Nippon Piston Ring Co., Ltd.

Fujio Anzai

Yoshiki Ishikawa

Munehiko Doi

Genshin Kojima

A cylinder liner for use in an internal combustion engine has an inner peripheral surface at which a surface treatment layer is formed upon water vapor treatment. The surface treatment layer has a surface configuration capable of providing excellent lubrication oil retaining function and initial break-in property as well as capable of being machined easily. The treatment surface of the cylinder liner has a plateau configuration providing a surface roughness Rz of 0.8 to 5.9 &#x3bc;m, and the plateau configuration is defined under DIN4776 by a reduced peak height Rpk of not more than 0.64 &#x3bc;m, a core roughness depth Rk of 0.05 to 1.8 &#x3bc;m, and a reduced valley depth Rvk of 0.15 to 3.3 &#x3bc;m. For grinding to the surface, a honing machine employs a grindstone containing metal bonded diamond grains at high density. Diamond grain size is not less than 4000.

Cylinder liner with its inner peripheral surface formed with surface treatment layer, and method for machining to the surface treatment layer

A cylinder liner formed of a cast iron and having an inner peripheral surface subjected to honing which forms cross-hatching grooves on the surface. A resultant surface roughness ranges from 0.4 &mgr;mR,to 0.8 &mgr;mR,, and an open phase rate of graphite is not less than 80% at the inner peripheral surface.

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Tochigi-ken, Japan

Fujio Anzai