Lubricating system for 4-cycle engine

摘要

In a 4-cycle engine in which a side cover (8) defining a first valve-operating chamber (9a) is bonded to one side of a crankcase (1), and a head cover (10) defining a second valve-operating chamber (9b) is bonded to a head portion (3) of a cylinder block (2), oil reservoir chambers (28 and 29) are formed in the crankcase and the side cover to surround a crank chamber (4) and the first valve-operating chamber. Oil supply passages (35 to 38) are provided to permit a portion of at least one of the oil reservoir chambers below an oil surface therein to communicate with the crank chamber so that the oil (0) passed through the oil supply passages can be scattered by the rotation of the crankshaft to produce an oil mist, at least one of said oil supply passages being provided in the crankshaft (5). The crank chamber is put into communication with the first valve-operating chamber through a one-way valve (42). A recovery bore (45) which opens into a bottom of the second valve-operating chamber for recovering liquefied oil is put into communication with a portion of at least one of the oil reservoir chambers above the oil surface. Thus, there is provided a lubricating system for the 4-cycle engine in which the size of the entire engine can be reduced, while reducing the number of parts to simplify the structure. <IMAGE>