Patent ID: 9683409
Date: 2017-06-20
CPC Classifications: E21B

Claim:
1. A mud motor bearing section having an upper end and a lower end, the bearing section comprising: a mandrel rotatably and coaxially disposed within a cylindrical housing having a longitudinal axis, wherein the mandrel comprises an inner cylindrical surface, an outer surface, and a port extending between the inner cylindrical surface and the outer surface, and wherein the housing comprises an inner surface; a cylindrical sleeve having an outer cylindrical surface, the sleeve being disposed within the inner cylindrical surface of the mandrel, the sleeve being coupled to the mandrel to form an annular piston chamber between the outer surface of the sleeve and the inner cylindrical surface of the mandrel; and an annular piston non-rotatingly disposed within the piston chamber, wherein the piston is adapted to move axially within the piston chamber, with the piston having an inner face sealingly engaging the outer surface of the sleeve, and an outer face sealingly engaging the inner cylindrical surface of the mandrel, wherein an end of the sleeve sealingly engages the inner cylindrical surface of the mandrel.