| As a novel gear transmission method,the face gear transmission has advantages over traditional bevel gear transmission in terms of larger meshing overlap ratio,stronger load-bearing capacity,and small pinion floating installation.Due to its excellent splitting and combining characteristics,it has unique advantages in the main transmission system of helicopters.Vibration characteristics in gear transmission have always been an important technical indicator for evaluating gear transmission performance.Exploring the dynamic performance of face gear transmission and studying the design methods for vibration reduction and noise reduction of face gear transmission systems have become one of the current hot research topics.Therefore,this paper focuses on the dynamic behavior of orthogonal straight-tooth face gear transmission systems,mainly including the modeling of the face gear transmission system,the solution of time-varying mesh stiffness considering installation errors,the establishment of a dynamic model,the analysis of system vibration characteristics,and the design of vibration reduction for face gears.The main contents are as follows:(1)Based on the principle of tooth profile machining for face gears,the tooth surface equation of face gears is derived,and a model of the face gear transmission system is constructed.Point contact analysis and installation error analysis of face gears are performed.Furthermore,a precise solution model for time-varying mesh stiffness of the face gear pair is established,taking into account installation errors and gear tooth modifications,using Tooth Contact Analysis(TCA)and Load Transmission Contact Analysis(LTCA)technologies.(2)Based on the constructed TCA and LTCA models,quasi-static meshing performance analysis of the face gear transmission is conducted,and parameters such as tooth surface contact imprint,geometric transmission error,load transmission error,tooth surface load distribution,and load distribution factor are obtained.Furthermore,combined with the aforementioned timevarying mesh stiffness solution model,time-varying mesh stiffness simulation calculations are performed.By separately considering the effects of three types of installation errors and the coupled effects of installation errors on the face gear pair during meshing stiffness simulation calculations,the influence laws of bias error,axis inclination error,and their coupled effects on time-varying mesh stiffness are obtained.(3)According to the tooth meshing principle and face gear tooth surface equation,the threedimensional discrete point coordinates of the face gear tooth surface and transition surface are calculated.Based on this,the face gear three-dimensional model is generated using Pro/E software.Then,Ansys finite element analysis software is used to perform meshing stiffness simulation,and time-varying mesh stiffness curves are obtained.The simulation results are compared with the results obtained from the model proposed in this paper to validate the correctness of the time-varying mesh stiffness solution model.(4)Based on the theory of concentrated parameter modeling in system dynamics,a multidegree-of-freedom translational-pendulum-torsional vibration-coupled system dynamic model of face gears was established,taking into account excitations such as time-varying mesh stiffness,tooth surface friction,backlash,and static transmission error.The model was solved using the4th-5th order variable-step Runge-Kutta method,and the dynamic response of the face gear transmission system was obtained.The effects of excitations such as time-varying mesh stiffness,tooth surface friction,and mesh frequency on the dynamic characteristics of the system were studied by combining the bifurcation diagram,time history plot,and Poincaré section diagram of the system.(5)Based on the gear vibration and noise reduction design theory,the face gear system was designed for vibration reduction through cylindrical gear modification.The effect of gear modification on the system’s time-varying mesh stiffness was studied by simulation before and after gear modification.By incorporating the time-varying mesh stiffness after gear modification into the dynamic model,the impact of gear modification on the system’s vibration characteristics was obtained. |
PDF Full Text Request