| 摘要 |
PURPOSE:To restrain deformation in the direction vertical to the compression direction of a core material and to enable the thickness of the injection mold part coated with FRP to be increased by providing cut parts to the core part on the parting line surface of an injection mold at least over its semi-spherical surface. CONSTITUTION:The inlet 6 of hardening liquid resin is provided by the injection mold 1 in the direction almost rectangular to the compression stress direction applied to the core material 2 and on the parting line surface. The core material 2 is provided with cut parts 5 at least on the semi-spherical surface, preferably all over the whole spherical surface on the portion facing the parting line surface of the injection mold 1. In this manner, since cut parts 5 are provided at least on the semi-sphere, preferably all over the spherical surface, when the core material 2 is compressed by the mold 1, the core material become hardly be deformed vertically by the adsorption of compression stress. Therefore the thickness of the FRP coated layer area on the parting line surface is made equal to that of other places and strength can be improved. |
