One Piece rear seal for servomotor

Claim 1

In a brake booster having a housing with an interior divided by a wall into a control chamber and an operational chamber, said wall having a projection that extends through an opening in said wall, said projection moving in said opening as the wall moves in the housing in response to a pressure differential between said control and operational chambers, the improvement in a seal which surrounds said projection to prevent communication of environmental air to said operational chamber along a flow path between the housing and projection that would effect said pressure differential, said seal comprising: a resilient body having a first end and a second end, said resilient body having a peripheral surface that extends from said first end to said second end, said peripheral surface having a first groove separated from a second groove by a cylindrical surface, a first rib adjacent said first groove and a second rib adjacent said first end and a flange adjacent said second groove, said first rib engaging said housing to form a first static seal with said housing, said second rib engaging said housing to form a second static seal with said housing, said housing having a lip that extends into said second groove to fix the position of said resilient body with respect to said opening, said resilient body having first and second lands located between first and second dynamic seals, said first and second dynamic seals engaging said projection to prevent communication of environmental air into said control chamber, said first and second dynamic seals flexing to allow said projection limited radial movement into engagement with said first and second lands which maintains the projection in substantial axial alignment.