Scientific Journal of KubSAU

In the materials of the article we mention the regularities of changes in the volume and surface solid temperature gradients and self-ventilated brake discs and illustrate their impact on the main operating parameters of the friction pairs of disk-to-pad brakes of the A 172 bus; the relationship between thermo-physical parameters of polished and matte surfaces with areas of brake discs of various types. The influence of the type of tests on the pairs of loaded with energy friction disk and pad brakes of the vehicle. We have set the intensity of heat exchange processes from the surfaces of the brake discs of various types. It is shown that this leads to increased surface temperature gradient. The volume and the surface temperature gradients of the brake discs were determined with the involvement of the hypothesis of summation of temperatures on the surface when you post the generated electric currents. It was found that in the surface layer of the working surface of a solid brake disc at its pulse heating under the influence of the temperature of the flash nucleate cracks due to the thermal fatigue of the material of the disk. The features of the design of the brake discs were considered as well. On the basis of the calculation and the experimental data we have shown a correlation between the emissivity of brushed and polished surfaces and their areas in the disk-to-pad brakes when using solid and self-ventilated discs

We’ve illustrated assessment of energy-loading of disk-pad brakes of the bus A172 in the preliminary stages of tests type I and II according to regulated standards of UNECE and we’ve established regularities of heat exchange processes in the interaction surfaces of solid and self-ventilated brake discs with high-speed currents of washing air

We have illustrated multiple factor analysis of the dynamic friction coefficient of the friction units in tribosystem and tribounits under laboratory conditions. As the tribosystem we had a model band-block brake with regime parameters of the control handle tension of the brake and brake work. By using the method of the mathematical planning of the extreme experiments, we have obtained functional dependence of the dynamic friction coefficient of the variable parameters in the form of a second-order polynomial, which adequately describe the processes under study. As tribounit at the micro- and nanoscale there was the reference change of the dynamic friction coefficient of the pair "Retinax FC-24A – Steel 35HNL" as a function of surface temperature, the values of which correspond to certain laws, based on the rise and fall of the characteristics of the dynamic friction coefficient. We have made the evaluation of the dynamic friction coefficient on the principle of the superposition with the multiple factor analysis of the following parameters: the process of forced cooling and heating; the processes of the polarization and depolarization in the contact patch of the micropoints of friction pairs; the type of the contacts of the micropoints depending on the work function of the electrons and ions from materials; the formation of primary and secondary structures on the surfaces of frictional contact; the destruction and restoration of the pellicles on surfaces, etc. We have analyzed the results of the studies of changes of the dynamic friction coefficient on the macro-, micro- and nanoscale and we have found the basic factors affecting its value

We've illustrated self-regulation (based on the work function of the metal friction element) and the regula-tion by quasiconstant unit loads on the contact patch of micropoints of metal-polymer friction pairs of band-block brake for the evaluation of process of their normal wear