Mandrel and bearing assembly for downhole drilling motor

摘要

A downhole drilling motor bearing assembly includes a tubular mandrel adapted to connect to a rotational power output of downhole motor. The bearing assembly includes a mandrel having: an upper end proximal to the downhole motor, a lower end with a pin connection distal from the motor, and a longitudinal passage through the mandrel from the upper end to the lower end. The assembly further includes at least one circumferential ring projecting radially outward from an outer surface of the tubular mandrel. The ring has an upper shoulder and a lower shoulder and a radial surface. A circumferential upper thrust bushing contacts the upper shoulder of the ring and a circumferential lower thrust bushing contacts the lower shoulder of the ring. An upper thrust bearing contacts the upper thrust bushing and a lower thrust bearing contacts the lower thrust bushing. A tubular bearing housing includes a longitudinal passage from an upper end of the housing to a lower end of the housing. The passage includes a lower portion with an internal diameter adapted to receive the lower end of the mandrel and an upper portion with a larger internal diameter adapted to receive the lower bearing and bushing and the outer radial surface of the circumferential ring projecting from the mandrel and the upper bushing and bearing.