| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston of an internal combustion engine which can reduce slide resistance of the piston caused by a lubricant when a load applied to the axial direction of the piston is small.SOLUTION: In a piston 7 of an engine 1, a skirt part 13 comprises: a center skirt part 13A in which a center resin coating layer 21A is formed, and a center part in the axial direction O of a piston crown part 9 becomes maximum in an outside diameter; an upper skirt part 13B in which an upper resin coating layer 21B is formed, and which is curved so that an upper part above an upper boundary 13a of the center skirt part 13A gradually becomes smaller in outside diameter toward the axial direction O from the center skirt part 13A; and a lower skirt part 13C in which a lower resin coating layer 21C is formed, and which is curved so that a lower part with respect to a lower boundary 13b of the center skirt part 13A gradually becomes smaller in outside diameter toward the axial direction O from the center skirt part 13A. In the resin coating layer 21, a surface of the center resin coating layer 21A is formed into a flat smooth face, and recesses 22, 23 for retaining oil are formed at the upper resin coating layer 21B and the lower resin coating layer 21C. |
