Kabushiki Kaisha Riken

Takuma Sekiya

Masayuki Sato

Yuuichi Murayama

Masaki Moronuki

Yuji Shima

Hiroshi Maruyama

Junya Takahashi

Youhei Iwamoto

Yuuichi Ishida

Kazuya Kameda

Katsuhiro Tsuji

Takayuki Ichikawa

Shigeo Inoue

Terushige Ueda

Keiji Honda

A sliding member having a hard carbon coating that has a thickness of 3 &#x3bc;m or more and demonstrates high peeling resistance and high wear resistance is provided. A sliding memberaccording to the present disclosure includes a base memberand a hard carbon coatingthat is formed on the base memberand has the hydrogen content of 3 atomic % or less and a thickness of 3 &#x3bc;m or more. When HM represents a Martens hardness of the hard carbon coatingand HIT represents an indentation hardness, the ratio HM/HIT is 0.40 or more.

Sliding member and piston ring

Provided is a sliding member having a hard carbon coating that makes high wear resistance compatible with a low coefficient of friction and that has excellent peeling resistance. A sliding member () includes a base member () and a hard carbon coating () formed on the base member (). The indentation hardness of the hard carbon coating () decreases gradually from the base member side to the surface side. The hard carbon coating () has an indentation hardness distribution at 0&#x2264;T/Ttotal&#x2264;0.6 approximated by a first line and an indentation hardness distribution at 0.9&#x2264;T/Ttotal&#x2264;1 approximated by a second line, and the intersection between the first line and the second line (T2/Ttotal, H2) satisfies Expression (1), (H3&#x2212;H1)&#xd7;T2/Ttotal+H1&#x3c;H2&#x2264;0.9&#xd7;H1, and Expression (2), 0.6&#x2264;T2/Ttotal&#x2264;0.9.

A combined oil control ring comprising a pair of annular side rails each having a gap, and an axially corrugated spacer expander arranged between the side rails; the corrugated spacer expander having on the inside seating tabs for pushing inner peripheral surfaces of the side rails; the side-rail-pushing surface of each seating tab being provided with a nitrided layer; an entire surface of each spacer expander except for those provided with the nitrided layer being coated with a plating film; and the plating film having Vickers hardness HV0.01 of 300 or less.

Combined oil control ring

The present invention provides a piston ring having excellent abrasion resistance to an aluminum alloy cylinder or cylinder liner formed of a mating material and is therefore capable of decreasing abrasion of the mating material. An exemplary piston ring has a hard carbon coating formed on an outer peripheral surface, and the hard carbon coating contains 0.5 atom % or more to less than 5 atom % of tungsten (W).

Piston ring

To provide a piston ring having a hard laminate coating having excellent scuffing resistance, wear resistance and peeling resistance, which can be used in an environment of high mechanical and thermal load in engines, the piston ring is provided on its outer peripheral sliding surface with a CrN-type hard coating as thick as 10-60 &#x3bc;m and comprising a CrN/CrCN laminate coating having hardness Hv of 1000 or more and residual compression stress of 1500 MPa or less, a laminate unit composed of a CrN layer and a CrCN layer being as thick as 30 nm or more; the CrN/CrCN laminate coating being formed by alternately laminating CrN layers and CrCN layers containing C dissolved in CrN by ion plating.

To provide a hard-amorphous-carbon-coated piston ring having low friction and excellent wear resistance and peeling resistance to reduce the fuel consumption of automobiles, an outer peripheral surface of a steel-made piston ring base material is provided with a primary layer constituted by a CrN/Cr laminate coating or a CrN/TiN laminate coating as thick as 10-60 &#x3bc;m, which is obtained by alternately laminating CrN-type chromium nitride and chromium metal or TiN-type titanium nitride, an intermediate layer of chromium metal and/or titanium metal as thick as 0.05-1.0 &#x3bc;m, and then a hard amorphous carbon coating as thick as 0.4-20 &#x3bc;m.

Piston 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.

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.

[Task] The chromium nitride ion-plating coating has a property that it is hard but is liable to peel off. Year by year, the required level of wear resistance and scuffing resistance becomes higher in a diesel engine. The property of a coating is improved to enhance the wear resistance and scuffing resistance and also to improve resistance against peeling off. [Means for Solution] (1) Composition is mainly composed of chromium, nitrogen, and carbon, and the concentration of carbon relative to the total concentration of the main components is from 4 to 8% by weight. (2) The crystal structure is that texture of the CrN (111) plane orientation is from 0.4 to 2.0 in terms of a CrN (111) structural coefficient. (3) Vickers hardness is from Hv 1600 to Hv 2000.

Growing community of inventors

Kashiwazaki, Japan

Takuma Sekiya