Experimental Research on Heavy-Duty Tractor Heat Performance of Brake 2009-01-3039
From the viewpoint of energy conservation and transformation, this paper researches on the braking heat generation and brake temperature change characteristics during heavy-duty tractors brake, and a temperature-predicting model of brake drum is established. According to this model, firstly the entire vehicle kinetic energy is distributed thrice between front and rear axle, tire and road surface friction and sliding friction between hoof and drum, between linings and brake drum, and then the input heat of each drum brakes is figured out through the transformed kinetic energy. Secondly, each brake drum absorbs the heat and results in temperature rise, and dynamics temperature of brake drum is calculated considered cooling due to radiation, conduction, and convection. Thirdly, according to a heavy-duty tractor cooling tests curves under different velocities, heat descending time and convection coefficient are enacted as two evaluation parameters of drum heat diffusivity; therefore the index formula of convective coefficients is induced. Finally, the repeated brake tests in accordance with national compulsory standards are carried out to verify the brake drum thermal model, and the result indicates that values of calculation have good consistency with the experimental results, then the model can be used to predict the brake hot performance in the design phase of heavy-duty tractor, so as to shorten the vehicle development cycle and reduce test cost.