| 摘要 |
PURPOSE:To prevent engine oil from concentrating in concave gapped parts on the periphery of a piston skirt part by providing notch grooves on upward- inclined faces provided inside a piston from the lower edge of the piston skirt part. CONSTITUTION:On both sides of the axial direction of a piston pin boss 31 of a piston skirt part 35, gapped parts 36 are provided to be concaved from the peripheral face, while a lower edge 35 of the skirt part is bent from both sides at right angles to the axial direction of the piston pin boss 31 toward the axial direction of the piston pin boss 31. Inclined faces 37 are provided on the lower edge 35 to be inclined upward inside a piston. On these inclined faces 37, a pair of notch grooves 38 more inclined is provided to hold the lower part of the gapped parts 36 between. |
