Fan structure and impeller thereof

Abstract

A fan structure at least includes a cap, an impeller, a bearing and a fixing shaft, wherein the cap comprises a bottom portion, a body and an accommodating space. The impeller comprises a hub and a coupling base having a ring wall and an accommodating slot. The bearing couples to the accommodating slot, and the fixing shaft penetrates through an axial hole of the bearing. The ring wall of the coupling base comprises at least one guidance hole exposing the fixing shaft. The guidance hole is in communication with the accommodating space and the accommodating slot. The lubricants can be collected inside the accommodating space of the cap through the guidance of the guidance hole to prevent the lubricants from leakage when the impeller is in rotation.

What is claimed is: 
     
         1 . A fan structure including:
 a cap having a body and an accommodating space surrounded by the body;   an impeller having a hub and a coupling base, the coupling base comprises a ring wall coupled to the hub and an accommodating slot surrounded by the ring wall, wherein the ring wall accommodated within the accommodating space of the cap comprises at least one guidance hole communicated with the accommodating space of the cap and the accommodating slot of the coupling base;   a bearing coupled to the accommodating slot of the coupling base and having an axial hole; and   a fixing shaft penetrating the axial hole, wherein the guidance hole of the ring wall reveals the fixing shaft.   
     
     
         2 . The fan structure in accordance with  claim 1 , wherein the ring wall comprises a top surface and a bottom surface, and the guidance hole is located between the top surface and the bottom surface. 
     
     
         3 . The fan structure in accordance with  claim 2 , wherein the guidance hole is recessed to the bottom surface. 
     
     
         4 . The fan structure in accordance with  claim 2 , wherein the guidance hole is recessed to the top surface. 
     
     
         5 . The fan structure in accordance with  claim 1 , wherein the bearing comprises a penetration hole communicated with the guidance hole of the ring wall and the axial hole, and the fixing shaft is revealed by the penetration hole. 
     
     
         6 . The fan structure in accordance with  claim 5  further includes a guidance passage composed of the penetration hole of the bearing and the guidance hole of the ring wall. 
     
     
         7 . The fan structure in accordance with  claim 5 , wherein the bearing further comprises an outer ring surface formed in a ladder shape, the outer ring surface comprises a first surface and a second surface, and the first surface is spaced apart from the ring wall to define an oil storage space communicated with the penetration hole of the bearing and the guidance hole of the ring wall. 
     
     
         8 . The fan structure in accordance with  claim 3 , wherein the body of the cap comprises a top edge, and the guidance hole of the ring wall comprises an upper surface lower than the top edge. 
     
     
         9 . The fan structure in accordance with  claim 4 , wherein the body of the cap comprises a top edge, and the guidance hole of the ring wall comprises an lower surface lower than the top edge. 
     
     
         10 . An impeller of a fan structure including:
 a hub; and   a coupling base having a ring wall coupled to the hub and an accommodating slot surrounded by the ring wall, wherein the ring wall comprises an inner surface, an outer surface and at least one guidance hole communicated with the inner surface and the outer surface.   
     
     
         11 . The impeller of a fan structure in accordance with  claim 10 , wherein the ring wall comprises a top surface and a bottom surface, and the guidance hole is located between the top surface and the bottom surface. 
     
     
         12 . The impeller of a fan structure in accordance with  claim 11 , wherein the guidance hole is recessed to the bottom surface. 
     
     
         13 . The impeller of a fan structure in accordance with  claim 11 , wherein the guidance hole is recessed to the top surface. 
     
     
         14 . A fan structure including:
 an impeller having a hub and a coupling base, the coupling base comprises a ring wall coupled to the hub and an accommodating slot surrounded by the ring wall, wherein the ring wall comprises an inner surface, an outer surface and at least one guidance hole communicated with the inner surface and the outer surface;   a bearing coupled to the accommodating slot of the coupling base and having an axial hole; and   a fixing shaft penetrating the axial hole, the fixing shaft is revealed by the guidance hole of the ring wall.   
     
     
         15 . The fan structure in accordance with  claim 14 , wherein the ring wall comprises a top surface and a bottom surface, and the guidance hole is located between the top surface and the bottom surface. 
     
     
         16 . The fan structure in accordance with  claim 15 , wherein the guidance hole is recessed to the bottom surface. 
     
     
         17 . The fan structure in accordance with  claim 15 , wherein the guidance hole is recessed to the top surface. 
     
     
         18 . The fan structure in accordance with  claim 14 , wherein the bearing comprises a penetration hole communicated with the guidance hole of the ring wall and the axial hole, and the fixing shaft is revealed by the penetration hole. 
     
     
         19 . The fan structure in accordance with  claim 18  further includes a guidance passage composed of the penetration hole of the bearing and the guidance hole of the ring wall. 
     
     
         20 . The fan structure in accordance with  claim 18 , wherein the bearing further comprises an outer ring surface formed in a ladder shape, the outer ring surface includes a first surface and a second surface, and the first surface is spaced apart from the ring wall to define an oil storage space communicated with the penetration hole of the bearing and the guidance hole of the ring wall.