Self-Aligning and Vibration Damping Bearings in a Submersible Well Pump

Abstract

An electrical submersible pump assembly has a centrifugal pump with stages, each having an impeller and a diffuser. A shaft extending from an electrical motor rotates the impellers. In the stages, a thrust runner is coupled to the shaft for rotation in unison. A bushing is non rotatably mounted in a receptacle in the diffuser. The bushing has a bore that receives the body of the runner in sliding, rotating engagement. The bushing has a thrust receiving end engaged by the thrust face of the runner in rotating, sliding engagement to transfer thrust from the runner to the diffuser. An elastomeric compliant member between a cylindrical exterior of the bushing and the receptacle allows limited radial movement of the bushing relative to the diffuser.

1 . An electrical submersible pump assembly, comprising:
 a plurality of modules, including a rotary pump module, a motor module, and a seal section module located between the motor module and the pump module;   a bearing in at least one of the modules, comprising:   a sleeve coupled to a drive shaft in said one of the modules for rotation therewith;   a bushing having a bore at receives the sleeve in sliding, rotational engagement;   a supporting member stationarily mounted in said one of the modules, the supporting member having a receptacle that receives the bushing, the supporting member being of less hardness than the bushing;   the bushing having an exterior portion of smaller diameter than a portion of the receptacle, defining an annular gap;   a resilient radial compliant member in the gap for allowing limited radial movement of the bushing relative to the supporting member; and   wherein the bushing is free to move axially a limited amount relative to the supporting member.   
     
     
         2 . The pump assembly according to  claim 1 , comprising:
 a key and keyway arrangement between the bushing and the supporting member for preventing rotation of the bushing relative to the supporting member.   
     
     
         3 . The pump assembly according to  claim 2 , wherein the key and keyway arrangement comprises a key integrally formed on the bushing and a slot in the receptacle. 
     
     
         4 . The pump assembly according to  claim 1 , wherein the radial compliant member comprises at least two axially spaced-apart rings. 
     
     
         5 . The pump assembly according to  claim 1 , wherein the compliant member comprises a layer of elastomeric material bonded to the bushing and to the receptacle. 
     
     
         6 . The pump assembly according to  claim 1 , wherein:
 the sleeve comprises a thrust runner having a thrust transferring face and a body with a cylindrical exterior;   the bushing has a thrust receiving face in sliding and rotational engagement with the thrust transferring face of the thrust runner, and a thrust transferring surface in engagement with a thrust receiving shoulder in the receptacle; and the pump assembly further comprises:   a resilient axial compliant member located between the thrust transferring surface and the thrust receiving shoulder.   
     
     
         7 . The pump assembly according to  claim 1 , wherein:
 said one of the modules comprises:   a centrifugal pump having a plurality of stages, each of the stages having an impeller and a diffuser, the bearing being located in at least one of the stages;   the sleeve comprises a thrust runner that receives thrust from the impeller of said one of the stages and has a thrust transferring face in engagement with a thrust receiving end of the bushing;   the bushing has a thrust transferring surface that engages a thrust receiving shoulder in the receptacle of said one of the stages; and   the supporting member comprises the diffuser of said one of the stages.   
     
     
         8 . An electrical submersible pump assembly, comprising:
 a centrifugal pump having a plurality of stages, each of the stages having an impeller and a diffuser, and a driven shaft that rotates the impellers;   an electrical motor that rotates the driven shaft;   a seal section coupled between the pump and the motor for reducing a pressure differential between lubricant in the motor and well fluid on an exterior of the motor;   at least one of the stages comprising:   a thrust runner coupled to the shaft for rotation therewith, the runner having a thrust face transverse to an axis of the shaft and-a body with a cylindrical exterior, the runner having a thrust receiving end positioned to receive thrust from the impeller of said at least one of the stages;   a bushing non rotatably mounted in a receptacle in the diffuser of said at least one of the stages, the bushing having a bore that receives the body of the runner in sliding, rotating engagement, the bushing having a thrust receiving end engaged by the thrust face in rotating, sliding engagement to transfer thrust from the runner to the diffuser;   an elastomeric radial compliant member between a cylindrical exterior of the bushing and the receptacle to allow limited radial movement of the bushing relative to the diffuser; and   wherein the bushing is axially movable relative to the receptacle a limited amount.   
     
     
         9 . The pump assembly according to  claim 8 , further comprising an elastomeric axial compliant member between the bushing and the receptacle that urges the bushing toward the thrust runner. 
     
     
         10 . The pump assembly according to  claim 8 , further comprising:
 a key and keyway arrangement between the bushing and the receptacle to prevent rotation of the bushing relative to the diffuser.   
     
     
         11 . The pump assembly according to  claim 8 , wherein the bushing is formed of a harder material than the material of the diffuser. 
     
     
         12 . The pump assembly according to  claim 8 , further comprising:
 an axially extending slot in the receptacle; and   a key integrally formed on the cylindrical exterior of the bushing that is located in the slot to prevent rotation of the bushing relative to the diffuser.   
     
     
         13 . The pump assembly according to  claim 8 , further comprising:
 a retaining shoulder on the bushing; and   a split retaining ring located in a mating recess in the receptacle and engaging the retaining shoulder, the retaining ring being positioned to allow limited axial movement of the bushing relative to the diffuser.   
     
     
         14 . The pump assembly according to  claim 8 , further comprising:
 a thrust receiving shoulder in the receptacle facing axially in a first direction;   a flange on the thrust receiving end of the bushing, the flange defining a thrust transferring surface that faces axially in a second direction and is in engagement with the thrust receiving shoulder; and   a resilient axial compliant member located. between the thrust receiving shoulder and the thrust transferring surface.   
     
     
         15 . The pump assembly according to  claim 8 , further comprising:
 a thrust receiving shoulder in the receptacle that faces axially in a first direction;   an upper bore section extending axially from the thrust receiving shoulder in the first direction;   a flange on the thrust receiving end of the bushing, the flange defining a thrust transferring surface that faces axially in a second direction and engages the thrust receiving shoulder; and   wherein the thrust runner has a flange that extends radially outward farther than the thrust receiving end of the bushing to form a hydraulic seal with the upper bore section.   
     
     
         16 . The pump assembly according to  claim 8 , wherein:
 the radial compliant member comprises a layer of elastomeric material between and bonded to the bushing and the receptacle, the layer extending an axial length of the bushing; and   the layer extends between a thrust transferring surface of the bushing and a thrust receiving surface of the diffuser to serve as an axial compliant member.   
     
     
         17 . An electrical submersible pump assembly, comprising:
 a centrifugal pump having a plurality of stages, each of the stages having an impeller and a diffuser, and a driven shaft that rotates the impellers;   an electrical motor that rotates the driven shaft;   a seal section coupled between the pump and the motor for reducing a pressure differential between lubricant in the motor and well fluid on an exterior of the motor;   at least one of the stages comprising:   a receptacle formed in the diffuser of said at east one of the stages, the receptacle having an upward facing thrust receiving shoulder, defining a smaller diameter bore section below the thrust receiving shoulder and a larger diameter bore section above the thrust receiving shoulder;   a thrust runner coupled to the shaft for rotation therewith, the runner having a body with a cylindrical exterior, an upward facing thrust receiving end on the body in engagement with the impeller of said one of the stages, a flange extending radially outward from the body and having a downward facing thrust transferring face;   a bushing having a bore that receives the cylindrical exterior of the body of the runner in sliding, rotating engagement, the bushing having an upward facing thrust receiving surface engaged by the thrust transferring face in rotating, sliding engagement to transfer thrust from the runner to the diffuser, the bushing having a flange with a downward facing thrust transferring surface that engages the thrust receiving shoulder in the receptacle, the bushing having a cylindrical exterior portion that locates within the smaller diameter bore section of the receptacle, the bushing have a greater hardness than the diffuser;   an elastomeric radial compliant member between the cylindrical exterior portion of the bushing and the smaller diameter bore section of the receptacle to allow limited radial movement of the bushing relative to the diffuser; and   an elastomeric axial compliant member between the thrust receiving shoulder in the receptacle and the flange.   
     
     
         18 . The pump assembly according to  claim 17 , wherein the axial compliant member comprises an elastomeric ring mounted within an annular groove formed in the thrust receiving shoulder in the receptacle. 
     
     
         19 . The pump assembly according to  claim 17 , further comprising:
 a key and slot arrangement between the bushing and the receptacle to prevent rotation of the bushing relative to the diffuser.   
     
     
         20 . The pump assembly according to  claim 17 , further comprising:
 an upward facing retaining ring shoulder on the bushing below and extending radially outward from the thrust receiving surface of the bushing; and   a split retaining ring located in a mating recess in the larger diameter bore section of the receptacle and engaging the retaining ring shoulder, the retaining ring being positioned to allow limited axial movement of the bushing relative to the diffuser.