| As a new underground coal mine auxiliary transportation system,monorail has the advantages of strong maneuverability,good safety,high transportation efficiency and not restricted by the floor conditions of the roadway.It is widely used in coal mines.As a transportation device for coal mines,braking System of monorail are very strict.The stability of the braking process and the temperature of the friction surface are crucial elements for brakes.A large amount of heat will be generated during the friction process of the brake,which may cause the temperature of the friction plate to be too high to affect the braking performance.Frictional heat not only affects the friction and wear characteristics of the brake,but also has a great impact on the thermal deformation,thermal cracking,vibration,noise and heat decline of the brake.Therefore,the research of brake temperature field is of great significance.In this paper,the study was started from the monorail crane overall structure.The braking conditions and spring parameters were calculated,and the dynamic simulation analysis model was established.According to the results of the dynamic simulation analysis,a research method that the second dynamic simulation analysis could be conducted on the basis of conversion results to compensate for the lack of theoretical design was proposed.Secondly,based on the heat transfer equation and the thermal boundary conditions of the braking process,a mathematical model of the braking system temperature field was established.The model was simplified and the finite element analysis model was established in the light of the structural characteristics and load of the brake.Then,the thermal-structural coupling simulation of the friction pair of the brake system was carried out,the temperature distribution of the brake pad surface under different braking conditions was obtained.In addition,the influences of brake pad size,friction coefficient and load on the temperature field were analyzed.The simulation results based on dynamics and finite element was compared with theoretical temperature field.The results show that with the increase of brake pad radius and force,the maximum temperature of friction surface decreases gradually after braking.Under the conditions of fixed breaking force Ff and fixed brake pad force,maximum temperature of friction surface increases with the friction coefficient increases after braking.Simulation analysis based on dynamics and temperature field is closer to the real braking condition than simulation analysis based only on theory temperature field.Finally,a point temperature measuring device was proposed to measure the temperature field of the friction surface after braking,which solved the problem of the limitation of the temperature measurement space and eliminated the influence of the change of the brake pad force caused by the embedded method on the temperature field. |
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