Abstract: Provided are an oil ring for an internal combustion engine and a piston assembly including the same, in which the oil ring for an internal combustion engine includes: a compression portion protruding from an upper portion of a body, in close contact with a cylinder inner wall and effectively limiting explosive gas generated in a combustion chamber; a scraper portion protruding from a lower portion of the body, in close contact with the cylinder inner wall and including a nose scraping off oil oversupplied to cylinder inner wall; and an oil suction portion being a space formed between the compression portion and the scraper portion to collect and discharge the oil oversupplied to cylinder inner wall, thereby reducing leakage of high-temperature and high-pressure gas generated in the combustion chamber, and preventing incomplete combustion caused by oil leaked into the combustion chamber.

Abstract: Provided are an oil ring for an internal combustion engine and a piston assembly including the same, in which the oil ring for an internal combustion engine includes: a compression portion protruding from an upper portion of a body, in close contact with a cylinder inner wall and effectively limiting explosive gas generated in a combustion chamber; a scraper portion protruding from a lower portion of the body, in close contact with the cylinder inner wall and including a nose scraping off oil oversupplied to cylinder inner wall; and an oil suction portion being a space formed between the compression portion and the scraper portion to collect and discharge the oil oversupplied to cylinder inner wall, thereby reducing leakage of high-temperature and high-pressure gas generated in the combustion chamber, and preventing incomplete combustion caused by oil leaked into the combustion chamber.

Abstract: Provided is a high pressure piston crown capable of withstanding a higher pressure than the existing piston crown by changing an internal structure of the piston crown reciprocating in a cylinder while being coupled with an upper portion of a piston skirt. The high pressure piston crown includes: a rib part 100 including a plurality of main ribs 110 that are radially disposed, have one side connected to a central portion C of the high pressure piston crown, and have a cross sectional area wider toward an outside of the high pressure piston crown; an oil gallery 200 formed by the rib part 100 and making cooling oil introduced from the piston skirt flow therein; and a lower plate 300 formed under the central portion C and connected to the rib part 100 to have an inside thereof connected to the oil gallery 200.

Abstract: The present invention relates to an alloy cast iron, and a piston ring containing the same, the alloy cast iron including: a pearlite matrix; and a graphite structure and a steadite-type eutectic structure which are precipitated in the pearlite matrix, wherein the steadite-type eutectic structure includes at least one element selected from boron (B) and vanadium (V), at least one element selected from chromium (Cr) and molybdenum (Mo), and copper (Cu).

Abstract: Provided is a high pressure piston crown capable of withstanding a higher pressure than the existing piston crown by changing an internal structure of the piston crown reciprocating in a cylinder while being coupled with an upper portion of a piston skirt. The high pressure piston crown includes: a rib part 100 including a plurality of main ribs 110 that are radially disposed, have one side connected to a central portion C of the high pressure piston crown, and have a cross sectional area wider toward an outside of the high pressure piston crown; an oil gallery 200 formed by the rib part 100 and making cooling oil introduced from the piston skirt flow therein; and a lower plate 300 formed under the central portion C and connected to the rib part 100 to have an inside thereof connected to the oil gallery 200.

Abstract: A piston assembly includes: a piston skirt; and a piston crown formed by a casting method and coupled to an upper portion of the piston skirt by using a stud bolt, wherein oil galleries are formed between an upper wall of the piston skirt and an upper wall of the piston crown, wherein an annular part having a circular ring shape and a plurality of ribs having a linear shape and radially arranged to form oil channels for flowing cooling oil are formed on the upper wall of the piston crown, and the plurality of ribs are divided into outer ribs and inner ribs by the annular part.

Abstract: A piston assembly includes: a piston skirt; and a piston crown formed by a casting method and coupled to an upper portion of the piston skirt by using a stud bolt, wherein oil galleries are formed between an upper wall of the piston skirt and an upper wall of the piston crown, wherein an annular part having a circular ring shape and a plurality of ribs having a linear shape and radially arranged to form oil channels for flowing cooling oil are formed on the upper wall of the piston crown, and the plurality of ribs are divided into outer ribs and inner ribs by the annular part.

Abstract: Disclosed herein is a hollow-type crankshaft for use in an internal combustion engine and a reciprocal type air compressor, which includes a crankshaft web for connecting a crankshaft journal to a crankshaft pin, the crankshaft comprising: a reinforcing groove portion 4 formed on the outer peripheral surfaces of the crankshaft pin 1 and the crankshaft journal 2, and formed with a slope portion 41 inclined inwardly from both lateral walls of thereof, and a reinforcing member 40 made of metal different from the basic material, the reinforcing member being inserted into, melt-jointed and cast in the reinforcing groove portion 4.

Abstract: Disclosed herein is a method for joining dissimilar metals without a need for a separate welding process. The method comprises applying a flux on a metal to be joined, inserting the metal into a mold, and injecting a molten metal into the mold. Thus, the base metal to be cast and the different metal are joined simultaneously with a casting process.

Abstract: A one piece piston for use in an internal combustion engine provided with a plurality of compression rings and oil rings on its circumferential surface includes ring grooves having a hole communicating with an inside of the piston, oil rings received in the ring grooves, respectively; and a keeping ring mounted between the oil rings and having on its internal surface a spring receiving groove whose inner diameter is larger than an outer diameter of a ring type spring, wherein a separation between an external surface of the ring groove and the internal surface of the keeping ring is maintained equal to that of the compression ring and a hole is formed to allow the ring groove to communicate with the inside of the piston.

Abstract: A one piece piston for use in an internal combustion engine provided with a plurality of compression rings and oil rings on its circumferential surface includes ring grooves having a hole communicating with an inside, of the piston, oil rings received in the ring grooves, respectively; and a keeping ring mounted between the oil rings and having on its internal surface a spring receiving groove whose inner diameter is larger than an outer diameter of a ring type spring, wherein a separation between an external surface of the ring groove and the internal surface of the keeping ring is maintained equal to that of the compression ring and a hole is formed to allow the ring groove to communicate with the inside of the piston.

Abstract: A one piece piston for use in an internal combustion engine provided with a plurality of compression rings and oil rings on its circumferential surface includes ring grooves having a hole communicating with an inside of the piston, oil rings received in the ring grooves, respectively; and a keeping ring mounted between the oil rings and having on its internal surface a spring receiving groove whose inner diameter is larger than an outer diameter of a ring type spring, wherein a separation between an external surface of the ring groove and the internal surface of the keeping ring is maintained equal to that of the compression ring and a hole is formed to allow the ring groove to communicate with the inside of the piston.

Abstract: A one piece piston for use in an internal combustion engine provided with a plurality of compression rings and oil rings on its circumferential surface includes ring grooves having a hole communicating with an inside of the piston, oil rings received in the ring grooves, respectively; and a keeping ring mounted between the oil rings and having on its internal surface a spring receiving groove whose inner diameter is larger than an outer diameter of a ring type spring, wherein a separation between an external surface of the ring groove and the internal surface of the keeping ring is maintained equal to that of the compression ring and a hole is formed to allow the ring groove to communicate with the inside of the piston.