Earth-boring bit with improved bearing seal

An earth-boring bit having an improved bearing seal assembly, the earth-boring bit comprising:

• a bit body;
• at least one bearing shaft depending inwardly and downwardly from the bit body, the bearing shaft having a base where it joins the bit body;
• a cutter mounted for rotation on each bearing shaft, the cutter including a primary seal surface that generally faces the base of the bearing shaft;
• a primary seal element having a substantially rigid seal ring that is in dynamic contact with the primary seal surface of the cutter and a resilient energizer disposed in substantially nonrotating contact with the rigid seal ring for urging the rigid seal ring against the primary seal surface of the cutter;
• and
• a resilient secondary seal element disposed at the base of the bearing shaft, the secondary seal element being in substantially nonrotating sealing engagement with the primary seal element and free of contact with the cutter.

An earth-boring bit having an improved bearing seal assembly, the earth-boring bit comprising:

• a bit body;
• at least one bearing shaft having an axis and depending inwardly and downwardly from the bit body, the bearing shaft having an outer diameter and a base where it joins the bit body;
• a cutter mounted for rotation on the bearing shaft, the cutter having an annular surface located radially outward from the bearing shaft and an axial seal surface extending from the annular surface in a plane substantially perpendicular to an axis of the bearing shaft, wherein the base of the bearing shaft, the annular surface, the outer diameter of the bearing shaft, and the axial seal surface define a seal cavity;
• a seal assembly located in the seal cavity, the seal assembly including a rigid seal ring in dynamic sealing contact with the axial seal surface;
• the seal assembly including an elastomeric energizer portion in substantially nonrotating sealing contact with the bearing shaft and substantially nonrotating sealing contact with the rigid seal ring for urging the rigid seal ring into sealing contact with the axial seal surface;
• and
• the seal assembly including an elastomeric seal portion disposed in sealing contact with the base of the bearing shaft, the elastomeric seal portion also being in sealing contact with the rigid seal ring, and wherein the rigid seal ring, the elastomeric energizer portion, and the elastomeric seal portion are free of contact with the annular surface of the cutter.