| 摘要 |
PURPOSE:To enable forced cooling of a piston and to improve seizure proof property of a piston pin, by so constituting that oil can be supplied to an oil sump provided at the lower part of a piston crown from the outside of a cylinder through an oil duct. CONSTITUTION:A first oil duct 18 is provided on the surface of a skirt part of a piston 9, in an engine wherein a piston pin 10 is fitted in a cylinder 6 slidably and an exhaust opening 15 and a pair of scavenging openings 16 are opened in the cylinder 6. Then, a second oil duct 20 which is extended up to an oil sump located at the lower side of a piston crown is provided. A discharge oil duct 22 which reaches to a place between the cylinder 6 and the piston 9 where lubrication and cooling are necessary is provided at the location separated from the second oil duct 20, and the above ducts 18, 20 and 22 are lubricated from an oil pump 25 through an inlet oil duct 23. Forced cooling of the piston 9 is carried out and its seizure proof property is improved as lubrication oil passes through the oil sump 21 with this device. |
