Motion Modeling And Accuracy Characteristic Analysis Of Shaft Rotation Deviation

As an important part of rotating parts in precision equipment,shafting is related to the performance and value of mechanical equipment.With the continuous development of mechanical equipment in the high-precision field,the research of high-precision shafting faces new challenges.As the core component of the slewing system,the performance of the bearing is closely related to the slewing accuracy of the shaft system.Based on the geometric relationship of the shaft system components and the load constraint relationship,this paper completes the establishment of the rotary motion model of the deep groove ball bearing and the double-fulcrum supporting shaft system,and analyzes the error factors of the shaft system rotary motion accuracy characteristics.The main research contents are as follows:(1)The geometric properties of the rigid body’s fixed-axis rotation error motion are explained,the shaft system rotation accuracy evaluation model is established,and the error motion is evaluated by the rotation error motion invariant,so that the evaluation result is no longer the local characteristic of the shaft system rotation error motion,Which can better reflect the overall nature of the shaft error motion.(2)Based on the geometric displacement relationship and load constraint relationship of the internal components of the bearing,a bearing rotation accuracy model is established.The model considers the influence of geometric errors of bearing components,elastic deformation,time-varying stiffness of the bearing and other factors on the rotation accuracy of the bearing.(3)A shafting rotation accuracy model is built based on the bearing rotation model.Using the finite element method,the rotating shaft is equivalent to the spatial beam element,and the bearing stiffness matrix and the shaft stiffness matrix are combined to form the overall stiffness matrix of the shaft system.Through numerical solution,the rotation state of the rotating shaft is obtained.The model reveals the coupling relationship among factors such as geometric errors,elastic deformation and shaft assembly parameters,and can reflect the impact of bearing accuracy characteristics,shafting structure configuration and matching status on shafting accuracy.(4)Based on the rotation accuracy model of the shaft system,the rotation accuracy characteristics of the shaft system are studied from the four aspects of bearing rolling element diameter error,axial load,radial load and load position.The results show that: the diameter error of the rolling element will cause the rotation error of the shaft system to have a certain periodicity.When the error rolling elements are arranged at intervals,the rotation accuracy of the shaft system is the highest.Changes in axial load and radial load have a greater impact on the axial error of the rotary motion of the shaft system,but have a small impact on the radial error.For a double-fulcrum supporting shaft system with symmetrical bearings,when the load position is in the middle of the two bearings,the rotation accuracy of the system is the best.Through the analysis of the accuracy characteristics of the rotating motion model of the shafting,the influence of rolling element errors and load conditions on the rotating accuracy of the shafting is obtained,which can effectively guide the selection of shaft assembly process parameters and the shaft under specific conditions.Make a judgment based on the rotation accuracy.