| Abstrakt: |
The materials of the article consider and substantiate, based on the heat balance and rate of heating and forced cooling of the rim of the brake drum of the vehicle, the conditions of its thermal stabilization state. The thermal stabilization state of the brake drum depends on the thermal and electrical component. At the first stage in laboratory conditions by heating determine the time of thermal saturation of the rim and the flange of the brake drum of the vehicle. In the second case, heat losses are determined by radiation and natural convective heat exchange from the brake drum of a motor vehicle heated above the allowable temperature for the friction lining material. In the third stage. under operating conditions, heat losses are determined by conductive heat exchange from parts of the surfaces of the flanges of the brake drums of vehicles in their interaction with the surfaces of the flanges of the hubs of the rear axle of the vehicle A when. the fourth stage in operating conditions by cyclic braking proves the thermal state of friction pairs of the rear brake mechanism above the allowable for the material friction pads at 275 - 350 ° C and fix the sliding thermocouples their surface temperatures. When two electrically conductive phases touch, which are the surface layers of friction pairs of brake devices, there is a difference of electric potentials, which is associated with the formation of a double electric layer, ie asymmetric distribution of charged particles at the phase interface. In the case of operation of the polymer overlay in the mode above the allowable temperature for its materials, their binders (formaldehyde resin) burn out and the formation of liquid islands (electrolyte) on the working surface of the overlay. Thus, we obtain the first electrolytic solution. The second electric solution is irrigated water, which falls on the unprotected surfaces of the metal friction element between its microprojections. In the latter are the products of wear of friction vapors, which are mixed with water. In the future, two electrolytic solutions collide with different concentrations, which contributes to the difference of electric potentials. The latter occur due to the presence of gradients of temperature and concentration and are called thermodiffusion potentials. Polished and matte surfaces of brake pulleys have different topography of microprojections. The latter is constant for the matte surfaces of the pulley, and variable for the treadmill of the pulley due to its frictional interaction. In this case, a special zone of microrelief is formed next to the submicrorelief during the operation of the pulley rim on its friction treadmill, which has a height of microroughnesses several orders of magnitude greater than that of submicrorelief. Occurrence and formation of double electric layers in the temperature range below and above the allowable temperature for friction lining materials plays a significant role in the contact interaction of their surfaces with the surfaces of the metal-friction element. The catalyst for electrons and ions is the inner surface of the rim of the brake drum of the vehicle. It should be noted that the catalyst does not initiate the interaction, on the one hand, ionizing air flows, washing the working surfaces of the friction pairs of the brakes, as well as gas mixtures released from the near-surface layers of the linings. On the other hand, ie the outer (matte) surface of the rim of the brake drum of the vehicle is washed by countercurrents of air when the vehicle is moving. The catalyst only accelerates the reactions to the interaction, which can occur in its absence, but much slower. The occurrence of thermal diffusion in the streams of mixtures that wash the working upper rim of the brake drum of the vehicle and friction pads with the drum drum pad open depends on the ratio of the volumes of heated and cold layers. In the bar-bath-brake brake, the thermodiffusion effect in the gas mixture, which is in the gaps between their friction pairs, is observed if the ratio of the volumes of the heated and cold parts of the gas mixture changes exponentially. The interfacial boundary on the blocking shell, which is the working surface of the brake drum of the vehicle, does not allow charge carriers in two directions. [ABSTRACT FROM AUTHOR] |
