Static And Dynamic Characteristics Analysis And Optimization Research Of Spindle Box For Motorized Spindle Of High Speed Gantry Machining Center

A high-speed gantry machining center(motorized spindle structure)has been developed on the basis of the gantry machining center of the machine spindle produced by a company.The rotational speed of the machine tool can reach 18000-24000 rpm.It is mainly used in high-speed cutting.It has the characteristics of high speed,high precision,high flexibility and environmental protection.It has higher requirements on static and dynamic characteristics to the machine tool.This topic mainly carries on the static and dynamic characteristic analysis and the structure optimization(topology optimization)to this kind of high-speed gantry machining center spindle box component.It has the vital significance to enhance the spindle box static rigidity and the structure natural frequency,can reduce the machine tool component weight as well.(1)The background and significance of the research on the static and dynamic characteristics of the spindle box for the motorized spindle of high-speed gantry machining center and the current research situation at home and abroad are summarized,and the main research contents and research ideas of this paper are sorted out,which points out the direction for the follow-up study and lays a foundation.(2)The static characteristics of the original axle box are analyzed.This paper briefly introduces the finite element method and the basic theory of statics,which lays a theoretical foundation for analyzing the static and dynamic characteristics of the spindle box by using Ansys Workbench.The results show that the static deformation and structural stress are large,so the topology optimization and parameter optimization of the original spindle box are needed.At the same time,it is also necessary to ensure that the static stiffness does not reduce,as far as possible to improve the low-order natural frequency of the structure,so it is still necessary to analyze the dynamic characteristics of the spindle box.(3)The dynamic characteristics of the original axle box are calculated and analyzed.The basic principle and basic steps of modal analysis of mechanical parts by finite element method are summarized.Finite element method is used to calculate the first six modes of the original spindle box.The results show that the low order natural frequencies of the original spindle box are low and need to be further optimized.(4)Using topology optimization method to optimize the structure of the original spindle box,in order to better meet the requirements of the use of motorized spindle machine tools.The principle and mathematical model of topology optimization are introduced,and more reasonable structural optimization design requirements are put forward.The optimum design scheme of the spindle box structure is obtained by cutting the redundant part of the box,adjusting the thickness of the front wall and side wall,rearranging the position of the reinforcement and strengthening the nut seat of the back wall.The weight of the box is reduced by 45kg.(5)The static and dynamic characteristics of the optimized spindle box are analyzed.The results show that the static deformation and deformation trend of the optimized spindle box have no obvious change compared with that before modal.The maximum deformation of the optimized spindle box changes from 0.088333mm to 0.086499mm with a decrease of 2%.However,the stress distribution of the optimized spindle box is more uniform and the maximum equivalent stress is reduced from 9.8036Mpa to 8.3056 MPa and the reduction is 15%.The results of modal analysis show that the natural frequencies of the optimized spindle box increase by 6%-18%at different stroke.After optimization,the weight of the structure is reduced by 45kg,which accounts for 7.8%of the total weight of the spindle box parts,and the optimization effect is good.In order to verify the reliability of finite element simulation and optimization effect,the dynamic characteristics of spindle box before and after optimization were measured.This study provides a reference and research ideas for the static and dynamic characteristics analysis and structural optimization of the spindle box used in high-speed gantry machining center,and lays a solid foundation for the follow-up design and improvement of the spindle box.