Static Characteristics Analysis Of A Hybrid Rotary Table And Optimization Of Texture Shapes

The rotary table,whose load-carrying capacity affects the performance of mechanical equipment significantly,is key part of large and heavy machine tools.The research objective of this project,a hybrid rotary table,carries the load mainly using the hydrodynamic pressure generated in hydrodynamic grooves when working.The groove shape plays an important role in determining the load-carrying capacity of the grooves,so designing and optimizing groove shapes is of great importance.On the basis of analyzing the lubrication performance of the rotary table,three optimization schemes of groove shapes are proposed.Specific work of this article reads as follows:(1)Geometric models of the hybrid rotary table and grooves on the upper surface of the middle ring were established firstly,then the computational model of oil film pressure was obtained.Next,hydrostatic performance characteristics of the rotary table such as load-carrying capacity and temperature rise were computed.Experiments were also carried out to verify the validity of the simulation results.(2)The hydrodynamic load-carrying capacity of the rotary table was set as the objective function and geometric parameters of spiral grooves affect the objective significantly were set as design variables to build an optimization model.Genetic algorithm was applied to solve the optimization model and the law of optimum solution under various working conditions was obtained.Through comparison between performance of the optimum groove and the original groove,the application value of the optimization model was proved.(3)Based on the spiral groove,a groove whose circumferential outline is expressed by logarithmic spiral equation combined with polynomial function was presented and the optimization model of its shape was established.Genetic algorithm was applied to solve the optimization model and the law of optimum solution under various working conditions was discussed.Through comparison between performance of the optimum changing-angle groove and the optimum spiral groove,the application value of the optimization model was proved.(4)A numerical model optimizing the shape of grooves with free boundary was proposed.The influence of the bottom shape of groove number on the optimum solution was discussed,and advantages as well as disadvantages of these optimization schemes were concluded by comparing the performance of these optimum grooves.The objective of the articles is to improve the load-carrying capacity of grooves by optimizing their shapes,and propose an effective optimization scheme by comparing the performance of the presented optimization methods.