Study on multi-roller rotary feed forming mechanism of spiral tube with uniform wall thickness

Abstract

The positive displacement motor is one of the most widely used downhole power drill in drilling operations. In order to solve the problem of short life of conventional positive displacement motor and the inner spiral surface of stator with equal wall thickness is difficult to process. This paper uses multi-roller rotary feed forming process to process spiral tube with uniform wall thickness. According to the indoor processing experiment of 5LZ73 spiral tube and tensile test of material, the finite element model of multi-roller rotary feed forming spiral tube was established. The forming analysis of the 5LZ73 spiral tube was simulated by finite element method and compared with the experimental results. The results verify that the numerical simulation method can accurately analyze the forming result of the spiral tube. The forming of 5LZ54 spiral tube was studied by finite element method, and the influence of forming speed, rolling surface arcs the radius, forming temperature, rolling depth, and friction coefficient on the processing of spiral tube was analyzed. The results show that when the pipe outer diameter is 56 mm, the pipe wall thickness is 5 mm, the rolling depth is 3.3 mm, the forming speed is less than 15 mm/s, the hot forming is adopted, the arc radius of the 304 stainless steel rolling surface is 6.3 mm, and the radius of the arc of the 20G rolling surface is 7.1 mm, so the formed spiral tube is of good quality. The research results have important engineering significance for improving the processing quality of the spiral tube and improving the working performance of the positive displacement motor.