Patent ID: 7492069

Claim:
A submersible well pump assembly, comprising: a motor having a housing containing a stator with a central passage therethrough, the housing adapted to be filled with lubricant; a rotor shaft assembly located within the central passage of the stator for rotation relative to the stator; a plurality of radial support bearings surrounding and spaced along a length of the shaft assembly for radially supporting the shaft assembly, each of the radial support bearings comprising a stationary outer member that is separated from the shaft assembly an annular clearance; first and second centrifugal impellers located in the housing for pumping lubricant to the bearings, each of the impellers being attached to and rotating with the shaft assembly; first and second diffusers associated with the first and second centrifugal impellers, respectively; an axial flow passage extending axially within the shaft assembly in fluid communication with an outlet of the second impeller and second diffuser such that all of the lubricant pumped by the impellers and the diffusers flows into the axial passage; an outlet in the shaft assembly at each of the bearings, each of the outlets comprising at least three ports in fluid communication with the axial flow passage and arranged substantially symmetrically about the shaft assembly for discharging lubricant radially outward into the clearance at a sufficient pressure to induce a film of lubricant in each the clearances between the shaft assembly and the outer members of the bearings; a rotary pump coupled to the motor exterior of the housing and driven by the shaft assembly of the motor the rotary pump having an intake adapted to be in fluid communication with a well fluid for pumping the well fluid; and the lubricant in the motor being sealed from the well fluid.