Dynamic Characteristic Analysis And Optimization Of Helical Gear System Of Mine Reducer

Mine reducer is a very important part of the coal mine machinery and equipment.It plays an irreplaceable role in the process of movement and power transmission.But it operates in the poor condition,works continuously for a long time,is affected by various impact loads.Its working performance directly affects the performance of the entire coal mine machinery and equipment.Therefore,it is necessary to study the dynamic characteristics of gear system of mine reducer and optimize the dynamic characteristics of gear system to improve the carrying capacity and service life of the mine reducer,reduce the vibration and noise.The main contents of this paper are as follows:(1)The two-stage parallel shaft gear system analysis model of mine reducer is established by Romax.The maximum contact stress、maximum bending stress and meshing misalignment of gears are obtained by statics analysis of gear system under the rated working condition.Then,the meshing state and the tooth surface load distribution of the two-stage gear pairs are analyzed to find out the pair of gears which bear larger and serious unbalance load.(2)The time-varying meshing stiffness and loaded transmission error curve of the output helical gear pair are calculated.The influences of different degrees of tooth surface wear on the meshing stiffness and transmission error of the helical gear are analyzed,which provide the basis for the analysis of dynamic characteristics of the gear system.(3)The modal flexibility of gear system under the error excitation of helical gear of the output stage is analyzed,and the first six modal frequencies of the system modal flexibility are found out.Then,the corresponding natural modal shapes are obtained by inherent modal analysis.The dynamic response of bearing force and bearing vibration acceleration of each bearing of the gear system is obtained,which is excited by the first stage harmonic of the output stage gears transmission error.The effect of different degrees of tooth surface wear on bearing force and bearing vibration acceleration is calculated.The definition of different types of tooth surface deviation is introduced,and the influences of different types of tooth profile deviation and helix deviation on the dynamic response of the system are analyzed.(4)The principle and method of the tooth profile and longitudinal direction modification of helical gear are introduced.In order to minimize the fIuctuation of gear transmission error,the tooth profile and longitudinal direction modification parameters of gear pair are chosen as the design variables,and the tooth surface of the gears are optimized by genetic algorithm.By analyzing the influence of each design variable on the fIuctuation of gear transmission error,the optimal design variables combination is obtained.Then the gear tooth surface is optimized twice,and the optimal modification scheme is obtained.The correctness of the optimization results is verified by comparing the gear meshing state and the tooth surface load distribution before and after optimization.