Analysis And Optimization Of Static And Dynamic Characteristics Of A Double Lead Linear Feed System For A Sliding Block Grinder

Linear rolling guide pair is mainly composed of sliding block and guide rail,which is the core functional component of various CNC equipment.The processing quality of sliding block raceway surface determines the performance and life of linear rolling guide pair.In order to ensure the machining accuracy,it is necessary to use grinding as the last process of slider processing,so it is necessary to develop high precision and efficient special grinding machine.Grinding wheel feed system is the key part of grinding machine,its performance directly affects the precision and efficiency of grinding.Aiming at the problem of high speed and high mechanical resolution in traditional ball screw feed system,a double lead linear feed system with both high speed and high mechanical resolution was proposed.In order to fully understand the performance of the new feed system in the design stage,the static and dynamic characteristics of the system were analyzed in this paper.Based on the analysis results,combined with intelligent optimization algorithm,the static and dynamic characteristics based multi-objective optimization was carried out,which effectively guided the production of the prototype.The main research contents of this paper include:1.Based on Hertz contact theory,the contact stiffness calculation models were established respectively for the double nut ball screw bonding surface,double nut roller screw bonding surface and rolling bearing bonding surface,and the initial preload stiffness of the rolling bonding surface was calculated.The variation law of contact stiffness of rolling joint surface with feed acceleration(axial working load)was investigated.The equivalent transfer stiffness model of the double lead linear feed system was established,and the variation law of the equivalent transfer stiffness with feed acceleration(axial working load)and preload was investigated.2.Based on the calculation results of the contact stiffness of the rolling joint surface,in the finite element simulation software of Workbench,the contact characteristics of the roller screw joint surface,the ball screw joint surface and the rolling bearing joint surface were equivalent treated by orthogonal "Spring" element,and the statics simulation model of the double lead linear feed system was established.The stress distribution and static deformation of the double lead linear feed system under grinding conditions were analyzed.3.The modal analysis of the double lead linear feed system was carried out,and the first six order modal information of the system was obtained,and the influence law of the contact stiffness of the rolling joint surface on the first six order natural frequency was explored.On the basis of modal analysis,harmonic response analysis is carried out,and amplitude-frequency characteristic curves of the system in three directions are obtained.The influence of damping on amplitude-frequency characteristic curve is discussed,which provides a reference for improving the dynamic characteristics of the system.4.A multi-objective optimization of the static and dynamic characteristics of the double lead linear feed system based on genetic algorithm is carried out,and the optimization results are verified by finite element method.The results show that the maximum deformation of the feed system decreases from 10.50μm to 7.23μm and the stiffness increases by 31.4% under the condition that the mass of the double guide system is almost constant.The first three natural frequencies were significantly increased by12.9%,9.67% and 9.59%,respectively.The effectiveness of the optimization scheme is proved.