| 摘要 |
PURPOSE:To restrain buckling at a valley part and lowering of fatigue resistance when a resin boot wherein an interval between a crest part and the valley part is comparatively narrow is manufactured. CONSTITUTION:An interval between a crest part 5 and a valley part 6 of a belly part of a boot is molded comparatively narrow. In manufacturing the boot, melt resin is injected into a cavity formed with an inner mold 12 having a projected part 14 and a recessed part 15 corresponding to the crest part 5 and the valley part 6 and a first split type die body of which an inner peripheral face is smooth, and a parison 17 having alternately a thin wall part 20 and a thick wall part 21 is molded in a softened state. Then, the inner mold 12 and parison 17 are provided in a second split type die body 19 having an inner peripheral face equal to a boot outer surface. Compressed air is jetted outward by opening a jetting part 16 to bring the parison 17 into swelling pressure contact with the inner peripheral face of the second split type die body 19. Even though the interval between the crest part 5 and the valley part 6 is narrow, a great amount of resin does not flow in a part forming the crest part 5 of the second split type die body 19, and making thick wall of the crest part and making thin wall of the valley part 6 are restrained. |
