2020 年 65 巻 6 号 p. 343-348
In recent years, friction reduction of piston rings is said to be the limit. This is because the LOC increases as the friction force decreases. Piston ring material technology has evolved. The spread of PVD and DLC has progressed. On the other hand, research on frictional force has not progressed much. As a result of relying solely on tension reduction to reduce frictional force, LOC deteriorated. This explanation examines recent evolution of piston rings. Based on these, It is summarized that the limitations of the current technology and issues for further friction reduction.