Abstract: A ring groove for a two-piece oil ring of a piston is provided that has ring body equipped with a coil expander, wherein the ring body has an upper outer surface and a lower outer surface, both orthogonal to the axial direction of the piston. The ring groove also has an upper inner surface and a lower inner surface, both orthogonal to the axial direction of the piston; a radially inward-most, bottom surface connecting the upper and lower inner surfaces; and oil drain holes, each having an opening thereof located on the bottom surface. The ring groove has an axial width slightly greater than the width of the two-piece oil ring.

Abstract: A cylinder liner for use in an internal combustion engine has an inner peripheral surface at which a surface treatment layer is formed upon water vapor treatment. The surface treatment layer has a surface configuration capable of providing excellent lubrication oil retaining function and initial break-in property as well as capable of being machined easily. The treatment surface of the cylinder liner has a plateau configuration providing a surface roughness Rz of 0.8 to 5.9 &mgr;m, and the plateau configuration is defined under DIN4776 by a reduced peak height Rpk of not more than 0.64 &mgr;m, a core roughness depth Rk of 0.05 to 1.8 &mgr;m, and a reduced valley depth Rvk of 0.15 to 3.3 &mgr;m. For grinding to the surface, a honing machine employs a grindstone containing metal bonded diamond grains at high density. Diamond grain size is not less than 4000.

Abstract: According to an embodiment of the present invention a piston ring for internal combustion engines for use with a piston and a cylinder, is provided that has an external circumferential sliding surface adapted to slid against the internal wall of the cylinder. The piston ring has an ion-plating deposition layer formed over the externtal circumferential sliding surface, the deposition layer having pores and being made of a mixture of a first chromium nitride of CrN type and a second chromium nitride of Cr2N type. The mixing ratios in the mixture are more than 45.5 and less than 98.0 weight percent for the first chromium nitride and the balance portion for the second chromium nitride. According to another embodiment of the present invention, a piston ring for internal combustion engines for use with a piston and a cylinder, is provided that has an external circumferential sliding surface adapted to slid against the internal wall of the cylinder.

Abstract: The present invention provides a piston ring comprising a piston ring main body and an expander ring arranged on an inner peripheral surface thereof, the expander ring comprising two oil expander rings, one of which is housed in a space in a spiral of the other. The expander ring is formed so that the pressing force in the diameter expanding direction is larger in a high temperature state than in a low temperature state. The expander comprises two different kinds of expander members. One of these expander members has the same functions as those of a conventional expander, and the other is a member in which there occurs a change in tension in the diametral direction with temperature. As a result, the pressing force of the master expander member having the same effects as those of the conventional expander is made variable.

Abstract: The present invention provides a chrome-plated sliding member free from periodical decreases in wear resistance or seizure resistance without the necessity to intentionally bend a multi-layer hard chrome plating film. This is a sliding member having a multi-layer hard chrome plating film on the sliding surface of the substrate 1. Microcracks 6 opening to the outer surface side of the individual hard chrome plating layers are distributed in hard chrome plating layers 2, 3, 4 and 5. The microcracks of the individual hard chrome plating layers comprise relatively shallow portions 6a where bottoms stop within a single layer, and relatively deep portions 6b and 6c where cracks run through two or more layers. The quantities of the microcracks expressed by the area ratios of microcracks on a cross-section of the hard chrome plating film include a quantity of the portions where cracks stop within a single layer within a range of from 1.5 to 35.

Abstract: A cam member of the present invention comprises solid lubricant having an average particle size of up to 100 &mgr;m in an amount of 0.5 vol. % to 3.0 vol. %. The solid lubricant is at least one selected from the group consisting of WS2, CaF2, BaF2, BN, MnS, MoS2, Cr2O3, MoO3, B2O3 and MgSiO3. The cam member is formed of a sintered alloy having a chemical composition comprising: C: from 1.5 to 3.8%; Cr: from 2.0 to 20.0%; Mo: from 0.5 to 3.0%; Si: from 0.2 to 1.0%; P: from 0.2 to 1.0%; Ni: up to 1.0% in volume; and the balance being Fe and incidental impurities. The sintered alloy has a matrix structure in which carbide is precipitated. The matrix structure mainly comprises pearlite.

Abstract: A cylinder liner and a piston ring adapted to be combined therewith in an internal combustion engine are provided that have excellent abrasion resistance, where iron oxide film is formed at least on a part of the inner circumferential surface of the cylinder liner, and metallic nitride film is formed at least on a sliding surface of the piston ring sliding along the cylinder liner.

Abstract: A ring groove for a two-piece oil ring of a piston is provided that has ring body equipped with a coil expander, wherein the ring body has an upper outer surface and a lower outer surface, both orthogonal to the axial direction of the piston. The ring groove also has an upper inner surface and a lower inner surface, both orthogonal to the axial direction of the piston; a radially inward-most, bottom surface connecting the upper and lower inner surfaces; and oil drain holes, each having an opening thereof located on the bottom surface. The ring groove has an axial width slightly greater than the width of the two-piece oil ring.

Abstract: An improved sliding member is provided that has a sliding surface and a deposition layer formed on the sliding surface utilizing an ion-plating method, wherein the deposition layer is composed mainly of chrome nitride, including CrN. The CrN of the chrome nitride has a preferred orientation of plane {111} and contains boron in an amount of not less than 0.05 and not more than 20 weight percent. The deposition layer further contains oxygen and/or carbon in an amount of not more than 15 weight percent. The improved sliding member exhibits excellent abrasion and scuff resistance and enhanced peeling resistance.

Abstract: The present invention provides a piston ring and a combined structure of a piston ring and a ring groove of piston having a hard carbon film which is excellent in wear resistance, scuffing resistance, cohesion resistance relative to the piston material and in peeling resistance. The above-mentioned object of the invention is achieved by continuously forming a hard carbon film 2 containing one or more elements selected from Si, W and Ni, or all of the outer peripheral surface 4, the inner peripheral surface 5, the top surface 6 and the bottom surface 7 of the piston ring 1. The hard carbon film contains Si and has an Si-containing film serving as a primer film for the hard carbon film. A Cr film should preferably be formed as primer film for the hard carbon film. It is desirable to have an ion-plating film as a primer film formed on the outer peripheral surface of the piston ring.

Abstract: A compression piston ring capable of reducing excessive surface pressure at a gap and adjacent portion thereto during engine operation, and capable of being produced at a low cost. The compression piston ring has generally circular shape without any notched portion. The compression piston ring has a dimensional requirements in that d1/a1 ranges from 40 to 60, and d1/h1 ranges from 30 to 55, in which d1 represents an inner diameter of the piston ring, a1 represents a radial length between inner and outer peripheral surfaces of the piston ring, and h1 represents an axial length of the outer peripheral surface. The compression piston ring is particularly available as a first compression piston ring for a supercharging type diesel engine providing high engine pressure.

Abstract: An internal combustion engine includes, in combination, an intake side valve system and an exhaust side valve system. Each of the valve systems comprises a valve seat and a valve member to be assembled with the valve seat, in which the valve seat has a base member including a matrix of iron-base sintered alloy and a dispersed Si—Cr—Mo—Co group intermetallic compound powder, the intermetailic compound powder having a hardness of Hv600 to Hv1000 and an average particle diameter of 20 to 70 &mgr;m, the matrix being contained at 10 to 50 mass % with reference to total mass of the base member, and the valve member has a base member including a matrix of martensitic steel and a nitriding diffusion layer formed to a valve face of the base member, the nitriding diffusion layer having a hardness of more than Hv500 and a thickness of more than 20 &mgr;m.

Abstract: An object of the present invention is to provide a sliding member which is coated a film having superior wear resistance, superior scuffing resistance and a superior property not to increase an amount of wear on an opponent material (an opponent attacking property). This object can be achieved by providing a sliding member coated by a Cr—B—N alloy film 4 on an outer surface 3 thereof. In this case, it is preferable that the Cr—B—N alloy film is formed through a physical vapor deposition, particularly ion plating, vacuum deposition, or sputtering. Further, it is preferable that the boron (B) content is within the range of 0.05-20 wt.%.

Abstract: A hollow cam shaft is composed of a hollow shaft having an inner hollow portion and an end piece which is pressure-welded to at least one end of the hollow shaft. The end piece comprises an end member which is pressure-welded to the one end of the hollow shaft and an enclosure member extending from the end member in an axial direction thereof so as to be inserted into the inner hollow portion of the hollow shaft at a time of pressure welding to define an enclosure space in the inner hollow portion of the hollow shaft. The enclosure member comprises a sealing portion having an outer shape substantially the same as an inner shape of the hollow shaft and a connection portion connecting an end surface of the end member of the end piece and the sealing portion so as to define said enclosure space between the enclosure member and the hollow shaft into which a burr generated at the pressure welding time is enclosed.

Abstract: A laminated chromium plating layers providing improved wear resistance and fatigue strength for use in mechanical parts of an internal combustion engine. The lamination is formed on a base body and contains a plurality of high hardness chromium plating layer and a plurality of low hardness chromium plating layer, and each high hardness chromium plating layer is formed upon each low hardness chromium plating layer to provide the lamination of alternating high hardness chromium plating layer and low hardness chromium plating layer.

Abstract: A piston ring combination including at least one compression ring and at least one oil ring. If a plurality of compression rings are provided, an outer peripheral surface of at least a top ring is formed with a first ion plating layer. The oil ring has a pair of side rails whose outer peripheral surfaces are formed with second ion plating layers. These layers are formed of Cr—N mixture. The first ion plating layer has a porous structure with a porosity ranging from 3 to 10% and a hardness ranging from 1000 to 1500 Hv. The second ion plating layer has a dense structure with a porosity ranging from 0 to 3% and a hardness ranging from 1800 to 2200 Hv.

Abstract: An improved thin 3-piece oil ring 1 of an axial width not greater than 2 mm, is provided that has a corrugated spacer expander 2 of a circumferentially successive, substantially U-shaped configuration, and circular, upper and lower side rails 3, 4 holding the spacer expander 2 therebetween. The spacer expander 2 has circumferentially spaced outer crowns 5 and circumferentially spaced inner crowns 6; each of the outer crowns 5 being connected with next adjacent ones of the inner crowns 6 on opposite sides thereof by a pair of connecting members 11. The spacer expander 2 has both of the most-end portions thereof extended radially outwardly from the most-end one of the inner crowns 6 thereof forming abutting members 15, 16 for abutting each other at the point of force P.

Abstract: The present invention provides a synchronizer ring excellent in strength and abrasion resisting property, used in a speed change gear. This synchronizer ring according to the invention is consisted of, by weight, C:0.2˜1.0%, Ni:1.0˜6.0%, Mo:0.6˜3.0%, Cu:1.0˜4.0% and the reminder Fe and inevitable impurities, and is made of Fe sintered alloy of which base composition comprises of mainly martonsite and bainite. And the base composition is preferably consisted of, by volume, martensite: 57˜80%, bainite: 17˜40%, austenite: 8% or less.

Abstract: According to an embodiment of the present invention, an improved sliding member is provided that has a sliding surface and a deposition layer formed on the sliding surface by means of an ion-plating method, where the deposition layer is composed mainly of CrN. The improvement comprises the CrN which has a preferred orientation of the plane {110}, where the deposition layer contains boron at a containing ratio not less than 0.05 and not more than 20 weight percent. According to another embodiment of the present invention, an improved sliding member is provided that has a sliding surface and a deposition layer formed on the sliding surface by means of an ion-plating method, where the deposition layer is composed mainly of CrN. The improvement comprises the CrN which has a preferred orientation of the plane {110}, where the deposition layer contains boron, at a containing ratio not less than 0.

Abstract: According to an embodiment of the present invention, an improved sliding member is provided that has a sliding surface and a deposition layer formed on the sliding surface by means of an ion-plating method, where the deposition layer is composed mainly of chrome nitride, including CrN. The improvement comprises the CrN of the chrome nitride which has a preferred orientation of the plane {100}, where the deposition layer contains boron at a containing ratio not less than 0.05 and not more than 20 weight percent. According to another embodiment of the present invention, an improved sliding member is provided that has a sliding surface and a deposition layer formed on the sliding surface by means of an ion-plating method, where the deposition layer is composed mainly of chrome nitride, including CrN. The improvement comprises the CrN of the chrome nitride which has a preferred orientation of the plane {100}, where the deposition layer contains boron, at a containing ratio not less than 0.