| Gear transmission is not only widely used in automobiles,ships and other fields,and the application in NC machine is more and more,with its compact structure,high bearing capacity,high efficiency,stable transmission ratio and so on.In the numerical control machine tool,the planetary gear transmission system is mainly used in the main drive and feed drive system,its dynamic performance directly affects the performance of the machine tool.Therefore,research on dynamic characteristics and transmission error of planetary gear transmission system used in the main drive system of CNC machine tool and feed system,which is important to improve the dynamic and static performance and machining precision.In this paper,the dynamic characteristics of planetary gear transmission system and its transmission error are studied based on a certain 2K-H type planetary gear reducer as the research object.Based on theoretical analysis and finite element analysis,the dynamic theory model and finite element analysis model of planetary gear were studied and established,and then the natural characteristics of the planetary gear transmission system and the dynamic response of the planetary gear transmission system are studied.On the basis of the dynamic model,the transmission error of the gear transmission system is analyzed and studied.The main research contents are as follows:(1)Based on the related literature at home and abroad,summarizes the current status of research on nonlinear analysis of planetary gear transmission system dynamics and the latest progress,initially identified the research ideas,research methods and means used to clear the research direction.(2)Using lumped mass modeling method,the planetary gear transmission of pure torsion and bending-torsional coupling nonlinear dynamics models were built to research the natural characteristics of the system,and the difference of the natural frequencies obtained by the two models is compared with the sensitivity analysis.It also provides the basis for calculating the initial time step of transient dynamics simulation.(3)On the basis of bending-torsional coupling dynamic model,time-varying meshing angle and gap were introduced and consider the gear tooth width direction swing due to uneven stress caused,the lateral-torsional-swing coupled nonlinear dynamic model of the planetary gear transmission system is established.And the fifth-order step-varying adaptive Runge-Kutta numerical integration method is used to solve the dynamic equation.Then the time doma:in method and the phase plane were used to analyze the dynamic response of the system.(4)The main source of transmission error of the system is analyzed from three aspects of manufacturing,assembly and operation.And based on the lateral-torsional-swing coupled nonlinear dynamic model,the transmission error of the planetary gear transmission system is studied.Taking into account contact ratio is not an integer so that the meshing stiffness of periodic changes affect the transmission accuracy of the transmission system,so this chapter focuses on the impact of the contact ratio of the transmission error.(5)Analysis of transient dynamics simulation of planetary gear model was carried based on FEM analysis software,and the analysis of the different meshing states of the sun gear and the planetary gear in a full engagement period provides a new way to solve the time-varying meshing stiffness.Based on the method of lumped mass model,this paper establishes the theoretical model of planetary gear transmission system,and studies its inherent characteristics,dynamic characteristics and transmission error.The influence of support stiffness on the performance of planetary gear transmission system is discussed,and the simulation analysis of planetary gear reducer is carried out by using large finite element analysis software.The research content of this paper lays a foundation for further research on the dynamic characteristics and structural optimization of planetary gear transmission system. |
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