A small bellows tube blank hydroforming process and special forming die

Abstract

The invention discloses a small-sized corrugated pipe blank hydraulic forming process. Firstly, the forming mold is installed, and the unformed bellows The tube blank is placed in the mold and the mold is sealed. Compress the upper sealing cover and the lower sealing cover, inject hydraulic oil into the unformed tube blank until the hydraulic oil fills the space between the upper sealing cover, the inner wall of the tube blank and the lower sealing cover. Then the forming press starts to pressurize continuously, and the tube blank is deformed and bulged by the pressure, and then the pressure is released. Remove the forming pad, pressurize, and at the same time the main oil cylinder of the forming press advances, and the two ends of the bellows blank are flanged and deformed to release the pressure. Finally, the forming die is replaced with a thin pad, and the main oil cylinder of the forming press is pushed forward without pressurization, so that the corrugated part in the middle of the corrugated pipe blank is deformed. After the completion, the forming mold is removed, and the formed corrugated pipe blank is taken out.

Description

technical field [0001] The invention relates to a hydroforming process, in particular to a hydroforming process for a small corrugated pipe blank with small wave depth and short single wave expansion length and a special forming mold piece. Background technique [0002] Half of the difference between the length of the outer diameter and the length of the inner diameter of the bellows is the wave depth, and the length of the corrugations between adjacent wave troughs after fully stretching is a single wave expansion. Such as figure 1 As shown, the ordinary corrugated pipe has a large wave depth and a long single wave expansion length. When the traditional hydroforming process is used to process the tube blank, it requires less pressure and is easy to bulge, so it is easy to form during processing. Ordinary corrugated pipes mostly adopt the multi-wave one-time molding method. After adjusting the relative position of the mold and the pipe blank, pressurize the inner cavity of ...

AI Technical Summary

Problems solved by technology

like figure 2 The shown small bellows has a small wave depth and a short single-wave expansion length. Generally, the single-wave forming process is used, but when encountering a bellows with a small absolute size, it will be difficult to achieve the ideal if the traditional hydroforming process is used. processing effect

First of all, it is necessary to use a forming die with extremely thin thickness; secondly, the tube blank is not easy to deform and bulge after being pressed because the length of the single wave expansion is too short; finally, because the wave depth is too small, the forming accuracy of the processed tube blank cannot be guaranteed.

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