| 摘要 |
PURPOSE:To introduce a lubricating oil to a connecting part between a crank web and a connecting rod accurately by forming a lip wall part which extends into a gap between the skirt part of a piston and said crank web, continuously with the lower wall surface of an oil feeding port. CONSTITUTION:When a piston 6 rises, a lubricating oil, together with an air fuel mixture, is fed into a crank chamber 2 from a reed valve 9 through an intake port 10. Then, the lubricating oil collides with the wall surface of the intake port 10, partly turning into a wall surface flow, which flows from a lower wall surface 10a and along a lip wall part which is continuously connected to the wall surface 10a, and is introduced to a gap between both opposite crank webs 4. Lubricating oil which flows into the crank chamber 2 in a mist condition is also introduced to the central part of the crank chamber 2, due to the lip wall part 12, without being splashed by the peripheral surface of a web 4, etc., colliding with a connecting rod 7. Accordingly, a connecting part between the web 4 and the connecting rod 7, i.e., the bearing part around a crank pin 5, and the sliding surfaces of the larger end part 7a of the connecting rod 7 and the web 4, can be lubricated. |
