Study On Time Varying Stiffness Calculating And Dynamics Modeling Of Fault Gear

Due to its extensive use of gear transmission systems in mechanical transmission,it is the most frequently failed part of machinery.In order to prevent catastrophic accidents caused by sudden failure of gears,it is necessary to study the mechanism and characteristics of gear failures.The complex working condition of gear transmission system and its load will have an impact on the gear failure.Therefore,the research on gear transmission system becomes extremely difficult,and the obstacle to the fault prediction technology of gear transmission can be imagined.Therefore,the dynamic modeling of gear failure and the calculation of gear tooth failure stiffness have important theoretical value and engineering valueIn this paper,a single-stage cylindrical spur gear is taken as the research object.The meshing stiffness model of healthy gear,chip gear,crack gear and broken gear is established by energy method.The time-varying characteristics of meshing stiffness are studied.In this paper,the dynamic model of gear transimission system is established.The faulty and fault-free gear transimission system is simulated and the dynamic response of gear transimission system is obtained.By analyzing and comparing the dynamic response of system with and without fault,The influence of gear dynamic characteristics provides a theoretical basis for the fault diagnosis of gear drive system.At the same time,in order to make the simulation of gear transmission system more convenient,this paper established the dynamic simulation interface of gear transmission system.The main contents of this paper are as follows:(1)Based on the energy method,the bending stiffness,axial compression stiffness,shear stiffness,Hertz stiffness and matrix stiffness were deduced.Finally,the computational model of time-varying meshing stiffness of healthy gears was obtained.And through the numerical calculation software to calculate the stiffness model,get the time-varying meshing stiffness of healthy gears.(2)On the basis of the calculation model of the health gear stiffness,combined with the characteristics of the gear failure,the time-varying meshing stiffness calculation model of the pinion with the chip fault,the crack fault and the broken tooth fault is obtained.And by numerical software,The time-varying meshing stiffness of pinion is simulated and the time-varying meshing stiffness of the faulty gear is obtained.(3)The dynamic model of 6-DOF spur gear transmission system is established in this paper,and the integrated time-varying mesh stiffness is introduced as the fault excitation parameters.The simulation results show that the dynamic response of healthy and faulty gears under different faults is simulated by using the time domain And frequency domain analysis method to analyze the result of dynamic simulation.By comparing with the dynamic response of healthy gear,the influence law between gear failure and vibration response was obtained.(4)The gear dynamics simulation model is integrated into a software to design the interactive interface of gear dynamics simulation,which can be more convenient to simulate the gear dynamics model through the interaction interface.