| As one of the important parts of the running gear of the Fuxing EMU,the wheel axle plays a vital role in the safe operation of the vehicle.With the continuous increase of the driving speed of the EMU and the continuous increase of the load,the relevant research on the stress distribution and fatigue reliability of the wheel and axle press fit area is of great significance.In this paper,a certain type of CRH EMU wheel axle is the research object,the press fit of the wheel axle is simulated and analyzed,and the influence of different parameter changes on the stress of the wheel axle press fit area is discussed.Based on the measured dynamic stress data of the line,the axle pressure is compiled The load spectrum of the key parts of the assembly and fit;the fatigue reliability of the key parts of the wheel and axle press is evaluated according to the compiled load spectrum.The specific research content is as follows:(1)Established the 3D finite element model and axisymmetric model of the wheel and axle fit,respectively carried out the simulation calculation of the press fit of the wheel and axle,and found the rationality of the axisymmetric model instead of the three-dimensional model for the analysis of the wheel and axle press fit.The axisymmetric model is used to study the influence of interference,friction coefficient and press-fitting speed on the stress of the contact part of the wheel-axle press-fitting and the wheel-axle press-fitting force,which provides a certain theoretical guidance for ensuring the quality of the wheel-axle press-fitting.(2)The stress concentration of the transition arc part near the axle press fitting surface is analyzed.Based on the factory design parameters of the axle,the axle press assembly is studied when the axle is different in the transition arc radius,the journal ratio and the hollowness change.With the influence of the stress distribution of the matching parts,the specific changes of the stress in the wheel seat area of the axle with these factors are obtained,and the results can be used as a reference for scientific researchers when designing axles.(3)Compilation of stress spectrum and load spectrum of the key parts of the axle press fit: Analyze and process the time domain signal of the calibration experiment of the force measuring wheelset,and solve the stress-load transfer coefficient of the axle;Analyzed the measured dynamic stress data,studied the distribution characteristics of the axle stress under the different working conditions of the straight curve and the empty load;compiled the stress spectrum of the key parts of the wheel axle press fit and the transverse and vertical load spectrum of the wheel axle;based on the nuclear density The method extrapolates the entire spectrum obtained from the analysis and processing,and obtains the full life load spectrum and stress spectrum under the service life of the wheel axle.(4)Fatigue reliability assessment of key parts of the axle press fitting: According to the fatigue life curve of the material and the Miner rule,the fatigue reliability of the key section of the axle press fitting is evaluated based on the full stress spectrum and the extended stress spectrum under the full life;The equivalent load and extreme value of the extrapolated load spectrum applied to the axle,and the fatigue reliability of the axle wheel seat area where strain gauges cannot be pasted in the actual measurement of the line are evaluated based on the simulation results;the results show that the axle meets the service life requirement.On this basis,taking into account the static stress generated by the axle press-fitting on the axle,a comprehensive stress spectrum considering the effect of the axle press-fitting is compiled,and the comprehensive stress spectrum is used to evaluate the fatigue reliability of the key parts of the axle press-fitting.It shows that the comprehensive stress spectrum is used to evaluate the fatigue reliability of the axles,which is beneficial to further ensure the safe operation of the EMU. |
