Cooling fan with anti-friction shaft and bearing set

Abstract

A cooling fan with anti-friction shaft and bearing set, which is able to decrease the friction between a metal shaft and a corresponding bearing, and thereby is capable of both reducing the noise and extending the lifetime of a cooling fan. The metal shaft of the cooling fan is coated with a layer of ceramic material. The corresponding bearing is also made of ceramic material. The cooling fan has a compression portion to orient the ceramic coating of the metal shaft to correspond to the bearing. The metal shaft contacts the inner surface of the bearing with its ceramic coating. The cooling fan of the present invention is thereby able to perform a high speed operation without generating noise.

1 . A cooling fan, comprising: 
 a casing with a collar and a receptive portion in the middle thereof;    a bearing which is made of ceramic material installed inside the collar;    a stator which is sleeved over the collar and rested above the receptive portion; and    a rotor which is received by the casing with a shaft which is coated with a ceramic layer supported by the bearing for decreasing the friction between the shaft and the bearing.    
   
   
       2 . The cooling fan of  claim 1 , wherein the shaft is made of metal.  
   
   
       3 . The cooling fan of  claim 1 , wherein the bearing is made into a cylinder.  
   
   
       4 . The cooling fan of  claim 1 , wherein the shaft has an annular groove formed at one end for fixing the shaft to the rotor.  
   
   
       5 . The cooling fan  claim 1 , wherein the shaft has a neck at the other end for securing the rotor on the casing.  
   
   
       6 . The cooling fan of  claim 1 , wherein the rotor further comprising: 
 a wheel;    a plurality of blades formed around the circumference of the wheel;    a permanent magnet installed inside the wheel; and    a compression portion.    
   
   
       7 . The cooling fan of  claim 6 , wherein the compression portion comprises a compression spring and a retainer.  
   
   
       8 . The cooling fan of  claim 7 , wherein the retainer is clipped onto a neck of the shaft for securing the rotor on the casing.  
   
   
       9 . The cooling fan of  claim 7 , wherein the compression spring presses against the bearing with one end and against the retainer with the other end.