Study On Friction Performance Of Wet Multi-Disc Brake

The wet multi-disc brake has been used widely in the mining rubber tire vehicle because of its large toque,good tightness and stable braking performance.But the various failure problems have occurred because of the complicated working environment and the working process of multiple physical field coupling,which endangers the safety of the coal mines.This paper,a mining rubber tire vehicle was used to be the object of research.The friction performance of brake was studied respectively for different working conditions under emergency braking and continuous braking on the basis of the previous studies.The main contents are as follows:Firstly,according to the tribological principle,the influence factors of friction performance for wet multi-disc brake were analyzed.And the calculation method and the testing principle of friction coefficient which evaluating the friction performance were introduced.Simultaneously,the friction process and mechanism of the wet multi-disc brake were analyzed,the contacting forms and the composition of friction were determined.Then the parameters of braking conditions were analyzed.Finally,the strained conditions were analyzed and the braking time was calculated.The above provide theoretical basis for the experiments and the simulations.Thie th,ermal-structural coupling theory of braking by friction was conducted on the basis of the tribological,heat transfer and elastic mechanics.And the 2D and 3D finite element models were established.The loading and thermal boundary conditions were confirmed.The change rules of temperature and stress under different working conditions was obtained by analyzing the temperature field and stress field.The testing experiments of brake performance were designed and carried out on the basis of the experimental design theory.The change of friction factor and frictional factor stability coefficient for different working conditions was obtained.By analyzing the different factors influence on the friction performance,the change rules of friction coefficient with the different factors and the values of the braking dangerous points were achieved.After contracting the rules with the results of the finite element simulation,the relationship between temperature,stress and friction properties was obtainedFinally,the mathematical model that the braking properties change with the temperature brake force and speed was established by the orthogonal regression test.And the significance test was conducted for the model.After analyzing the results of experiments,the effects of multiple factors on friction properties were obtained.And the optimal parameters in the working conditions for mining rubber tire were predicted by using the model,which provides some basics and experience for design and control of wet multidisc brake.