Fault Simulation Of Gear System Base On Rigid-flexible Coupling Dynamic Model And Experimental Study

The gear transmission system is widely used in industrial equipment,and its health directly affects the reliability of equipment.According to the classification of structure,the gear transmission system can be divided into fixed-axis gear system and planetary gear system.Due to the different structures,the characteristics of the vibration response signals are greatly different.The study on the box vibration response signal characteristics of fixed-axis gear system and planetary gear system under the condition of fault and fault speed fluctuation is conducive to better condition monitoring and fault diagnosis of gear system.(1)Based on the multi-body dynamics software LMS Virtual.Lab,the advantages and disadvantages of gear contact force and CAD contact force in gear box fault simulation were studied.Compared with gear contact force,CAD contact force is more suitable for gearbox failure simulation.(2)The rigid-flexible coupling model of the fixed-axis gearbox was established by means of CAD contact force,and the correctness of the fixed-shaft gearbox model is verified under the fixed-speed operating conditions and the speed fluctuation conditions.Under the condition of constant speed,with the increase of the degree of fault,the amplitude and width of the fault modulation sideband corresponding to the impact type fault and the stationary fault respectively increase.Because of the existence of the fault-speed fluctuation,the vibration response of stationary fault and impact fault has a phase modulated side frequency band with the speed fluctuation frequency as the interval on both sides of the meshing frequency.The amplitude of the phase modulation side band and the frequency band width is closely related to the lowfrequency component of the speed amplitude spectrum.Lastly,the simulation results are verified by experiments,and the frequency domain characteristics of vibration response obtained by experiments are completely consistent with the simulation results.(3)The rigid-flexible coupling model of planetary gearbox is established.Considering the speed fluctuation of the sun float,the peak near each order of the meshing frequency order and double sun gear revolution order modulate sidebands has the modulation sidebands which is modulated by twice the sun gear relative rotation frequency order.Considering the speed fluctuations caused by the sun gear stationary type fault or impact type fault,asymmetric phase modulation sidebands at intervals of the fault frequency order appear at the peak order near each order of the meshing frequency order,twice the absolute revolution frequency modulation sidebands of the sun gear,twice the relative revolution frequency modulation sidebands of the sun gear.The amplitude and width of the phase modulation sidebands are also closely related to the low-frequency components of the rotation speed amplitude spectrum.Through experiments,the frequency domain characteristics of the vibration response of the box under the conditions of the sun gear steady-type fault and impact-type fault are obtained,and the correctness of the simulation is verified.