Liquid filling shearing bending formation method for small bending radius rectangular tube

The invention discloses a liquid filling shearing bending formation method for a small bending radius rectangular tube and relates to a liquid filling shearing bending formation method. The invention aims to solve the problem that a small bending radius rectangular tube cannot be formed by the conventional bending processes. The method comprises the following steps: step 1, filling stage: placing a rectangular tube in a die cavity, mounting rectangular seal punches, inserting a medium input pipeline in one of the rectangular seal punches and filling a liquid medium in the rectangular tube, and propelling the rectangular seal punches inwards to implement the sealing; and step 2, formation stage: pressurizing the liquid medium in the rectangular tube, wherein a driving device drives a moving module to move in the tangent direction of the rectangular tube relative to a fixing module, and the rectangular seal punches at two ends of the rectangular tube are fed inwards in the axial direction to enable the pressure of the liquid in the rectangular tube to increase or keep constant and the rectangular tube to be deformed, keep the pressure, and relieve the pressure, and the driving device drives the moving module to open model and take out a tube. The method is used for the liquid filling shearing bending formation of the rectangular tube.