Blade wheel structure for axial fan

Abstract

A blade wheel structure for axial fan includes a hub and a plurality of blades circumferentially outward extended from the hub. Each of the blades has a tip portion, which is located at a windward side of the blade and is curved in shape. With the curved tip portions of the blades, it is able to create largely increased air pressure and reduce the noise produced during fan operation.

1 : A blade wheel structure for axial fan, comprising:
 a hub; and   a plurality of blades radially outward extended from the hub; each of the blades having a front tip portion located at a windward side of the respective blade and a rear tip portion located at one side of the blade opposite to the front tip portion, the front tip portion being curved in circular arc shape and overlapping with the rear tip portion of the adjacent blade in an axial direction;   wherein each of the front tip portions further includes a first arc and a second arc, and the first arc and the second arc together define the circular arc.   
     
     
         2 : The blade wheel structure for axial fan as claimed in  claim 1 , wherein the hub has a center point defined in a central area thereof; a radius from the center point to a circumference of the hub defining a first pitch circle; a second pitch circle concentric with the first pitch circle being defined at an outer side of the first pitch circle with a first radial distance spaced between the first and the second pitch circle; and a third pitch circle concentric with the first pitch circle being defined at an outer side of the first pitch circle with a second radial distance spaced between the first and the third pitch circle; the first radial distance being from 0.1 to 0.9 times of the radius of the first pitch circle; and the third pitch circle passing outmost edges of the blades. 
     
     
         3 : The blade wheel structure for axial fan as claimed in  claim 2 , wherein the first arc being extended from a point, at where the tip portion meets the second pitch circle, to the third pitch circle; and the second arc being extended from another end, at where the tip portion meets the first pitch circle, to the second pitch circle.