portion;   a first insert ring disposed within said mounting portion;   an axially extending portion extending in a first axial direction from said mounting portion;   a radially extending portion extending radially inwardly from an end of said axially extending portion;   a generally conically shaped seal portion extending from an end of said radially extending portion in a direction opposite said first axial direction, said seal portion including a radially inner face adapted to engage a rotary member; and   a second ring disposed within said first insert ring and defining a bumper spaced from said axially extending portion by a gap distance, said second ring limiting axial movement of said radially extending portion relative to said mounting portion to prevent the axially extending portion from deflecting more than 60 degrees from parallel with a central axis.   
     
     
         2 . The dynamic seal according to  claim 1 , wherein said first insert ring and said second ring are both generally L-shaped. 
     
     
         3 . A dynamic seal, comprising:
 an annular mounting portion;   an axially extending portion extending in a first axial direction from said mounting portion, said mounting portion defining a bumper surface spaced radially outward from said axially extending portion by a gap distance, wherein said bumper surface is formed from a metal insert over-molded within said mounting portion;   a radially extending portion extending radially inwardly from an end of said axially extending portion;   a generally conically shaped seal portion extending from an end of said radially extending portion in a direction opposite said first axial direction, said seal portion including a radially inner face adapted to engage a rotary member, wherein said gap distance prevents the axially extending portion from deflecting more than 60 degrees from parallel with a central axis.   
     
     
         4 . The dynamic seal according to  claim 3 , wherein said insert includes an axially extending portion disposed within said mounting portion and an arm portion extending from said axially extending portion that is bent radially inward and defines said bumper. 
     
     
         5 . The dynamic seal according to  claim 3 , wherein said insert includes an axially extending bumper portion defining said bumper. 
     
     
         6 . The dynamic seal according to  claim 5 , wherein said insert includes a C-shaped cross-section. 
     
     
         7 . The dynamic seal according to  claim 5 , wherein said insert includes a radially extending portion extending radially outwardly from said axially extending bumper portion toward an outer surface of said mounting portion. 
     
     
         8 . The dynamic seal according to  claim 7 , wherein said insert includes an axially extending portion extending from an outer end of said radially extending portion and reinforcing said mounting portion.