Electronic fluid pump

Abstract

A fluid pump includes a pump housing having a housing cavity with an inlet and an outlet. An encapsulated stator assembly is positioned within the housing cavity and at least partially defines a fluid passage from the inlet to the outlet. A polymeric capsule member encloses and seals the encapsulated stator assembly, protecting the motor from, and providing heat transfer to, the working fluid. A stator provides a magnetic field which drives a rotor assembly. The rotor assembly rotates an impeller for pumping fluid from the inlet to the outlet.

What is claimed is:  
     
         1 . A fluid pump for pumping liquid, comprising: 
 a housing having a housing cavity therein with an inlet and an outlet;    an encapsulated stator assembly positioned in the housing cavity to cooperate with the housing and to at least partially define a liquid passage from the inlet to the outlet;    wherein the encapsulated stator assembly is enclosed and sealed from the pumped liquid by a polymeric capsule member and the polymeric capsule member defines a rotor cavity having an opening;    an impeller rotatably positioned at the inlet and having an impeller axis; and    a rotor assembly rotatably located inside the rotor cavity and connected to the impeller for rotating the impeller for pumping liquid through the passage from the inlet to the outlet.    
     
     
         2 . The fluid pump of  claim 1 , wherein the rotor assembly is sealingly protected from the liquid by a seal cartridge assembly, the seal cartridge assembly being positioned within the opening.  
     
     
         3 . The fluid pump of  claim 1 , wherein the polymeric capsule member comprises a thermally conductive, electrically insulative material.  
     
     
         4 . The fluid pump of  claim 1 , wherein the encapsulated stator assembly comprises a plurality of steel laminations, a plurality of copper windings, and a plurality of motor power leads.  
     
     
         5 . The fluid pump of  claim 4 , wherein the polymeric capsule member orients the motor power leads with substantial circumferential symmetry around the impeller axis.  
     
     
         6 . The fluid pump of  claim 4 , further comprising a circuit board assembly located near the outlet and interfacing with the motor power leads.  
     
     
         7 . The fluid pump of  claim 1 , further comprising a diffuser, wherein the diffuser comprises an inner wall formed by an outer wall of the encapsulated stator assembly, an outer wall formed by an inner wall of the housing, and a plurality of diffuser vanes.  
     
     
         8 . The fluid pump of  claim 7 , wherein the outer wall of the encapsulated stator assembly is configured with the diffuser vanes.  
     
     
         9 . The fluid pump of  claim 1 , wherein the rotor assembly includes a rotor with a rotor shaft.  
     
     
         10 . The fluid pump of  claim 9 , wherein the rotor shaft is supported by a front bearing and a rear bearing.  
     
     
         11 . A fluid pump for pumping liquid, comprising: 
 a housing having a housing cavity therein with an inlet and an outlet;    an encapsulated stator assembly enclosed and sealed by a polymeric capsule member, wherein the polymeric capsule member defines a rotor cavity having an opening;    an impeller rotatably positioned at the inlet and having an impeller axis;    a rotor assembly rotatably located inside the rotor cavity and connected to the impeller for rotating the impeller for pumping liquid through the passage from the inlet to the outlet; and    a seal cartridge assembly positioned within the opening for sealing the rotor assembly within the rotor cavity.    
     
     
         12 . The fluid pump of  claim 11 , wherein the polymeric capsule member comprises a thermally conductive, electrically insulative material.  
     
     
         13 . The fluid pump of  claim 11 , wherein the encapsulated stator assembly comprises a plurality of steel laminations, a plurality of copper windings, and a plurality of motor power leads.  
     
     
         14 . The fluid pump of  claim 13 , further comprising a circuit board assembly located near the outlet and interfacing with the motor power leads.  
     
     
         15 . The fluid pump of  claim 11 , further comprising a diffuser, wherein the diffuser comprises an inner wall formed by an outer wall of the encapsulated stator assembly, an outer wall formed by an inner wall of the housing, and a plurality of diffuser vanes.  
     
     
         16 . The fluid pump of  claim 15 , wherein the outer wall of the encapsulated stator assembly is configured with the diffuser vanes.  
     
     
         17 . The fluid pump of  claim 11 , wherein the rotor assembly includes a rotor with a rotor shaft.  
     
     
         18 . The fluid pump of  claim 17 , wherein the rotor shaft is supported by a front bearing and a rear bearing.  
     
     
         19 . A fluid pump for pumping liquid, comprising: 
 a housing having a housing cavity therein with an inlet and an outlet;    an encapsulated stator assembly positioned in the cavity, wherein an outer wall of the encapsulated stator assembly forms an inner boundary of the liquid flow path and an inner wall of the housing forms an outer boundary of the liquid flow path;    wherein the encapsulated stator assembly is enclosed and sealed by a polymeric capsule member and the polymeric capsule member defines a rotor cavity having an opening;    wherein a plurality of motor power leads are encased in the encapsulated stator assembly; and    wherein the motor power leads are at least partially within the liquid flow path for cooling the motor power leads.    
     
     
         20 . The fluid pump of  claim 19 , wherein the rotor assembly is sealingly protected from the liquid by a seal cartridge assembly, the seal cartridge assembly being positioned within the opening.  
     
     
         21 . The fluid pump of  claim 19 , wherein the polymeric capsule member comprises a thermally conductive, electrically insulative material.  
     
     
         22 . The fluid pump of  claim 19 , wherein the polymeric capsule member orients the motor power leads with substantial circumferential symmetry around the impeller axis.  
     
     
         23 . The fluid pump of  claim 19 , further comprising a circuit board assembly located near the outlet and interfacing with the motor power leads.  
     
     
         24 . The fluid pump of  claim 19 , further comprising a diffuser, wherein the diffuser comprises an inner wall formed by the outer wall of the encapsulated stator assembly, an outer wall formed by the inner wall of the housing, and a plurality of diffuser vanes.  
     
     
         25 . The fluid pump of  claim 24 , wherein the outer wall of the encapsulated stator assembly is configured with the diffuser vanes.  
     
     
         26 . The fluid pump of  claim 19 , wherein the rotor assembly includes a rotor with a rotor shaft.  
     
     
         27 . The fluid pump of  claim 26 , wherein the rotor shaft is supported by a front bearing and a rear bearing.  
     
     
         28 . A fluid pump for pumping liquid, comprising: 
 a housing having a housing cavity therein with an inlet and an outlet;    an encapsulated stator assembly enclosed and sealed by a polymeric capsule member, wherein the polymeric capsule member defines a rotor cavity having an opening; and    wherein the polymeric capsule member comprises a thermally conductive, electrically insulative material.    
     
     
         29 . The fluid pump of  claim 28 , wherein the encapsulated stator assembly comprises a plurality of steel laminations, a plurality of copper windings, and a plurality of motor power leads.  
     
     
         30 . The fluid pump of  claim 29 , further comprising a circuit board assembly located near the outlet and interfacing with the motor power leads.  
     
     
         31 . The fluid pump of  claim 28 , further comprising a diffuser, wherein the diffuser comprises an inner wall formed by an outer wall of the encapsulated stator assembly, an outer wall formed by an inner wall of the housing, and a plurality of diffuser vanes.  
     
     
         32 . The fluid pump of  claim 31 , wherein the outer wall of the encapsulated stator assembly is configured with the diffuser vanes.  
     
     
         33 . A fluid pump for pumping liquid, comprising: 
 a housing having a housing cavity therein with an inlet and an outlet;    an impeller rotatably positioned at the inlet and defining an impeller axis, the impeller including a slot oriented substantially perpendicular to the impeller axis;    an encapsulated stator assembly enclosed and sealed by a polymeric capsule member, the encapsulated stator assembly including a plurality of steel laminations, a plurality of copper windings, and a plurality of motor power leads, the polymeric capsule member defining a rotor cavity having an opening and including a thermally conductive, electrically insulative material, the motor power leads exiting the housing through a side of the housing;    a rotor assembly disposed inside the rotor cavity and connected to the impeller for rotating the impeller for pumping liquid through the passage from the inlet to the outlet, the rotor assembly including a rotor and a rotor shaft;    a drive pin transversely disposed through the rotor shaft and configured to cooperate with the impeller slot for driving the impeller;    front and rear bearings disposed on opposite ends of the rotor shaft for rotatably supporting the rotor shaft; and    a diffuser including a plurality of diffuser vanes, each of the diffuser vanes being of split construction and having a portion substantially parallel to the impeller axis.