Thin fan structure

Abstract

A thin fan structure includes a case, a fan impeller, a circuit board, a silicon steel sheet and a winding assembly. The case has a receiving space and a bearing cup protruding into the receiving space. The bearing cup is formed with a bearing hole. The fan impeller has a hub section, multiple blades and a shaft extending from a center of the hub section. A magnetic member is annularly disposed on inner circumference of the hub section. The circuit board is disposed in the receiving space. The silicon steel sheet disposed on the circuit board has a base section and multiple first magnetic conductive sections, which together define a receiving space. The winding assembly is fixedly disposed in the receiving space. The winding assembly has a bottom section attached to the base section and a side section attached to the first magnetic conductive sections.

What is claimed is: 
     
         1 . A thin fan structure comprising:
 a case having a receiving space and a bearing cup protruding from a center of the case into the receiving space, the bearing cup being formed with a bearing hole;   a fan impeller having a hub section and multiple blades outward extending from a circumference of the hub section, a shaft axially extending from a center of the hub section, the shaft being rotatably disposed in the bearing hole, a magnetic member being annularly disposed on inner circumference of the hub section;   a circuit board disposed in the receiving space and fitted around the bearing cup;   a silicon steel sheet disposed on the circuit board, the silicon steel sheet having a base section and multiple first magnetic conductive sections upward protruding from a circumference of the base section, the base section and the first magnetic conductive sections together defining a receiving space; and   a winding assembly fixedly disposed in the receiving space, the winding assembly having a bottom section and a side section, the bottom section being attached to the base section, the side section being correspondingly attached to the first magnetic conductive sections.   
     
     
         2 . The thin fan structure as claimed in  claim 1 , wherein a bearing with a shaft hole is received in the bearing hole, the shaft being inserted in the shaft hole. 
     
     
         3 . The thin fan structure as claimed in  claim 1 , wherein the first magnetic conductive sections are discontinuously arranged on the circumference of the base section at intervals. 
     
     
         4 . The thin fan structure as claimed in  claim 1 , wherein the winding assembly is connected with the silicon steel sheet by means of press fit or adhesion. 
     
     
         5 . The thin fan structure as claimed in  claim 1 , wherein the winding assembly is a self-adhesive winding assembly. 
     
     
         6 . The thin fan structure as claimed in  claim 1 , wherein multiple second magnetic conductive sections protrude from the circumference of the base section in a direction reverse to that of the first magnetic conductive sections. 
     
     
         7 . The thin fan structure as claimed in  claim 6 , wherein the first and second magnetic conductive sections are reversely arranged in alignment with each other. 
     
     
         8 . The thin fan structure as claimed in  claim 6 , wherein the first and second magnetic conductive sections are reversely alternately arranged. 
     
     
         9 . The thin fan structure as claimed in  claim 6 , wherein the first and second magnetic conductive sections are integrally formed. 
     
     
         10 . The thin fan structure as claimed in  claim 1 , wherein the base section is formed with multiple perforations. 
     
     
         11 . The thin fan structure as claimed in  claim 1 , wherein each first magnetic conductive section has a magnetic conductive portion protruding from one side of the first magnetic conductive section.