| 摘要 |
PROBLEM TO BE SOLVED: To improve productivity for highly accurate hollow component parts, enabling a core with a small surface roughness of the inside surface of the hollow portion, by forming by die casting a cylinder block and other component members and by providing by enveloping a hollow insert member during forging. SOLUTION: A cylinder block 1 is, for example, an aluminum high pressure die cast product. For making it, a hollow insert member 5 (set core) coaxial with a liner surface 3 on a thick portion that surrounds the cylindrical liner surface 3 facing a combustion chamber 2 so that the insert member is integrally enveloped during forging. The liner surface 3 is made of a hard chilled layer of fine structure formed by contact of molten metal to a cold metal die. The liner surface 3 is formed so that it can therefore withstand sliding motions of a piston for a long time by means of insertion of the cast iron sleeve or hardening of the liner surface. The hollow space of the insert member 5 forms a coolant chamber 12 that is connected to the discharge port of the coolant pump via an inlet 13.
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