Impeller for an axial flow fan and axial flow fan

Abstract

An impeller for an axial flow fan includes a plurality of blades arranged around a rotating shaft and a hub portion having a side peripheral portion surrounding the rotating shaft as viewed from a direction parallel to the rotating shaft, wherein an end portion on the rotating shaft side of each of the plurality of blades is coupled to the side peripheral portion, the plurality of blades includes a blade having a first type of shape and a blade having a second type of shape, and a thickness of the end portion on the rotating shaft side in the rotating shaft direction of the first type of shape is greater than the thickness of the end portion on the rotating shaft side in the rotating shaft direction of the second type of shape.

What is claimed is: 
     
         1 . An impeller for an axial flow fan comprising:
 a plurality of blades arranged around a rotating shaft; and   a hub portion having a side peripheral portion surrounding the rotating shaft, wherein   an end portion on the rotating shaft side of each of the plurality of blades is coupled to the side peripheral portion,   the plurality of blades includes a blade having a first type of shape and a blade having a second type of shape, and   a thickness of the end portion on the rotating shaft side in the rotating shaft direction of the first type of shape is greater than the thickness of the end portion on the rotating shaft side in the rotating shaft direction of the second type of shape.   
     
     
         2 . The axial flow fan impeller according to  claim 1 , wherein
 the number of blades having the first type of shape of the plurality of blades is two or more, and   each of the blades having the first type of shape is adjacent to other blade having the first type of shape around the rotating shaft.   
     
     
         3 . The axial flow fan impeller according to  claim 1 , wherein
 the number of blades having the first type of shape of the plurality of blades is two or more, and   the plurality of blades are arranged in a state where the blades having the first type of shape are located at asymmetric positions.   
     
     
         4 . The axial flow fan impeller according to  claim 1 , wherein
 each of the plurality of blades comprises a first surface facing a suction port of a gas;   and a second surface facing an exhaust port of the gas, and
 the first type of shape has a part located at the end portion on the rotating shaft side, at least one of the first surface and the second surface has a portion coupled to the side peripheral portion through a curved surface at the end portion on the rotating shaft side. 
   
     
     
         5 . The axial flow fan impeller according to  claim 4 , wherein
 the curved surface has a recessed shape recessed toward the inside of the blade.   
     
     
         6 . The axial flow fan impeller according to  claim 4 , wherein
 the curved surface has a fillet surface shape.   
     
     
         7 . A axial flow fan comprising:
 an axial flow fan impeller according to  claim 1 ; and   a casing rotatably supporting the axial flow fan impeller around the rotating shaft, wherein   a motor rotating the axial flow fan impeller is attached to the casing.   
     
     
         8 . The axial flow fan according to  claim 7 , wherein
 the motor is an motor of outer rotor type, and   a rotor yoke of the motor is attached to the hub portion.   
     
     
         9 . An axial flow fan impeller comprising:
 a plurality of blades arranged around a rotating shaft; and   a hub portion having a side peripheral portion surrounding the rotating shaft, wherein   an end portion on the rotating shaft side of each of the plurality of blades is coupled to the side peripheral portion,   the plurality of blades includes a blade having a first type of shape and a blade having a second type of shape, and   the shape of the end portion of the first type of shape is different from the shape of the end portion in the rotating shaft direction of the second type of shape on the rotating shaft side.