A Simple Method for Calculating Maximal Surface Temperature of Mine Hoister's Brake Shoe During Emergency Braking

摘要

Since the emergency braking process of the mine hoister is very short, and also because the brake shoe generally has very poor conductivity of heat, so in engineering, in order to simplify the calculation of the maximal surface temperature of the brake shoe during an emergency braking, it may be feasible to take no account of the heat that the brake shoe has transferred into the surroundings. Based on the basical theory of heat transfer and the thoughts above, a simple mathematics model for calculating the maximal surface temperature of the brake shoe, was established in the paper. By contrasting of the calculation results with the experiment and simulation values, it had shown that the model can reflect correctly the changing rules of the brake shoe's surface temperature during emergency braking, that is, the temperature rises obviously with the increasing of the initial braking velocity. Because the heat transferred into the surroundings had been ignored during modeling, so the maximal surface temperature calculated by the model is always higher than the experiment value, and the difference increases gradually with the initial braking velocity increasing. When the initial braking velocity is no higher than 12 m/s, and the braking time is less than 8 s, which is also the actual working conditions of the mine hoister in China, the maximal surface emperature of the brake shoe which is calculated by the model, is quite similar with the actual value, and the deviation is no bigger than 5%.