Assembled type impeller of a cooling fan

Abstract

An assembled type impeller includes a main impeller, and a secondary impeller; the main impeller has a hub, main blades on the hub, an extension portion next to one end of the hub, and a top portion over an upper end of the extension portion; the secondary impeller has a hub, secondary blades on the hub thereof, and a top portion over an upper end of the hub thereof; the secondary impeller is joined to the main impeller with the hub thereof being tightly fitted onto the extension portion, and with the secondary blades being connected to respective ones of the main blades to form larger blades; in manufacturing the main impeller, first a motor housing is positioned in a mold for the main impeller, and then the main impeller is made by means of injection molding; thus, the main impeller and the motor housing can be naturally connected together.

What is claimed is:  
     
         1 . An assembled type impeller of a cooling fan, comprising a main impeller having a hub, and a plurality of main blades on an outer side of the hub; the main impeller having a “ ”-shaped extension portion next to one end of the hub thereof; and 
 a secondary impeller having a hub, and a plurality of secondary blades on an outer side of the hub thereof; the secondary impeller being joined to the main impeller with the hub thereof being closely fitted onto the extension portion of the main impeller, and with the secondary blades being connected to respective ones of the main blades to form larger blades.  
 
     
     
         2 . The assembled type impeller of a cooling fan as claimed in  claim 1 , wherein the extension portion is next to an upper end of the hub of the main impeller, and the main impeller is further formed with a top portion over the “ ”-shaped extension portion thereof, and the secondary impeller is further formed with a top portion over an upper end of the hub thereof for the hub to have a “ ”-shape; the top portion of the secondary impeller being closely pressed against the top portion of the main impeller after the impellers are connected together.