Abstract:Time varying mesh stiffness is one of the main reasons leading to the vibration in a gear transmission system.In order to obtain more accurate dynamic characteristics of gear systems,it is important to investigate the influence of sliding friction and tooth deviation of a gear pair on mesh stiffness.A complete mesh stiffness model was proposed base on the improved energy method with consideration of sliding friction.According to parameter equations of cutting tool tooth flank,the parameter equations of both involute tooth profile and transition curve of gears can be obtained.The presented model considered the influence of wear and profile modification on mesh stiffness by utilizing parameter equations of gear tooth flank and the total mesh stiffness of two meshing gear pairs was obtained by the relationship of tooth clearances derived from tooth deviations and deformation under loading.The influence of tool fillet radius and sliding friction on gear meshing stiffness was analyzed.The total mesh stiffness,load sharing ratio between two meshing tooth pairs and loaded static transmission errors of wear gears and profile modification gears under different loading conditions were investigated.Numerical simulations showed that mesh stiffness decreases with the decrease of tool tip fillet radius.Sliding friction between meshing gear teeth increases the meshing stiffness during the access process but decreases it during the recess process,and the greater the friction,the greater the amount of change in stiffness.Especially under light loading condition,nonuniform wear of tooth profile induces remarkable mesh stiffness reduction and contact ratio decrement.When the load is greater than the profile modification design load,the benefits of modification are not obvious.If the load is lighter than the profile modification design load,the following problems may arise,such as a lack of mesh stiffness,a decrease in contact ratio and a significant increment of loaded static transmission.