Patents Assigned to Nippon Piston Ring Co., Ltd.
  • Publication number: 20120261886
    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.
    Type: Application
    Filed: March 26, 2010
    Publication date: October 18, 2012
    Applicant: NIPPON PISTON RING CO., LTD.
    Inventors: Atsushi Chiba, Kazuhiro Fujimura, Iwao Hiraishi, Makoto Kajiwara
  • Publication number: 20120205876
    Abstract: 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: Application
    Filed: November 30, 2009
    Publication date: August 16, 2012
    Applicant: Nippon Piston Ring Co., Ltd.
    Inventors: Kazuhiro Fujimura, Atsushi Chiba, Naoyuki Akimoto, Iwao Hiraishi
  • Patent number: 8240676
    Abstract: There is provided a piston ring which can effectively prevent aluminum adhesion phenomenon to the piston ring. The piston ring includes a piston ring main body and a surface coating film on either upper or lower surface of the piston ring main body, or both the upper and lower surfaces of the piston ring. The surface coating film includes heat-resistant resin and copper based powder contained therein.
    Type: Grant
    Filed: February 27, 2007
    Date of Patent: August 14, 2012
    Assignees: Nippon Piston Ring Co., Ltd., STT Inc.
    Inventors: Tomotaka Kariya, Hideshi Hitosugi, Makoto Tsuruta
  • Patent number: 8181968
    Abstract: A piston ring includes a piston ring body and a surface coating film formed on at least one of upper and lower surfaces of the piston ring body. The surface coating film comprises a heat-resistant resin and a metal powder contained in the heat-resistant resin, and a phosphate coating film is formed, as base coating film of the surface coating film, on a surface on which the surface coating film of the piston ring body is formed.
    Type: Grant
    Filed: August 22, 2008
    Date of Patent: May 22, 2012
    Assignees: Nippon Piston Ring Co., Ltd., STT Inc.
    Inventors: Etuo Tamegai, Hiromi Ishikawa, Tomotaka Kariya, Makoto Tsuruta
  • Publication number: 20120061920
    Abstract: An oil ring mechanism of a piston includes a circumferential ring groove formed in an outer peripheral surface of the piston, and a two-piece oil ring having a ring-shaped ring main body that is arranged in the ring groove and urged in the outer peripheral direction inside the ring groove by a coil expander arranged on the inner peripheral side of the oil ring main body. On lower side surface on a crankcase side of a side wall surface of the ring groove that is on the opposite side of the ring groove from an engine combustion chamber, first and second recessed portions that reduce the abutment area where a lower surface of the ring main body abuts against the lower side surface formed in a lower side abutment surface that serves as a surface for abutting against the lower surface of the ring main body.
    Type: Application
    Filed: March 30, 2010
    Publication date: March 15, 2012
    Applicants: NIPPON PISTON RING CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA
    Inventors: Hiroyuki Nishiura, Naoya Okada, Kenji Hayama, Youhei Hashimoto, Hideshi Hitosugi, Ryosuke Naka
  • Patent number: 7954822
    Abstract: A wire material for a coil expander capable of manufacturing a coil expander that is unlikely to cause disadvantages such as abnormal wear and resultant reduction in strength The wire material for a coil expander is used for a coil expander of a combination piston ring having a piston ring and the coil expander for pressing and urging the piston ring outward in the radial direction thereof, wherein a cross-sectional shape thereof is a rectangular shape, and when the coil expander is formed by using the wire material for a coil expander, the surface of the wire material for a coil expander, constituting an outer peripheral surface of the coil expander, is formed into a convex curved shape.
    Type: Grant
    Filed: January 7, 2005
    Date of Patent: June 7, 2011
    Assignees: Nippon Piston Ring Co., Ltd., Toyota Jidosha Kabushiki Kaisha
    Inventors: Nobuyuki Matsushima, Chikako Sasao, Takao Suzuki
  • Publication number: 20110023808
    Abstract: It is an object of the present invention to provide a valve seat product in which the amount of hard particles added to improve the wear resistance of a valve seat of an internal combustion engine is increased, and is excellent in the mechanical strength and machinability.
    Type: Application
    Filed: March 25, 2009
    Publication date: February 3, 2011
    Applicant: Nippon Piston Ring Co., Ltd.
    Inventors: Kenichi Sato, Hiroshi Oshige, Takeshi Haniu
  • Publication number: 20100319647
    Abstract: An object of the present invention is to provide a cylinder structure reduced in mutual damage caused by a sliding operation of a piston ring and a cylinder liner when the piston ring having a linear expansion property which follows linear expansion of the cylinder liner made of an aluminum alloy is used. In order to achieve the object, a combination structure of the piston ring and the cylinder liner for an internal combustion engine described below is employed. In the cylinder liner for an internal combustion engine, the inner circumferential surface satisfies the conditions, a ten-point height of roughness profile (RzJIS94) of 0.5 ?m to 1.0 ?m, a core roughness depth (Rk) of 0.2 ?m to 0.4 ?m, a reduced peak height (Rpk) of 0.05 ?m to 0.1 ?m and a reduced valley depths (Rvk) of 0.08 ?m to 0.2 ?m. In the piston ring, the sliding surface against to an inner circumferential surface in the cylinder liner satisfies the conditions, a ten-point height of roughness profile (RzJIS94) of not more than 1.
    Type: Application
    Filed: November 27, 2008
    Publication date: December 23, 2010
    Applicant: NIPPON PISTON RING CO., LTD.
    Inventors: Katsuaki Ogawa, Tsugane Hirase
  • Patent number: 7854191
    Abstract: A three-piece oil ring and a combination of the three-piece oil ring and a piston, those capable of realizing improved sealing property and reduction in lubrication oil consumption with avoiding generation of sticking even at low tension and thin width of the ring. The three-piece oil ring includes a spacer expander 10 and two side rails. The spacer expander has a radially inner end portion provided with seating tabs 13 protruding in an axial direction and having radially outer inclined surfaces for urging inner peripheral surfaces of the first and second side rails. The spacer expander has a radially outer end portion provided with side rail support portions 14 projecting in the axial direction for supporting axial end faces of the first and second side rails. A seating tab angle of the outer inclined surface relative to an axis is in a range of 10 to 20 degrees, and a ratio of 2X/Y is in a range of from 0.04 to 0.
    Type: Grant
    Filed: January 30, 2007
    Date of Patent: December 21, 2010
    Assignee: Nippon Piston Ring Co., Ltd
    Inventor: Tomotaka Kariya
  • Publication number: 20100253006
    Abstract: A steel product having a composition which contains by mass C: 0.01 to 1.9%, Si: 0.01 to 1.9%, Mn: 5.0 to 24.0% with balance consisting of Fe and unavoidable impurities and a steel product described above which further contains Cr: 18.0% or below and/or Ni: 12.0% or below in addition to the above essential elements. The above steel products may each further contain Al: 1% or below and/or N: 0.3% or below and the above steel products may each further contain one or more elements selected from among Nb, Ti, Zr, Mo and Cu in a total amount of 4.0% or below. The steel products can sufficiently follow the thermal expansion of a cylinder made of an aluminum alloy and thus enables the production of a piston ring which is suitable for use as a piston ring to slide on the inner face of a cylinder bore made of an aluminum alloy in an internal combustion engine and which can retain excellent sealing properties.
    Type: Application
    Filed: November 28, 2008
    Publication date: October 7, 2010
    Applicant: NIPPON PISTON RING CO., LTD
    Inventors: Yoshiki Ishikawa, Seisuke Takaki, Motonobu Onoda
  • Publication number: 20100239451
    Abstract: The invention provides a flake graphite cast iron being highly strong and excellent in workability such as cutting performance, which is suitable for use, for example, in internal combustion engine parts and the like, and a production method thereof without using a misch metal. Specifically, the flake graphite cast iron according to the invention includes an A-type graphite with a uniformly and disorderly distributed existence form without directionality; and has a chemical composition containing 2.8 to 4.0 mass % of C, 1.2 to 3.0 mass % of Si, 1.1 to 3.0 mass % of Mn, 0.01 to 0.6 mass % of P, 0.01 to 0.30 mass % of S and the remainder being Fe and inevitable impurities, wherein the ratio (Mn/S) of the Mn content to the S content is within a range of 3 to 300.
    Type: Application
    Filed: June 25, 2008
    Publication date: September 23, 2010
    Applicants: Incorporated National University Iwate University, Nippon Piston Ring Co., Ltd.
    Inventors: Hiroshi Horie, Toshinori Kowata, Yoshiki Ishikawa
  • Publication number: 20100224146
    Abstract: A method for manufacturing a shaft member having a sintered part bonded thereto is simple and provides an increased process yield and a high accuracy in position and angle of the sintered part. A green compact is prepared by subjecting a metal or alloy powder to a compression molding. A projection formed on an outer peripheral surface of the shaft member is embedded into the green compact, while chipping partially the green compact with the projection, to combine the green compact with the shaft member. Then, a sintering is carried out.
    Type: Application
    Filed: December 27, 2006
    Publication date: September 9, 2010
    Applicant: NIPPON PISTON RING CO., LTD.
    Inventors: Takeshi Kuwahara, Atsuya Aoki, Masahiro Shinzawa, Hiroshi Takiguchi
  • Patent number: 7629057
    Abstract: A preform main body of an iron species preform for forming a metal matrix composite inserted in an aluminum species alloy base material to be cast-in is bored with a first to fourth through holes communicating an inner peripheral face and an outer peripheral face. In a cast-in step, shrinkage in a peripheral direction of the inner peripheral face and the outer peripheral face of the iron species preform in accordance with solidification of the melted aluminum species alloy is uniformly received by shrinkage in accordance with solidification of the melted aluminum species alloy invading the through holes, movement thereof in the peripheral direction is restrained, a clearance can be prevented from being brought about at an interface, a cast-in performance is excellent and a stable bonding strength of the interface is achieved.
    Type: Grant
    Filed: September 28, 2006
    Date of Patent: December 8, 2009
    Assignees: Fuji Jukogyo Kabushiki Kaisha, Nippon Piston Ring Co., Ltd
    Inventors: Teruyuki Oda, Hiroshi Takiguchi
  • Patent number: 7566504
    Abstract: An iron species preform for forming a metal matrix composite is inserted in an aluminum species alloy member to be cast-in. The aluminum species alloy member has bearing faces having a section in a semicircular arc shape. An inner peripheral face of the iron species preform is provided with a plurality of inner side grooves. The inner side groove includes flat portions and groove bottom portions continuous to two end edges continuous to the inner peripheral face and opposed to each other. In a cast-in step, shrinkage in a peripheral direction accompanied by solidifying a melted aluminum species alloy is uniformly received by the respective inner side grooves, movement in the peripheral direction is restrained, a clearance at an interface can be prevented from being brought about, so that a cast-in performance is excellent, and stable bonding strength and close contact of the interface can be ensured.
    Type: Grant
    Filed: September 28, 2006
    Date of Patent: July 28, 2009
    Assignees: Fuji Jukogyo Kabushiki Kaisha, Nippon Piston Ring, Co. Ltd
    Inventors: Teruyuki Oda, Hiroshi Takiguchi
  • Patent number: 7510196
    Abstract: An oil ring for an internal combustion engine capable of securing an area of an oil-passing hole without deteriorating the strength of the oil ring. To achieve this the oil ring is provided with an oil-passing hole including: two arc portions disposed at both ends in circumferential direction, so as to be opposed to each other; two parallel straight portions disposed so that a widthwise direction distance therebetween is longer than a width of the arc portion; and inclined portions for connecting the arc portions and the parallel straight portions to each other.
    Type: Grant
    Filed: July 5, 2005
    Date of Patent: March 31, 2009
    Assignees: Nippon Piston Ring Co., Ltd., Toyota Jidosha Kabushiki Kaisha
    Inventors: Keishi Nanno, Kazuhito Seki, Shiro Shibata
  • Publication number: 20090058014
    Abstract: There is provided a piston ring which can effectively prevent aluminum adhesion phenomenon to the piston ring. The piston ring includes a piston ring main body and a surface coating film on either upper or lower surface of the piston ring main body, or both the upper and lower surfaces of the piston ring. The surface coating film includes heat-resistant resin and copper based powder contained therein.
    Type: Application
    Filed: February 27, 2007
    Publication date: March 5, 2009
    Applicants: NIPPON PISTON RING CO., LTD., STT INC.
    Inventors: Tomotaka Kariya, Hideshi Hitosugi, Makoto Tsuruta
  • Publication number: 20090051123
    Abstract: A piston ring includes a piston ring body and a surface coating film formed on at least one of upper and lower surfaces of the piston ring body. The surface coating film has a most outside surface layer including a heat-resistant resin and a metal powder contained in the heat-resistant resin and a base bottom layer formed nearest the piston ring body and including a heat-resistant resin. The base bottom layer may also include a metal powder.
    Type: Application
    Filed: August 22, 2008
    Publication date: February 26, 2009
    Applicants: NIPPON PISTON RING CO., LTD., STT INC.
    Inventors: Tomotaka KARIYA, Etuo Tamegai, Hiromi Ishikawa, Makoto Tsuruta
  • Publication number: 20090051122
    Abstract: A piston ring includes a piston ring body and a surface coating film formed on at least one of upper and lower surfaces of the piston ring body. The surface coating film comprises a heat-resistant resin and a metal powder contained in the heat-resistant resin, and a phosphate coating film is formed, as base coating film of the surface coating film, on a surface on which the surface coating film of the piston ring body is formed.
    Type: Application
    Filed: August 22, 2008
    Publication date: February 26, 2009
    Applicants: NIPPON PISTON RING CO., LTD., STT INC.
    Inventors: Etuo TAMEGAI, Hiromi Ishikawa, Tomotaka Kariya, Makoto Tsuruta
  • Patent number: 7493882
    Abstract: 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: Grant
    Filed: August 30, 2007
    Date of Patent: February 24, 2009
    Assignee: Nippon Piston Ring Co., Ltd.
    Inventors: Iwao Hiraishi, Katsuaki Ogawa, Hiromi Ishikawa, Tsugane Hirase, Kazuhiro Sameshima
  • Publication number: 20090026711
    Abstract: A generally circular compression piston ring having an outer peripheral surface, an inner peripheral surface, and a pair of end faces splitting the circular shape in a radial direction thereof for defining a gap portion. The ring has a first portion including a notched portion formed at the inner peripheral surface and extending over a predetermined circumferential length portion starting from the end face, and a second portion other than the first portion. The second portion has a radial thickness ranging from 2.0 mm to 6.0 mm. The notched portion is a plane shape gradually reaching the outer peripheral surface toward the end face. The end face has a radial thickness ranging from 0.2 times to less than 0.5 times as large as the radial thickness of the second portion. The outer peripheral surface defines a center serving as a center of a center angle, and the predetermined circumferential length portion is defined by the center angle ranging from 26.5 degrees to 14 degrees.
    Type: Application
    Filed: July 21, 2008
    Publication date: January 29, 2009
    Applicant: NIPPON PISTON RING CO., LTD.
    Inventors: Mitsuru URABE, Kazuhiko Kanno