Fan

Abstract

A fan includes a frame, an impeller, and a motor. The impeller includes a hub, blades, and air-guiding plates. The hub has a tapered shape and the width of the hub gradually increases. The hub has an air vent. The blades are disposed around the outer periphery of the hub. The air-guiding plates are disposed around the inner periphery of the hub. The motor is disposed in the frame, and connects to and drives the impeller to rotate. The motor includes a stator structure and a rotor structure. The rotor structure includes a shaft, a magnetic conductive housing, and a magnetic element. One end of the shaft connects to the magnetic conductive housing. The magnetic element is disposed around the inner periphery of the magnetic conductive housing and located corresponding to the stator structure. The top surface of the magnetic conductive housing has at least one opening.

What is claimed is: 
     
         1 . A fan, comprising:
 a frame;   an impeller, comprising:
 a hub having a tapered shape, wherein a width of the hub gradually increases along a direction from a top portion of the hub to a bottom portion of the hub, and the hub has at least an air vent, 
 a plurality of blades disposed around an outer periphery of the hub, and 
 a plurality of air-guiding plates disposed around an inner periphery of the hub; and 
   a motor disposed in the frame, wherein the motor connects to and drives the impeller to rotate, and the motor comprises:
 a stator structure, and 
 a rotor structure comprising a shaft, a magnetic conductive housing, and a magnetic element, wherein one end of the shaft connects to the magnetic conductive housing, the magnetic element is disposed around an inner periphery of the magnetic conductive housing and located corresponding to the stator structure, and a top surface of the magnetic conductive housing has at least an opening. 
   
     
     
         2 . The fan according to  claim 1 , wherein a size of the air vent is greater than or equal to 3 mm, or an equivalent area of the entire air vent is greater than or equal to 7 mm 2 . 
     
     
         3 . The fan according to  claim 1 , wherein the air vent is disposed on the top portion of the hub. 
     
     
         4 . The fan according to  claim 3 , wherein a size of the air vent is greater than or equal to 3 mm, or an equivalent area of the entire air vent is greater than or equal to 7 mm 2 . 
     
     
         5 . The fan according to  claim 3 , wherein the air vent is disposed between the top portion of the hub and front edges of the blades contacting the outer periphery of the hub. 
     
     
         6 . The fan according to  claim 5 , wherein a size of the air vent is greater than or equal to 3 mm, or an equivalent area of the entire air vent is greater than or equal to 7 mm 2 . 
     
     
         7 . The fan according to  claim 1 , wherein the frame comprises a base, and a distance between a top portion of the base and the bottom portion of the hub is greater than or equal to 1.0 mm. 
     
     
         8 . The fan according to  claim 1 , wherein each of the air-guiding plates extends from the inner periphery of the hub to an axis of the hub. 
     
     
         9 . The fan according to  claim 1 , wherein a ratio of a height of each of the air-guiding plates to a distance from the top portion of the hub to the bottom portion of the hub ranges from 0.3 to 1.2. 
     
     
         10 . The fan according to  claim 1 , wherein a ratio of a length of each of the air-guiding plates to a diameter of the magnetic conductive housing ranges from 0.1 to 0.9. 
     
     
         11 . The fan according to  claim 10 , wherein the length of each of the air-guiding plates is greater than or equal to 10 mm, and a distance between each of the air-guiding plates and an axis of the hub is greater than or equal to 4 mm. 
     
     
         12 . The fan according to  claim 10 , wherein a thickness of each of the air-guiding plates is greater than or equal to 1.0 mm. 
     
     
         13 . The fan according to  claim 1 , wherein each of the air-guiding plates has a rib shape or a wing shape. 
     
     
         14 . The fan according to  claim 1 , wherein the air-guiding plates are arranged with equivalent interval angles. 
     
     
         15 . The fan according to  claim 1 , wherein the air-guiding plates are arranged with inequivalent interval angles. 
     
     
         16 . The fan according to  claim 8 , wherein the air-guiding plates have the same lengths, thicknesses, heights, or shapes. 
     
     
         17 . The fan according to  claim 8 , wherein at least one of lengths, thicknesses, heights, or shapes of the air-guiding plates are different. 
     
     
         18 . The fan according to  claim 1 , wherein the inner periphery of the frame is configured with an air-guiding curved surface disposed at an air inlet side of the fan.