Optimization And Reliability Analysis Of JS40 Mine Gear Reducer

Gear reducer is an essential part of coal mine equipment, which takes on coal, materials and other important task of power transmission. Domestic coal mine gear recuder has an unreasonable structure. The distribution of multistage reducer’ ratios has significant influence on structure, volume, weight and working performance. The optimization design is the key to satisfy the intensity index achieving lightweight and improving the reliability. According to the distribution of ratios, the optimization design model has been established.Coal mine reducer’s operational condition is severe, installation maintenance is difficult. Under the working condition, the gear box scrap cycle is short. The reliability of gear reducer directly affects the production, economic and safety problems. The increasement of the gear box’s reliability and the improvement of lightweight have great pratical significance. The gear products do not have the conditions of large sample test, so that the problem of reliability analysis is outstanding, the reliability of gear reducer needs urgently to improve. The reliability analysis of fatigue strength has been studied which is based on Monte Carlo method in this paper. This method has laid a certain theoretical basis on the insufficient fatigue life experiment data of gear reliability analysis.1 Based on the equal strength and equal lubrication, the optimization model has been established, which was separated the spiral bevel gears from cylindrical gears. The optimization of the bevel gears has been achieved through selecting gear strength, the diameter of big gear, the transmission ratio as constraint condition. The stepwise optimization of cylindrical gear system has been used, namely a two-stage cylindrical gears’ contacting strength optimization and intergrated optimization design. The modules have been determined at the first step, the calucation of comprehensive optimization has been accomplished by introducting the modification coefficient, tooth shape coefficient, bending strength at the second step. The method can well satisfy the gear transmission about the lubrication, strength and the life of design requirements.2 Based on the strength calculation standars for gears, together with the stress and strength interference theories, the reliability calculation models have been established, which cover those for gear bending fatigue strength, contact fatigue strength and adhesion. The random numbers have been generated by Monte Carlo method, the reliability caculation of those gears’ failure modes have been carried out. The simulation of the stress and strength’ distribution characteristics has been accomplished. The bending stress obeys normal distribution, the allowable bending stress obeys logarithm normal distribution. The calculation contact stress obeys normal distribution, the allowable contact stress obeys logarithm normal distribution. Finally, the series system reliability is compared with multimodal failure related theoretical, the results prove that the calculation of reliability is correct by Monte Carlo method.3 On the basis of theoretical research on gear geometric design, strength calculation, reliability analysis, the calculation of gear geometrical parameters and reliability analysis program have been developed by Monte Carlo, the optimization design parameters are verified correctness by an example. The humanized interface saves time and remarkably raises the calculation efficiency.