PURPOSE: To reduce the number of parts by a method in which a crank case half having a cylinder head, a block part and a skew opening part is integrally molded, and the skew opening part is closed with the other crank case half.
CONSTITUTION: The main block 1 consisting of a cylinder head 2, a cylinder block 3 formed below the cylinder head 2, and a crank case half 4 formed below the cylider block 3 is molded integrally by cast molding method. Then, an opening 6 is formed in the axial direction of a crankshaft from part 3a of the lower part of the cylinder block 3 to the lower end bottom 4a of the crank case half 4. On the other hand, the crank case half 11 to be joined with the opening 6, having a floor 12 and a wall 13, is integrally molded by cast molding method. Thus, the outside part of the internal combustion engine can be made up of two parts, and therefore, the reduction of the number of parts including connecting parts and also the elimination of the needs for machining of connecting parts can be attained and the number of machining and assembling processes can be reduced.
OKANO TAKEO
NAKAMURA KENJI
