| 摘要 |
PURPOSE:To improve wear resistance without applying high component chromium steel to the whole surface of basic material, by forming a chromium layer subjected to nitriding treatment on the outer peripheral surface of a shaft or inner peripheral surface of the shaft receiving area. CONSTITUTION:The sliding area of a shaft 8, namely a port facing the upper and lower bearing bodies and rollers serving as a receiving part is sheathed en bloc with each of sleeves 10 serving as a chromium layer and consisting of such metal containing chromium as, for instance, stainless steel, through those means such as pressing or shrinkage fit etc. Each of these sleeves 10 has been subjected to nitriding treatment before being fit around the shaft 8. Accordingly, a dispersion layer 13, consisting of the first layer 11 comprising principally Fe-Cr-N and the second layer 12 subjected to Fe-Cr-N dispersion below first layer 11, is formed on the surface layer of each sleeve 10. |
