Oil passage structure for engine

A lubricating device for an engine, the engine including a generator housed in a generator chamber formed between a crankcase and a generator cover connected to the crankcase, the generator including a rotor fixed to an end portion of a crankshaft rotatably supported by the crankcase and a stator fixed to the crankcase, the lubricating device comprising:

• a block side return oil passage, said block side return oil passage being provided in a cylinder block of the engine and being in communication with a head side return oil passage provided in a cylinder head of the engine, said block side return oil passage being in communication with the generator chamber in order to return oil from the cylinder head to an oil pan through the generator chamber;
• and
• a branch oil passage in communication with an intermediate portion of said block side return oil passage, said branch oil passage being provided in the cylinder block and being formed so as to allow a part of the oil flowing through said block side return oil passage to bypass the generator chamber and flow to the oil pan.