Water pump

Abstract

The present invention provides a water pump capable of minimizing the runout of a shaft of an impeller even if a bearing supporting the shaft is provided only at one location. This water pump includes a pump cover, a motor case having a partition wall part, an impeller that is rotatably housed in a pump chamber, a shaft, a radial bearing, a rotor base formed with a shaft connecting part to which the shaft is press-fitted and fixed, an inner magnet that is fixed to an outer periphery of the rotor base, and a stator core mounted in the motor case. A substantially cylindrical bearing housing part is formed in partition wall part, the radial bearing is inserted and fixed to the bearing housing part, the radial bearing is disposed in the rotor base, and an axial direction overall length of the radial bearing is positioned within a substantial area of an axial direction overall length of the inner magnet.

1 . A water pump, comprising:
 a pump cover;   a motor case having a partition wall part which forms a pump chamber together with the pump cover;   an impeller that is rotatably housed in the pump chamber;   a shaft that is directly connected to the impeller and that is penetratively inserted from a shaft through-hole formed on the partition wall part into the motor case;   a radial bearing for pivotally supporting the shaft;   a rotor base formed with a substantially cylindrical tubular part and a shaft connecting part which is formed at a diametrical direction center in the tubular part and to which the shaft is press-fitted and fixed;   an inner magnet that is fixed to an outer periphery of the rotor base; and   a stator core that is positioned at an outer periphery of the inner magnet and mounted in the motor case,   wherein a substantially cylindrical bearing housing part is formed in the partition wall part with the shaft through-hole as a diametrical center, the radial bearing is inserted and fixed to the bearing housing part along an axial direction, the radial bearing is disposed in the rotor base, and an axial direction overall length of the radial bearing is positioned within a substantial area of an axial direction overall length of the inner magnet.   
     
     
         2 . The water pump according to  claim 1 ,
 wherein the axial direction overall length of the radial bearing intersects with a virtual center line of the axial direction overall length of the inner magnet.   
     
     
         3 . The water pump according to  claim 1 ,
 wherein the axial direction overall length of the radial bearing intersects with a virtual center line of the axial direction overall length of the inner magnet, and an axial direction overall length of a shaft connecting part of the rotor base is positioned within an area of the axial direction overall length of the inner magnet.   
     
     
         4 . The water pump according to  claim 1 ,
 wherein a thrust bearing is mounted at the location of the shaft connecting part of the rotor base via an elastic member, and the radial bearing and the thrust bearing are in contact with each other in a mutually slidable manner.   
     
     
         5 . The water pump according to  claim 2 ,
 wherein a thrust bearing is mounted at the location of the shaft connecting part of the rotor base via an elastic member, and the radial bearing and the thrust bearing are in contact with each other in a mutually slidable manner.   
     
     
         6 . The water pump according to  claim 3 ,
 wherein a thrust bearing is mounted at the location of the shaft connecting part of the rotor base via an elastic member, and the radial bearing and the thrust bearing are in contact with each other in a mutually slidable manner.