MICROPORE ENGAGEMENT SURFACES FOR EARTH BORING BIT

摘要

An earth boring bit has sliding engaging surfaces between a cone assembly and a bearing pin. Micropores are formed in at least one of the engaging surfaces. Each of the micropores has a leading portion and a trailing portion. The leading portion is at a more gradual slope than the trailing portion. The micropores are located in a pattern of a greater density in a region of the engaging surfaces that operate at higher pressures than in other regions.