SEALED BEARING DRILL BIT WITH DUAL-SEAL CONFIGURATION

摘要

A sealed-bearing drill bit for use in an earthen annulus is provided having a dual seal arrangement. The drill bit includes at least one leg having a journal segment, and a roller cone mounted upon the journal segment and forming at least one bear ing cavity therebetween. An annular primary seal is disposed between the leg and rol ler cone and between the bearing cavity and the earthen annulus. An annular secondar y seal is disposed between the annular primary seal and the earthen annulus and is capable of substantially preventing the ingress of debris from the earthen annul us to the annular primary seal.