Dynamic Simulation Of Herringbone Gear And Vibration Analysis Of Gearbox

The gear transmission,which is characterized by compact-sized,constant drive ratio and long service life,has become one of the most important transmission types and achieved rapid expansion.The time-varying mesh stiffness caused by the elastic deformation of gears and the cyclical continuing change of the gear pair makes the dynamic meshing force vary with time and finally leads to strong vibration of the gear box.In addition,during the process of meshing impact,the gear impact performance,the tooth contact dynamic stress,the dedendum bending dynamic stress and other performance index determine the bearing capacity directly.So it's of great significance to exactly predict the meshing stiffness and dynamic meshing performance index of gears and the vibration of the gear box.In this paper,based on the finite element analysis method for a certain herringbone gear box,the transmission system's dynamic simulation and the gear box's impact response analysis are performed.Firstly,the general solution process of the dynamic problems of the gear transmission system is summarized;taking some incentive parameters,i.e.,the gear transmission error,the comprehensive meshing stiffness and the meshing damping into consideration,the mathematical model of the herringbone gear transmission system which contains six degrees of freedom is built,and its corresponding mass matrix,damping matrix,stiffness matrix and external force vector are obtained.Secondly,starting from the helical gear transmission error with loading and using the static contact algorithm,the time-varying mesh stiffness of helical gears is obtained first,based on which,the time-varying mesh stiffness of the herringbone gear is easily calculated according to their parallel relationship;in addition,the effects of the gear hub,load and elastic modulus on the meshing stiffness of half of the herringbone gear are studied.Then,a herringbone gear model with all the meshing teeth is constructed in ABAQUS software;on the basis of it,the curves of the dynamic meshing performance index are acquired using the explicit dynamic contact algorithm and the effects of system damping,rotational speed and load on the gear dynamic meshing performance and the dynamic dedendum bending stress are studied.At last,the finite models of the gear transmission system and the gear box are built respectively;the modal analysis with constraints of the active-following axes and the gear box is performed;by the simulation analysis on multi-body dynamics of the herringbone gear transmission system,the reaction forces of the bearings of the active-following axes are calculated,and then the vibration response of the gear box is achieved combining with the modal superposition method.The study for the meshing stiffness and dynamic meshing performance of the herringbone gear transmission system and the vibration response of the gear box can be used to predict their dynamic characteristics under specific conditions to a degree,which can provide guidance to the dynamic design and vibration control.