Design And Process Study On Weld Special Tube For Tractor Front Axle

Under the support of national preferential policies, the income of Chinese farmers has increased significantly compared to the past, but Chinese farmers still cannot accept the rise of product prices. Therefore, it is the users’expectation to have high-quality and low-cost products in future society. It is the trend brought by industries’constant competition and continuous improvement of technological innovation.In order to meet market and customer needs, while reducing production costs, we propose to use welding special pipes to substitute seamless special pipes for tractor front axle. In this paper, we will study on welding special pipes for front tractor axle to conduct force analysis and strength check for front tractor axle with traditional theory computing method. Meanwhile, we will verify the performance of welding special pipe to see if it can meet the actual use requirement of products through practical tests.In this article, firstly, based on two dimension engineering drawing of Yihe axle product and combined with related knowledge of mechanics of materials and mechanical design, we made force analysis for front tractor axle under four different conditions of normal running condition, emergency braking during running condition, side slipping during running condition and dynamic load condition for running on uneven road, so as to find out insecurity section and making intensity check for it to ensure use requirement for the product.Secondly, according to theoretical analysis, we designed and machined welding special tube used by inner and outer sleeve of TJ72.31.001 front tractor axle and assembled it to 7502 tractor.We also made material composition inspection, tensile test as well as flaring test for the welding special tube. Meanwhile, we had vertical bending fatigue test and horizontal bidirectional loading bending fatigue test for the assembled front beam. The whole tractor vehicle was conducted with reliability test under the bumpy movement and impact conditions. By making related tests for the whole vehicle and components, we can ensure the strength requirement for the product in actual use. Then, the four main influence factors in production process of welding special tube are discussed and detailed analyzed from each factor, namely material, forming process, HF welding process and heat treatment process. We optimize the production process parameters for welding special tube based on these influence factors.Then, we made simple analysis for the advantage and disadvantage for welding special tube. The main advantages are:firstly, good concentricity. The wall thickness is more even which avoids the difficult assembly between inner sleeve and outer sleeve; secondly, good welding performance. It eliminates the welding defects for the connecting piece between inner and outer sleeves; thirdly, good price. It reduces the material cost for the product. The main disadvantage is that the production process for weld special tube is hard to control, especially the welding parameter in welding process.At last, we make an outlook for the wide use of welding special tube in the future. Now the welding special tube has been started batch verification for the front tractor axle in TJ72 type tractor. If there is no problem with the verification, we will popularize and apply it in the inner and outer sleeve for 25 series,40 series and 80 series front axle assembly. Finally, the entire inner and outer sleeves for front tractor axle will be comprehensively changed from seamless special tube to welding special tube.The research result of this article can provide reference for front tractor axle verification as well as design, fabrication, test and process optimization for special welding tube.