Abstract: A sealed, pressure-equalizing lubrication system for a rotary rock bit is shown. The system includes a lubricant-filled container having an outlet and a portion of the container includes a flexible diaphragm. The container is mounted in a chamber in the journal axle portion of the bit, immediately adjacent and open to the sealed bearing cavity of the bit cutter, with the outlet disposed adjacent the cavity. A bleed hole is provided from the back face of the bit to the chamber adjacent the diaphragm causing the diaphragm to be responsive to the pressure of the external downhole fluid. The adjacency of the reservoir to the sealed bearing cavity permits the pressure of the lubricant adjacent the seal to be immediately responsive to the pressure of the downhole fluid at the diaphragm to prevent pressure differentials between the lubricant and the fluid at the seal.

Abstract: A rolling cone cutter earth boring bit is provided having a pair of facing thrust bearing surfaces, one such surface on the rolling cone and the other surface on the journal pin. The latter surface defines an annular groove which has separate arcuate segments thereof filled with a hardfacing material and machined to provide a complimentary engaging surface with the cone thrust bearing surface. The spaces in the groove between the hardfacing segments define pockets providing lubricant reservoirs and debris traps for the immediately adjacent thrust bearing surfaces.

Abstract: Lubricant is circulated from a lubricant reservoir to the bearings of a rotary rock bit and back to the lubricant reservoir by a lubricant circulation system that is operated by rotation of the cone cutter upon the bearing pin of the bit. A seal is positioned between the rolling cone cutter and the arm of the bit to maintain lubricant in the bearing area and to prevent fluid and materials in the borehole from entering the bearing area. A lubricant reservoir is located in the bit body. A first passage connects the lubricant reservoir with the bearing area to channel lubricant from the lubricant reservoir to the bearing area. A second passage extends from the bearing area to the lubricant reservoir to allow lubricant to be channeled back to the lubricant reservoir.

Abstract: A sealing system acts as a barrier to the drilling fluid, pulverized cuttings and other materials in the borehole to prevent the materials from entering the bearing area of a rotary rock bit. The bit body and the base of the cone cutter cooperate to retain the seal unit. The seal is located in a groove and an effective seal is provided without reducing the bearing capacity of the bit's bearing system. The sealing system allows excessive pressures in the lubricant to be relieved.