| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston which reduces oil consumption. SOLUTION: The piston 1 comprises: a piston body 3 for an internal combustion engine, having a ring groove 7 inclined upward so that it approaches a head part 11 as it approaches a cylinder wall 2; and an upper piston ring 21 positioned on the side closer to the head part 11 and a lower piston ring 121 positioned on the side farther from the head part 11 in two layers in the ring groove 7. The thickness T1 at the inner peripheral surface 21i of the upper piston ring 21 is smaller than the thickness T2 at the outer peripheral surface 21u. The thickness T3 at the inner peripheral surface 121i of the lower piston ring 121 is larger than the thickness T4 at the outer peripheral surface 121u. The mass of the upper piston ring 21 and that of the lower piston ring 121 are substantially equal to each other. COPYRIGHT: (C)2006,JPO&NCIPI
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