| 摘要 |
PURPOSE:To prevent counterflow of oil and reduce oil consumption by forming a recess in those parts of the side face of a skirt which are oriented in the axial direction of a piston pin, wherein the recess is continued to a ring-shaped groove and extends till the bottom of the skirt. CONSTITUTION:A ring-shaped groove 13 is formed at the upper periphery of a skirt 8 below a groove 12 for fitting of oil ring 11 formed at the outside surface of a piston 4. A recess 14, whose top is continued to said ring-shaped groove 13, is formed at those parts of side face of skirt 8 which are oriented in the axial direction of a piston pin 5. The oil which has flowed into the groove 13, sinks along a passage 16 and an oil sump 15 in said recess 14 to drop into the crank case from the bottom of the oil passage 16. This can prevent counterflow of the oil to contribute to reduction of oil consumption. |
