In theory, the higher the gear machining accuracy level, the better the dynamic performance of the gear drive system, but the higher the accuracy, the higher the cost.It is necessary to compare and analyze the dynamic characteristics under different machining accuracy levels for gear transmission system, so as to adopt reasonable gear machining accuracy and provide reference for further dynamic performance optimization design.
The load sharing coefficient of planetary transmission system is related to the phase difference of time-varying meshing rigidity of each gear pair and various errors existing in the system. Among them, reducing errors plays a great role in improving load sharing characteristics.In order to guarantee the load-sharing performance of planetary gear drive and keep the machining accuracy level of each gear of planetary gear unchanged, the fixed shaft gears are adopted 5-stage accuracy, 6-stage accuracy and 7-Stage accuracy respectively.According to the mechanical design manual, the pitch deviation and tooth tolerance of each fixedin microns can be obtained with 6-stage accuracy and 7-Stage accuracy.
The bearing and shaft forces of the gear drive system are related to the meshing forces of each gear, and the maximum meshing forces of the no-load gear are consistent with the change trend of the mean square root value.Emphasis is placed on analyzing the influence of different gear machining accuracy levels on the maximum dynamic meshing force of each gear pair.Under gear 1-8, the maximum dynamic engagement force of each gear pair under different gear machining accuracy is shown as the figure. The transverse coordinates, the maximum dynamic engagement force of inner and outer gear pairs representing planetary row, the transverse coordinates 1 and 2 represent the maximum dynamic engagement force of inner and outer gear pairs in planetary row K 1, and the transverse coordinates 5-8 represent the maximum dynamic engagement force of each fixed-axle gear respectively.
It can be seen from the diagram that gear machining accuracy has little influence on dynamic characteristics in 1-4 gears, which indicates that improving the precision level of gears can not significantly improve the dynamic characteristics of gear transmission system in low gears.Under 5-8 gear, the dynamic load of gear system is very sensitive to the change of gear machining accuracy level. At the same time, with the improvement of accuracy, the dynamic load of gear transmission system is significantly reduced.For example, under 7-Stage accuracy, the maximum dynamic engagement force of most gear pairs in 6-8 gears can increase by 50%-100% compared with that of 5-stage accuracy and 6-stage accuracy.
At the same time, because the precision level of planetary gear drive remains unchanged, the dynamic load changes slightly in each gear.In general, improving the gear machining accuracy level does not improve the dynamic characteristics of the gear drive system in low gear, but it can significantly improve the dynamic characteristics of the gear drive system in high gear.