| 摘要 |
PURPOSE:To prevent the opening of a split die due to a bulge forming pressure by covering the outer periphery of a lower die and upper die with the outer cylinder having a gap, pressing the end face of a die and outer cylinder by a face body and cylinder from both ends and applying a water pressure, etc., on a hermetically sealed gap. CONSTITUTION:The outer periphery of splitted upper and lower dies 4, 5 is covered by the integrated outer cylinder 3 having a gap and the right and left outer surface at the center of the outer cylinder is supported by the fixing jig 23 brought into contact with a truck to absorb the elastic deformation of the outer cylinder. The right and left side faces of the center of both ends frames 2 of the tie bar receiving the reaction force of the axial force applied on the blank inside the split die and the end face sealing force is supported by a supporting base 21. The core in the upper and lower directions of the frame is constantly held even is the plane bending deformation of the frame is caused. The opening of the split die is completely constrained with the water pressure lower than the forming pressure in bulge forming and the same core can be held even if the bending deformation of the frame of both ends frame part and the deformation of the outer cylinder at bulge forming time are caused.
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