| 摘要 |
PURPOSE:To improve the uniformity in solidification of molten metal, the water- tightness of a water jacket and the strength of a cylinder barrel by cooing a sand core for forming water jacket at below the specific temp. and setting the sand core in a cavity of a metallic mold. CONSTITUTION:The mold is opened, and a sleeve 3 having almost real circle section, is fixed to insert in a positioning projection 22, to set a standing. Next, the sand core 59 is cooled at <=0 deg.C, and id really set by engaging the core seats 31 with each core print 63. Then, a core bar 70 is inserted as movable in the cylinder part of the sand core 59, under descending the upper mold 9. After that, the molten metal is supplied into the well part 14 of the lower mold 11 and filled up into the cavities C1 and C2 by ascending a plunger 16. The plunger 16 is shifted at the prescribed velocity, and so the sand core 59 is perfectly enclosed by the molten metal. As the sand core 59 is cooled, the molten metal brought into contact with it is promoted to cool near the cooling velocity for the molten metal at a metallic mold M side. In this way, all over the molten metal is uniformly solidified in the mold, and so development of the casting defects is prevented. Further, the circumferences of the barrel 1 and the outer wall of block 4 are chilled, to show layer-state having fine structure.
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