1954 年 20 巻 92 号 p. 274-279
In the reciprocating machines, such as internal combustion engines and compressors, etc., the pressure distribution of the piston ring which exerts on the cylinder wall changes gradually due to wear of the cylinder wall and also the piston ring itself. Then, if we use the piston ring which exerts initially uniform pressure on the cylinder wall, the life of this piston ring for good action is not very long, causing gas leakage and increasing the consumption of lubricating oil owing to the decrease of the spring power near the gap ends of the piston ring by the local wear during operation. As the counter-measure for this, if we use the piston ring of the elliptical pressure distribution named E type ring, the spring power being more intense for the gap direction, the pressure distribution of the piston ring should be equalized by the local wear of the piston ring during operation, and then the spring power for the gap direction is decreased gradually. For these reasons, the life of the E type piston ring for good action becomes considerably long. In our researches, we measured peripheral forms of piston rings which were closed by using flexible steel bands with different sizes. From these results, the theoretical calculation was carried out concerning the pressure distribution of the E type piston ring on the cylinder wall, when the diameter of the piston ring is different a liitle from than of the cylinder bore. Moreover, it was made clear from our calculations that if we want to make such a piston ring as has the elliptical pressure distribution which exerts more intense pressure for the gap direction, we may make the diameter of the piston ring a little larger than that of the cylinder bore and further, the state of pressure distribution of the piston ring with normal size in the worn cylinder bore was also made clear.