Fan and impeller thereof

Abstract

An impeller used in a fan is provided. The impeller includes a hub and a plurality of blades disposed around the hub. The hub has at least one curve-shape surface. A fan comprises a fan frame, an impeller, and a motor. The impeller disposed in the fan frame comprises a hub and a plurality of blades disposed around the hub, wherein the hub has at least one curve-shape surface and an airflow guiding structure disposed on an outer circumference of the hub. The motor is disposed in the impeller for driving the impeller.

1 . An impeller, comprising:
 a hub comprising an airflow guiding structure formed with an outer circumference of the hub; and   a plurality of blades disposed around the hub.   
   
   
       2 . The impeller of  claim 1 , wherein the hub has a top surface and a bottom surface, and an outer diameter of the hub increases progressively from the top surface to the bottom surface. 
   
   
       3 . The impeller of  claim 2 , wherein a ratio of the outer diameter of the top surface and the outer diameter of the bottom surface is smaller than 0.45. 
   
   
       4 . The impeller of  claim 4 , wherein the airflow guiding structure comprises at least one curve-shape surface. 
   
   
       5 . The impeller of  claim 4 , wherein a tangential angle between the curve-shape surface and the top surface is between 0 and 45 degrees. 
   
   
       6 . The impeller of  claim 4 , wherein an angle between the curve-shape surface and the bottom surface is between 30 and 75 degrees. 
   
   
       7 . The impeller of  claim 4 , wherein an angle between a horizontal line and a line connecting both ends of the curve-shape surface of the hub is smaller than 70 degrees. 
   
   
       8 . A fan, comprising:
 a fan frame;   an impeller disposed in the fan frame, and comprising a hub and a plurality of blades disposed around the hub, wherein the hub comprises an airflow guiding structure formed with an outer circumference of the hub; and   a motor disposed in the fan frame for driving the impeller to rotate.   
   
   
       9 . The fan of  claim 8 , wherein the airflow guiding structure and the hub are integrally formed as a single unit. 
   
   
       10 . The fan of  claim 8 , wherein the hub has a top surface and a bottom surface, and an outer diameter of the hub increases progressively from the top surface to the bottom surface. 
   
   
       11 . The fan of  claim 10 , wherein a ratio of the outer diameter of the top surface and the outer diameter of the bottom surface is smaller than 0.45 or a ratio of the outer diameter of the top surface of the hub and an inner diameter of the fan frame is smaller than 0.35. 
   
   
       12 . The fan of  claim 10 , wherein a tangential angle between the airflow guiding structure and the top surface of the hub is between 0 and 45 degrees or an angle between the airflow guiding structure and the bottom surface of the hub is between 30 and 75 degrees. 
   
   
       13 . The fan of  claim 8 , wherein a ratio of a height of the hub and a height of the fan frame is greater than 0.6. 
   
   
       14 . The fan of  claim 8 , wherein the airflow guiding structure comprises at least one curve-shape surface. 
   
   
       15 . The fan of  claim 14 , wherein an angle between a horizontal line and a line connecting both ends of the curve-shape surface of the hub is smaller than 70 degrees. 
   
   
       16 . The fan of  claim 8 , wherein the fan flame comprises a main body, and the main body has a first guiding angle and a second guiding angle at the inlet and the outlet respectively, and the first guiding angle and the second guiding angle are formed along the inclined plane for guiding more airflow in and out. 
   
   
       17 . The fan of  claim 16 , wherein the fan frame comprises a base and a plurality of connecting elements disposed between the main body and the base. 
   
   
       18 . The fan of  claim 17 , wherein the blades extend beyond the airflow guiding structure to cover the base. 
   
   
       19 . The fan of  claim 17 , wherein the connecting element, the main body, and the base are integrally formed as a single unit. 
   
   
       20 . The fan of  claim 17 , wherein the connecting elements comprise a plurality of ribs or stationary blades.