Integrated motor bearing and rotor

1. An electric submersible well pump assembly, comprising:

a rotary pump;

an electrical motor connected to the pump for lowering into a well, the motor comprising:

a motor housing filled with a dielectric lubricant and having a longitudinal axis;

a stator formed of a stack of stator disks mounted within the motor housing, the stator having an inner diameter defining a stator bore;

a motor shaft extending through the bore;

a rotor mounted to the shaft for rotation therewith and comprising a stack of rotor disks;

axially spaced-apart radial stabilizing portions along the rotor having outer peripheries that are greater in outer diameter than remaining portions of the rotor, the outer peripheries of the stabilizing portions rotating with the rotor and being closely spaced to the inner diameter of the stator to radially stabilize the shaft; wherein:

the rotor is made up of larger diameter rotor sections alternating with smaller diameter rotor sections, each of the rotor sections comprising a plurality of the rotor disks, the rotor disks within the larger diameter rotor sections having larger outer diameters than the rotor disks within the smaller diameter rotor sections; and

the rotor disks of the larger diameter rotor sections serve as the stabilizing portions.

2. The assembly according to claim 1 , wherein:

all of the rotor disks within the larger diameter rotor sections have larger outer diameters than the rotor disks within the smaller diameter rotor sections.

3. The assembly according to claim 1 , wherein:

the rotor disks of the larger outer diameter rotor sections are secured together as a unit; and

the rotor disks of the smaller outer diameter rotor sections are secured together as a unit.

4. The assembly according to claim 1 , wherein the rotor disks of the larger outer diameter rotor sections have a same axial thickness as the rotor disks of the smaller outer diameter rotor sections.

5. The assembly according to claim 1 , wherein outer peripheries of the rotor disks of the larger outer diameter rotor sections are spaced from inner edges of the stator disks by a small gap that creates a liquid film with the lubricant during operation.

6. An electric submersible well pump assembly, comprising:

a rotary pump;

an electrical motor connected to the pump for lowering into a well, the motor comprising:

a motor housing filled with a dielectric lubricant and having a longitudinal axis;

a stator formed of a stack of stator disks mounted within the motor housing, the stator having an inner diameter defining a stator bore;

a motor shaft extending through the bore;

a rotor mounted to the shaft for rotation therewith and comprising a stack of rotor disks;

a plurality of axially spaced-apart metal sleeves mounted to the rotor for rotation therewith, each of the sleeves having an outer diameter larger than the rotor disks to radially stabilize the shaft; and

wherein each of the sleeves has a greater axial dimension than any of the rotor disks.

7. The assembly according to claim 6 , wherein:

the rotor is made up of rotor sections, each of the rotor sections comprising a plurality of the rotor disks sandwiched between with upper and lower end rings, each of the rotor sections having conductive rods extending through the rotor disks, spaced around the shaft and joined to the end rings;

each of the metal sleeves circles at least one of the end rings and outer edges of the rotor disks next to the end rings of at least some of the rotor sections; and

each of the sleeves has a greater axial dimension that an axial thickness of each of the end rings.

8. The assembly according to claim 6 , wherein:

the rotor is made up of rotor sections, each of the rotor sections comprising a plurality of the rotor disks sandwiched between upper and lower end rings, each of the rotor sections having conductive rods extending through the rotor disks, spaced around the shaft and joined to the end rings; and

the sleeves are mounted to the upper and lower ends of each of the rotor sections.

9. The assembly according to claim 6 , wherein the outer diameters of the sleeves are spaced from inner edges of some of the stator disks by a small gap that creates a liquid film of the lubricant during operation.

10. The assembly according to claim 6 , wherein each of the sleeves surrounds outer edges of some of the rotor disks.

11. An electric submersible well pump assembly, comprising:

a rotary pump;

an electrical motor connected to the pump for lowering into a well, the motor comprising:

a motor housing filled with a dielectric lubricant and having a longitudinal axis;

a stator formed of a stack of stator disks mounted within the motor housing, the stator having an inner diameter defining a stator bore;

a motor shaft extending through the bore;

a rotor mounted to the shaft for rotation therewith and comprising a stack of larger outer diameter and smaller outer diameter rotor disks;

wherein the larger outer diameter rotor disks have greater outer diameters than the lesser outer diameter rotor disks to radially stabilize the shaft; wherein:

the rotor is made up of rotor sections, each of the rotor sections containing a plurality of the larger diameter and the smaller diameter rotor disks sandwiched between end rings that are joined by conductor rods; and

the larger outer diameter rotor disks are located adjacent each of the end rings.