| The herringbone gear transmission has a number of advantages,such as stable transmission,high carrying capacity,large carrying capacity and so on.And it is widely used in heavy machinery,aerospace,shipbuilding and other industries.In recent years,the herringbone planetary reducer is developing rapidly towards high speed,light weight,and precision,which has put forward higher requirements for its vibration and noise reduction and lightweight design.How to accurately evaluate the dynamic performance of the gearbox has become a research hotspot in the engineering field.Under the support of the National Key R & D Program(Project Number:2018YFB2001502),this paper gives a finite element modeling method for herringbone gears and bearings,and uses nonlinear simulation technology to carry out dynamic contact analysis of the herringbone gear pair and a research on vibration characteristics of a NGW herringbone planetary reducer.The main research contents are as follows:The tooth profile equation of the helical gear with tooth profile modification is derived,and the APDL command stream for the finite element parametric modeling of internal and external herringbone gears is compiled.Combined with planetary gearing conditions,a finite element model of herringbone planetary gear pair is established.Combined with the Hertz contact theory,the elastic deformation and initial clearance at any azimuth angle are determined after ignoring the friction and lubrication effects of the bearing rollers and the inner and outer raceways.The structure and force form are analyzed,the internal load distribution law of the bearing is derived,and the force-displacement curve is obtained.The finite element model of cylindrical roller bearing in the dynamic analysis of herringbone planetary reducer is established.A finite element contact analysis model of the outer meshing herringbone gear pair is established.The dynamic change law of the contact stress,contact force and contact area of the herringbone gear pair during the meshing process are obtained by using LSDYNA simulation analysis.The effects of different speed,center distance error and tooth profile modification amount on dynamic contact characteristics are explored.The establishment of the finite element model of the gear pair-shaft-bearing-box system level herringbone planetary reducer is completed,and the free modal analysis and model correction of the box and herringbone planetary gear transmission system are carried out.Through the transient dynamics simulation analysis,the stress of each part of the reducer and the vibration displacement,velocity,acceleration andnoise of the specified measuring point of the box are obtained.The effect of different bearing radial clearance and tooth profile modification on the vibration characteristics of planetary reducer is studied,and it is concluded that radial clearance will increase the vibration intensity of the box. |
