To manufacture a bellows of large diameter through hydrostatic forming by building a liner into a plurality of split dies, mounting a metallic stock tube inside, applying the hydraulic pressure thereto to expand the metallic stock tube, detaching the liner, axially applying the pressure to the die while re-applying the hydraulic pressure, and extruding the metallic stock tube into the gap between split dies.
A liner 53 is built in, split dies 8, 52 are arranged, and a metallic stock tube 1 is set inside. An upper end part 1a and a lower end part 1b of the metallic stock tube 1 are clamped to an upper die 51a and a lower die 5b in a sealed condition. The pressurized medium is fed to a hydraulic pressure chamber 10 of the metallic stock tube 1, and the metallic stock tube 1 is expanded in the arrow direction. The hydraulic pressure is fed to the hydraulic pressure chamber 10 of the metallic stock tube 1, and the metallic stock tube 1 is expanded in the arrow direction. The hydraulic pressure in the hydraulic pressure chamber 10 is removed, and the liner 53 is detached. The metallic stock tube 1 is inserted in the split dies 8, 52, and the pressure in the axial direction is applied to the upper die 51a while applying the hydraulic pressure to the hydraulic pressure chamber 10. The split dies 8, 52 are pressed in the axial direction and the metallic stock tube 1 is extruded between the split dies 8, 52.
NAKAMURA KEIICHI
OOGA KIMIO
SHIRATA SATORU
OTA KATSURO
KAIHATSU TOSHIHIKO
YOSHIIKE KIYOKATSU
SUZUKI ISAO
KOBAYASHI TOSHIAKI
HITACHI SETSUBI ENG KK