Kabushiki Kaisha Riken

Tadahiko Watanabe

Junichi Takahashi

Gyo Muramatsu

Yunzhi Gao

Satoshi Koizumi

Masahiro Nakazawa

Tetsuji Miyashita

Ryo Obara

To provide a combined oil control ring with a function of preventing the separate rotation of side rails for a long period of time even under fretting fatigue, seating tabs of a spacer expander are provided with substantially longitudinal projections and recesses on their side-rail-pushing surfaces in a circumferential direction, the width m of a bottom surface being larger than the circumferential length m' of the top surface in each projection, and a surface connecting the top surface to a recess surface having a bulging shape.

Combined oil control ring

An oil ring for an internal combustion engine is provided that can prevent adhesion and deposition of oil sludge even during long-time operation of the engine, can thereby prevent the occurrence of sticking of the oil ring components to each other, and can maintain a good oil control function. At least part of the surface of the oil ring for an internal combustion engine is coated with a metal coating having a surface free energy of 40 mJ/mor less and a hydrogen bonding strength of 1.0 mJ/mor less. A coating of Ni, Cu, or an alloy containing Ni or Cu is used as the metal coating.

Oil ring for internal combustion engine

Growing community of inventors

Kashiwazaki, Japan

Tadahiko Watanabe