Electric fluid pump

Abstract

An electric fluid pump includes a rotor including a permanent magnet, and including a radially outer peripheral surface covered by resin. An impeller faces a first axial end side of the rotor. A support shaft is disposed in a hole, wherein the hole extends axially of the rotor and the impeller, and through radially inside of the rotor and the impeller. A plain bearing part is configured to support the rotor and the impeller rotatably with respect to the support shaft. A first groove is formed in the radially outer peripheral surface of the rotor, and extends from the first axial end side of the rotor to a second axial end side of the rotor opposite to the first axial end side.

What is claimed is: 
     
         1 . An electric fluid pump comprising:
 a rotor including a permanent magnet, and including a radially outer peripheral surface covered by resin;   an impeller facing a first axial end side of the rotor;   a support shaft disposed in a hole, wherein the hole extends axially of the rotor and the impeller, and through radially inside of the rotor and the impeller;   a plain bearing part configured to support the rotor and the impeller rotatably with respect to the support shaft; and   a first groove formed in the radially outer peripheral surface of the rotor, and extending from the first axial end side of the rotor to a second axial end side of the rotor opposite to the first axial end side.   
     
     
         2 . The electric fluid pump as claimed in  claim 1 , further comprising a second groove formed in an axial end surface of the second axial end side of the rotor, and extending from a radially inside end side of the rotor to a radially outside end side of the rotor. 
     
     
         3 . The electric fluid pump as claimed in  claim 2 , wherein:
 the permanent magnet is inside of the rotor; and   the second groove extends from a location inside of the permanent magnet outwardly in a radial direction of the rotor.   
     
     
         4 . The electric fluid pump as claimed in  claim 2 , wherein:
 the rotor includes a rotor core in which the permanent magnet is disposed; and   the second groove extends from a location inside of the rotor core outwardly in a radial direction of the rotor.   
     
     
         5 . The electric fluid pump as claimed in  claim 2 , wherein the second groove includes a longitudinal end at the radially outside end side, wherein the longitudinal end is inside of the radially outer peripheral surface of the rotor in a radial direction of the rotor, and close to a longitudinal end of the first groove at the second axial end side of the rotor in a circumferential direction of the rotor. 
     
     
         6 . The electric fluid pump as claimed in  claim 1 , wherein:
 the rotor includes therein the permanent magnet as a first permanent magnet and includes therein a second permanent magnet adjacent to the first permanent magnet in a circumferential direction of the rotor; and   the first groove is arranged between the first permanent magnet and the second permanent magnet in the circumferential direction, and configured to accommodate part of a coil for magnetizing the permanent magnets.   
     
     
         7 . The electric fluid pump as claimed in  claim 1 , wherein the electric fluid pump is a water pump configured to suck and discharge water by rotation of the impeller. 
     
     
         8 . An electric fluid pump comprising:
 a rotor including a permanent magnet;   an impeller facing a first axial end side of the rotor;   a support shaft disposed in a hole, wherein the hole extends axially of the rotor and the impeller, and through radially inside of the rotor and the impeller;   a plain bearing part configured to support the rotor and the impeller rotatably with respect to the support shaft;   a first groove formed in a radially outer peripheral surface of the rotor, and extending from the first axial end side of the rotor to a second axial end side of the rotor opposite to the first axial end side; and   a second groove formed in an axial end surface of the second axial end side of the rotor, and extending from a radially inside end side of the rotor to a radially outside end side of the rotor.   
     
     
         9 . The electric fluid pump as claimed in  claim 8 , wherein:
 the permanent magnet is inside of the rotor; and   the second groove extends from a location inside of the permanent magnet outwardly in a radial direction of the rotor.   
     
     
         10 . The electric fluid pump as claimed in  claim 8 , wherein:
 the rotor includes a rotor core in which the permanent magnet is disposed; and   the second groove extends from a location inside of the rotor core outwardly in a radial direction of the rotor.   
     
     
         11 . The electric fluid pump as claimed in  claim 8 , wherein the second groove includes a longitudinal end at the radially outside end side, wherein the longitudinal end is inside of the radially outer peripheral surface of the rotor in a radial direction of the rotor, and close to a longitudinal end of the first groove at the second axial end side of the rotor in a circumferential direction of the rotor. 
     
     
         12 . The electric fluid pump as claimed in  claim 8 , wherein:
 the rotor includes therein the permanent magnet as a first permanent magnet and includes therein a second permanent magnet adjacent to the first permanent magnet in a circumferential direction of the rotor; and   the first groove is arranged between the first permanent magnet and the second permanent magnet in the circumferential direction, and configured to accommodate part of a coil for magnetizing the permanent magnets.   
     
     
         13 . The electric fluid pump as claimed in  claim 8 , wherein the electric fluid pump is a water pump configured to suck and discharge water by rotation of the impeller. 
     
     
         14 . An electric fluid pump comprising:
 a rotor configured to be rotationally driven by an electromagnetic force;   an impeller disposed coaxially with the rotor;   a support shaft disposed in a hole, and configured to support the rotor and the impeller rotatably through a plain bearing part, wherein the hole extends axially of the rotor and the impeller, and through radially inside of the rotor and the impeller; and   an outflow forcing system configured to force part of fluid by centrifugal force acting on the fluid to flow out to a second axial end side of the impeller and the rotor through a clearance between the support shaft and the hole, wherein the fluid is sucked by rotation of the impeller from a first axial end side of the impeller and the rotor opposite to the second axial end side.   
     
     
         15 . The electric fluid pump as claimed in  claim 14 , wherein the electric fluid pump is a water pump configured to suck and discharge water by rotation of the impeller.