Lubricating apparatus for an engine

A lubricating apparatus for an engine, the engine including a crankshaft;

• at least one journal bearing for supporting the crankshaft;
• and an oil pan for storing a lubricating oil reserve, the apparatus comprising:
• a pump having a discharge port and an inlet port communicating with the oil pan, for pumping the oil up from the oil pan to discharge its oil from the discharge port;
• an oil supplying passage for providing fluid communication between said discharge port and the bearing for the crankshaft to supply the oil from said pump to the bearing;
• an oil flow passage formed between the crankshaft and the bearing to communicate with said oil supplying passage, so that the crankshaft and the bearing are cooled by oil flowing through the oil flow passage
• an oil returning route connected to said oil supplying passage via said oil flow passage, for leading the oil from the bearing to the oil pan;
• and
• control means provided along said oil returning route for controlling the flow of oil in accordance with the warming-up condition of the engine, said control means allowing the oil to return from the bearing to the oil pan via said oil returning route when the temperature of the engine is lower than a predetermined temperature.

A lubricating apparatus for an engine, the engine including a crankshaft;

• at least one journal bearing for supporting the crankshaft;
• and an oil pan for storing a lubricating oil reserve, the apparatus comprising:
• a pump having a discharge port and an inlet port communicating with the oil pan, for pumping the oil up from the oil pan to discharge its oil from the discharge port;
• an oil supplying passage for providing fluid communication between said discharge port and the bearing for the crankshaft to supply the oil from said pump to the bearing;
• an oil flow passage formed between the crankshaft and the bearing to communicate with said oil supplying passage, so that the crankshaft and the bearing are cooled by oil flowing through the oil flow passage;
• and
• an oil returning route connected to said oil supplying passage via said oil flow passage, for leading the oil from the bearing to the oil pan, wherein said oil returning route includes an exterior oil passage formed in said housing, for providing fluid communication between the bearing and the outside of said housing;
• wherein the engine further includes a housing for holding the bearing, said housing comprising two housing parts which are secured to each other with a bolt, thereby holding the bearing therebetween;
• and
• wherein said exterior oil passage includes a circular groove formed around said bolt.