Performance Analysis And Fault Diagnosis Of High-speed Train Gearbox

In recent years,my country’s high-speed railways have developed rapidly under the strong support of the state,and breakthroughs have been made in key technologies,not only in terms of mileage,but also in terms of speed.As a key transmission equipment for high-speed trains,gearboxes are operating under high-speed and heavy-load conditions for a long time,making their force and vibration signals very complicated.Therefore,it is very necessary to perform performance analysis and fault diagnosis of high-speed train gearboxes.The following researches are carried out in this paper:(1)The common fault types in gearboxes of high-speed trains are analyzed,and the vibration model of meshing gears is theoretically analyzed.When a gear fails,the frequency domain of the vibration signal will have a modulation sideband centered on the meshing frequency and the rotation frequency of the shaft where the faulty gear is located.The basic structure and vibration mechanism of the high-speed train gearbox bearing are explained.The calculation method of the characteristic frequency of bearing failure.(2)Using Geomagic Wrap software CAD reverse engineering technology to model the gearbox case of high-speed trains,use SolidWorks software to establish the gears and bearing parts of the gearbox,and assemble them with the case.Furthermore,the finite element modal analysis of the box was carried out,and the natural frequencies and modal shapes of each order of the box were obtained.It is found that due to the high natural frequency of the box,the low-frequency excitation of the train will not cause resonance of the box,and when resonance is caused by external excitation,the box may be deformed and eventually lead to the failure of the box.(3)Taking into account the track irregularities of high-speed trains,the UM software is used to establish the complete high-speed train model,and the external excitations of the gearbox under two working conditions,no track spectrum and with track spectrum,are obtained.In consideration of the above external excitation,the rigid-flexible coupling gearbox is simulated and the results show that the gearbox dynamics is studied by detecting the vibration signal at the point on the box,and it is known that the upper end of the pinion of the upper box and the lower box are The bottom vibration displacement and acceleration are relatively large,and the vibration displacement and vibration acceleration near the large gear of the upper case are relatively small.Experiments have been carried out to verify the reliability of the simulation model.(4)The high-speed train gearboxes containing faulty gears and faulty bearings were simulated and researched.Wavelet packets were used to de-noise the vibration signals of the box body by layers.The cyclic autocorrelation function was used to obtain the fault characteristic frequency,and the fault characteristic frequency was obtained.Compared with the theoretical value,the deviations are all less than 1%,which indicates that the wavelet packet noise reduction and cyclic autocorrelation function demodulation method is suitable for the fault diagnosis of high-speed train gearboxes.