APPARATUS FOR HYDRAULIC SHAPING OF TUBULAR BLANKS Russian patent published in 2004 - IPC

FIELD: plastic metal working, namely hydraulically shaping tubular blanks, for example thin-wall and elongated tubular blanks. SUBSTANCE: apparatus includes detachable die for placing blank; coaxially mounted and turned one to another punches for upsetting blank; drive units for moving punches. Each drive unit has hydraulic cylinder with coaxially arranged low-pressure cavity and high-pressure cavity, through axial duct provided in body of piston and in rods of hydraulic cylinder; pump station communicated with die cavity; multiplicator for synchronous feed of high pressure to hydraulic cylinders. High-pressure cavity is separated from low-pressure cavity by means of piston joining rods of hydraulic cylinder. Rod of low- pressure cavity is used as punch for upsetting; it has stepped turned end that may be freely introduced to opening of blank. Elastic sealing is arranged in gap between end of said rod of low-pressure cavity and flange of sleeve movably introduced inside axial duct at limitation of its axial motion value. Each rod of high pressure cavity at initial position of piston enters central opening of bottom of hydraulic cylinder at forming chamber for preliminarily supplying pressure communicated with high-pressure cavity through annular gap of fitting of joined surfaces. EFFECT: enhanced operational reliability of apparatus, improved quality of hydraulically shaped tubular articles of thin-wall and elongated blanks, less loss of yield, elimination of necessity for applying compression axial effort to end of blank, stabilized position of sealing, lowered hazard of hydraulic shock. 3 cl, 4 dwg