| 摘要 |
To the surface of the sliding portion of the metal-product, the shots having the hardness larger than that of the metal-product and the shape of almost sphere are injected. By heating the surface of the metal-product to the temperature higher than a predetermined temperature, very small concave portions each having a circular arc-shaped cross section are formed due to the impulse force of the shots. Thus, the structure of the surface layer of the sliding portion is minuted so as to have large internal stress, hardness and toughness. Since the surface layer of the sliding portion has the large toughness, the sliding portions get to fit each other while they are sliding for long time to be rubbed each other, thereby frictional resistance is decreased. Further, since the very small concave portions are formed on the surface of the sliding portion, the surface tension of a lubricating oil is not decreased so that a stable oil film is formed. In addition, the surface has the large hardness and toughness, even if the sliding is performed for long time, the above concave portions are not deformed so that the stable oil film can be maintained. <IMAGE> |
