Abstract: A magnesium alloy is provided which does not contain a rare earth and which achieves, in a high-temperature region of about 200° C., both satisfactory mechanical properties and thermal conductivity. A magnesium alloy including Mg, Ca, Al and Si, where a content of Ca is less than 9.0 mass %, a content of Al is equal to or more than 0.5 mass % but less than 5.7 mass %, a content of Si is equal to or less than 1.3 mass % and Al+8Ca?20.5%.

Abstract: A magnesium alloy is provided which does not contain a rare earth and which achieves, in a high-temperature region of about 200° C., both satisfactory mechanical properties and thermal conductivity. A magnesium alloy including Mg, Ca, Al and Si, where a content of Ca is less than 9.0 mass %, a content of Al is equal to or snore than 0.5 mass % but less than 5.7 mass %, a content of Si is equal to or less than 1.3 mass % and Al+8Ca?20.5%.

Abstract: A cooling system for a piston of an internal combustion engine includes a cooling channel (34) designed as an oil passage embedded in the piston and arranged adjacent to a top ring groove, and an oil supply portion (8) that supplies oil to the cooling channel. An amount of oil supplied from the oil supply portion to the cooling channel is made larger when an amount of heat generated in a combustion chamber is large than when the amount of heat generated in the combustion chamber is small.

Abstract: A piston device for internal combustion engines includes a first compression ring and a second compression ring in an outer circumference of a piston, wherein the second compression ring includes a notch extending from the inner circumference to the outer circumference on a lower surface of at least one of a pair of ends of the ring, and a gap between the ring ends at the notch on the second compression ring is larger than a gap between the ring ends of the first compression ring, and a gap between the ring ends at the section other than the notch on the second compression ring is the same or smaller than the gap between the ring ends of the first compression ring, and the second compression ring contains an outer circumferential surface comprised of a tapered surface decreasing the ring radial thickness towards the upper side, and an axial parallel surface formed below the tapered surface.

Abstract: A piston 1 contains multiple ring grooves 2, 3 on the outer circumference of the piston 1, and piston rings 4, 10 are mounted in the ring grooves 2, 3. The piston 1 contains oil path grooves 7, 9 extending respectively to the outer circumference of the piston 1 on the upper and lower surfaces of the lowermost ring groove 2, and an oil path groove 12 extending to the outer circumference of the piston 1 on the lower surface of the ring groove 3 just above the lowermost ring groove 2. The weight of the lowermost piston ring 4 is equal to or smaller than the weight of the piston ring 10 just above the lowermost piston ring 4; and expanders 5, 11 are installed on the rear side of the piston rings 4, 10 respectively.

Abstract: A piston device for internal combustion engines includes a first compression ring and a second compression ring in an outer circumference of a piston, wherein the second compression ring includes a notch extending from the inner circumference to the outer circumference on a lower surface of at least one of a pair of ends of the ring, and a gap between the ring ends at the notch on the second compression ring is larger than a gap between the ring ends of the first compression ring, and a gap between the ring ends at the section other than the notch on the second compression ring is the same or smaller than the gap between the ring ends of the first compression ring, and the second compression ring contains an outer circumferential surface comprised of a tapered surface decreasing the ring radial thickness towards the upper side, and an axial parallel surface formed below the tapered surface.

Abstract: To manufacture a connecting rod including positioning grooves having a function of positioning a bearing metal at low cost. A big end part of a split type connecting rod is fractured in two after inserting an approximately cylindrical die into a bearing hole. The die has projections corresponding to locking grooves on an outer circumferential surface thereof. The die includes a pair of split dies having tapered faces, each expanding an opening on an edge of an end face of each of the split die halves. The tapered faces are formed by partially notching mating surfaces by pressing the inner circumferential surface of the bearing hole with the projections by a movement of the pair of split dies in a radial direction of the bearing hole.

Abstract: In a hollow valve for an internal combustion engine, including a stem portion, an umbrella portion provided at one end of the stem portion, a gastight cavity that communicates the interior of the stem portion with that of the umbrella portion, and a coolant contained in the cavity, the umbrella portion has a wall portion (a lower cap) having a combustion-chamber-side wall that forms a part of a wall of a combustion chamber of the engine, and a cavity-side wall that forms a part of a wall of the cavity, and at least one high-thermal-conductivity member is provided on the cavity-side wall, for conduction of heat between the wall portion and one of at least the coolant and the stem portion as a heat-conduction medium.

Abstract: A piston 1 contains multiple ring grooves 2, 3 on the outer circumference of the piston 1, and piston rings 4, 10 are mounted in the ring grooves 2, 3. The piston 1 contains oil path grooves 7, 9 extending respectively to the outer circumference of the piston 1 on the upper and lower surfaces of the lowermost ring groove 2, and an oil path groove 12 extending to the outer circumference of the piston 1 on the lower surface of the ring groove 3 just above the lowermost ring groove 2. The weight of the lowermost piston ring 4 is equal to or smaller than the weight of the piston ring 10 just above the lowermost piston ring 4; and expanders 5, 11 are installed on the rear side of the piston rings 4, 10 respectively.

Abstract: The present invention provides combustion catalysts that have high exhaust gas-purifying activity and are less expensive than conventional ones. The catalysts include: (1) A calcium salt, amorphous silica, and a copper compound, (2) Amorphous silica, and a copper compound, (3) (1) At least one of crystalline silica and amorphous silica, (2) a calcium salt, and (3) a copper oxide, and (4) (1) At least one of crystalline silica and amorphous silica, and (2) a copper oxide.

Abstract: To manufacture a connecting rod including positioning grooves having a function of positioning a bearing metal at low cost. A big end part of a split type connecting rod is fractured in two after inserting an approximately cylindrical die into a bearing hole. The die has projections corresponding to locking grooves on an outer circumferential surface thereof. The die includes a pair of split dies having tapered faces, each expanding an opening on an edge of an end face of each of the split die halves. The tapered faces are formed by partially notching mating surfaces by pressing the inner circumferential surface of the bearing hole with the projections by a movement of the pair of split dies in a radial direction of the bearing hole.

Abstract: A valve seat, press-fitted into a cylinder head of an internal combustion engine, containing an iron-based sintered alloy, includes a valve-seating section and a head-seating section. The valve-seating section and the head-seating section are monolithically formed by a sintering process and form a double layer structure. The valve-seating section includes a first iron-based sintered alloy member that has a porosity of 10 to 25 percent by volume and a sintered density of 6.1 to 7.1 g/cm3 and contains hard particles dispersed in a matrix. The head-seating section includes a second iron-based sintered alloy member that has a porosity of 10 to 20 percent by volume and a sintered density of 6.4 to 7.1 g/cm3.

Abstract: The present invention provides combustion catalysts that have high exhaust gas-purifying activity and are less expensive than conventional ones.

Abstract: A valve seat, press-fitted into a cylinder head of an internal combustion engine, containing an iron-based sintered alloy, includes a valve-seating section and a head-seating section. The valve-seating section and the head-seating section are monolithically formed by a sintering process and form a double layer structure. The valve-seating section includes a first iron-based sintered alloy member that has a porosity of 10 to 25 percent by volume and a sintered density of 6.1 to 7.1 g/cm3 and contains hard particles dispersed in a matrix. The head-seating section includes a second iron-based sintered alloy member that has a porosity of 10 to 20 percent by volume and a sintered density of 6.4 to 7.1 g/cm3.

Abstract: A microalloyed steel easy to separate by fracture splitting at low temperatures, which comprises from 0.15 to 0.35 wt % carbon, from 0.5 to 2.0 wt % silicon, from 0.5 to 1.5 wt % manganese, from 0.03 to 0.15 wt % phosphorus, from 0.01 to 0.15 wt % sulfur, from 0.01 to 0.5 wt % copper, from 0.01 to 0.5 wt % nickel, from 0.01 to 1.0 wt % chromium, from 0.001 to 0.01 wt % soluble aluminium, from 0.005 to 0.035 wt % nitrogen, from 0.001 to 0.01 wt % calcium, and from 0.001 to 0.01 wt % oxyge ough separation by fracture splitting at a low temperature, e.g., a connecting rod for engines.

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 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 bearing metal positioning structure in a split connecting rod with lowered production cost and improved accuracy in positioning the bearing metal. The bearing metal positioning structure includes a pair of bearing metal halves, each of which is formed into a circular arc shape traversing 180 degrees. The pair of bearing metal halves have flat mating planes which abut one another to form a cylindrical bearing metal. A pair of projections are disposed on each of the mating planes at both axial ends so as to project radially outwardly therefrom. Locking grooves to be engaged with the pairs of projections, and additional locking grooves, are integrally die-formed simultaneously with the production of a die-formed body of the split connecting rod.

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 cold forging steel excellent in grain coarsening prevention and delayed fracture resistance and method of producing the same are provided that enable omission of a step of annealing or spheroidization annealing before cold forging and improvement of delayed fracture resistance of a high-strength component used with a heat-treated surface. The cold forging steel is a steel of a specified composition having dispersed in the matrix thereof particles of not greater than 0.2 &mgr;m diameter of one or more of TiC, Ti(CN), NbC, Nb(CN) and (Nb, Ti)(CN) in a total number of not less than 20/100 &mgr;m2. The method of producing a cold forging steel includes the steps of heating this steel to not lower than 1050° C., hot-rolling the steel into steel wire or steel bar, and slowly cooling the steel at a cooling rate of not greater than 2 C./s during cooling to a temperature not higher than 600° C. to obtain a steel having dispersed in the matrix thereof particles of not greater than 0.