Research On Vibration Reduction Of XG50 Gearbox Of Wheel Loader Based On Particle Damping

XG50 gear case is one among core countershaft products manufactured by Xiamen XGMA Machinery Co.,Ltd.(XGMA).It is widely assembled in construction machinery,such as mining loaders,in complicated working conditions,contributed by its easy structure,great gearing efficiency and transmission ratio and high durability.However its violent vibration generated are incompliance with national and industrial standards,which blocks normal working of loaders.Hence,XGMA started a special project coded with NVH to deal with shock absorption.But,unfortunately,the related measures on improvements on rigidity of the case and machining precision of the gear failed.Given that,the paper is centered on particle damping technology deployed for the shock absorption,depending on discrete element method(DEM)combined with simulated analysis and real model test.Specially,the method acts on via augmented granular material into existing lightening holes of gearbox so as to increase structural damping and mollify the related vibration,which is of significance on theoretical research and engineering application in connection with damping and noise deduction.Specifications are listed as follows:Firstly,DEM-based simulated analysis is implemented for a connection between particle-filled ratio and operating condition of gearbox.A probe is conducted into inter-granular inelastic collision and frictional damping mechanism for the gear against centrifugal loads.Further study is,meanwhile,carried on calculation of the particle damping and mechanism trigged by the systemic excitation.And effect law on the anti-vibration imposed on a variety of loads,particle-filled ratios under rotated speed,and particulate matters.It is founded that there is no obvious effect driven by rotated speed on function of particle damper but obvious on particle-filled ratio if the particulate matter is fixed;performance of the particle damper is most effective if the ratio approximates to 96%.Damping effect of the damper is restricted by different loads,and the effect is best under the ratio ranged from 92%to 96%.The vibration can be reduced,to maximum degree,for the damper based on materials of particles,which is demonstrated that the reduction is maximized by ferroalloy particles under the same weight and by tungsten alloy ones under the same volume.Secondly a test bench is created in accordance with structures and operation principles of XG50 gear case.The bench goes into effect via simulated conditions of changing rotated speed and loading frequency and a comprehensive simulated test on account of anti-vibration plans designed by differentiated particle damping.In the end,it is concluded that simulation analysis perfectly fits test result and a detailed scheme on the XG50 is formulated to absorb shock in the help of particle damping technology,which works out through a comparison between theoretical calculation and practical text result examined by an effective value of vibration acceleration for the bearing block,facilitated by the test bench of dynamic gear and acquisition instrument of dynamic signal.