Abstract: A hydrodynamic bearing (16) for a cutter cone assembly (12) that rotates around a journal (14). The bearing (16) comprises a plurality of grooves (88) on an outer surface (90) to produce undulations (82) on an inner surface (84) upon insertion of the bearing (16) into a bearing recess (94). Undulations (82) act as pockets to collect lubricant which is forced upon rotation of the bearing (16) between the outer journal surface (86) and the inner bearing surface (84) to produce a hydrodynamic film.

Abstract: A sealed bearing rock bit for drilling oil wells and the like that includes a spring bearing member rotatably supporting the cutters on the pins of the bit. The resiliency of the spring bearing member on each pin is utilized to bias an annular seal member in a direction to maintain a face-type seal in fluid-tight, sealing engagement preventing loss of lubricant from the bit and preventing the ingress of deleterious material into the bit.

Abstract: In accordance with an illustrative embodiment of the present invention, a thrust bearing member is positioned between the rolling cutter or cone and the bearing pin of a rock bit and comprises wound wire such as a closed spiral coil spring that provides spaced-apart bearing surfaces with open areas therebetween. The flexibility of the spiral spring tends to spread the load between several bearing areas to thereby reduce concentrations of stress and the occurrence of localized high temperatures and wear, and the spacing of the bearing surfaces provides wear and contamination particle traps as well as lubricant reservoirs, to significantly increase the useful life of the bearing.

Abstract: In accordance with an illustrative embodiment of the present invention, a bearing positioned between the rolling cutter or cone and the bearing pin of a rock bit comprises wound wire such as a closed helical coil spring that provides spaced-apart bearing surfaces with open areas therebetween. The flexibility of the helical spring tends to spread the load between several bearing areas to thereby reduce concentrations of stress and the occurrence of localized high temperatures and wear, and the spacing of the bearing surfaces provides wear and contamination particle traps as well as lubricant reservoirs, to significantly increase the useful life of the bearing.

Abstract: An earth boring drill bit has hard metal inserts in its cutter shells that are spaced to eliminate rows. Each insert has a surrounding boundary zone with inner and outer loops corresponding to the minimum and maximum desired distances between centerlines of inserts, respectively. Each insert has at least one insert located randomly in its boundary zone. In selecting the locations, a first insert is arbitrarily located. The location of a second insert is randomly selected within the boundary zone of the first insert. The location of a third insert is randomly located within the boundary zone of the second insert, so long as it does not come any closer to the first insert than the minimum desired distance between inserts. Each succeeding insert is chosen in this manner.

Abstract: An earth boring bit has a friction or journal bearing with features that allow cooling fluid to be circulated near the bearing. The bit is of the type having rotatable cutters carried by depending bearing pins. A bushing is stationarily mounted on the bearing pin, with the bushing's inner surface in contact with the outer surface of the bearing pin. One of the surfaces has a plurality of grooves that extend at least partially around the bearing pin. Passages are formed in the bearing pin and bit for circulating cooling fluid through the grooves. The cutter is mounted on the bushing in rotating and sliding contact to form a journal bearing.