| Shearer is the key equipment of fully mechanized mining in modern coal mine, the transmission of shearer mainly rely on gears, so the strength and life of gear have great influence on the safe operation of shearer and coal mining. The fault caused by gear happens every year. Therefore, it is of great significance for the operation and maintenance of the shearer to research on fatigue behavior and wear condition.In this paper, shearer transmission gear and oil monitoring technique are studied, research background and research status at home and abroad are introduced on the basis of consulting lots of reference. Fatigue behavior and wear properties of gear material 18Cr2Ni4 W and 17 Cr Ni Mo6 were tested and compared. Two on-line oil monitoring equipments which based on ferrography and particle counting technique separately were designed to monitoring the wear condition of transmission system according to oil analysis technique. The main content and conclusions of this thesis are as follows:On-line oil monitoring systems suitable for shearer transmission system were designed. Senors capable of monitoring viscosity, water content and contamination level of oil are intergarted, based on which the on-line oil monitoring system was built. According to the monitored data, wear condition of transmission gear could be analysed. Oil monitoring system based on ferrography can effectively monitor the shape and size of debris while the system based on particle counting technique could make a valid judgment on debris concentration and degree of contamination of the oil.FZG gear test machine was used to simulate shearer gearbox. The viriation of oil properties, concentration and size of debris, and surface texture during gearbox operates were gained through on-line oil monitoring equipments and off-line analysis methods. It was found that as the gearbox runs, the viscosity of oil under low temperature rises, viscosity-temperature performance deteriorates, the water percent of the oil rises. The higher the load is, the worse the oil viscosity-temperature performance and viscority under low-temperature performance get. The relationship of equilibrium temperature and operational condition is similar with "bathtub curve". Abnormal wear would increase temperature sharply.Scanning electron microscope, ferrography and particle size analyzer were used to observe the surface texture and shape features. The results show that concentration and size of debris grow as wear become serious, while the content of debris in 15-80 μm increases. The concentration of debris increases as the load increases. 18Cr2Ni4 W gear produce less debris than 17 Cr Ni Mo6 gear under same conditions, so 18Cr2Ni4 W shows better wear resistance. Besides, it was found that the debris of shearer transmission and gear text machine are mainly fatigue peeling block particle and thick laminar wear particles which are both produced by gears.A contamination level standard of shearer transmission was devised by combining NAS1638, SAE AS4059 and characteristics of gear debris. The contamination level of normal wear is below 8 and it means abnormal wear happens when contamination level is higher than 9. Besides, warning standard and corresponding measures of on-line oil monitoring for shearer transmission was made according to the standards of changing oil and the contamination level.In summary, the on-line oil monitoring system can effectively monitor the operational status of the shearer gear, the warning standard of oil monitoring is capable of issuing warning and corresponding countermeasures against abnormality of transmission system. |
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