| 摘要 |
PURPOSE:To prevent the generation of blowholes in a fiber-reinforced cylinder block stock by mounting a cylindrical fiber molding to the outside peripheral surface of a core for forming a cylinder bore and pouring a molten metal into cavities in such a manner that a back pressure is generated. CONSTITUTION:The opening degrees of small-diameter parts 32a, 33a are throttled by closing pins 34, 35 and the preheated cylindrical fiber molding F is mounted to the outside peripheral surface of the core 41 for forming the cylinder bore. The molten metal is successively poured from a runner 17 of a drag 11 via a gate 19 into the 2nd and 1st cavities C2, C1. The gas such as air in the cavities C1, C2 is lifted by the molten metal and is discharged upward from vent holes 32, 33. Since the opening degrees of the small-diameter parts 32, 33a are throttled, the back pressure is generated in the cavities C1, C2 an acts uniformly over the entire molten metal surface, thereby suppressing waving. The back pressure horizontally raises the molten metal surface to prevent the generation of blowholes. The small-diameter parts 32a, 33a are closed by the pins 34, 35 when the molten metal is fully filled into the 3rd, 4th cavities C3, C4. The molten metal is thoroughly solidified under the prescribed pressure, by which the matrix is made denser and stronger.
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