Non-sliding carrier bearing in submersible pump motor and method of installation
A submersible well pump motor has features to prevent the carrier bearing from sliding axially along the stator due to thermal growth of the rotor. The rotor has a shaft and rotor sections spaced apart from each other. Carrier bearings are located between the rotor sections, each having an anti-rotation member that frictionally engages the inner diameter of the stator to prevent spinning of the carrier bearing. A deflectable thrust washer may be located between ends of the carrier bearing and the rotor sections. The thrust washer reduces in thickness in response to an axial thermal growth force due to axial thermal growth movement of the rotor sections and shaft. The thermal growth force is less than an amount of dislodging force required to cause the anti-rotation member to axially move relative to the stator. Rather than deflectable thrust washers, sacrificial thrust washers that dissolve prior to normal operation may be used.
1. A submersible well pump motor, comprising:
a stator having an inner diameter;
a rotor within the inner diameter of the stator, the rotor having a shaft and first and second rotor sections spaced apart from each other, the shaft having an axis;
a carrier bearing located between the first and second rotor sections and having an anti-rotation member that engages the inner diameter of the stator to prevent spinning of the carrier bearing, the carrier bearing comprising:
a sleeve mounted to the shaft for rotation therewith, the sleeve having a first end spaced axially from the first rotor section;
a first deflectable thrust washer located between the first end of the sleeve and the first rotor section, the first thrust washer comprising a ring in contact with the first rotor section, another ring in contact with the first end of the sleeve, and a wavy spring between the rings, the wavy spring urging the rings apart from each other; wherein:
one of the rings has a larger diameter counterbore that defines a cylindrical outer wall, a smaller diameter counterbore concentric with the larger diameter counterbore and defining an axially facing shoulder surrounded by a cylindrical inner wall, and a plurality of circumferentially spaced apart axially extending lugs formed in the outer wall;
the other of the rings has a plurality of circumferentially spaced apart slots that receive the lugs to prevent relative rotation, and an annular lip that inserts into the smaller diameter counterbore; and
the wavy spring is located in the smaller diameter counterbore between the shoulder and the lip.
2. A submersible well pump assembly, comprising:
a rotary pump;
an electrical motor;
a drive shaft extending along a longitudinal axis from the motor into the pump for driving the pump;
a stator in the motor and having an inner diameter;
a rotor within the inner diameter of the stator, the rotor having rotor sections spaced apart from each other;
a sleeve mounted to the shaft for rotation therewith, the sleeve having an upper end axially spaced from an upper one of the rotor sections by an upper gap, the sleeve having a lower end axially spaced from a lower one of the rotor sections by a lower gap;
a carrier body located between the upper one of the rotor sections and the lower one of the rotor sections, the carrier body surrounding the sleeve and having a carrier body anti-rotation member that engages the inner diameter of the stator to prevent spinning of the carrier body;
an upper thrust washer located in the upper gap, the upper thrust washer having an upper ring in contact with the upper one of the rotor sections and a lower ring in contact with the upper end of the sleeve;
an annular upper wavy spring between the upper and lower rings of the upper thrust washer and urging the upper and lower rings of the upper thrust washer apart from each other;
an upper thrust washer anti-rotation member engaging the upper and lower rings of the upper thrust washer to prevent relative rotation;
a lower thrust washer located in the lower gap, the lower thrust washer having an upper ring in contact with the lower end of the sleeve and a lower ring in contact with the lower one of the rotor sections;
an annular lower wavy spring between the upper and lower rings of the lower thrust washer and urging the upper and lower rings of the lower thrust washer apart from each other;
a lower thrust washer anti-rotation member engaging the upper and lower rings of the lower thrust washer to prevent relative rotation; wherein:
one of the rings of the upper thrust washer has a larger diameter counterbore, defining a cylindrical outer wall at a periphery of said one of the rings, and a smaller diameter counterbore, defining a cylindrical inner wall and an axially facing shoulder;
the other of the rings of the upper thrust washer has an annular lip that extends into the smaller diameter counterbore; and
the wavy spring of the upper thrust washer is located in the smaller diameter counterbore between the shoulder and the lip.
3. The submersible well pump assembly according to claim 2 , wherein the upper thrust washer anti-rotation member comprises:
axially extending lugs formed in the outer cylindrical wall; and
mating slots formed in a periphery of the other of the rings that receive the lugs.