CRANKCASE FOR MULTICYLINDER ENGINE

摘要

PROBLEM TO BE SOLVED: To ensure a sufficient large opening area for a breathing hole in a multicylinder engine. SOLUTION: One of the journal walls of a series four-cylinder engine is provided with an oil passage 42 and a tapped hole 45 as a bolt tightened portion. The center C1 of a breathing hole 24 made in the journal wall is offsetΔc to the center C2 of a breathing hole 25 formed in an adjacent journal wall for escaping from the oil passage 42 and the tapped hole 45. In this way, the size of the breathing hole 24 is large enough to reduce friction loss without complicating the oil passage 42 and reducing the size of the tapped hole 45.