| 摘要 |
PURPOSE:To prevent the contact of a stress concentrated part at bellows expansion time and to make the stress distribution uniform by making the radius of curvature of the inner surface of the outer layer bellows and of the outer surface of the inner layer bellows equal through making each layer of the parallel part of multilayer bellows come in a tight contact state and by providing a gap on the stress concentrating part of the crest and root parts. CONSTITUTION:A bellows blank tube 3 is bulged by installing a halved forming die 2 on the outer side, by leading a liquid pressure into the bellows blank tube 3 and raising the liquid pressure inside the blank tube to the prescribed pressure. A liquid or gas is poured then between layers by a filling pipe 6. At this time due to the place where the metal die 2 is placed being resistant to the hoop stress the bellows blank tube 3 only which exists between there is bulged and at the same time compressed in the axial direction by a press and the place which becomes the bulged crest part of the bellows blank tube 3 is formed in the bellows shape further by buckling. |
