PROBLEM TO BE SOLVED: To provide a crankcase structure quickening the return of oil by suppressing change and lowering of oil surface in an oil pan due to the inclination of an internal combustion engine, thus preventing the exposure of an oil suction port to prevent an air lock of an oil pump.;SOLUTION: The crankcase structure of a crankcase 2 for the internal combustion engine 1 supporting a crank shaft 3 and a transmission 4 and having the oil pan 61 at the lower part, wherein the oil suction port 66 using the oil pump 62 for sucking oil from the oil pan 61 is provided in the bottom of the oil pan 61, includes an oil return port 74 for returning the oil to the oil pan 61 after lubricating the crank shaft 3 or the transmission 4. It further includes partition walls 71L, 71R for partitioning the crank shaft 3 from the oil pan 61 or partition walls 72L, 72R for partitioning the transmission 4 from the oil pan 61, and oil removal parts 78, 78' which is connected to the partition walls and at least parts of which are arranged above the oil surface of the proper amount of oil stored in the oil pan at the time of stopping the internal combustion engine.;COPYRIGHT: (C)2011,JPO&INPIT
展开▼
