Kabushiki Kaisha Riken

Kabushiki Kaisha Rikon

Masahiro Nakazawa

Satoshi Koizumi

Tadahiko Watanabe

Miyuki Usui

Nobuo Katayama

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

In a combined oil ring having a spacer expander to be installed between a pair of upper and lower side rails, a plurality of axially protruding inner peripheral protruding portions are formed on the inner peripheral side of the spacer expander along its peripheral direction. The inner peripheral protruding portions press the inner peripheral surface of the side rails. On the outer peripheral side of the spacer expander, a plurality of slits are formed, and a plurality of connecting portions are located in the peripheral direction isolated by the slits. On the plurality of connecting portions, axially protruding outer peripheral protruding portions are formed.

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Kashiwazaki, Japan

Masahiro Nakazawa