| 摘要 |
PROBLEM TO BE SOLVED: To circulate a lubricating oil without using a special oil pump even in every operating conditions of an engine, and prevent oil dipping of a piston by inducing the lubricating oil in a crank chamber to an outside chamber when the engine falls sideways so as to avoid the invading oil to a combustion chamber. SOLUTION: A crank chamber 32 and a valve system chamber 16 are communicated with each other through a control valve 39 which is opened when the crank chamber 32 is boosted up, and which is closed when it is decompressed, at an upper part of a lubricating oil surface in the crank chamber. In the valve system chamber 16, its upper part is communicated with the atmosphere, and its lower part is communicated with the crank chamber 32 through an orifice 38. In the case where pressure in the crank chamber 32 is identified as Pc and pressure in the valve system chamber 16 is identified as Pv, the relation of Pc<Pv is set up at the time of an engine operation. The crank chamber 32 is composed of an inside chamber 32a in which a crank part 8a is disposed, and an outside chamber 32b communicated with a bottom part of the inside chamber 32a. When the engine E falls sideways, much lubricating oil is received to the outside chamber 32b.
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