Research On The Design Method And Dynamic Characteristics Of Bionic Gear Tooth Profile

Tooth broken is a common form of failure during gear meshing.It usually breaks from the root of the tooth.The main reason for the failure is the concentration of stress at the root of the tooth and the greater alternating stress during operation.In this disertation,a bionic gear is designed based on the involute tooth profile and the bionic stretch triangle,the meshing stiffness of the bionic gear pair is calculated using the finite element method,and the nonlinear dynamic characteristics of the bionic gear pair and the bionic gear-bearing system are analyzed.The main research contents of the thesis are as follows:(1)The simplified tangent curve is obtained through the bionic connection bearing method of the stretched triangle style of the tree trunk and the ground:y=a·tan(b·x)+c,as the transition curve of the involute gear tooth profile,using involute and tangent The function curve and arc are combined into a bionic gear tooth profile.The tangent curve is optimized using the finite element embedded optimization module,and a bionic gear with lower uniform stress,reasonable load distribution and higher carrying capacity is designed.An example is used to verify the advantages of the bionic gear over conventional involute gears in terms of static and dynamic tooth root bending stress.(2)The change of the tooth profile of the bionic gear reduces the tooth root bending stress and the load deformation value of the gear,which in turn also changes the time-varying meshing stiffness of the gear.The finite element method is used to calculate the time-varying meshing stiffness of the bionic gear and the involute gear,and the theoretical value of ISO6336 is compared to verify the correctness of the stiffness calculation method.The meshing stiffness of the bionic gear is increased by an average of 14% compared with the involute gear.The optimization of the shape of the bionic gear at the tooth root reduces the normal load force and the transmission error value of the gear meshing,and finally improves the time-varying meshing stiffness of the gear.(3)Based on the nonlinear dynamics theory,the dynamic characteristics of the bionic gear meshing pair are studied,and the time-varying meshing stiffness,transmission error,and tooth backlash are introduced into the torsional vibration model of the bionic gear meshing pair with single degree of freedom,using Runge-Library The tower method solves the time history diagram,phase diagram and Poincaré map of the system.Compared with the involute gear meshing pair model,the vibration displacement amplitude and vibration velocity amplitude of the bionic gear are smaller than those of the conventional involute gear.Better vibration characteristics.(4)The bearing support stiffness is introduced into the dynamic model,considering the vibration of the tooth surface friction in the direction of the vertical meshing line and the influence of the friction torque,a six-degree-of-freedom gear-bearing dynamic model is constructed.The phase diagram,time history diagram,Poincaré cross-section diagram and FFT spectrum diagram of the bionic gear-bearing system are obtained.The bifurcation diagram of the system is solved.Compared with the involute gear,the chaotic range of the bionic gear is smaller,the periodical motion state is entered earlier,the vibration displacement amplitude and the velocity amplitude are smaller,and the system dynamics characteristics are better.