Valve lifter and method of producing the same
AssigneesHitachi, Ltd., Hitachi Powdered Metals Co., Ltd.
InventorsHisanobu Kanamaru, Yosimi Sugaya
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Abstract
A valve lifter has a cylindrical lifter body portion made of an alloy tool steel which body portion extends in the axial direction of the valve lifter, and a head portion made of the alloy tool steel and formed integrally with the body portion which head portion extends at a right angle to the axis. The head portion has an outer surface constituting a cam-contact surface provided with a coating layer, and an inner surface constituting a valve-pressing portion provided with a valve-pressing protrusion. The head portion has a macrostructure of plastic flow oriented in a direction perpendicular to the above-mentioned axis. Disclosed also is a method for producing this valve lifter.
Claims4
A valve lifter comprising:
- a cylindrical lifter body portion made of an alloy tool steel and extending in the axial direction of the valve lifter;
- and
- a head portion made of said alloy tool steel and formed integrally with said body portion which head portion extends at a right angle to said axis;
- said head portion having an outer surface constituting a cam-contract surface provided with a coating layer, said coating layer being composed of a carburized layer obtained by carburizing, quenching and tempering of the outer layer of said head portion, and a nitrided surface obtained by soft-nitriding of said carburized layer, and an inner surface constituting a valve-pressing portion provided with a valve-pressing protrusion, said head portion having a macrostructure of plastic flow oriented in a direction perpendicular to said axis.
Dependencies are inferred from the claim text.