Sealing means for roller cone drill bit

摘要

A sealed-bearing drill bit 10 for use in an earthen annulus is provided having a dual seal arrangement. The drill bit 10 includes at least one leg 20 having a journal segment 23, and a roller cone 18 mounted upon the journal segment 23, forming at least one bearing cavity 75 therebetween. An annular primary seal 38 is disposed between the bearing cavity 75 and the earthen annulus. An annular secondary seal 52 is disposed between the annular primary seal 38 and the earthen annulus and is capable of substantially preventing the ingress of debris from the an earthen annulus to the annular primary seal 38.