Patent ID: 11555426

Abstract:
In an internal combustion engine, an oil return passage extending from a breather chamber can be formed without increasing the number of component parts and without increasing the size of the internal combustion engine. The internal combustion engine (1) comprises an engine block (30) defining a cylinder (2); a case member (19) fastened to a lower part of the engine block to define a crank chamber jointly with the engine block; a bearing member (50) fastened to the engine block in the crank chamber to rotatably support a crankshaft; a breather chamber (113) defined in the engine block; an inlet passage (112) formed in the engine block to communicate the crank chamber with the breather chamber; a connection pipe (114) communicating the breather chamber with an intake device; and an oil return passage (150) formed at least in the bearing member, and extending from a bottom part of the breather chamber to an oil return port (147) opening at an outer surface of the bearing member. The oil return port may be provided in a lower part of the bearing member.