Research On Modification Method Of Planetary Gears Of AT Transmission

As the core component of the power transmission of the AT transmission,the planetary gear train has obvious advantages in terms of transmission efficiency,transmission ratio range and load carrying capacity.At present,the domestic research on the gear modification of the MT transmission has been more comprehensive,but the research on the modification of the AT planetary gear multi-mesh pair gear is not yet in-depth.In this paper,the dynamic model of the AT transmission and the finite element model of the housing,planet carrier and ring gear are established.The contact spot experiment of the AT planetary gear train and the modal experiment of the housing are carried out.The influence of the meshing characteristics of the multi-mesh tooth surface is analyzed.According to the law,the sensitivity range of the modification factor is determined.A method for modifying the multi-mesh pair gear is proposed in conjunction with the orthogonal experiment method,and the influence of the modification factor of the planetary gear train on the performance of the AT system is studied.The research work of this paper mainly includes the following aspects:The principle and method of the tooth profile and tooth shape modification factor of the planetary gear system are theoretically explained,and the calculation formulas of the amount of drum shape and deflection of the helix angle with pin shaft floating,structural flexibility and gear manufacturing errors are introduced,This paper introduces the theoretical methods of maximum modification amount,modification curve and modification length of tooth root and root modification.A finite element model of the AT transmission housing,planet carrier and ring gear was established,and the dynamic characteristics of the planet carrier,ring gear and housing were analyzed,and the correctness of the shell finite element model was verified by the shell modal experiment.Established a planetary gear train dynamics model and an AT transmission dynamics model,and based on the planetary gear train dynamics model,preliminary analysis of the planetary gear train tooth surface meshing misalignment and contact spots,and through the contact spot experiment to verify the power of the AT planet gear train Learn the accuracy of the model.Based on the dynamic model of the AT transmission,the effects of the flexible deformation of the planet carrier,the ring gear and the housing on the planetary gear transmission error,meshing misalignment and other meshing characteristic parameters are analyzed.The influence of the pin shaft floating error on the planetary gear transmission error,load sharing coefficient and other meshing characteristic parameters is analyzed,and the influence law between the pin shaft tilt error and the modification factor is studied.Finally,the influence rule of gear manufacturing errors on the strength of planetary gears is analyzed,and the influence rule of planetary gear manufacturing accuracy and shape modification factors is also studied.Taking the normal load and contact stress of the tooth surface as the targets,the sensitivity range of the tooth direction and tooth profile modification factors of each meshing pair were determined respectively.Taking gear transmission error and contact fatigue strength coefficient as the optimization goals,the key modification factors and the modification scheme of multi-mesh pair gears were determined through orthogonal experiments.Based on the AT transmission dynamics model,the influence of the modification factor on the transmission error,strength,system transmission efficiency,vibration acceleration and noise radiation characteristics of the AT transmission gear is analyzed.The modification program obviously optimizes the performance of the AT transmission system and provides a feasible guide for subsequent AT system optimization.