Patent ID: 8181720
Filing Date: 2012-05-22
Classification: E21B,F16C

Abstract:
1. A bearing assembly for a downhole motor, comprising: a housing having a central axis, an upper end, a lower end, a through passage extending between the upper end and the lower end, a radially inner surface defining the through passage, and a radially outer surface; a mandrel rotatably disposed within the through passage of the housing; an upper seal assembly radially positioned between the housing and the mandrel; a lower seal assembly radially positioned between the housing and the mandrel, wherein the lower seal assembly is axially positioned proximal the lower end of the housing; a thrust bearing assembly radially positioned between the housing and the mandrel, wherein the thrust bearing assembly is axially positioned between the upper seal assembly and the lower seal assembly; a lubricating fluid radially disposed between the housing and the mandrel and axially disposed between the upper seal assembly and the lower seal assembly; wherein the lower end of the housing comprises a first check valve radially positioned between the radially inner surface and the radially outer surface of the housing, wherein the check valve is in fluid communication with the lubricating fluid, wherein the first check valve is adapted to allow at least a portion of the lubricant to exit the bearing assembly at a predetermined pressure differential.