US 6,655,026 B1 · Production process for connecting rod for internal combustion engine

Abstract

Material for a connecting rod for an internal combustion engine is carburized and quenched, a carburized layer formed on the bearing portion is ground until the portion which exhibits the maximum compressive residual stress, and a shot-peening processing is performed on the ground surface. The invention produces a bearing portion having surface characteristics in which maximum compressive residual stress is imparted, and therefore, remarkable improvement in the fatigue strength in the bearing portion can be obtained. Furthermore, a large number of concavities formed by the shot-peening processing can be efficiently employed as an oil reservoir, so that sliding properties and lubrication can be improved, and the occurrence of problems such as fretting corrosion, galling, and seize can also be solved, and the galling and problems of the seize can be prevented.

Claims14

Dependent claims

A production process for a connecting rod for an internal combustion engine, the process comprising the steps of:

(a) carburizing and quenching for forming a carburized layer at a surface layer of a material of the connecting rod for the internal combustion engine;
(b), after step (a), grinding the carburized layer formed in a bearing portion of the material until a depth at which compressive residual stress exhibits a maximum value, wherein the carburized layer remains at a depth of at least 0.15 mm after grinding;
and
(c), after step (b), shot-peening a surface ground by step (b).

1 more element

Dependencies are inferred from the claim text.

Production process for connecting rod for internal combustion engine

Life of this patent

Production process for connecting rod for internal combustion engine

Life of this patent

Abstract

Claims14