Section-variable hollow component forming device and method

The invention provides a section-variable hollow component internal forming device and a section-variable hollow component forming method, belongs to the technical field of hydraulic formation, and solves the problems that when a hollow component with a large hydraulic formation section size difference of a traditional tubular product is formed, axial feeding is difficult, the deformation uniformity is poor and the like. A closed cavity is formed by an upper die base, a left puncher pin, a right puncher pin and a lower die base; a puncher pin liquid injection hole is formed on the left puncher pin or the right puncher pin; a pressurizing device is communicated with the puncher pin liquid injection hole through a liquid channel; and the puncher pin liquid injection hole is used for injecting a liquid medium into a pipe blank. A pipe blank is placed into a die cavity and the puncher pins at the two ends are used for fixing the pipe blank; the upper die base is moved downwards to form a sealed hollow cavity with the lower die base; a force transfer medium is injected into the tubular product from the puncher pin injection hole at one side to pressurize; and the formation of a diameter-changing tube piece is realized under the matching effect of moving the left and right puncher pins to the inner side. After the formation, pressure in the die cavity can be removed after the formation, the upper die base is removed to separate the left and right puncher pins, and the formed piece is taken out. The section-variable hollow component forming device and the section-variable hollow component forming method are suitable for forming the hollow component with the great change of the section size and the circular-section or non-circular-section diameter-changing part.