The axial vibration of double helical gear transmission can cause the imbalance of axial force which could influence the change of gear engaging position

oscillation of the gearbox casing and even the failure of high speed and high power double helical gear transmission.According to the structure of double helical gear transmission

it can be viewed as two helical gear pairs with axial movements

and the dynamics model and vibration equations are established using the lumped parameter method.Considering time-varying stiffness

transmission error

helix angle error and eccentric error

and so on

forced vibration responses of the double helical gear transmission system are numerically solved

and the axial vibration displacements and their changing trends with helix angle errors are obtained.It is concluded that the axial vibration of herringbone gear transmission is due to the helix angle error and the time-varying mesh stiffness

which lays a foundation for the stiffness design of plain thrust bearing.