Bearing Fatigue Reliability Analysis And Flange Structure Optimization Of Tire Blank Unloading Equipment In Giant Tire Building

After the giant engineering tire has completed the building process,the tire blank needs to be unloaded from the building machine for the next process.The traditional tire unloading method is single-point hoisting by crane,and manpower hits the tire blank to make it detach from the forming machine.For a 6-ton tire blank,the traditional unloading method is time-consuming and labor-intensive,and is prone to deformation of the tire blank and personnel safety issues.The self-designed tire unloading machine in this study realizes automatic and smooth tire unloading.While clamping the tire blank for space movement,it ensures the accuracy and performance of the tire blank,and solves the efficiency and safety problems of traditional tire unloading.When the tire blank unloading machine repeatedly drives the tire blank to realize a series of spatial actions such as turning and erecting,it puts forward high requirements on the mechanical properties and mechanism design capabilities of the equipment.Therefore,the mechanical analysis of this tire unloading equipment is carried out in this study.In view of the fatigue durability and structural design of the rotating connecting parts,the fatigue reliability and optimized design of the rotating connecting structure with large bearing capacity in the tire unloading machine is mainly studied.The main contents of this paper are as follows:Firstly,according to the multi-body dynamics theory,the virtual prototype of the tire unloader is established by using the numerical simulation platform,and the dynamic load spectrum of the key parts of the tire unloader is obtained.The rationality of the simulation results is verified by using the actual operation parameters of the tire unloader.Based on the load spectrum of the key parts,the fatigue life of the bearings and flanges on the tire unloader is predicted according to the equivalent stress method.Secondly,considering that the bearing at the lowest rocker arm bears complex random multiaxial stress and the material will produce additional strengthening effect,according to the critical interface multiaxial fatigue theory,the critical interface multiaxial fatigue life prediction model of the bearing is established by using the combination of numerical simulation and theoretical calculation.Thirdly,according to the different-dimensional interference fatigue reliability theory,the fatigue reliability model of the bearing at the bottom rocker arm is established by using the mathematical statistics method and the fatigue test data of the group method.Finally,according to the multi-objective optimization theory,the size parameters of flange connectors are optimized by using neural network and genetic algorithm.The research conclusions of this paper are as follows,the impact load on the bearing at the top guide wheel of the tire unloading machine can reach up to 260k N,and the resultant force of the bearing at the bottom rocker arm when the tire is turned over is 40k N.The life of the two bearings is both 10~3h.After the tire unloading machine completed 10~5tire unloadings,the fatigue reliability of the bearing at the bottom rocker arm dropped to 0.82.The connecting flange at the rotating part of the fixed ring has the shortest life due to the large torque,and the equivalent time is about171h.The life after structural optimization is increased by 71%compared with the original life,and the quality is reduced by 0.9%.