Round axial fan with balancing structure

Abstract

A round axial fan with balancing structure includes a hub; a ring-shaped band located around an outer side of the hub to thereby define an annular flow passage between the hub and the ring-shaped band; a plurality of blades located in the annular flow passage; and a plurality of recesses circumferentially spaced on and along the ring-shaped band, each of the recesses internally defining a receiving space for at least one balancing element to fit therein. With these arrangements, it is able to achieve weight balance of the round axial fan for the latter to rotate in a balanced state and to avoid any vibration due to unbalanced rotation of the round axial fan.

1 . A round axial fan with balancing structure, comprising:
 a hub;   a ring-shaped band located around an outer side of the hub to thereby define an annular flow passage between the hub and the ring-shaped band;   a plurality of blades located in the annular flow passage, the blades respectively having a radially inner end connected to an outer circumferential surface of the hub and a radially outer end connected to an inner circumferential surface of the ring-shaped band; and   a plurality of recesses circumferentially spaced on and along the ring-shaped band, each of the recesses internally defining a receiving space for at least one balancing element to fit therein; whereby a weight distribution of the round axial fan can be adjusted by fitting the balancing elements in right ones of the recesses for the round axial fan to rotate in a balanced state.   
     
     
         2 . The round axial fan with balancing structure as claimed in  claim 1 , further comprising a magnetic ring fitted to an inner circumferential surface of the hub. 
     
     
         3 . The round axial fan with balancing structure as claimed in  claim 1 , further comprising a central shaft located at a center of the hub. 
     
     
         4 . The round axial fan with balancing structure as claimed in  claim 1 , wherein the recesses are circumferentially spaced on and along end faces of the ring-shaped band. 
     
     
         5 . The round axial fan with balancing structure as claimed in  claim 1 , wherein the ring-shaped band has a first end face and a second end face separately located at two opposite sides of the ring-shaped band. 
     
     
         6 . The round axial fan with balancing structure as claimed in  claim 5 , wherein the recesses are circumferentially spaced on and along at least one of the first or/and the second end face of the ring-shaped band. 
     
     
         7 . The round axial fan with balancing structure as claimed in  claim 5 , wherein a radius of the first end face relative to a center of the hub is equal to a radius of the second end face relative to the center of the hub. 
     
     
         8 . The round axial fan with balancing structure as claimed in  claim 5 , wherein a radius of the first end face relative to a center of the hub is larger than a radius of the second end face relative to the center of the hub. 
     
     
         9 . The round axial fan with balancing structure as claimed in  claim 5 , wherein a radius of the second end face relative to a center of the hub is larger than a radius of the first end face relative to the center of the hub.