Abstract: Provided is a combined oil ring that can provide reduction in oil consumption of the engine oil without degrading the oil sealing performance between the lower surface of the side rail and the lower surface of the oil ring groove even when the tension of the combined oil ring is reduced.

Abstract: To provide a piston ring for an internal combustion engine, particularly a second compression ring, which has excellent wear resistance and can achieve both lower fuel consumption and efficient combustion. The above-described problem is solved by a piston ring (1) for an internal combustion engine formed so as to have a tapered shape by a peripheral surface (14) that gradually projects outward from a top to a bottom, and a radial cross-sectional shape of a Napier ring.

Abstract: Provided is a combined oil ring that can provide reduction in oil consumption of the engine oil without degrading the oil sealing performance between the lower surface of the side rail and the lower surface of the oil ring groove even when the tension of the combined oil ring is reduced.

Abstract: To provide a piston ring for an internal combustion engine, particularly a second compression ring, which has excellent wear resistance and can achieve both lower fuel consumption and efficient combustion. The above-described problem is solved by a piston ring (1) for an internal combustion engine formed so as to have a tapered shape by a peripheral surface (14) that gradually projects outward from a top to a bottom, and a radial cross-sectional shape of a Napier ring.

Abstract: A multi-piece oil ring includes an oil ring main member in which two rails are connected together by a columnar part and which has a roughly I-shaped cross section; and a coil expander disposed in an inner circumferential groove formed on the inner circumferential surface of the columnar. Each rail in the oil ring main member possesses a sliding section protuberance whose tip possesses a jutting portion. The axial length of the jutting portion is 0.02-0.18 mm. The change rate of the axial length of the individual jutting portion is in the range of 0 to 80% at least in a region of from its sliding surface to be faced to a cylinder, which is positioned at the tip of the jutting portion, to a position of 0.03 mm away from the aforementioned sliding surface in the radial direction of the oil ring main member.

Abstract: A multi-piece oil ring includes an oil ring main member in which two rails are connected together by a columnar part and which has a roughly I-shaped cross section; and a coil expander disposed in an inner circumferential groove formed on the inner circumferential surface of the columnar. Each rail in the oil ring main member possesses a sliding section protuberance whose tip possesses a jutting portion. The axial length of the jutting portion is 0.02-0.18 mm. The change rate of the axial length of the individual jutting portion is in the range of 0 to 80% at least in a region of from its sliding surface to be faced to a cylinder, which is positioned at the tip of the jutting portion, to a position of 0.03 mm away from the aforementioned sliding surface in the radial direction of the oil ring main member.

Abstract: A multi-piece oil ring includes an oil ring main member in which two rails are connected together by a columnar part and which has a roughly I-shaped cross section; and a coil expander disposed in an inner circumferential groove formed on the inner circumferential surface of the columnar. Each rail in the oil ring main member possesses a sliding section protuberance whose tip possesses a jutting portion. The axial length of the jutting portion is 0.02-0.18 mm. The change rate of the axial length of the individual jutting portion is in the range of 0 to 80% at least in a region of from its sliding surface to be faced to a cylinder, which is positioned at the tip of the jutting portion, to a position of 0.03 mm away from the aforementioned sliding surface in the radial direction of the oil ring main member.

Abstract: The second compression ring is formed such that the outer peripheral surface shape has a tapered face, and the radial cross-sectional shape is a rectangular ring, a scraper ring, or a Napier ring, and has a piston ring base and a hard film provided at least on an outer peripheral sliding surface thereof. The piston ring base is composed of a low-alloy steel or carbon steel having a Vickers hardness of Hv 350 Hv 550. The outer peripheral sliding surface is formed so that the axial length is from 0.01 to 0.30 mm between the outer edge end part of the tapered outer peripheral sliding surface and an imaginary line contacting with a lower end surface where a curved surface having a diameter that decreases gradually inward from the outer edge end part toward the lower end in the axial direction is parallel to a ring underside.

Abstract: Provided is a piston ring such that it is possible to sufficiently inhibit adhesive wear when the piston ring is mounted to a piston for a diesel engine in which at least the piston ring groove in the piston is formed from steel or cast iron. Disclosed is a piston ring mounted to a piston for a diesel engine, wherein the load length ratio (Rmr2) (in accordance with JIS B0601:2001) of the top surface and bottom surface of the piston ring satisfies each of the following conditions: Rmr2 (0.5%, 0.3[mu]m)=20% and Rmr2 (0.5%, 0.4[mu]m)=40%.

Abstract: The second compression ring is formed such that the outer peripheral surface shape has a tapered face, and the radial cross-sectional shape is a rectangular ring, a scraper ring, or a Napier ring, and has a piston ring base and a hard film provided at least on an outer peripheral sliding surface thereof. The piston ring base is composed of a low-alloy steel or carbon steel having a Vickers hardness of Hv 350 Hv 550. The outer peripheral sliding surface is formed so that the axial length is from 0.01 to 0.30 mm between the outer edge end part of the tapered outer peripheral sliding surface and an imaginary line contacting with a lower end surface where a curved surface having a diameter that decreases gradually inward from the outer edge end part toward the lower end in the axial direction is parallel to a ring underside.

Abstract: A high-quality internal combustion engine oil ring which stably keeps oil consumption low for a long period and in which the shapes of an upper rail and a lower rail can be formed at low cost with high accuracy. The internal combustion engine oil ring has a recessed stepped portion formed at a corner of a sliding surface of an outer peripheral sliding projection in sliding contact with a cylinder inner wall surface of at least one of a first rail and a second rail constituting an oil ring main body, in a shape in vertical cross-section along a sliding direction of the first rail and second rail, and a wall surface of the recessed stepped portion has an arcuate surface having a radius of curvature of 0.02 mm to 0.08 mm.

Abstract: The second compression ring is formed such that the outer peripheral surface shape has a tapered face, and the radial cross-sectional shape is a rectangular ring, a scraper ring, or a Napier ring, and has a piston ring base and a hard film provided at least on an outer peripheral sliding surface thereof. The piston ring base is composed of a low-alloy steel or carbon steel having a Vickers hardness of Hv 350 Hv 550. The outer peripheral sliding surface is formed so that the axial length is from 0.01 to 0.30 mm between the outer edge end part of the tapered outer peripheral sliding surface and an imaginary line contacting with a lower end surface where a curved surface having a diameter that decreases gradually inward from the outer edge end part toward the lower end in the axial direction is parallel to a ring underside.

Abstract: A high-quality internal combustion engine oil ring which stably keeps oil consumption low for a long period and in which the shapes of an upper rail and a lower rail can be formed at low cost with high accuracy. The internal combustion engine oil ring has a recessed stepped portion formed at a corner of a sliding surface of an outer peripheral sliding projection in sliding contact with a cylinder inner wall surface of at least one of a first rail and a second rail constituting an oil ring main body, in a shape in vertical cross-section along a sliding direction of the first rail and second rail, and a wall surface of the recessed stepped portion has an arcuate surface having a radius of curvature of 0.02 mm to 0.08 mm.

Abstract: Provided is a piston ring such that it is possible to sufficiently inhibit adhesive wear when the piston ring is mounted to a piston for a diesel engine in which at least the piston ring groove in the piston is formed from steel or cast iron. Disclosed is a piston ring mounted to a piston for a diesel engine, wherein the load length ratio (Rmr2) (in accordance with JIS B0601:2001) of the top surface and bottom surface of the piston ring satisfies each of the following conditions: Rmr2 (0.5%, 0.3[mu]m)=20% and Rmr2 (0.5%, 0.4[mu]m)=40%.

Abstract: A multi-piece oil ring includes an oil ring main member in which two rails are connected together by a columnar part and which has a roughly I-shaped cross section; and a coil expander disposed in an inner circumferential groove formed on the inner circumferential surface of the columnar. Each rail in the oil ring main member possesses a sliding section protuberance whose tip possesses a jutting portion. The axial length of the jutting portion is 0.02-0.18 mm. The change rate of the axial length of the individual jutting portion is in the range of 0 to 80% at least in a region of from its sliding surface to be faced to a cylinder, which is positioned at the tip of the jutting portion, to a position of 0.03 mm away from the aforementioned sliding surface in the radial direction of the oil ring main member.

Abstract: A combination of piston and piston ring includes a piston having a piston ring groove in which at least the groove portion of the piston is made of steel, a piston ring made of cast iron and fitted into the piston ring groove, and a hard coat film formed to at least an outer peripheral sliding surface of the piston ring.

Abstract: A combination of piston and piston ring comprises a piston having a piston ring groove in which at least the groove portion of the piston is made of steel, a piston ring made of cast iron and fitted into the piston ring groove, and a hard coat film formed to at least an outer peripheral sliding surface of the piston ring.

Abstract: An object of the present invention is to provide a polishing apparatus which is capable of configuring a surface of a polishing tool without damaging the polishing tool. In order to solve the above-mentioned problem, the present invention provide a rotary machining apparatus comprising a polishing tool for polishing a sample; a rotary disk for holding the polishing tool; a tool for configuring a surface of the polishing tool; and a position adjusting mechanism for adjusting a gap between the tool and the polishing tool, which comprises a rotating mechanism for rotating the tool; and a sensor for sensing a change in the rotation of the rotating mechanism, a height at starting to configure the polishing tool using the tool being determined based on the change in the rotation obtained by the sensor.

Abstract: A method and apparatus is disclosed for forming a cellulose film suitable for direct food contact by precipitation from a solution of cellulose water and a tertiary amine oxide cellulose solvent. After precipitation of a cellulose gel from the solution, the gel is washed at ever increasing temperatures and then dried to provide a cellulose film having a solvent level to not more than 40 ppm. Portions of the wash water is collected and treated to recover the solvent for reuse.

Abstract: The tubular extrusion of a thermoplastic nonderivatized cellulose solution about a mandrel and through a long air gap in excess of 304 mm is facilitated by use of a mandrel which is extensible from the extrusion die. On extrusion start-up, the mandrel extends a short length from the die. For steady-state operation, the mandrel is extended its full length from the die. Also disclosed is a mandrel structure to facilitate the introduction of a nonsolvent liquid into the interior of the extruded tube at a high location on start-up of extrusion and at a lower location during steady-state operation.