Study On Nonlinear Dynamic Meshing Force Of Involute SplineCouplings In Aero-engine With Misalignment

Because of excellent load-bearing and transmission performance,involute spline couplings are widely used in important power transmission systems with large shaft diameters and large torques.As the loads are difficult,the involute spline couplings will be damaged seriously due to the vibration while running.In this work,based on the results and the deficiency of investigation on the involute spline coulings from home country and abroad,the involute spline coupling was taken as the object.Based on dynamic method,the change of the nonlinear meshing force and meshing torque of the involute spline coupling under misalignment were studied.Finally,the theoretical research results were verified by the vibration test of the spline coupling,which lays a good numerical foundation for the design of aviation involute spline coupling with high reliability,high precision and high life.The specific work of this thesis mainly covers the following aspects:(1)Designing the parameters and checking the strength.The structural design of the involute spline coupling was carried out according to aviation conditions,and the geometrical parameters of it were determined.Checking the strength according to the tooth surface contact,root bending,root shear and other strength conditions.Finally,the working conditions were met the working conditions;(2)Establishment of the dynamic model and equation of involute spling coupling.With the methods of mechanical dynamics and gear dynamics,a dynamic model of lateral and torsional vibrations of the involute spline coupling system was established.The dynamic differential equations were deduced,as well as the rigid body displacement and dimensionless were eliminated;(3)Deduction of mathematical formula of dynamic meshing force in involute spline coupling.The geometrical method was used to derive the formula of the relativity displacement and the meshing stiffness formula of the single teeth in the case of lateral vibration;the formula of the total meshing moment of the involute spline under the condition of misalignment and the total meshing were investigated.As well as the force component along the coordinate axis;(4)Analysis of the impact of misalignment on dynamic meshing force and meshing torque.The derived meshing moment formula and the total meshing force components along the coordinate axis were substituted into the established dynamic differential equations and solved in Matlab using numerically method.The total meshing force of the spline coupling in parallel misalignment along the x-axis was analyzed.The influence of misalignment on component,meshing torque,normal meshing force on one tooth along the x-axis,dynamic load coefficient and fluctuation amplitude were studied;the value and distribution of normal meshing force and their components along the coordinate axis at a certain time with misalignment were studied too.The results showed that when the splines were aligned,the load on each tooth was the same,and the component force in the X direction was not generated,so there was no excitation in the corresponding direction;The increase of misalignment will increase the amplitude and fluctuation range of the engagement force,engagement torque and dynamic load coefficient,and will seriously affect the loading of each tooth;(5)Experiment on vibration characteristics of involute spline couplings was carried out.Experiments were performed at different speeds,the theoretical results under different conditions were calculated and compared with the numerical results,the results was compared with the experiment.