| 摘要 |
PURPOSE:To aim at the promotion of lightweightness in a connecting rod in having its bearing performance kept intact, by forming an oil groove on a bearing surface of a small end part of the connecting rod and then applying soft nitriding on the surface. CONSTITUTION:Soft nitriding is applied to a small end part 3 of a connecting rod 1, that is, a bearing surface 10 of a bearing part. With this process, a very hard nitriding layer 12 is formed on the bearing surface composed of steel material. Moreover, an oil groove 11 is formed on the said bearing surface in advance of this soft nitriding, and on a surface of this oil groove, there is provided with the nitriding layer as well. In consequence, on top of that bearing performance is maintainable to the full, use of a bush being so far installed in a fitting part of a piston is no longer required, so that weight of the connecting rod is well reducible. |
