Abstract: A sintered alloy for valve seats is comprised of carbon at 1 to 2 percent by weight, chromium at 3.5 to 4.7 percent by weight, molybdenum at 4.5 to 6.5 percent by weight, tungsten at 5.2 to 7.0 percent by weight, vanadium at 1.5 to 3.2 percent by weight, and the remainder of iron and unavoidable impurities. Enstatite particles at 1 to 3 percent by weight, hard alloy particles (A) with a Vickers hardness of 500 to 900 at 15 to 25 percent by weight, and hard alloy particles (B) with a Vickers hardness of 1000 or more at 5 to 15 percent by weight (A+B=35 percent by weight or less) are dispersed in the matrix of the sintered alloy skeleton distributed with carbide. Copper or copper alloy at 15 to 20 percent by weight is infiltrated into pores of the skeleton.

Abstract: A cutting machine 7 cuts an acrylic sheet 4 with brittle fracture by driving a cutting blade 11 into the acrylic sheet 4. The cutting blade 11 is installed below the acrylic sheet 4, an acrylic sheet pressing member 9 is installed above the acrylic sheet 4, the cutting blade 11 is fixed, and the acrylic sheet pressing member 9 is capable of moving up and down. In a different configuration of the invention, a member to support the acrylic sheet 4 may be installed and fixed and the cutting blade 11 may be moved up and down.

Abstract: A combined oil ring 4 is comprised of an oil ring 5 having upper and lower rails 7 and 8, and an expander 6 for applying contact pressure radially outwards on the oil ring 5. The outer circumferential surface 11 of the upper rail 7 of the oil ring 5 is comprised of a flat surface 11a with an axial width of 0.05 to 0.3 millimeters, a curved surface 11b joining to the upper end of the flat surface 11a and to the upper surface 12 of the upper rail 7, and a curved surface 11c joining to the lower end of the flat surface 11a and to the lower surface 13 of the upper rail 7. The lower rail 8 is formed in the same way.

Abstract: Disclosed are an insert of pour-around die casting, which is incorporated by an aluminum alloy die casting and has an organic film formed on the surface of the insert, wherein the organic film contains a higher fatty acid ester, a petroleum sulfonate and a mineral oil and has a thickness of from 0.5 to 2 &mgr;m, a rust preventive oil used therefor, and a method for incorporating the insert with an aluminum alloy die casting.

Abstract: A sintered alloy for valve seats is comprised of carbon at 1 to 2 percent by weight, chromium at 3.5 to 4.7 percent by weight, molybdenum at 4.5 to 6.5 percent by weight, tungsten at 5.2 to 7.0 percent by weight, vanadium at 1.5 to 3.2 percent by weight, and the remainder of iron and unavoidable impurities. Enstatite particles at 1 to 3 percent by weight, hard alloy particles (A) with a Vickers hardness of 500 to 900 at 15 to 25 percent by weight, and hard alloy particles (B) with a Vickers hardness of 1000 or more at 5 to 15 percent by weight (A+B=35 percent by weight or less) are dispersed in the matrix of the sintered alloy skeleton distributed with carbide. Copper or copper alloy at 15 to 20 percent by weight is infiltrated into pores of the skeleton.

Abstract: A conventional undercoating method in repair painting on a damaged vehicle, which includes many working processes, possesses drawbacks of being low in working efficiency and making a finally repaired area exceedingly larger than an initial damaged area. To overcome the drawbacks, the invention provides a undercoat forming method using newly developed putty composed of specific compositions, which is capable of forming a thick coating layer. According to the invention, the processes of polishing of the coating layer by dry sanding and applying the putty respectively can be performed in one operation.

Abstract: A piston ring is made of martensitic stainless steel. Except for the outer circumferential surface of the piston ring, a nitrided layer having a Vickers hardness of 700 or more is formed on the upper and lower surfaces and inner circumferential surface, and a nitrided layer having a Vickers hardness of less than 700 is formed below the nitrided layer. A hard film is then formed by ion plating only on the outer circumferential surface of the piston ring. The hard film formed by ion plating and the nitrided layer with a Vickers hardness of 700 or more are separated without making contact in the vicinity of at least one of corner sections formed by the upper and lower surfaces and outer circumferential surface. The distance is within a range of 0.001 to 0.3 mm. The nitrided layers can be formed just on the upper and lower surfaces of the piston ring.

Abstract: The present invention provides a cast iron component for enveloped casting which is characterized by that the cast iron component has a surface to which enveloped casting is applied and which has a surface roughness such that a maximum height Ry is from 65 to 260 &mgr;m and a mean spacing of profile irregularities Sm is from 0.6 to 1.5 mm; an enveloped casting product using it; and a method for its production.

Abstract: A combined oil ring is comprised of an oil ring and an expander. The cross section of the oil ring is a generally I-shape, and the outer circumferential surfaces of outer rail portions form sliding surfaces to make contact with the cylinder wall surface. The cross section of an expander installation groove formed on the inner circumferential surface of the oil ring is formed in a rectangular shape, and an expander formed of axially corrugated ring-shaped plate material is mounted in the expander installation groove. The expander is formed by forming a rectangular cross sectional plate material in a corrugated shape in the direction of plate thickness and further forming in a ring shape. The expander installation groove of the oil ring is not limited to a rectangular shaped cross section.

Abstract: A nitrided layer is formed on a piston ring and a hard film is formed by arc ion plating on the nitrided layer at the outer circumferential surface. The hard film has a crystal structure comprised of mixed phases of CrN and TiN, and contains oxygen in a solid solution state in the CrN and TiN crystals. The hard film comprises chromium of 40 to 75 percent by weight, titanium of 10 to 40 percent by weight, oxygen of 0.5 to 15 percent by weight, and the remainder of nitrogen. The crystal particle size is within 1 &mgr;m. The Vickers hardness of the hard film is in a range of 1300 to 2300. The crystals of CrN and TiN have a preferred orientation of (200) surface or preferred orientation of (111) surface parallel to a surface being covered, and has a columnar structure developing in a columnar shape from the base material toward the film surface. Carbon in a solid solution state may be contained instead of oxygen, and both oxygen and carbon may be contained in a solid solution state.

Abstract: The outer circumferential surface of a second ring is comprised of an outer circumferential surface with a taper face having an outer diameter that increases towards the downward direction, and an outer circumferential surface having the same outer diameter and extending slightly in a perpendicular direction from the lower edge of the taper-faced outer circumferential surface. An annular groove is formed near the outer circumference on a lower surface of the second ring. The annular groove is formed along the entire circumference of the ring and is open at end surfaces of the ring. The annular groove is open to a space between the third land of a piston and the inner circumferential surface of a cylinder.

Abstract: A piston ring has a diamond-like carbon film formed in a thickness of 0.5 to 30 micrometers over an under film on the upper and lower surfaces. The under film is directly formed on the surfaces, or formed on a hard surface treatment layer consisting of a gas nitrided layer or a chromium plating film. The diamond-like carbon is configured with any one of an amorphous carbon structure, an amorphous carbon structure having partly a diamond structure, or an amorphous carbon structure having partly a graphite structure. The under film is comprised of one or more elements selected from the group consisting of silicon, titanium, tungsten, chromium, molybdenum, niobium and vanadium in an atomic content of 70 percent or more and below 100 percent, and the remaining content consisting of carbon, or one or more of said elements in an atomic content of 100 percent. The films may also be formed in the same way on the outer circumferential surface of the piston ring.

Abstract: The present invention provides a piston ring structural body composed of an outer ring continuously formed of a resinous material, an inner ring continuously formed of a resinous material and a ring tensile force applying member for pressing the outer ring radially outwards via the inner ring. The piston ring structural body has a construction wherein the outer ring continuously formed of polyimide is pressed outwards in the radial direction of the piston by a coil expander via the inner ring continuously formed of PTFE. A sliding face of the outer ring, which slides on a cylinder wall, is divided into upper and lower sliding faces, whose respective upper edge portions are provided with chamfers. A contact portion of the inner ring that contacts the coil expander is provided with an upper inclined face extending inwards and upwards and a lower inclined face extending inwards and downwards. The angles of inclination of the upper and lower inclined faces range from 30° to 60°.

Abstract: A piston ring is formed over the entire surface with a gas nitrided layer. A diamond-like carbon film is formed in a thickness of 0.5 to 30 micrometers over the gas nitrided layer at the upper and lower surfaces. The diamond-like carbon film has a surface structure in which diamond-like carbon has been deposited in nodular shapes in sizes of 0.5 to 5 micrometers. The diamond-like carbon is configured with any one of an amorphous carbon structure, an amorphous carbon structure having partly a diamond structure, or an amorphous carbon structure having partly a graphite structure.

Abstract: A combined oil ring is comprised of an oil ring and an expander. The cross section of the oil ring is a generally I-shape, and the outer circumferential surfaces of outer rail portions form sliding surfaces to make contact with the cylinder wall surface. The cross section of an expander installation groove formed on the inner circumferential surface of the oil ring is formed in a rectangular shape, and an expander formed of axially corrugated ring-shaped plate material is mounted in the expander installation groove. The expander is formed by forming a rectangular cross sectional plate material in a corrugated shape in the direction of plate thickness and further forming in a ring shape. The expander installation groove of the oil ring is not limited to a rectangular shaped cross section.

Abstract: The present invention provides a sealing structure employing a piston ring structural body of a type wherein an outer ring continuously formed of a resinous material is pressed radially outwards by a metal coil expander via a metal inner ring provided with an abutment. The piston ring structural body has a construction wherein the outer ring continuously formed of polyimide is pressed radially outwards by the coil expander via the steel inner ring provided with the abutment. A sliding face of the outer ring, which slides on a cylinder wall, is divided by a groove into upper and lower sliding faces, whose respective upper edge portions are provided with chamfers.

Abstract: A cylinder liner which comprises an inner face, wherein a portion of the inner face in the vicinity of a top dead center of a top ring is a phosphate coating which is obtained by mechanically removing a crystal layer formed by a treatment with a phosphate, and the lower portion of the inner face is a cast-iron face; and a method for its production.

Abstract: A piston ring is formed over the entire surface with a gas nitrided layer and a hard film with a thickness of 0.5 to 30 micrometers on the gas nitrided layer at the upper and lower surfaces. The hard film comprises diamond-like carbon in which are dispersed one or more elements selected from the group consisting of silicon, titanium, tungsten, chromium, molybdenum, niobium, and vanadium. The diamond-like carbon is configured with any one of an amorphous carbon structure, an amorphous carbon structure having partly a diamond structure, or an amorphous carbon structure having partly a graphite structure. The content of the above elements is 5 to 40 atomic percent, and the hard film has a Vicker's hardness in a range from 700 to 2,000. The hard film may be formed directly on the upper and lower surfaces of the piston ring in a thickness from 0.

Abstract: A piston ring is formed over the entire surface with a gas nitrided layer and a hard film with a thickness of 0.5 to 10 micrometers on the gas nitrided layer at the outer circumferential surface. The hard film comprises diamond-like carbon in which are dispersed carbides of one or more elements selected from the group consisting of silicon, titanium, tungsten, chromium, molybdenum, niobium, and vanadium. The diamond-like carbon is configured with any one of an amorphous carbon structure, an amorphous carbon structure having partly a diamond structure, or an amorphous carbon structure having partly a graphite structure. The content of the above elements is 5 to 40 atomic percent, and the hard film has a Vicker's hardness in a range from 700 to 2,000. A chromium plating film or ion plating film may be used instead of the gas nitrided layer.

Abstract: A hard film is covered on the outer circumferential surface of a piston ring by means of an arc ion plating. The hard film has a mixture of crystal structure of CrN and crystal structure of Mo.sub.2 N containing oxygen in a solid solution state, and comprises chromium at 40 to 78 percent by weight, molybdenum at 3 to 35 percent by weight, oxygen at 3 to 20 percent by weight and the remainder of nitrogen. The crystal particle size is less than 1 .mu.m. The Vickers hardness is within a range from 1600 to 2500. The film thickness is preferably 1 to 60 .mu.m. Carbon in a solid solution state at 0.5 to 8 percent by weight may be substituted for the oxygen. Alternatively, both oxygen and carbon may be contained in a solid solution state with oxygen at 3 to 20 percent by weight, carbon at 0.5 to 8 percent by weight with the total content of carbon and oxygen within 25 percent by weight.