Hole turning forming process at mouth of egr shell

Abstract

The invention provides a hole flanging forming process of an EGR shell opening. The hole flanging forming process comprises the steps that (1) an EGR preformed shell is manufactured through a pipe hydraulic bulging process; (2) a datum bottom hole of a flange is manufactured in the to-be-machined end of the preformed shell through a punching die, and subjected to hole flanging, and a preformed flange is obtained; (3) the preformed flange is subjected to high-frequency annealing treatment, and then the preformed flange is reshaped to primarily obtain the straight arm opening diameter dimensional accuracy of the flange; and (4) the inner wall of the preformed flange treated through the step (3) is rolled to generate plastic deformation until the flange straight arm dimension reaches the design accuracy. Firstly, the high-precision flange is integrally formed on the EGR shell through working procedures such as hydraulic bulging, punching, hole flanging, annealing, shaping and rolling, a large EGR shell high-precision flange ring is advantageously produced, machining and welding deformation of a single part can be reduced, and the machining cost of the type of products is lowered.

Description

technical field [0001] The invention relates to the processing technology of auto parts, in particular to the molding process of the flange ring at the mouth of the EGR shell. Background technique [0002] EGR system (exhaust gas recirculation system) is a technology and method used to reduce nitrogen oxides in automobile exhaust emissions. It must be used for automobile exhaust emissions to meet Euro IV and V standards. The principle and function of the cooler: During the combustion process of the car, a high temperature of about 500-600° will be generated, and the exhaust gas must be cooled before it can be refluxed, otherwise the emission effect will not be achieved. This process is completed in the EGR cooler. If the EGR gas is not cooled, the hot backflow exhaust gas will heat the intake air, resulting in a significant increase in the combustion temperature and pressure in the engine cylinder, offsetting the effect of EGR on reducing NOx, and in severe cases, it will al...

AI Technical Summary

Problems solved by technology

The flange on the existing large EGR shell cannot be hydroformed, but can only be split, that is, a single flange is machined and then welded with the shell as a whole. The processing cost is high and the production cycle is long.

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