Integrated endshield and pump volute for an electric pump and method of forming an electric pump

Abstract

An electric pump comprises a stator, a rotor, and an endshield. The interface plate is fixed to the stator and is configured to couple the electric motor to a pump. The pump volute is formed as an integral portion of the endshield, thereby minimizing the axial length of the electric pump. A drainage passageway is provided on the endshield to harmlessly drain away any fluid that seeps past the pump's seals. In one embodiment of the invention, the drainage passageway is a groove that faces the stator and is configured to facilitate the evaporation of and leak fluid by channeling the fluid near the stator, which warms the fluid and thereby increases the fluid's evaporation rate.

What is claimed is: 
     
         1 . An electric pump for use in an appliance, said electric pump comprising:
 a stator;   a rotor including a shaft rotatable about an axis;   a pump volute;   an impeller at least in part positioned inside the pump volute;   an endshield fixed to the stator and defining a shaft opening,   said shaft extending through the shaft opening along the axis; and   a seal positioned between the endshield and the shaft,   said shaft including
 an impeller section at least substantially adjacent the impeller, and 
 a motor section at least substantially adjacent the stator, 
 said seal positioned between the impeller section and the motor section, 
 said seal and said endshield configured to cooperatively at least substantially prevent ingress of fluid from the impeller section to the motor section, 
   said endshield and said volute being monolithically formed,   said endshield at least in part defining a drainage passageway in fluid communication with the motor section such that any fluid that leaks to the motor section from the impeller section is received by the drainage passageway.   
     
     
         2 . The electric pump of  claim 1 ,
 said pump further comprising a bearing that supports the shaft,   said endshield supporting the bearing.   
     
     
         3 . The electric pump of  claim 2 ,
 said bearing directly engaging the motor section of the shaft.   
     
     
         4 . The electric pump of  claim 1 ,
 said endshield presenting a front face facing the volute and a back face facing the stator,   said back face at least in part defining the drainage passageway.   
     
     
         5 . The electric pump of  claim 1 ,
 said drainage passageway comprising a groove exposed to the stator and defined by the endshield.   
     
     
         6 . The electric pump of  claim 1 ,
 said drainage passageway extending to a reservoir.   
     
     
         7 . The electric pump of  claim 6 ,
 said endshield defining the reservoir,   said reservoir being exposed to the stator.   
     
     
         8 . The electric pump of  claim 7 ,
 said reservoir being spaced from the stator and configured such that heat from the stator is operable to initiate evaporation of fluid retained in the reservoir.   
     
     
         9 . The electric pump of  claim 1 ,
 said volute comprising a spiral formation.   
     
     
         10 . The electric pump of  claim 1 ,
 said endshield supporting the stator in the appliance.   
     
     
         11 . An electric pump for use in an appliance, said electric pump comprising:
 a rotor including a shaft rotatable about an axis;   a stator presenting opposite ends spaced along the axis;   a pump volute; and   an endshield fixed to one of the ends of the stator,   said endshield and said volute being monolithically formed.   
     
     
         12 . The electric pump of  claim 11 , further comprising:
 an impeller at least in part positioned inside the pump volute; and   a seal positioned between the endshield and the shaft,   said endshield defining a shaft opening,   said shaft extending through the shaft opening along the axis,   said shaft including
 an impeller section at least substantially adjacent the impeller, and 
 a motor section at least substantially adjacent the stator, 
 said seal positioned between the impeller section and the motor section, 
 said seal and said endshield configured to cooperatively at least substantially prevent ingress of fluid from the impeller section to the motor section, 
 said endshield at least in part defining a drainage passageway in fluid communication with the motor section such that any fluid that leaks thereto from the impeller section is received by the drainage passageway. 
   
     
     
         13 . The electric pump of  claim 12 ,
 said drainage passageway comprising a groove defined by the endshield.   
     
     
         14 . The electric pump of  claim 13 ,
 said groove being exposed to the stator.   
     
     
         15 . The electric pump of  claim 12 ,
 said drainage passageway extending to a reservoir.   
     
     
         16 . The electric pump of  claim 12 ,
 said endshield defining the reservoir,   said reservoir being exposed to the stator.   
     
     
         17 . The electric pump of  claim 16 ,
 said reservoir being spaced from the stator and configured such that heat from the stator is operable to initiate evaporation of fluid retained in the reservoir.   
     
     
         18 . The electric pump of  claim 11 ,
 said pump further comprising a bearing that supports the shaft,   said endshield supporting the bearing.   
     
     
         19 . An improved electric pump comprising a stator, a rotor, an endshield, and a bearing, the rotor having a rotor shaft, the endshield being fixed to the stator and comprising a shaft opening, the shaft opening extending through the endshield, the rotor shaft extending through the shaft opening, the bearing being supported by the endshield, the bearing at least partially supporting the rotor shaft in a manner allowing the rotor shaft to revolve relative to the endshield, the improvement comprising:
 a fluid pump volute, the fluid pump volute and the endshield being monolithically formed together as a single part;   a drainage passageway formed in the endshield, the drainage passageway extending downward from the shaft opening and being configured and adapted to channel liquid downward from the shaft opening via gravity; and   a fluid reservoir formed by the endshield, the drainage passageway operatively connecting the shaft opening to the fluid reservoir, the fluid reservoir being exposed to and spaced from a surface of the stator.   
     
     
         20 . The electric pump of  claim 19 ,
 wherein the fluid reservoir comprises a recess in a generally horizontal surface of the endshield that is beneath the stator.