| 摘要 |
PURPOSE:To permit easy parting with a decreased tight contact area and to decrease the man-hours for forming a cast hole by dividing an equal diameter core having a cast hole forming part radially within the perpendicular plane in the axial direction and stepwise dividing the tight contact movement of the divided bodies at the time of drawing the hole forming part. CONSTITUTION:A fiber-reinforced composite cylindrical body Cf for constituting the cast hole forming part of a cylinder block is perpendicularly held by the hollow cylinddical core 10 having an equal diameter over the entire length in tight contact therewith. The core 10 is radially divided 101-103 within the plane perpendicular to the axial direction and is supported by a lower die 8 and a post 16 provided with a projecting part 163 for guiding. The divided body 101 of the divided bodies 101-103 is first slipped by the difference of the notches 141-143 of the lower die 8 from the projecting parts 131-133 of said bodies and in succession the bodies 102, 103 are stepwise begun to be slipped at the time of ejecting and pulling up the core by a knock-out pin 20 after casting. The tight contact area with the cylindrical body Cf is, therefore, stepwise decreased and the easy parting is permitted. Since the cylindrical body Cf has the equal diameter, the subsequent man-hours for finishing the hole are decreased.
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