Electric submersible pump rotor assembly with bearing spacer configured for thrust washer support

Abstract

An exemplary rotor assembly for an ESP motor can comprise a rotor module concentrically disposed on a drive shaft; a bearing assembly concentrically disposed about the drive shaft in proximity to the rotor module; a thrust washer concentrically disposed about the drive shaft and axially between the bearing assembly and the rotor module; and an axial support flange disposed concentrically about the drive shaft and axially between the thrust washer and the rotor module. In some embodiments, the axial support flange can abut the thrust washer. Disclosed embodiments may reduce dishing of the thrust washer when the motor is in operation, which can be particularly useful in embodiments having concavities formed in an axial face of the bearing bushing or the thrust washer which can influence flow of lubrication fluid between the bushing and the thrust washer to create a hydrodynamic force.

What is claimed is: 
     
         1 . A rotor assembly for an ESP motor comprises:
 a rotor module concentrically disposed on a drive shaft, wherein the rotor module is configured to rotate with the drive shaft, while being operable to slide axially on the drive shaft;   a bearing assembly concentrically disposed about the drive shaft in proximity to the rotor module;   a thrust washer concentrically disposed about the drive shaft and axially between the bearing assembly and the rotor module; and   an axial support flange disposed concentrically about the drive shaft and axially between the thrust washer and the rotor module, wherein the axial support flange axially abuts the thrust washer;   wherein the bearing assembly comprises a journal sleeve concentrically disposed about the drive shaft and a bushing assembly disposed concentrically about the journal sleeve, wherein the journal sleeve is free to rotate within the bushing assembly.   
     
     
         2 . The rotor assembly of  claim 1 , wherein the axial support flange is configured to limit axial dishing of the thrust washer to less than 100 micron. 
     
     
         3 . The rotor assembly of  claim 1 , wherein the journal sleeve comprises an outer diameter, and the axial support flange extends radially outward at least approximately to the outer diameter of the journal sleeve; and wherein the bushing assembly comprises an outer diameter, and the axial support flange extends radially outward less than the outer diameter of the bushing assembly. 
     
     
         4 . The rotor assembly of  claim 1 , wherein:
 the rotor module comprises:
 a lamination stack concentrically disposed about the drive shaft and configured to rotate with the drive shaft, 
 a plurality of cage bars disposed axially within the lamination stack and concentrically disposed about the drive shaft, and 
 a cage ring connected to the plurality of cage bars at each end of the lamination stack and concentrically disposed about the drive shaft; and 
   the axial support flange does not extend radially outward as far as the cage bars.   
     
     
         5 . The rotor assembly of  claim 4 , wherein the cage ring comprises a flange gap on an axially exterior surface, and the flange gap extends radially outward beyond the axial support flange. 
     
     
         6 . The rotor assembly of  claim 1 , further comprising a thrust washer support which is disposed concentrically on the drive shaft and axially between the rotor module and the bearing assembly, wherein the axial support flange extends radially outward from the thrust washer support. 
     
     
         7 . The rotor assembly of  claim 6 , wherein the thrust washer support comprises a seating surface which extends axially from the axial support flange towards the bearing bushing assembly, and the thrust washer is concentrically disposed on the seating surface. 
     
     
         8 . The rotor assembly of  claim 7 , wherein the thrust washer support further comprises a module spacing portion which extends axially from the axial support flange towards the rotor module, and wherein the module spacing portion of the thrust washer support extends radially beyond the seating surface, but extends radially less than the axial support flange. 
     
     
         9 . The rotor assembly of  claim 7 , further comprising a support sleeve concentrically disposed on the drive shaft, wherein the support sleeve is disposed radially between the bearing assembly and the drive shaft, and wherein the thrust washer support is disposed axially between the support sleeve and the rotor module. 
     
     
         10 . The rotor assembly of  claim 6 , further comprising a support sleeve concentrically disposed on the drive shaft, wherein:
 the support sleeve is disposed radially between the bearing assembly and the drive shaft;   the thrust washer support is disposed axially between the support sleeve and the rotor module;   the thrust washer is concentrically disposed on the support sleeve;   the thrust washer support axially abuts the support sleeve; and   the axial support flange is disposed at an axial end of the thrust washer support in proximity to the support sleeve.   
     
     
         11 . The rotor assembly of  claim 1 , wherein concavities are formed in an axial face of the bushing assembly or an axial face of the thrust washer, wherein the axial face of the bushing assembly is disposed proximate to the axial face of the thrust washer, and wherein the concavities are configured to influence flow of lubrication fluid between the bushing assembly and the thrust washer to create a hydrodynamic force against the bushing assembly and the thrust washer when the drive shaft rotates. 
     
     
         12 . A method for assembling a rotor assembly for an ESP motor comprising:
 disposing a bearing assembly concentrically about a drive shaft;   disposing a rotor module concentrically on the drive shaft adjacent to the bearing assembly, wherein the rotor module is configured to rotate with the drive shaft while being operable to slide axially on the drive shaft;   disposing a thrust washer concentrically about the drive shaft and axially between the rotor module and the bearing assembly;   disposing an axial support flange concentrically about the drive shaft and axially between the thrust washer and the rotor module, wherein the axial support flange axially contacts the thrust washer.   
     
     
         13 . The method of  claim 12 , further comprising:
 providing a bearing assembly, wherein the bearing assembly has a journal sleeve and a bushing assembly;   providing a thrust washer, wherein an outer diameter of the thrust washer is greater than an inner diameter of the bushing assembly and an outer diameter of the thrust washer is less than an outer diameter of the bushing assembly; and   providing the axial support flange, wherein the axial support flange is configured to limit axial dishing of the thrust washer to less than 100 micron.   
     
     
         14 . The method of  claim 13 , wherein:
 the journal sleeve of the bearing assembly comprises an outer diameter, and the axial support flange extends radially at least approximately to the outer diameter of the journal sleeve; and   the axial support flange extends radially less than the outer diameter of the bushing assembly.   
     
     
         15 . The method of  claim 12 , further comprising disposing a thrust washer support concentrically on the drive shaft and axially between the bearing assembly and the rotor module, wherein the thrust washer support is configured to rotate with the drive shaft while being operable to slide axially on the drive shaft, and the axial support flange extends radially outward from the thrust washer support. 
     
     
         16 . The method of  claim 15 , further comprising providing the thrust washer support, wherein the thrust washer support has a seating surface extending from the axial support flange axially towards the bearing assembly and a module spacing portion extending axially from the axial support flange towards the rotor module, wherein disposing the thrust washer concentrically about the drive shaft comprises disposing the thrust washer onto the seating surface and rotationally fixing the thrust washer to the seating surface. 
     
     
         17 . The method of  claim 15 , further comprising disposing a support sleeve concentrically on the drive shaft, wherein:
 the support sleeve is configured to rotate with the drive shaft while being operable to slide axially on the drive shaft, and the bearing assembly is concentrically disposed on the support sleeve;   disposing the thrust washer concentrically about the drive shaft comprises concentrically disposing the thrust washer on the support sleeve;   the thrust washer support is axially disposed between the support sleeve and the rotor module;   the axial support flange is disposed at an axial end of the thrust washer support in proximity to the support sleeve; and   disposing the thrust washer on the support sleeve comprises rotationally fixing the thrust washer to the support sleeve.   
     
     
         18 . The method of  claim 12 , further comprising providing the thrust washer and the bearing assembly, wherein the bearing assembly comprises a bushing, and wherein concavities are formed in an axial face of the bushing or an axial face of the thrust washer, wherein the axial face of the bushing is disposed proximate to the axial face of the thrust washer, and wherein the concavities are configured to influence flow of lubrication fluid between the bushing and the thrust washer to create a hydrodynamic force against the bushing and the thrust washer when the drive shaft rotates. 
     
     
         19 . An ESP motor comprising the rotor assembly of  claim 1 . 
     
     
         20 . A method of using a rotor assembly for an ESP motor comprises:
 assembling the rotor assembly using the method of  claim 12 ;   assembling the ESP motor with the rotor assembly therein;   assembling an ESP assembly comprising the ESP motor coupled to an ESP pump;   inserting the ESP assembly downhole in a wellbore; and   pumping formation fluids from the wellbore to the surface using the ESP assembly.