Encapsulated rotor for permanent magnet submersible motor

Abstract

A rotor for a submersible motor includes a shaft and a hub. The hub is: disposed around the shaft, torsionally connected to the shaft, and made from a magnetically permeable metal or alloy. The rotor further includes permanent magnets disposed around the hub; and a polymer shroud encapsulating the permanent magnets and molded to the hub.

1 . A method of making a rotor core, comprising:
 disposing permanent magnets around a hub made from a magnetically permeable metal or alloy;   assembling a mold around the magnets and the hub; and   injecting a polymer into the mold, thereby encapsulating the permanent magnets and molding the permanent magnets to the hub.   
     
     
         2 . The method of  claim 1 , wherein:
 the polymer is a mixture of a resin and a hardener, and   the resin and hardener are mixed as the sealant is injected into the mold.   
     
     
         3 . The method of  claim 1 , wherein the polymer is molten when injected into the mold. 
     
     
         4 . The method of  claim 1 , wherein adjacent permanent magnets have alternate poles. 
     
     
         5 . The method of  claim 1 , wherein each permanent magnet is polarized in a radial or essentially radial direction. 
     
     
         6 . The method of  claim 1 , wherein:
 the hub has ribs extending from an outer surface thereof and spaced around the outer surface, and   the magnets are disposed in pockets formed between the ribs.   
     
     
         7 . The method of  claim 1 , further comprising fastening the permanent magnets to the hub. 
     
     
         8 . The method of  claim 1 , further comprising mounting the encapsulated rotor core onto a shaft, thereby forming a rotor. 
     
     
         9 . The method of  claim 8 , further comprising inserting the rotor into a stator, thereby forming a motor.