Provided is a sintered bush including a porous metallic sintered body including: a iron (Fe) based matrix containing a martensite structure; and one or more kind of metal matrix selected from copper (Cu), tin (Sn), and nickel (Ni), in which a lubricant which has oil separation of 5 to 10% at an operational temperature of 60 to 80° C. and is semisolid or solid at room temperature is impregnated in pores of the porous sintered body.
1. A sintered bush made of porous metallic sintered body, wherein the porous metallic sintered body comprises:
an iron (Fe) based matrix containing a martensite structure; and metal matrix of copper (Cu), tin (Sn), nickel (Ni), and carbon,
wherein the sintered bush is used under a contact pressure of 8 kg/mm 2 or more and a fluctuation velocity of the range of 1 to 8 cm/sec,
wherein a lubricant is impregnated in pores of the porous sintered body, the lubricant having an oil separation rate of 5 to 10 wt % at an operational temperature of 70 to 80 degrees Celsius,
wherein the lubricant includes a wax of 20 wt %, a thickener of 10 to 20 wt %, an additive of 2 wt %, and a residual amount of base oil and being semisolid or solid at room temperature,
wherein the wax has a softening temperature of 150 degrees Celsius or less and a weight average molecular weight of 300 to 4000.
2. A sintered bush made of porous metallic sintered body, wherein the porous metallic sintered body comprises: an iron (Fe) based matrix containing a martensite structure; and metal matrix of copper (Cu), fin (Sn), nickel (Ni) and carbon,
wherein the sintered bush is used under a contact pressure of 8 kg/mm 2 or more and a fluctuation velocity of the range of 1 to 8 cm/sec;
wherein a lubricant is impregnated in pores of the porous sintered body, the lubricant having an oil separation rate of 2 wt % or less at an operational temperature of 40 to 80 degrees Celsius,
wherein the lubricant includes a wax of 20 wt %, a thickener of 10 to 20 wt %, an additive of 2 wt %, and a residual amount of base oil and being semisolid or solid at room temperature,
wherein the wax has a softening temperature of 150 degrees Celsius or less and a weight average molecular weight of 300 to 4000,
wherein a lubricant is impregnated in the pores of the porous sintered body, the lubricant having an oil separation rate of 5 to 10 wt % at an operational temperature of 70 to 80 degrees Celsius.
3. The sintered bush according to claim 1 , wherein the lubricant has consistency of NLGI level 2 or less.
4. The sintered bush according to claim 1 , wherein the pores have an average size of 50 to 200 μm and porosity of 15 to 25%, and a ratio of the pores of which the size is more than 200 μm among the entire pores is 1 to 5% or less.
5. The sintered bush according to claim 1 , wherein the additive comprises an extreme pressure additive, solid lubricative particles, or both the extreme pressure additive and the solid lubricative particles.
6. The sintered bush according to claim 1 , wherein the base oil has kinematic viscosity in the range of 50 to 1500 cSt at a temperature of 40 degrees Celsius.
7. The sintered bush according to claim 1 , wherein the copper has a content of 7 to 20 wt %, tin has a content of 1 to 7 wt %, nickel has a content of 0.3 to 4 wt %, and carbon has a content of 0.2 to 2 wt % with respect to the total weight of the porous metallic sintered body.
8. The sintered bush according to claim 1 further comprise one or more kinds of mixture of metals selected from boron (B), chromium (Cr), molybdenum (Mo), vanadium (V), tungsten (W), and manganese (Mn).
9. The sintered bush according to claim 1 , wherein the wax comprises one of a solid polymer wax and a general wax,
wherein the solid polymer wax has weight average molecular weight of 500˜2000 and the general wax has weight average molecular weight of 300˜1000.
10. The sintered bush according to claim 9 , wherein the solid polymer wax comprises at least one of polyethylene, polyolefin, polyester, epoxide, and urethane, and the general wax comprises at least one of paraffin wax, microcrystal wax, ethylene bisstearamides, and cotton seed wax.