Eccentricity tolerant valve stem seal assembly

摘要

An eccentricity tolerant valve stem seal assembly includes an elastomeric seal having an upper metal retainer extending down and within an upper seal portion which has an inwardly directed sealing lip for contacting a valve stem. There are also a flexible middle and a lower seal portions. The lower seal portion is connected to a lower metal seal retainer that is disposed up to a lower edge of the middle seal portion. The flexible middle seal portion allows the upper seal portion to flex from an eccentric valve stem without losing the sealing function of the sealing lip. In cooperation with the above described structure, a separate cover may be in a tight tolerance fit with the lower seal retainer over top of the eccentricity tolerant valve stem seal, in order to limit axial displacement of the upper portion of the seal due to high manifold pressure.

主权项

1. An eccentricity tolerant valve stem seal assembly, comprising:
an upper elastomeric seal portion having a radially inwardly directed upper sealing lip in contact with a valve stem; an upper seal retainer disposed radially outwardly from the upper sealing lip and axially disposed down and into the upper elastomeric seal portion, wherein the upper seal retainer has a lower portion integrally connected to and unitary with an upper portion of the upper seal retainer; a flexible middle elastomeric seal portion disposed completely radially outward of the outermost periphery of a valve guide, wherein a bottom tip of the upper seal retainer axially extends down to a position having the same axial height as a top of the valve guide to define a top of the flexible middle elastomeric seal portion; a lower elastomeric seal portion; and a separate lower seal retainer disposed up to a lower edge of the flexible middle elastomeric seal portion with an exterior surface of the lower elastomeric seal portion disposed on an interior surface of the lower seal retainer, wherein an axially oriented top edge of the lower valve seal retainer defines a bottom of the flexible middle elastomeric seal portion; wherein the lower seal retainer is mechanically decoupled from the upper seal retainer by way of the flexible middle elastomeric seal portion.