| 摘要 |
PURPOSE:To control that corrosion is not generated on a mold surface abutting against an insert by discharging outside corrosive gas breaking into at the time of molding, by providing a vent hole communicating with the outside on about the central part of the mold surface against which the insert is abutted. CONSTITUTION:Corrosive gas is generated from an adhesive agent applied to an insert 6 through influence of heat of a rubber molding tool and the corrosive gas remains within a cavity 5. The generated corrosive gas is broken into a gap between the insert 6 and a mold surface 54 abutting against the insert 6. The corrosive gas is pressed by casting pressure of unvalcanized compound rubber and discharged outside 8 through a vent hole 7. In this instance, as the vent hole 7 is formed of a small diameter part 70 and large diameter part 71, discharge of the corrosive gas is performed effectively and corrosion of the mold surface 54 abutting against the insert 6 is prevented.
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