Drive Flank Engagement Between Rotating Components and Shaft of Electrical Submersible Well Pump

Abstract

A well pump has a shaft with at least one shaft drive flank extending a length of the shaft. Impellers are located between non-rotating diffusers. Each impeller has a hub with an impeller hub bore through which the shaft extends. The impeller hub bore has at least one impeller drive flank that is in flush contact with the shaft drive flank to impart rotation to the impeller. The shaft drive flanks may be on opposite sides of the shaft and parallel with each other. The shaft may have six of the shaft drive flanks symmetrically arranged around the shaft and joining each other. The shaft drive flanks may be three involute curved surfaces that join each other.

1 . A well pump assembly, comprising:
 a pump having a housing with a longitudinal axis;   a shaft extending through the housing on the axis, the shaft having at least one shaft drive flank integrally formed thereon and extending substantially a length of the shaft;   a plurality of diffusers fixed in the housing against rotation, each of the diffusers having diffuser passages extending from a diffuser inlet to a diffuser outlet, each of the diffusers having a diffuser bore through which the shaft extends; and   an impeller located between each of the diffusers, the impeller having impeller passages extending from an impeller inlet to an impeller outlet, the impeller having an impeller hub with an impeller hub bore through which the shaft extends, the impeller hub bore having at least one impeller drive flank integrally formed therein that is in flush contact with the shaft drive flank to impart rotation to the impeller.   
     
     
         2 . The pump assembly according to  claim 1 , wherein the at least one shaft drive flank comprises a plurality of shaft drive flanks symmetrically arranged around an exterior of the shaft. 
     
     
         3 . The pump assembly according to  claim 1 , wherein the at least one shaft drive flank comprises two of the shaft drive flanks on opposite sides of the shaft and parallel with each other. 
     
     
         4 . The pump assembly according to  claim 1 , wherein the at least one impeller drive flank comprises at least six of the impeller drive flanks symmetrically arranged around the impeller hub bore and joining each other. 
     
     
         5 . The pump assembly according to  claim 1 , wherein the at least one impeller drive flank comprises three involute curved surfaces that join each other. 
     
     
         6 . The pump assembly according to  claim 1 , wherein the at least one impeller drive flank comprises a single flat surface asymmetrically formed in the impeller hub bore. 
     
     
         7 . The pump assembly according to  claim 1 , further comprising:
 spacer rings through which the shaft extends, the spacer rings being positioned between and in abutment with the impeller hub, each of the spacer rings having a bore through which the shaft passes, the bore in the each of the spacer rings having at least one spacer ring drive flank that mates with the shaft drive flank.   
     
     
         8 . The pump assembly according to  claim 1 , further comprising:
 a shaft coupling on a driven end of the shaft, the shaft coupling having a coupling bore with at least one coupling drive flank that mates with the shaft drive flank.   
     
     
         9 . The pump assembly according to  claim 1 , wherein:
 an exterior of the impeller hub is cylindrical and in rotating, sliding contact with the diffuser bore in one of the diffusers.   
     
     
         10 . A well pump assembly, comprising:
 a pump having a housing with a longitudinal axis;   a shaft extending through the housing on the axis, the shaft having at least one shaft drive flank extending substantially a length of the shaft, wherein a line normal to a midpoint of the shaft drive flank passes through the axis;   a plurality of diffusers fixed in the housing against rotation, each of the diffusers having diffuser passages extending from a diffuser inlet to a diffuser outlet, each of the diffusers having a diffuser bore through which the shaft passes but does not contact; and   an impeller located between each of the diffusers, the impeller having impeller passages extending from an impeller inlet to an impeller outlet, the impeller having an impeller hub with an impeller hub bore through which the shaft extends, the impeller hub bore having at least one impeller drive flank integrally formed therein that mates with the shaft drive flank to impart rotation to the impeller, wherein a line normal to a midpoint of the impeller drive flank passes through the axis.   
     
     
         11 . The pump assembly according to  claim 10 , wherein:
 the impeller hub has a cylindrical exterior with a wall thickness measured between the impeller drive flank and the cylindrical exterior;   the wall thickness between the impeller drive flank and the cylindrical exterior is greatest at the midpoint of the impeller drive flank; and   the wall thickness between the impeller drive flank and the cylindrical exterior is least at ends of the impeller drive flank.   
     
     
         12 . The pump assembly according to  claim 10 , wherein the at least one impeller drive flank comprises two flat surfaces formed on opposite sides of the impeller hub bore, the flat surfaces being parallel with each other. 
     
     
         13 . The pump assembly according to  claim 10 , wherein the at least one impeller drive flank comprises six flat surfaces, defining a hexagonal configuration for the impeller hub bore. 
     
     
         15 . The pump assembly according to  claim 10 , wherein:
 the at least one impeller drive flank comprises three involute, curved surfaces formed in the impeller hub bore; and   each of the curved surfaces has a radial center point that is offset from the axis.   
     
     
         16 . The pump assembly according to  claim 10 , wherein the impeller drive flank comprises a single flat surface formed on one side of the impeller hub bore. 
     
     
         17 . A well pump assembly, comprising:
 a pump having a housing with a longitudinal axis;   a shaft extending through the housing on the axis, the shaft having a plurality of shaft drive flanks extending substantially a length of the shaft and symmetrically arranged around the shaft;   a plurality of diffusers fixed in the housing against rotation, each of the diffusers having diffuser passages extending from a diffuser inlet to a diffuser outlet, each of the diffusers having a diffuser bore through which the shaft passes but does not contact; and   a plurality of impellers, each of the impellers being located between each of the diffusers, each of the impellers having impeller passages extending from an impeller inlet to an impeller outlet, each of the impellers having an impeller hub with an impeller hub bore through which the shaft extends, the impeller hub bore having a plurality of impeller drive flanks, each of the impeller drive flanks being in flush contact with one of the shaft drive flanks.   
     
     
         18 . The pump assembly according to  claim 17 , wherein:
 the shaft drive flanks are flat, on opposite sides of the shaft and parallel with each other.   
     
     
         19 . The pump assembly according to  claim 17 , wherein the shaft drive flanks comprise six flat surfaces symmetrically arranged around the shaft and joining each other. 
     
     
         20 . The pump assembly according to  claim 17 , wherein the shaft drive flanks comprise three involute curved surfaces that join each other.