OIL-SEALED MUD MOTOR BEARING ASSEMBLY WITH MUD-LUBRICATED OFF-BOTTOM THRUST BEARING

摘要

A bearing assembly for a mud motor has a mandrel rotatably disposed within a cylindrical housing, with a rolling-element thrust bearing disposed within an oil-sealed annular chamber between the mandrel and the housing, for resisting on-bottom axial thrust loads. Off-bottom axial thrust loads are resisted by a mud-lubricated thrust bearing assembly located above the oil-sealed chamber. The lower end of a drive shaft adapter coupled to the mandrel is used to provide an upper load-transferring shoulder for the off-bottom thrust bearing, with a lower load-transferring shoulder being provided in association with the housing. The upper and lower shoulders come into mating contact under off-bottom thrust loading, with the upper shoulder rotatable (with the mandrel) relative to the lower shoulder.