Abstract: In a piston of an internal combustion engine in which a recessed portion that holds an intake air swirling flow is formed on a crown surface of the piston, the crown surface includes a heat insulating film formation portion having a heat insulating film whose thermal conductivity is lower than a base material of the piston, the heat insulating film whose thermal capacity per volume is smaller than the base material of the piston, and a heat insulating film non-formation portion provided at a position on the more outside of a cylinder bore side of the internal combustion engine than the heat insulating film formation portion, the heat insulating film non-formation portion not having the heat insulating film.

Abstract: A sliding mechanism 1 includes a first sliding member 10 and a partner second sliding member 20 configured to slide relative to the first sliding member 10. The first sliding member 10 includes a matrix phase 11 and a hard phase 13 that is harder than the matrix phase 11, in which the hard phase 13 is embedded in the matrix phase 11 in a dispersed state. The second sliding member 20 includes a base 21 and a surface-treatment layer 23 that is formed on the sliding surface 20 of the base 21 and is harder than the matrix phase 11.

Abstract: A gear pair includes a first gear and a second gear that are engaged and paired with each other, wherein the arithmetic average roughness Ra of the tooth surface of the first gear is less than 0.10, and the arithmetic average roughness Ra of the tooth surface of the second gear is equal to or greater than 0.15. An improvement of the transmission efficiency is achieved due to the improved composite roughness of the gear pair. Accordingly, both of the improvement of the transmission efficiency of the gears and an improvement of the pitting fatigue life are achieved at low cost.

Abstract: A method for producing a laminated member includes a step of spraying a mixture in a non-molten state including a plurality of precipitation hardening copper alloy particles and a plurality of hard particles that have non-spherical shapes having a median aspect ratio of equal to or more than 1.2 and are harder than the copper alloy particles onto a base substrate to form a coating layer on the base substrate.

Abstract: A laminate includes a base substrate, and a coating layer formed on the base substrate. The coating layer includes a copper alloy portions derived from precipitation-hardening copper alloy particles and hard particle portions which are harder than the copper alloy portions, the hard particle portions are derived from hard particles, and the parts bond with each other via an interface. Each of the hard particle portions has a non-spherical shape. A sliding member includes the laminate in at least one sliding portion. A method for manufacturing a laminate includes a step of spraying a mixture in a non-molten state including precipitation-hardening copper alloy particles and hard particles having a non-spherical shape and being harder than the copper alloy particles onto a base substrate, to form a coating layer on the base substrate.

Abstract: A sliding member includes: a base; a chromium-based hard chromium plated layer formed on the surface of the base; a hard carbon layer that is mainly composed of carbon element and is formed on the hard chromium plated layer. The hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm. A method for producing the sliding member involves heating the surface of the base on which the chromium-based hard chromium plated layer has been formed at a temperature of 250° C. or more so that the hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm, and thereafter forming the hard carbon layer mainly composed of carbon element on the hard chromium plated layer.

Abstract: A sliding member includes: a base; a chromium-based hard chromium plated layer formed on the surface of the base; a hard carbon layer that is mainly composed of carbon element and is formed on the hard chromium plated layer. The hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm. A method for producing the sliding member involves heating the surface of the base on which the chromium-based hard chromium plated layer has been formed at a temperature of 250° C. or more so that the hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm, and thereafter forming the hard carbon layer mainly composed of carbon element on the hard chromium plated layer.

Abstract: A sliding member includes: a base; a chromium-based hard chromium plated layer formed on the surface of the base; a hard carbon layer that is mainly composed of carbon element and is formed on the hard chromium plated layer. The hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm. A method for producing the sliding member involves heating the surface of the base on which the chromium-based hard chromium plated layer has been formed at a temperature of 250° C. or more so that the hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm, and thereafter forming the hard carbon layer mainly composed of carbon element on the hard chromium plated layer.

Abstract: A gear pair includes a first gear and a second gear that are engaged and paired with each other, wherein the arithmetic average roughness Ra of the tooth surface of the first gear is less than 0.10, and the arithmetic average roughness Ra of the tooth surface of the second gear is equal to or greater than 0.15. An improvement of the transmission efficiency is achieved due to the improved composite roughness of the gear pair. Accordingly, both of the improvement of the transmission efficiency of the gears and an improvement of the pitting fatigue life are achieved at low cost.

Abstract: A sliding mechanism includes first and second members slidable relative to each other and a grease composition interposed between the first and second members and containing a thickening agent and a base oil, wherein the grease composition contains lithium 12-hydroxystearate as the thickening agent and dioctyl sebacate and/or poly-?-olefin as the base oil; and wherein at least one of the first and second member has a sliding surface coated with a hard carbon film of diamond-like carbon.

Abstract: A low friction assembly is desired. The present invention relates to a new low-friction lubrication assembly comprising a first member relatively slidable against a second member, the first member having chemical affinity with an OH-group on its sliding surface; and one or more oxygen containing compounds, provided on the sliding surface of the first member and being able to produce a tribofilm attached to the sliding surface of the first member through hydrogen bond interactions. Preferably the second member comprises a similar OH-terminated sliding surface wherein an oxygen containing compound (lubricant)-supported interface between the first and second sliding surfaces results in a H- and/or OH-terminated interface developing repulsive forces thereinbetween.

Abstract: A sliding mechanism 1 includes a first sliding member 10 and a partner second sliding member 20 configured to slide relative to the first sliding member 10. The first sliding member 10 includes a matrix phase 11 and a hard phase 13 that is harder than the matrix phase 11, in which the hard phase 13 is embedded in the matrix phase 11 in a dispersed state. The second sliding member 20 includes a base 21 and a surface-treatment layer 23 that is formed on the sliding surface 20 of the base 21 and is harder than the matrix phase 11.

Abstract: A sliding member includes: a base; a chromium-based hard chromium plated layer formed on the surface of the base; a hard carbon layer that is mainly composed of carbon element and is formed on the hard chromium plated layer. The hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm. A method for producing the sliding member involves heating the surface of the base on which the chromium-based hard chromium plated layer has been formed at a temperature of 250° C. or more so that the hydrogen concentration of the hard chromium plated layer is equal to or less than 150 mass ppm, and thereafter forming the hard carbon layer mainly composed of carbon element on the hard chromium plated layer.

Abstract: A sliding device includes a sliding bearing, and a shaft which is rotatable and in slidable contact with the sliding bearing in presence of a lubricating oil. The sliding bearing has a surface hardness smaller than a surface hardness of the shaft. Additionally, the sliding bearing has a surface roughness Ra of not larger than 0.2 micrometer, and the shaft has a surface roughness of not larger than 0.05 micrometer.

Abstract: [Object] To provide a nanoparticle-containing lubricating oil composition which demonstrates a low friction coefficient and realizes a further fuel economy. [Solving Means] A nanoparticle-containing lubricating oil composition comprising a base oil, an additive having hydroxyl group, and nanoparticle. A nanoparticle-containing lubricating oil composition comprising a base oil, an ashless friction modifier having hydroxyl group, and nanoparticle. A nanoparticle-containing lubricating oil composition comprising a base oil, an additive having hydroxyl group, and nanoparticle having a particle diameter of 1 to 100 nm. A nanoparticle-containing lubricating oil composition comprising a base oil, an ashless friction modifier having hydroxyl group, and nanoparticle having a particle diameter of 1 to 100 nm.

Abstract: A sliding mechanism includes first and second members slidable relative to each other and a grease composition interposed between the first and second members and containing a thickening agent and a base oil, wherein the grease composition contains lithium 12-hydroxystearate as the thickening agent and dioctyl sebacate and/or poly-?-olefin as the base oil; and wherein at least one of the first and second member has a sliding surface coated with a hard carbon film of diamond-like carbon.

Abstract: An oil ring Ro for an internal combustion engine according to the present invention includes at least one selected from the group consisting of hard carbon, CrN and TiN that covers an outer periphery 1 of the oil ring. A radius of curvature R at an outermost portion T of the oil ring in a sliding direction is 0.3 mm or more.

Abstract: A lubricant composition applicable to a sliding section or sliding member of an automotive internal combustion engine or power transmission apparatus to significantly lower a friction coefficient. The lubricant composition contains a base oil for a lubricating oil, an oxygen-containing organic compound, a diamond nano-particle and a dispersant for the diamond nano-particle.

Abstract: There is provided a sliding member including a base body and a hard carbon coating formed on the base body to define a sliding surface for sliding contact with an opposing member under lubrication according to one embodiment of the present invention. The hard carbon coating has an outermost surface portion lower in hydrogen content than a remaining portion thereof, or an outermost coating layer lower in hydrogen content than at least one other coating layer.

Abstract: [Object] A low friction assembly is desired. [Solving Means] The present invention relates to a new low-friction lubrication assembly comprising a first member relatively slidable against a second member, the first member having chemical affinity with an OH-group on its sliding surface; and one or more oxygen containing compounds, provided on the sliding surface of the first member and being able to produce a tribofilm attached to the sliding surface of the first member through hydrogen bond interactions. Preferably the second member comprises a similar OH-terminated sliding surface wherein an oxygen containing compound (lubricant)-supported interface between the first and second sliding surfaces results in a H- and/or OH-terminated interface developing repulsive forces thereinbetween.