Abstract: A combined oil ring includes an oil ring having upper and lower rails formed integrally at an outer circumferential side of the oil ring to slide on a cylinder wall; a coil expander installed at an inner circumferential side of the oil ring to force the oil ring radially outwards; and a side rail installed at an upper side of the oil ring and having no torsion along an axial direction of the oil ring.

Abstract: Evaluation results are shown in Table 1. The embodiments 1-9 possess a high thermal conductivity and high bonding strength. However, the thermal conductivity has dropped in the comparative examples 1, 2 and 4 with a low surface area ratio and in the comparative example 3 with a high surface area ratio. The comparative example 2 with a low projection height has a low bonding strength, and the comparative example 3 with a high projection height has a drop in the thermal conductivity. The thermal conductivity has declined in the comparative example 1 with relatively few projections, and the thermal conductivity has declined in the comparative example 4 with many projections. The comparative example 5 with no projections and having a rough casting surface does not have sufficient bonding strength.

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 cylinder liner for insert casting which is excellent in heat conductivity with a cylinder block is provided, the cylinder liner for insert casting of the present invention comprising a cylinder liner for insert casting 2 which is formed with projections 5 with heights of 0.3 to 1.2 mm and undercut parts 6 in a ratio of 20 to 80/cm2 on an outer circumferential surface 4 over which, in turn, a thermally sprayed layer 7 is covered, wherein the thermally sprayed layer 7 is comprised of a ferrous material and wherein a ratio of a surface area of a thermally sprayed layer 7 surface at a certain region on the outer circumferential surface 4 of the liner with an area of the region is 12 to 23. The thermally sprayed layer preferably has a thickness of 0.01 to 0.2 mm. The thermally sprayed layer is preferably formed using a wire shaped thermal spraying material.

Abstract: To provide a piston ring tension measurement apparatus which can stably measure a piston ring for suitable tension, the piston ring tension measurement apparatus of the present invention comprises: a table 1 which supports a measured piston ring 5; a first band 3 which is to be wound around an outer circumferential part of the measured piston ring 5 and which is fastened at its two end sides by fasteners 4 and 6; a second band 8 which is to be wound around an outer circumferential part of the measured piston ring 5 where the first band 3 is not wound; a fastener 11 for fastening one end side of the second band 8; a tension imparting means 14, 15, and 16 for making the second band 8 move in a direction squeezing the measured piston ring 5; and a load cell 10 which measures a tension which is imparted to the second band 8.

Abstract: A cylinder liner has an upper portion and a lower portion with respect to an axial direction of the cylinder liner. A high thermal conductive film is provided on an outer circumferential surface of the upper portion. A low thermal conductive film is provided on an outer circumferential surface of the lower portion. The cylinder liner reduces temperature difference of a cylinder along its axial direction.

Abstract: The present invention provides a cylinder liner excellent in adhesion and heat conductivity with a cylinder block. The cylinder liner 1 of the present invention is formed from cast iron or steel. The cylinder liner 1 is formed with a thermal sprayed coated film 6 at its outer circumferential surface 3 and top surface 4. As the thermal sprayed material, Al, an Al alloy, Fe, an Fe alloy, Zn, a Zn alloy, Cu, a Cu alloy, etc. is used. The cylinder liner 1 is cast around a cylinder block formed from an aluminum alloy or other light alloy, by insert casting, at its outer circumferential surface 3, top surface 4, and bottom surface 5. The cylinder liner 1 is chamfered at the connecting edges of its top surface 4 and inner circumferential surface 7. The thermal sprayed coated film 6 is preferably formed at the top surface 4 part to extend over the chamfering part.

Abstract: A combination oil ring prevented from freeze up of the side rails and spacer expander, that is, a combination oil ring of the present invention provided with a top and bottom pair of side rails 11 and 12 and a spacer expander 13 having large numbers of top pieces 14 and bottom pieces arranged separated in the axial direction and circumferential direction and alternating in the circumferential direction, connecting pieces 16 connecting adjoining top pieces 14 and bottom pieces 15, and ear parts 17 and 18 formed rising up at the inner circumference side ends of the top pieces 14 and bottom pieces 15 for pushing against the side rails 11 and 12, in which combination oil ring 10, grooves 19 and 20 are formed in at least one surfaces of top surfaces of the top pieces 14 and bottom surfaces of the bottom pieces 15, and through holes 17a and 18a by which the grooves 19 and 20 are communicated are formed in the ear parts 17 and 18.

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 cylinder liner for insert casting used in a cylinder block is provided. The cylinder liner includes an outer circumferential surface having a plurality of projections. Each projection has a constricted shape. A film of a metal material is formed on the outer circumferential surface and the surfaces of the projections. As a result, the cylinder liner ensures sufficient bond strength with the casting material of a cylinder block, and sufficient thermal conductivity with the cylinder block.

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: An engine includes: a cylinder block; and a piston ring, in which the cylinder block has a cylinder liner portion formed of an aluminum-based composite reinforced by a ceramic containing at least either of a silicon carbide and an alumina, and in which the piston ring is coated with a nitride film (20) including a vanadium nitride layer (21) exposed on an outer circumferential sliding surface (17).

Abstract: A combined oil ring includes an oil ring having upper and lower rails formed integrally at an outer circumferential side of the oil ring to slide on a cylinder wall; a coil expander installed at an inner circumferential side of the oil ring to force the oil ring radially outwards; and a side rail installed at an upper side of the oil ring and having no torsion along an axial direction of the oil ring.

Abstract: An insert casting structure includes a cylinder liner made of cast iron and inserted within aluminum alloy through insert casting and having a plurality of projections on an outer circumferential surface of the cylinder liner, wherein when the thickness of a cast iron portion to the base of the projection is set as L1, and the thickness of an integrated piece made up of the cast iron portion and an aluminum alloy portion is set as L2, the thermal conductivity is 35 to 80 W/mK when measured under the condition of L1/L2=0.45.

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 cylinder liner for insert casting and a method for manufacturing the cylinder liner are provided. The cylinder liner and the method are applied to cylinder blocks and improve the adherence and the bonding strength with a cylinder block material in a favorable manner. The cylinder liner satisfies the following requirements: (i) the height of projections 1P is in a range between 0.5 mm and 1.0 mm, inclusive; (ii) the number of the projections 1P is in a range between 5 and 60, inclusive, per cm2 on the outer circumferential surface; (iii) the area ratio of regions each encircled by a contour line of a height of 0.4 mm is in a range between 10% and 50%, inclusive; (iv) the area ratio of regions each encircled by a contour line of a height of 0.2 mm is in a range between 20% and 55%, inclusive; (v) the region each encircled by a contour line of the height of 0.4 are independent from each other; and (vi) the area of the regions each encircled by a contour line of the height of 0.4 mm is in a range between 0.

Abstract: A combined oil ring 1 is comprised of an oil ring 2 with a generally I-shaped cross section including upper and lower rails 6, 7 joined by a web 8 for sliding on an inner circumferential surface 10 of a cylinder 9, and a coil expander 3 to press the oil ring 2 radially outwards. The combined oil ring 1 contains a seal member 14 for sealing a gap of the oil ring 2 and capable of making contact with the upper rail 6 in an outer circumferential groove 12 formed by the web 8 and the upper and lower rails 6, 7. The seal member 14 may include a structure where the edge of the seal member 14 is bent, and catches in a window hole 13 formed on the web 8 of the oil ring 2.

Abstract: A piston ring 1 for internal combustion engines comprises a hard film 2 formed on at least an outer circumferential sliding surface of the piston ring 1. The hard film 2 includes chromium, nitrogen and silicon as structural elements and the same crystal structure as CrN, and is composed of a crystal phase where silicon is contained in a solid solution state in a crystal lattice at an atomic ratio between 1 and 9.5 percent. The hard film may be the following film. Namely, a hard film is composed of a mixed phase of a crystal phase and an amorphous phase; the crystal phase includes chromium, nitrogen and silicon as structural elements and the same crystal structure as CrN and moreover includes silicon contained in a solid solution state in a crystal lattice; the amorphous phase includes silicon, nitrogen and chromium as structural elements; the ratio of the amorphous phase in the hard film is 4.5 percent or less; and the silicon content in the hard film is between 1 and 9.5 percent at an atomic ratio.

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: A cutting machine 10 includes an upper blade 12A and a lower blade 12B installed at upper and lower positions, and resilient members 19A, 19B installed on both sides of the blades and protruding more than the blades for supporting a hard plastic sheet 7 during cutting. The resilient members installed on both sides of either of the upper and lower blades include a resilient member at a section near the blade and a resilient member at a section far from the blade, and the hardness of the resilient member at a section near the blade is different from the hardness of the resilient member at a section far from the blade.