| Hydraulic automatic gearbox is the main components of mine truck transmission system. Particularly the box should have high bearing capacity and reliability to adapt to the complex operation condition of mine cars. On account of its large power, complex structure and long design cycle, the transmission of domestic research and production is little and the domestic mining vehicles generally equip foreign transmission box. Therefore, it is very important to design and research the transmission of the mine vehicle.Firstly, gear number of hydraulic automatic gearbox is determined by the working conditions of mine car. The relation of mechanism freedom and the files and the planetary gear number is calculated from double-row planet-gear transmission. Base on double-line planetary gear, the different forms of multi-row planetary are found out by the adjacency matrix. By lever representation, various combinations of the planetary row are analyzed, and find out the control elements corresponding to the gear. According to the requirement of transmission gears, the transmission scheme is analyzed and the reasonable control component scheme is found.The basic structure of the planetary gearbox is designed, which is determined by the transmission scheme. Based on the power and speed of the mine vehicle, the basic parameters of the planetary gear are got by strength analysis and design of the planetary transmission mechanism through the traditional static method. By gear transmission ratio formula the basic parameters of the planetary are simplified and regarded as optimized parameters. According to the equal strength condition optimization objectives are set up, and regarded the design principle of the planetary gear as the constraint condition. After the optimization for the basic parameters of the planetary gear, the parameters are obtained accord with the equal strength conditions. Romax software is used to compare the stress and life of the planetary gear before and after optimization. As the result the stress of the gear is more balanced and the life is higher.The gear system dynamic performance is required to be studied based on the dynamic stability requirements of the planetary gear mechanism of the transmission box. According to the working condition of the gearbox, the translation-torsion dynamic model of the fifth and third gear transmission mechanism is established by lumped parameter method after the torque converter lock. The characteristics and sensitive of natural fraqenzy and vibration model of the gear system is obtained after analysis. The dynamic characteristic is more complex because of the incentive of the engine and hydraulic converter to the planetary gear system. Regarding the engine and hydraulic variable converter’s output as the main internal incentive and considering time-varying meshing stiffness and transmission error as dynamic incentives, the pure torsion dynamic mechanics model of the first gear is established. After simulating the condition by the Simulink software, the dynamic performance and frequency spectrum characteristics is got. |
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