Research On Pneumatic Braking System Of Mine Electric Locomotive

As one of the main tools of underground transport,the mining electric locomotive is utilized for 80% of the coal.Owing to the tractive tramcar without brake rigging,the braking performance of electric locomotive is of great significance to make sure the safe operation for the underground transport.At present,the brake rigging of electric locomotive concludes two major ones: hand wheel brake-shoe and pneumatic brake-shoe.As for the hand wheel brake-shoe,there exist many problems on the mechanical braking device,like the halfway of braking,travel with large empty,complex operation and so on.As for the latter,the pneumatic braking available now is such a mechanical device with pneumatic control rather than handwheel control.And there are still a lot of limitations when it's utilized in the case of emergency braking.Thus,it's of necessity and significance to design such a braking system with simple operation and high braking efficiency.As for the problems existing in the brake system of electric locomotive,this paper firstly puts forward a design of pneumatic brake system.And according to the main parameters from the study of the mining electric locomotive with 12 t,it chooses the tentative lectotype and makes the calculation of the main components.Next,the forces of the cartwheel and vehicle during the braking process are analyzed,which contributes to the establishment of dynamics model of the locomotive.Then,based on the theory of pneumatic transmission,the brake valve,the brake chamber and the mathematical model of brake are established in turn.Finally,with the help of Matlab/Simulink,a simulation model of the brake system of electric locomotive is set up.Through the simulation analysis of the dynamic process of pneumatic brake system,the law is obtained that the parameters of air chamber pressure,displacement of pushrod,braking torque and others which indicates that the brake system can make immediate response to the changes in pedal force.Also,the pedal force is ascertained when the electric locomotive slips under different rail surface conditions,which facilitates the driver's controlling the pedal force.Meanwhile,it's obtained that the braking distance is less than the limited range of colliery safety through the simulation analysis of brake performance,which shows that the braking performance of brake system meets the braking requirement of electric locomotive.Besides,it's studied that the system parameters exert influence on the brake system,which provides guidance for the trial-production of prototype.Further,with the help of ANSYS/Workbench,the rule of wheel temperature field distribution is analyzed under two kinds of working conditions,emergency braking and downhill holding brake.And it's recognized that the highest temperature of wheel in the process of braking is less than 150°C,the limit of colliery safety.According to the research results,the trial production of prototype of the mining electric locomotive is conducted.Meanwhile,the prototype is on industrial test.And the experimental result shows that the air impermeability and braking performance of pneumatic brake system meet the requirement of safe coal transportation.Besides,the highest air pressure is ascertained through the measurement of pressure drop of the air tank.