Study On Mechanism Of Friction Driving For Automatic Welding Of Whole Position Pipeline

With the economic development of the country, the demand for energy will gradu ally increase. Coal occupies a very large proportion in China’s energy structure. With the adjustment of energy industry structure, the proportion of oil and natural gas will gradually increase, and then change the single energy structure, For oil and gas transportation, pipeline transportation is the most economical and reliable way. During pipe line laying, the all position automatic welding machine is more and more applied because of its stable welding quality, fast welding speed and strong environmental adaptability. Therefore, it is very important to study the all position automatic welding equipment with higher transmission accuracy, more stable performance and more convenient operation.In order to improve the transmission accuracy and ensure the stability of motion of the welding torch, this paper mainly adopts the combination of triangular tooth type friction wheel and the flexible track system, which is often used in the high precision machine tool, even in large astronomical telescope. Comparing to rack and pinion drive, the friction drive system is not only able to provide enough transmission accuracy, but also can be used in flexible track which is more portable, which is more convenient for loading and unloading.This paper establishes the overall three-dimensional model of the all position automatic welding machine through the Inventor software, and analyzes the dynamic of the whole position automatic welding machine in different welding conditions, and ultimately determine the power range provided by the transmission system in the normal work of the whole machine.The contact between the triangular tooth friction wheel and a variety of flexible track is analyzed by using the finite element software Nastran. It is necessary to study the correlation between the wheel-rail system and then range of rolling friction. In the case of providing then required frictional force, we must ensure that the track will not occur serious deformation and abrasion. Through the finite element analysis and experimental comparison, a basic pressure displacement relation is obtained, which can guide the friction calculation.Based on the relationship of the pressure and displacement, rolling friction between the triangular tooth friction wheel and a variety of flexible track is analyzed by using non-Hertz elastic-plastic theory, and the rolling friction coefficient of different materials and friction wheel and rolling resistance coefficient is obtained.In order to ensure the stability of the whole position pipeline automatic welding machine, the wear and tear of the friction wheel and rail are estimated.By testing for the prototype of all position automatic pipeline welding machine, it is found that all position automatic pipeline welding adopting the combination of the friction wheel and the flexible track can meet requirements of the running system by welding torch.