| Planetary gear transmission belongs to field of compound gear transmission,is a kind of over-constrained transmission,often used in the core of important equipment,in transmission process is prone to uneven load,fracture and crack and other external problems and stiffness excitation,error effect,meshing impact and other internal problems.Most of existing studies on planetary gear transmission system focus on fault diagnosis methods and load sharing characteristics of system,but there are few studies on dynamic characteristics of the transmission system.Therefore,this topic takes singlestage involute spur gear planetary transmission system in the NGW type planetary gear reducer as research object.By combining simulation and theory,dynamics simulation model and shift-torsional dynamics model of the planetary gear transmission system are established respectively,and changing rules of the meshing force of the system under different driving values and load conditions are analyzed.Vibration response of transmission system under influence of rotative speed,eccentric error,tooth profile error and backlash is studied,and dynamic characteristics of system under influence of various factors are obtained.The main research contents and results are as follows:(1)Finite element analysis method was used to simulate and solve meshing stiffness of the sun gear and planet gear,and planet gear and ring gear against the single tooth respectively.Meshing stiffness of single tooth was superimposed to obtain meshing stiffness of multi-tooth meshing,and the comprehensive meshing stiffness of gear system was sorted out.Modal analysis of planetary gear transmission system was carried out,and changes of lower order natural frequency and frequency of vibration of system were obtained,and validity of model and results were verified.(2)Factors that have little influence on dynamic characteristics of transmission system were simplified,and translation-torsional dynamics model of transmission system of involute spur cylindrical planetary gear was established.System dynamics equation was derived according to geometric relationship in model,which laid foundation for subsequent solution and study of dynamic characteristics of gear system.(3)Based on Hertz contact theory,a virtual prototype of NGW planetary gear reducer was established,speed and contact force of meshing gears of some components in transmission system were analyzed respectively.Variation trend of each physical quantity in transmission system in time domain and frequency domain was obtained.It was found that variation range and period of gear meshing force varied with change of system speed.(4)System dynamics equation was established in MATLAB,and the ODE45 function was called to solve equation.Dynamic characteristics of planetary gear transmission system were analyzed based on bifurcation and chaos theory,time domain diagram,phase diagram,Poincare cross sectional view and fast Fourier transform(FFT)spectrum map were obtained under specific conditions.It is found that when the rotation speed of sun gear is changed,the system basically keeps periodic motion state under the condition of medium-low speed operation,and motion state begins to change under the condition of high speed operation.When eccentric error,tooth profile error or backlash value is changed at the same speed,system shows rich vibration response characteristics,which provides data support for studying the variation trend of dynamic characteristics of system under various error factors. |
PDF Full Text Request