| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston of an internal combustion engine in which an oil film is appropriately formed on a coating layer of a basic diameter part of a skirt part and the surrounding thereof upon the piston rising.SOLUTION: The piston adopts a structure provided with groove parts 26, 31 which includes: an introduction passage 25 which is formed from an end part of the piston head part 7 side of a coating layer 17 to the neighborhood of the end part of the piston head part 7 side of a basic diameter part 11a; and a lead-out passage 30 which is displaced in the circumferential direction from the end part of the basic diameter part side of the introduction passage to an end part of the skirt end side of the coating layer 17 as at least one side of coating layer of a pair of skirt parts 10. According to such a configuration, as the piston rises, lubricant remaining on the wall surface of the cylinder is made influent from the upper side of the skirt part to the neighborhood of the basic diameter part through the introduction passage formed on the coating layer of the skirt part. The lubricant that is made influent temporarily gets to stagnant at a junction point of the introduction passage and the lead-out passage. When getting to stagnant, the lubricant leaks out between the coating layer and the cylinder wall surface to form an oil film onto the outer circumferential surface of the basic diameter part and the surrounding thereof. |
