ROCK BIT BEARING STRUCTURE

摘要

A rock bit has a rotary cutter cone journaled on a fixed journal bearing shaft with the radial load being taken by a cylindrical journal bearing. She friction bearing portion of the fixed shaft has a groove extending around the periphery of the shaft. The groove is filled with a bearing metal over an arc on the lower load bearing fraction of the shaft. the retaining unfilled portion of the groove is connected through a lubricant supply passage in the bit body with a pressure-compensated grease reservoir in the bit body, to supply lubrication to the journal bearing.