Toyota Jidosha Kabushiki Kaisha

Hideo Nonoyama

Toshiharu Fukuizumi

Akiyoshi Morita

Kiyokazu Uruno

In a process for producing a surface remelted chilled layer camshaft by using a high density energy irradiation and self-cooling, a cam is rotated around the center axis of the camshaft and a position of a torch for the irradiation (e.g., a TIG arc torch) is controlled so as to form an angle between a tangential line of the cam surface and a horizontal line at a melting position in a lower side of the horizontal line in a direction opposite to the camshaft rotation direction being from 30.degree., preferably 20.degree., to zero degree.

Process for producing surface remelted chilled layer camshaft

A process for producing a surfactant remelted chilled layer camshaft with cams subjected to a remelting chilling treatment comprising steps of melting a sliding cam surface by irradiating a high density energy (e.g., a TIG arc) and forming a continuous chill layer by self-cooling. Then, at places where a formed molten metal pool may be caused to sag by the force of gravity, the melting action is interrupted to solidify the molten metal pool, and is resumed so as to overlap a former formed chill layer portion and a following chill layer portion.

A process for producing a remelted and chilled camshaft comprises the steps of melting a sliding cam surface by TIG arc and forming a chill layer by self-cooling. When two adjacent cams are in positions at which a mutual influence from the magnetic arc blow of the TIG arc current applied to the cams can be felt, a melting current applied to two arc torches is alternately changed so that the sliding cam surface of one cam is melted while the other cam is in the nonmelted state.

Process for producing a remelted and chilled camshaft

This invention concerns an improvement in cast iron material and chilled iron material. The cast iron material has a C.E. value of not more than 4.3 in which cerium is added in the form of a mischmetal upon casting to a cerium content of from 0.005 to 0.035 wt %. The chilled cast iron article has a chilled layer formed by remelting at least a portion of the surface of the cast iron of a predetermined shape composed of the above-mentioned cast iron by a high density energy source such as tungsten inert gas (TIG) arc, laser or electron beam.

Cast iron making by cerium addition

A process for producing a camshaft with cams include the steps of forming a surface hardened layer in each of the cams by a remelting chilling treatment using high density energy (e.g., a TIG arc), characterized in that after the remelting chilling treatment, the camshaft is cooled by passing a cooling medium through a through hole formed longitudinally in the camshaft. As a result of the cooling, the neighboring untreated cam has a temperature of up to 250.degree. C. Elongation of the camshaft due to thermal expansion is so small that no melt-down end portion defects appear.

Process for producing camshaft with cams subjected to remelting chilling

A method of producing a cast iron camshaft including the steps of applying a high-density energy source, such as a TIG arc, a laser beam, and an electron beam over the entire sliding surface of a cam to melt the surface portion and cooling the cam by dissipating the localized heat through the camshaft itself so as to form a double structure hardened layer consisting of a chilled layer having a large amount of cementite and a hardened layer of martensite. This method omits the preheating of the camshaft prior to the high-density energy irradiation.

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Toyota, Japan

Hideo Nonoyama