US 4,905,538 A · Camshaft

Abstract

A camshaft of a valve operating system for an internal combustion engine, is formed of iron-based alloy casting and has cam sections, each of which is in slidable contact with a heat resistant tip of a rocker arm. The cam section is formed at its surface portion with a surface hardened layer formed of an air-cooled chilled structure. The surface hardened layer is formed by remelting a part of the surface of the casting after preheating. An intermediate hardened layer of a heat affected zone is formed in contact with the surface hardened layer and has a thickness ranging from 0.5 to 2.0 mm. The intermediate hardened layer is formed of a mixed structure of bainite transformation phase and troostite and is formed by being thermally affected during the remelting.

Claims9

Dependent claims

A camshaft formed of iron-based alloy casting, comprising:

a cam section;
a first hardened layer of air-cooled chilled structure and formed in at least a part of said cam section, said first layer forming at least a part of surface of the said cam section and being formed by remelting the iron-based alloy casting after preheating;
and
a second hardened layer of a heat affected zone and in contact with said first hardened layer, said second hardened layer having a thickness ranging from 0.5 to 2.0 mm and being formed of a mixed structure of bainite transformation phase and troostite, said heat affected zone being formed by being thermally affected under said remelting.

1 more element

Dependencies are inferred from the claim text.

Camshaft

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Camshaft

Life of this patent

Abstract

Claims9