| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a piston of an internal combustion engine allowing, for example, visual inspection to determine application of a predetermined double layer coating film from the appearance of the piston. <P>SOLUTION: A coating film composition of two layers of a lower layer coating film composition 22 and an upper layer coating film composition 21, is applied to an outer peripheral surface of both skirt parts 8 and 9 of a base material 1a of the piston 1 made of an aluminum alloy. When applying the lower layer coating film composition, a first window part 30 of a small square shape is simultaneously arranged in a substantially central position and a lower side position in the peripheral direction of both skirt parts. Meanwhile, when applying the upper layer coating film composition, a second window part 31 of a small square shape is simultaneously arranged in a substantially central position and an upper side position in the peripheral direction of both shirt parts, and this forming position becomes a position nonoverlapping with a forming position of the first window part. Thus, when both coating film compositions are applied, both window parts assume a blocked-up state, and when the coating film composition of only one side is not erroneously applied, any window part assumes an opened state. <P>COPYRIGHT: (C)2012,JPO&INPIT |
