Large-diameter thin-wall small-bending-radius bent pipe with straight sections at two ends and hydraulic forming device and forming method thereof

Abstract

The invention discloses a large-diameter thin-wall small-bending-radius bent pipe with straight sections at the two ends and a hydraulic forming device and forming method thereof, and belongs to the technical field of thin-walled tube bent pipes. The bent pipe forming technological process comprises the steps of preparing a straight pipe blank, numerically controlling the bent pipe, putting a bentpipe blank into a mold and closing the mold, feeding a push head, filling liquid and pressurizing, taking the bent pipe, and cutting the bent pipe. The method has the advantages of being capable of numerically controlling the bent pipe and hydraulically forming the bent pipe at the same time, and has a good forming effect on bent pipes with long straight sections at the two ends and small bendingradius. The mold in the hydraulic forming process adopts an insert structure with damping ribs, and the problems of outer side breakage and inner side wrinkling generated when a small-bending-radiuspipe with straight sections at the two ends is formed through a traditional method are solved. The method is simple in process and high in efficiency, and the produced parts are low in thinning rate.

Description

technical field [0001] The invention relates to the technical field of thin-wall pipe bends, in particular to a hydroforming device and a forming method for large-diameter thin-wall bends with small bending radius and straight sections at both ends. Background technique [0002] Bends are generally formed by CNC bends, ball push bends, liquid-filled bends, and tailor welding after half-shell drawing. The bending radius R of CNC pipe bending process is generally in ( is the pipe diameter), when the bending radius , the efficiency of CNC pipe bending is low, the reliability of parts is poor, the inner wall of the elbow is scratched, the mouth is easy to ellipse, and the bending radius , it cannot be bent. The ball push bending process has low efficiency and poor reliability, although the bending radius can be formed elbows, but cannot form elbows with straight sections above 20mm at both ends, and the bending radius And when the thickness of the pipe wall is less t...

AI Technical Summary

Problems solved by technology

The bending radius R of CNC pipe bending process is generally in ( is the pipe diameter), when the bending radius , the efficiency of CNC pipe bending is low, the reliability of parts is poor, the inner wall of the elbow is scratched, the mouth is easy to ellipse, and the bending radius , do not bend

The ball push bending process has low efficiency and poor reliability, although the bending radius can be formed elbows, but cannot form elbows with straight sections above 20mm at both ends, and the bending radius And when the thickness of the pipe wall is less than 1.5mm, the inner side is easy to wrinkle

Although the liquid-filled elbow process can form a bending radius The elbow, but the mold will increase with the increase of the length of the straight section at both ends of the elbow, and the thinning of the outer R will also increase, and defects such as wrinkling, buckling, and cracking will appear

The bending process of half-shell drawing and tailor welding adopts the method of split manufacturing, first using sheet metal to form half of the bending pipe, and then welding to form, this method is inefficient, and the dimensional accuracy and reliability of the parts are poor

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