Sintered bearing and preparation method thereof

Abstract

The present invention relates to a sintered bearing and a preparation method thereof, wherein the method comprises: a step for forming a mixed powder by mixing metal powder, kish graphite, and lubricant; forming a molded body by applying pressure to the mixed powder; forming a sintered body by sintering the molded body; and impregnating the sintered body in oil. The invention is prepared by adding 0.01-10 parts by weight of kish graphite to metal powder and thus provides excellent abrasion resistance, strength, and self lubricity.

What is claimed is: 
     
         1 . A sintered bearing, comprising metal powder, kish graphite, and a lubricant. 
     
     
         2 . The sintered bearing of  claim 1 , comprising, based on a total weight thereof, 0.01˜10 parts by weight of the kish graphite, 0.01˜1.0 parts by weight of the lubricant, and a balance of the metal powder. 
     
     
         3 . The sintered bearing of  claim 1 , wherein the metal powder is one or more selected from the group consisting of a pure iron system, an iron-copper system, an iron-carbon system, an iron-carbon-copper system, a bronze system, and an iron-carbon-copper-nickel system. 
     
     
         4 . The sintered bearing of  claim 1 , wherein the kish graphite is a byproduct of iron production. 
     
     
         5 . A method of manufacturing a sintered bearing, comprising:
 mixing metal powder, kish graphite, and a lubricant, thus forming a powder mixture;   applying pressure to the powder mixture, thus forming a molded body;   sintering the molded body, thus forming a sintered body; and   impregnating the sintered body with oil.   
     
     
         6 . The method of  claim 5 , wherein the powder mixture comprises, based on a total weight thereof, 0.01˜10 parts by weight of the kish graphite, 0.01˜1.0 parts by weight of the lubricant, and a balance of the metal powder. 
     
     
         7 . The method of  claim 5 , wherein the metal powder is one or more selected from the group consisting of a pure iron system, an iron-copper system, an iron-carbon system, an iron-carbon-copper system, a bronze system, and an iron-carbon-copper-nickel system. 
     
     
         8 . The method of  claim 5 , wherein the kish graphite is in a powder form having a particle size of 50 mesh or less. 
     
     
         9 . The method of  claim 5 , wherein the kish graphite has a purity of 90˜100% after refining. 
     
     
         10 . The method of  claim 5 , wherein the lubricant contains zinc stearate (C 36 H 70 O 4 Zn), Acrawax (C 38 H 76 N 2 O 2 ), Kenolube paraffin, or any combination thereof. 
     
     
         11 . The method of  claim 5 , wherein a pressure of 50˜350 MPa is applied to the powder mixture at room temperature. 
     
     
         12 . The method of  claim 5 , wherein the molded body is performed so that the molded body has a compact density of 5.4˜7.0 g/cm 3 . 
     
     
         13 . The method of  claim 5 , wherein the molded body is sintered at 850˜1300° C. under atmospheric pressure. 
     
     
         14 . The method of  claim 5 , wherein the molded body is sintered for 1˜6 hr. 
     
     
         15 . The method of  claim 5 , wherein the sintered body is impregnated at 50˜150° C. in a vacuum.