Research On Reliability Of Chain Transmission System Of Scraper Conveyor Under Multi Engineering Conditions

The chain transmission system is the core subsystem of the scraper conveyor. In running process, the round link chain and sprocket will bear large static load and dynamic load, and are always in the environment under the impact and cycle load. Their respective performance and interaction property will directly affect the overall performance of the the scraper conveyor. Therefore, the stability and reliability of the chain transmission system will directly affect the work efficiency and transmission capacity of the whole machine. With the constant progress and development of the manufacturing technology of the coal mining equipment in China, the driving power and transmission capacity of the scraper conveyor become larger and larger, so the requirement to the reliability of the chain transmission system will be higher and higher. This thesis takes the reliability of the chain transmission system of the scraper conveyor under multi engineering conditions as the research object, aim at improving the comprehensive properties of the scraper conveyor, providing the method for the structure design and optimization of key parts of the chain transmission system and providing a certain theoretical basis for the safe operation and the improvement of the economic benefit of the chain transmission system, which have widely engineering application background and a certain academic research value.To reduce the cost of the simulation, this thesis establishes the simplified virtual prototype model of the key parts(namely, welding ring, forging ring, V-lock chain ring, scraper and sprocket) in the chain transmission system. The mechanical properties and fatigue damage of key parts are analyzed using the finite element method. The simulation results show that the key parts of the chain transmission system have good mechanical properties and impact resistance, and the fatigue failure is the main failure form of key parts; the anti-fatigue performance of the welding ring without considering the welding defect is better than the forging ring; there exist the low cycle fatigue and high cycle fatigue in the V-lock chain ring; the damage of the scraper under the condition of starting with full load is 1956 times larger than that under the condition of non-load starting, and the damage of the sprocket under the condition of starting with full load is the maximum. The mathematical model of the reliability of the chain transmission system is established based on the failure time weibull distribution fuction of the scraper chain. The simulation analysis of the chain transmission system is executed using MATLAB programming. The age distribution of the round link chain and the dynamic change law of the chain transmission system are analyzed and discussed when the scraper chain transports different materials. The optimum maintenance periods of the scraper chain system under different materials are selected by considering the safety and economy of the scraper chain system. The simulation results show that the optimum maintenance period of the system is 0.5 month when the material is the gangue; the optimum maintenance period of the system is 1.5 months when the material is the middlings; the optimum maintenance period of the system is 2.5 months when the material is the raw coal; the optimum maintenance period of the system is 5 months when the material is the clean coal.