Abstract: Disclosed is an air compressor in which a driving shaft and a crankshaft tube that surrounds the driving shaft are axially coupled, a clutch is installed between the driving shaft and a rear end of the crankshaft tube, and an air cylinder including a steam cylinder, a piston spaced apart at a certain distance from the steam cylinder, and an interval former installed between the steam cylinder and the piston is installed in a crankcase that forms a pump chamber, to prevent frictional ring plates that rub steel ring plates of the clutch together from being worn by a determined thickness or more by the interval former and simultaneously to cut off supplying of compressed air to the inlet of the air cylinder by the interval former in such a way that a connection state between the driving shaft and the crankshaft tube is continuously maintained.

Abstract: Disclosed is a sintered steel alloy for wear resistance at high temperatures, which is applied to a valve seat of an internal combustion engine including an automobile. The sintered steel alloy includes: 10.0 to 14.0 parts by weight of cobalt powder; 5.0 to 9.0 parts by weight of molybdenum powder; 1.5 to 4.1 parts by weight of chromium powder; 0.7 to 1.3 parts by weight of carbon powder; 1.0 to 1.8 parts by weight of manganese powder; 0.4 to 1.2 parts by weight of silicon powder; 0.2 to 0.8 parts by weight of sulfur powder; and 0.1 to 0.7 parts by weight of vanadium powder, based on 100 parts by weight of iron powder, and thus a service life of the valve seat is extended.

Abstract: Disclosed is an air compressor in which a driving shaft and a crankshaft tube that surrounds the driving shaft are axially coupled, a clutch is installed between the driving shaft and a rear end of the crankshaft tube, and an air cylinder including a steam cylinder, a piston spaced apart at a certain distance from the steam cylinder, and an interval former installed between the steam cylinder and the piston is installed in a crankcase that forms a pump chamber, to prevent frictional ring plates that rub steel ring plates of the clutch together from being worn by a determined thickness or more by the interval former and simultaneously to cut off supplying of compressed air to the inlet of the air cylinder by the interval former in such a way that a connection state between the driving shaft and the crankshaft tube is continuously maintained.

Abstract: The present invention relates to a cylinder liner and a method of manufacturing the cylinder liner. A cylinder liner according to the present invention has an outer surface covered by casting metal when a cylinder block is manufactured by integral casting, in which a plurality of engraved grooves is formed throughout the outer surface of the cylinder liner to increase bonding force between the casting metal and the outer surface of the cylinder liner.

Abstract: The present invention relates to a cylinder liner and a method of manufacturing the cylinder liner. A cylinder liner according to the present invention has an outer surface covered by casting metal when a cylinder block is manufactured by integral casting, in which a plurality of engraved grooves is formed throughout the outer surface of the cylinder liner to increase bonding force between the casting metal and the outer surface of the cylinder liner.