Bushings and oil bearing are made of iron base alloy, Iron and copper alloys, Copper alloy material by pressing, Sintering, Plastic post-processing process, the internal space, can have certain work, because oil storage and shaft sleeves or oil-retaining bearing, friction between the heat oil from internal surface and seepage through to the collar or oil-retaining bearing surface, a thin layer of oil film automatically adjust the flow of oil lubrication system. It is by the mold, the size of the one-time forming high accuracy