Electric pump

Abstract

An electric pump includes a stator, a rotor, a shaft, a bearing part, and a pump unit. The stator has a magnetic part, and the stator forms a rotation magnetic field when a coil of the stator is energized. The bearing part has a longitudinal central position that is positioned on an imaginary plane perpendicular to a rotation axis of the rotor. The imaginary plane is positioned within an inner range defined between longitudinal end portions of the magnetic part of the stator.

1 . An electric pump comprising:
 a stator that has a magnetic part, the stator forming a rotation magnetic field when a coil of the stator is energized;   a rotor that is rotatably provided at a position radially inward of the stator, the rotor being rotated about a rotation axis of the rotor by the rotation magnetic field formed by the stator;   a shaft that is rotatable integrally with the rotor;   a bearing part that rotatably supports the shaft; and   a pump unit that has a housing provided with an inlet port and a discharge port, the pump unit suctioning fluid through the inlet port and discharging fluid through the discharge port based on rotation of the shaft, wherein:   the bearing part has a longitudinal central position that is positioned on an imaginary plane perpendicular to the rotation axis of the rotor; and   the imaginary plane is positioned within an inner range defined between longitudinal end portions of the magnetic part of the stator.   
     
     
         2 . The electric pump according to  claim 1 , wherein:
 the stator has a longitudinal central position that is positioned on the imaginary plane, on which the longitudinal central position of the bearing part is positioned.   
     
     
         3 . The electric pump according to  claim 1 , wherein:
 the bearing part is a first bearing part, the electric pump further comprising a second bearing part that rotatably supports the shaft, wherein:   the second bearing part has a longitudinal central position that is positioned on the other imaginary plane perpendicular to the rotation axis of the rotor, the other imaginary plane being positioned out of the inner range along the rotation axis of the rotor.   
     
     
         4 . The electric pump according to  claim 3 , wherein:
 the magnetic part of the stator has a longitudinal central position that is positioned on the imaginary plane, on which the longitudinal central position of the first bearing part is positioned.   
     
     
         5 . The electric pump according to  claim 3 , wherein:
 the shaft is displaceable in a radial direction of the rotor at the first bearing part by a first displaceable amount; and   the shaft is displaceable in the radial direction at the second bearing part by a second displaceable amount that is smaller than the first displaceable amount.   
     
     
         6 . The electric pump according to  claim 1 , wherein:
 the pump unit includes:
 an inner rotor that has external teeth formed at an outer periphery thereof, the inner rotor being rotatable integrally with the shaft; and 
 an outer rotor that has internal teeth formed at an inner periphery thereof, the internal teeth being meshed with the external teeth; and 
   the housing rotatably receives therein the inner rotor and the outer rotor.