Patents by Inventor Iwao Hiraishi
Iwao Hiraishi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11047479Abstract: A method for producing a piston ring for a cylinder that moves in a sliding direction includes providing a piston ring base material having an upper surface, a lower surface and an outer circumferential surface having a first recess between the upper surface and the lower surface, forming a hard film in the first recess and on a cylindrical surface at a predetermined thickness, and removing, by performing a polishing process on the sliding surface, the hard film formed on the cylindrical surface and a part of the piston ring base material disposed adjacent to the removed hard film, to form a second recess. The second recess is formed by removing an area of the removed part of the piston ring base material as a result of polishing the sliding surface due to a difference in the hardness of the hard film and the piston ring base material.Type: GrantFiled: November 15, 2019Date of Patent: June 29, 2021Assignee: NIPPON PISTON RING CO., LTD.Inventors: Kazuhiro Fujimura, Atsushi Chiba, Naoyuki Akimoto, Iwao Hiraishi
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Publication number: 20200080638Abstract: A method for producing a piston ring for a cylinder that moves in a sliding direction includes providing a piston ring base material having an upper surface, a lower surface and an outer circumferential surface having a first recess between the upper surface and the lower surface, forming a hard film in the first recess and on a cylindrical surface at a predetermined thickness, and removing, by performing a polishing process on the sliding surface, the hard film formed on the cylindrical surface and a part of the piston ring base material disposed adjacent to the removed hard film, to form a second recess. The second recess is formed by removing an area of the removed part of the piston ring base material as a result of polishing the sliding surface due to a difference in the hardness of the hard film and the piston ring base material.Type: ApplicationFiled: November 15, 2019Publication date: March 12, 2020Inventors: Kazuhiro FUJIMURA, Atsushi CHIBA, Naoyuki AKIMOTO, Iwao HIRAISHI
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Patent number: 10514097Abstract: A method for producing a piston ring for a cylinder that moves in a sliding direction includes providing a piston ring base material having an upper surface, a lower surface and an outer circumferential surface having a first recess between the upper surface and the lower surface, forming a hard film in the first recess and on a cylindrical surface at a predetermined thickness, and removing, by performing a polishing process on the sliding surface, the hard film formed on the cylindrical surface and a part of the piston ring base material disposed adjacent to the removed hard film, to form a second recess. The second recess is formed by removing an area of the removed part of the piston ring base material as a result of polishing the sliding surface due to a difference in the hardness of the hard film and the piston ring base material.Type: GrantFiled: August 9, 2017Date of Patent: December 24, 2019Assignee: NIPPON PISTON RING CO., LTD.Inventors: Kazuhiro Fujimura, Atsushi Chiba, Naoyuki Akimoto, Iwao Hiraishi
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Patent number: 10330198Abstract: 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.Type: GrantFiled: June 22, 2018Date of Patent: June 25, 2019Assignee: NIPPON PISTON RING CO., LTD.Inventors: Atsushi Chiba, Kazuhiro Fujimura, Iwao Hiraishi, Makoto Kajiwara
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Publication number: 20180363778Abstract: 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.Type: ApplicationFiled: June 22, 2018Publication date: December 20, 2018Inventors: Atsushi Chiba, Kazuhiro Fujimura, Iwao Hiraishi, Makoto Kajiwara
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Patent number: 10030772Abstract: 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.Type: GrantFiled: March 26, 2010Date of Patent: July 24, 2018Assignee: NIPPON PISTON RING CO., LTD.Inventors: Atsushi Chiba, Kazuhiro Fujimura, Iwao Hiraishi, Makoto Kajiwara
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Publication number: 20170335965Abstract: A method for producing a piston ring for a cylinder that moves in a sliding direction includes providing a piston ring base material having an upper surface, a lower surface and an outer circumferential surface having a first recess between the upper surface and the lower surface, forming a hard film in the first recess and on a cylindrical surface at a predetermined thickness, and removing, by performing a polishing process on the sliding surface, the hard film formed on the cylindrical surface and a part of the piston ring base material disposed adjacent to the removed hard film, to form a second recess. The second recess is formed by removing an area of the removed part of the piston ring base material as a result of polishing the sliding surface due to a difference in the hardness of the hard film and the piston ring base material.Type: ApplicationFiled: August 9, 2017Publication date: November 23, 2017Inventors: Kazuhiro FUJIMURA, Atsushi CHIBA, Naoyuki AKIMOTO, Iwao HIRAISHI
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Patent number: 9464717Abstract: 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%.Type: GrantFiled: January 28, 2011Date of Patent: October 11, 2016Assignee: NIPPON PISTON RING CO., LTD.Inventors: Michihiro Ito, Naoyuki Akimoto, Iwao Hiraishi, Makoto Kajiwara, Atsushi Chiba
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Patent number: 8820750Abstract: 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.Type: GrantFiled: March 31, 2011Date of Patent: September 2, 2014Assignee: Nippon Piston Ring Co., Ltd.Inventors: Atsushi Chiba, Kazuhiro Fujimura, Iwao Hiraishi, Makoto Kajiwara
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Publication number: 20130181410Abstract: 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.Type: ApplicationFiled: March 31, 2011Publication date: July 18, 2013Applicant: NIPPON PISTON RING CO., LTDInventors: Atsushi Chiba, Kazuhiro Fujimura, Iwao Hiraishi, Makoto Kajiwara
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Publication number: 20130043659Abstract: 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%.Type: ApplicationFiled: January 28, 2011Publication date: February 21, 2013Applicant: NIPPON PISTON RING CO., LTD.Inventors: Michihiro Ito, Naoyuki Akimoto, Iwao Hiraishi, Makoto Kajiwara, Atsushi Chiba
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Publication number: 20120261886Abstract: 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.Type: ApplicationFiled: March 26, 2010Publication date: October 18, 2012Applicant: NIPPON PISTON RING CO., LTD.Inventors: Atsushi Chiba, Kazuhiro Fujimura, Iwao Hiraishi, Makoto Kajiwara
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Publication number: 20120205876Abstract: A piston ring is provided at its outer periphery with a sliding surface, wherein in a cross section thereof which is perpendicular to a radial direction of the piston ring, the sliding surface includes a first sliding surface which occupies a predetermined region from one end thereof, and a second sliding surface which occupies a region extending from one end to the other end of the first sliding surface, the first sliding surface is formed of hard film, the second sliding surface is not formed of hard film, and the second sliding surface exists at a position deviated inward from a phantom line extending from the first sliding surface toward the other end.Type: ApplicationFiled: November 30, 2009Publication date: August 16, 2012Applicant: Nippon Piston Ring Co., Ltd.Inventors: Kazuhiro Fujimura, Atsushi Chiba, Naoyuki Akimoto, Iwao Hiraishi
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Patent number: 7493882Abstract: A combination of a cylinder liner and a piston ring, wherein the cylinder liner includes, silicon: 23.0-28.0% by weight, magnesium: 0.80-2.0% by weight, copper: 3.0-4.5% by weight, iron: 0.25% by weight or less, nickel: 0.01% by weight or less, wherein surface roughness profile of the inner circumference surface has Rz=0.5 to 1.0 ?m, Rk=0.2 to 0.4 ?m, Rpk=0.05 to 0.1 ?m, Rvk=0.08 to 0.2 ?m, wherein the piston ring includes carbon: 0.6-0.7% by weight, chrome: 13-14% by weight, molybdenum: 0.2-0.4% by weight, silicon: 0.25-0.50% by weight, manganese: 0.2-0.5% by weight, and wherein carbides with the diameter of 5.0 ?m and less are 4-10%.Type: GrantFiled: August 30, 2007Date of Patent: February 24, 2009Assignee: Nippon Piston Ring Co., Ltd.Inventors: Iwao Hiraishi, Katsuaki Ogawa, Hiromi Ishikawa, Tsugane Hirase, Kazuhiro Sameshima
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Publication number: 20080053396Abstract: The disclosed is a combination of a cylinder liner and a piston ring which contacts to a inner circumference surface of the cylinder liner at the pressure of 0.03 to 0.2 MPa, wherein the composition of the cylinder liner includes, silicon: 23.0 to 28.0% by weight, magnesium: 0.80 to 2.0% by weight, copper: 3.0 to 4.5% by weight, iron: 0.25% by weight or less, nickel: 0.01% by weight or less, and the rest: unavoidable impurities and aluminum, and wherein surface roughness profile of the inner circumference surface has Rz 0.5 to 1.0 ?m, Rk=0.2 to 0.4 ?m, Rpk=0.05 to 0.1 ?m, Rvk=0.08 to 0.2 ?m, meanwhile, wherein the composition of a piston ring includes carbon: 0.6 to 0.7% by weight, chrome: 13 to 14% by weight, molybdenum: 0.2 to 0.4% by weight, silicon: 0.25 to 0.50% by weight, manganese: 0.2 to 0.5% by weight, and the rest: unavoidable impurities and iron, and wherein carbides with the diameter of 5.Type: ApplicationFiled: August 30, 2007Publication date: March 6, 2008Applicant: NIPPON PISTON RING CO., LTD.Inventors: Iwao HIRAISHI, Katsuaki Ogawa, Hiromi Ishikawa, Tsugane Hirase, Kazuhiro Sameshima