| 摘要 |
PURPOSE:To heighten a lubricating effect lying between a cylinder inner wall and a piston ring sliding surface as well as to improve sliding characteristics in a cylinder, by installing a lot of oil holding concave parts whose each sectional form is of almost U-shaped type by means of a photetching process, on the cylinder inner wall of an engine. CONSTITUTION:On the inner wall of a cylinder liner 2, there are provided with a lot of oil holding concave parts 5 whose each sectional form is os almost U- shaped type by means of a photoetching process and has a circular opening form independent with one another, engraved at equal pitch intervals over the whole inner wall surface. In this case, the said oil holding concave parts 5 are set down to 10-50% in terms of area ratio, while it is desirable that deepness be below a straight line connecting a point of depth 50mu at the area ratio of 10% to a point of depth 30mu at the area ratio of 50% as well as be above a straight line connecting a point of depth 10mu at the area ratio of 10% to a point of depth 3mu at the area ratio of 50%. |
