Impeller

Abstract

An impeller includes a wheel hub and a plurality of blades. The blade has a blade root, and the blade connects to the wheel hub through the blade root. The blades have different lengths. Each blade has an included angle between the blade root and the wheel hub, and the included angles of the blades are different. A centroid of the blades is located at an axis center of the impeller. The impeller is further configured with a blade reinforcement structure.

What is claimed is: 
     
         1 . An impeller, comprising:
 a wheel hub; and   a plurality of blades, wherein each of the blades has a blade root, the blade connects to the wheel hub through the blade root, the blades have different lengths, each of the blades has an included angle between the blade root and the wheel hub, the included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller.   
     
     
         2 . The impeller of  claim 1 , wherein the included angles of the blades are changed gradually in order, and the lengths of the blades are gradually changed corresponding to the gradually changed included angles, so that the centroid of the blades is located at the axis center of the impeller. 
     
     
         3 . The impeller of  claim 2 , wherein the lengths of the blades and the included angles of the blades are gradually changed with an equal difference. 
     
     
         4 . The impeller of  claim 2 , wherein a difference of the lengths of adjacent two of the blades is 1%˜10%. 
     
     
         5 . The impeller of  claim 2 , wherein a difference of the included angles of adjacent two of the blades is 1%˜10%. 
     
     
         6 . The impeller of  claim 1 , wherein noise frequencies caused by the blades are different. 
     
     
         7 . The impeller of  claim 1 , further comprising:
 a blade enhancement structure disposed around the wheel hub and connecting to the blades.   
     
     
         8 . The impeller of  claim 1 , wherein the blades are a balanced asymmetric structure, so that the centroid of the blades is located at the axis center of the impeller. 
     
     
         9 . An impeller, comprising:
 a wheel hub;   a plurality of blades, wherein each of the blades has a blade root, the blade connects to the wheel hub through the blade root, the blades have different lengths, each of the blades has an included angle between the blade root and the wheel hub, the included angles of the blades are different, and a centroid of the blades is located at an axis center of the impeller; and   a blade enhancement structure disposed around the wheel hub and connecting to a part of the blades.   
     
     
         10 . The impeller of  claim 9 , wherein the blade enhancement structure is disposed on two or more of the blades. 
     
     
         11 . The impeller of  claim 9 , wherein the blade enhancement structure is discontinuously disposed around the wheel hub to connect the blades.