Impeller of Cooling Fan

Abstract

An impeller of a cooling fan includes a metal base, a shaft and a plurality of plastic blades. The metal base includes a shaft-coupling portion, a first assembling portion apart from the shaft-coupling portion, and a flat portion between the shaft-coupling portion and the first assembling portion, wherein the flat portion oppositely has a first flat surface and a second flat surface, and a permanent magnet is mounted on the first flat surface. The shaft has a fixing end coupled with the shaft-coupling portion of the metal base. Each of the plastic blades has a second assembling portion coupled with the first assembling portion of the metal base.

What is claimed is: 
     
         1 . An impeller of a cooling fan, comprising:
 a metal base comprising a shaft-coupling portion, a first assembling portion apart from the shaft-coupling portion, and a flat portion between the shaft-coupling portion and the first assembling portion, wherein the flat portion oppositely has a first flat surface and a second flat surface, and a permanent magnet is mounted on the first flat surface;   a shaft having a fixing end coupled with the shaft-coupling portion of the metal base; and   a plurality of plastic blades, wherein each plastic blade has a second assembling portion coupled with the first assembling portion of the metal base.   
     
     
         2 . The impeller of the cooling fan as claimed in  claim 1 , wherein the second assembling portions jointly form an enclosing ring coupled with the first assembling portion of the metal base. 
     
     
         3 . The impeller of the cooling fan as claimed in  claim 1 , wherein the first assembling portion of the metal base has a plurality of through holes, and the second assembling portions of the plastic blades fill up the through holes. 
     
     
         4 . The impeller of the cooling fan as claimed in  claim 3 , wherein the through holes are arranged in a circular route adjacent to a periphery of the metal base, and any adjacent two of the through holes are spaced out a predetermined distance apart. 
     
     
         5 . The impeller of the cooling fan as claimed in  claim 1 , wherein the first assembling portion of the metal base has a plurality of saw teeth at a periphery of the metal base, and the second assembling portions of the plastic blades couple with the saw teeth at the periphery of the metal base. 
     
     
         6 . The impeller of the cooling fan as claimed in  claim 1 , wherein the first assembling portion of the metal base has an inclined section forming the periphery of the metal base, and the second assembling portions of the plastic blades couple with the inclined section of the first assembling portion of the metal base. 
     
     
         7 . The impeller of the cooling fan as claimed in  claim 6 , wherein the second assembling portions couple with the inclined section of the first assembling portion by covering both of first and second surfaces of the inclined section, wherein the first surface connects with and extends from the first flat surface of the flat portion, and the second surface connects with and extends from the second flat surface of the flat portion. 
     
     
         8 . The impeller of the cooling fan as claimed in  claim 6 , wherein a through hole is disposed in the inclined section and extends from a first surface of the inclined section to a second surface of the inclined section, and the second assembling portions fill the through hole, with the first surface connecting with and extending from the first flat surface of the flat portion, and with the second surface connecting with and extending from the second flat surface of the flat portion. 
     
     
         9 . The impeller of the cooling fan as claimed in  claim 1 , wherein the first assembling portion of the metal base has a stair section, and the second assembling portions of the plastic blades couple with the stair section of the first assembling portion of the metal base. 
     
     
         10 . The impeller of the cooling fan as claimed in  claim 9 , wherein the second assembling portions couple with the stair section of the first assembling portion by covering both of first and second surfaces of the stair section, wherein the first surface connects with and extends from the first flat surface of the flat portion, and the second surface connects with and extends from the second flat surface of the flat portion. 
     
     
         11 . The impeller of the cooling fan as claimed in  claim 9 , wherein the stair section includes a radial extension extending in a radial direction of the metal base and an axial extension extending in an axial direction of the metal base, with the axial extension linking the flat portion and the radial extension. 
     
     
         12 . The impeller of the cooling fan as claimed in  claim 9 , wherein through holes are disposed in at least one of the axial and radial extensions of the stair section and extend from a first surface of the stair section to a second surface of the stair section, and the second assembling portions fill the through hole, with the first surface connecting with and extending from the first flat surface of the flat portion, and with the second surface connecting with and extending from the second flat surface of the flat portion. 
     
     
         13 . The impeller of the cooling fan as claimed in  claim 1 , wherein the flat portion and the first assembling portion are coplanar. 
     
     
         14 . The impeller of the cooling fan as claimed in  claim 1 , wherein the flat portion and the first assembling portion are non-coplanar. 
     
     
         15 . The impeller of the cooling fan as claimed in  claim 14 , wherein, in an axial direction of the shaft-coupling portion of the metal base, the flat portion has a first axial thickness, the first assembling portion has a second axial thickness, and a ratio of the second axial thickness to the first axial thickness falls in a range between 1.1 and 8.5. 
     
     
         16 . The impeller of the cooling fan as claimed in  claim 15 , wherein the ratio of the second axial thickness to the first axial thickness falls in a range between 1.1 and 4. 
     
     
         17 . The impeller of the cooling fan as claimed in  claim 9 , wherein the flat portion and the first assembling portion are non-coplanar. 
     
     
         18 . The impeller of the cooling fan as claimed in  claim 17 , wherein, in an axial direction of the shaft-coupling portion of the metal base, the flat portion has a first axial thickness, the first assembling portion has a second axial thickness, and a ratio of the second axial thickness to the first axial thickness falls in a range between 1.1 and 8.5. 
     
     
         19 . The impeller of the cooling fan as claimed in  claim 18 , wherein the ratio of the second axial thickness to the first axial thickness falls in a range between 1.1 and 4. 
     
     
         20 . The impeller of the cooling fan as claimed in  claim 1 , wherein the first and second flat surfaces are uncovered. 
     
     
         21 . The impeller of the cooling fan as claimed in  claim 1 , wherein the first and second flat surfaces are covered with a plastic or rustproof layer. 
     
     
         22 . The impeller of the cooling fan as claimed in  claim 1 , wherein an axial end face of the fixing end is at a same level of or is lower than the second flat surface.