Patent ID: 7780424
Filing Date: 2010-08-24
Classification: F04D,F16C

Abstract:
1. An electric submersible pump assembly for use in a well, comprising: an electrical motor having a lubricant-filled housing, a rotor, a stator, and a shaft having an axis; a rotary pump driven by the motor; a plurality of bearings in the motor for radially stabilizing the shaft, at least one of the bearings in the motor being immersed in the lubricant in the motor and having a bearing housing; bearing surfaces comprising a plurality of pads mounted symmetrically within the bearing housing and about the shaft, wherein a radius of curvature of an inner surface of the plurality of pads is equal to a radius of the shaft; a pivot element positioned between and in contact with an outer side of each pad and the bearing housing, wherein each pad is pivotable about the pivot element; and at least one pair of retainer spring assemblies for each of the pads, each retainer spring assembly extending from the bearing housing to one of the pads and exerting an outward force on each pad relative to the axis to maintain contact of each pad with the pivot element, one of the retainer spring assemblies in each of the pairs being axially located from the pivot element in one axial direction, and the other of the retainer spring assemblies being axially located from the pivot element in an opposite axial direction.