Kabushiki Kaisha Riken

Tokusen Kogyo Co., Ltd.

Junya Takahashi

Yuji Shima

Masaki Moronuki

Takuma Sekiya

Yuuichi Murayama

Masayuki Sato

Ryouichi Kamon

To provide a price-competitive compression ring having excellent thermal conductivity and thermal sag resistance, which can be used in a high-thermal-load environment of high-compression-ratio engines, steel identified by the material number of SUP10 in JIS G 4801, which contains small amounts of alloying elements, is used, and a piston ring wire is annealed before an oil-tempering treatment such that spheroidal cementite having an average particle size of 0.1-1.5 &#x3bc;m is dispersed in a tempered martensite matrix, thereby suppressing the movement of dislocation and creep even at 300&#xb0; C., and improving thermal sag resistance.

Compression ring and its production method

To provide a high-thermal-conductivity piston ring having excellent scuffing resistance and wear resistance, which can be used in a high-heat-load environment in engines, a TiN coating as thick as 10-60 &#x3bc;m, in which the texture coefficient of a (220) plane is 1.1-1.8 in X-ray diffraction on the coating surface, larger than those of (111) and (200) planes, is formed under the optimized ion plating conditions on a peripheral surface of the piston ring. Also, to obtain excellent sliding characteristics with low friction without losing excellent thermal conductivity of TiN, a hard amorphous carbon coating is formed on the TiN coating.

Piston ring

A high-thermal-conductivity piston ring having excellent scuffing resistance and wear resistance, which can be used in a high-heat-load environment in engines is provided. Also, to provide a piston ring with low friction for contributing to the improvement of fuel efficiency, a TiN coating as thick as 10-60 &#x3bc;m, in which the texture coefficient of a (111) plane is 1.2-1.65 in X-ray diffraction on the coating surface, with the texture coefficient of a (111) plane&#x3e;the texture coefficient of a (220) plane&#x3e;the texture coefficient of a (200) plane, is formed under the optimized ion plating conditions on a peripheral surface of the piston ring. Further, to obtain excellent sliding characteristics with low friction without losing excellent thermal conductivity of TiN, a hard amorphous carbon coating is formed on the TiN coating.

Growing community of inventors

Kashiwazaki, Japan

Junya Takahashi