Self-lubricating elastomeric seal with polarized graphite

A rotary cone rock bit for drilling subterranean formations comprising;

• a bit body including a plurality of journal pins each extending from a leg portion of the bit and having a bearing surface;
• a cutter cone rotatably mounted on each journal pin and including a bearing surface;
• a grease adjacent the bearing surfaces;
• and
• a dynamic annular seal for retaining the grease between the bearing surfaces comprising:
• a body portion and a surface portion both being flexible and resilient, and each being formed from an elastomeric composition selected from materials consisting of highly-saturated nitrile elastomers, nitrile-butadiene rubber, highly-saturated nitrile-butadiene rubber, and mixtures thereof, wherein the elastomeric composition at least adjacent a surface portion additionally comprises polarized graphite.

A rotary cone rock bit for drilling subterranean formations comprising:

• a bit body including a plurality of journal pins each extending from a leg portion of the bit and having a bearing surface;
• a cutter cone rotatably mounted on each journal pin and including a bearing surface;
• a pressure-compensated grease reservoir in communication with such bearing surfaces;
• a grease in the grease reservoir and adjacent the bearing surfaces;
• and
• a dynamic O-ring seal for retaining the grease between the bearing surfaces comprising:
• a resilient and flexible elastomeric body having a static sealing surface along a first body portion and a dynamic sealing surface along a second body portion, the elastomeric composition further comprising polarized graphite uniformly distributed in at least the dynamic sealing surface.