Rotor section with center tube for submersible pump assembly motor

A submersible well pump assembly, comprising:

• a pump;
• a motor having a stator containing motor windings and having a central bore with a longitudinal axis, the motor having a rotatable motor shaft, an upper rotor section separated from an intermediate rotor section by an upper radial bearing, and a lower rotor section separated from the intermediate rotor section by a lower radial bearing;
• a pressure equalizer coupled to the motor to reduce a pressure differential between lubricant in the motor and a hydrostatic pressure of well fluid on the exterior of the motor;
• each of the upper, intermediate and lower rotor sections comprising:
• a plurality of disks stacked together, each of the disks having a central opening and slots circumferentially spaced around the central opening;
• a plurality of rods extending through the slots parallel with the axis;
• a center tube extending through the central openings of the disks, the center tube having an outer diameter in an interference fit with the central openings of the disks, causing the center tube to rotate in unison with the disks, the center tube having an inner diameter that receives the motor shaft;
• and
• a slot and key arrangement between the inner diameter of the center tube and the motor shaft for rotating the motor shaft in unison.

A submersible well pump assembly, comprising:

• a pump;
• a motor having a longitudinal axis, a rotatable motor shaft, and upper and lower rotor sections axially separated from each other by a radial bearing;
• each of the upper and lower rotor sections comprising:
• a plurality of disks stacked together, each of the disks having a central opening and slots circumferentially spaced around the central opening;
• a plurality of metal rods extending through the slots parallel with the axis;
• upper and lower end rings secured to upper and lower ends, respectively, of the metal rods;
• a center tube extending through the central openings of the disks and being rigidly attached to the disks, the center tube having an inner diameter that receives the motor shaft;
• a slot and key arrangement between the inner diameter of the center tube and the motor shaft for rotating the motor shaft in unison;
• wherein
• the center tube of the upper rotor section has a lower end located below lower end ring of the upper rotor section;
• the center tube of the lower rotor section has an upper end located above the upper end ring of the lower rotor section and into abutment with the lower end of the center tube of the upper rotor section;
• and
• the radial bearing has a hub that receives in rotating sliding contact the lower end of the upper rotor section and the upper end of the lower rotor section.