LAUSR

Abstract This paper presents a novel calculation method for dynamic excitation of the 3-D modified double-helical gear pair in consideration of actual contact state. The 3-D modification method combines tip, root, and axial modification. Firstly, the tooth surface equation of double-helical gear with 3-D modification is derived and the calculation method for time-varying mesh stiffness (TVMS) of the modified double-helical gear pair is proposed and the effects of modification parameters on TVMS are studied. Secondly, the tooth surface load distribution is analyzed on the basis of TVMS for the double-helical gear pair. Accounting the influence of modification parameters on tooth surface friction coefficient, the time-varying friction excitation (TVFE) of the modified double-helical gear pair is researched. Besides, combining approach mesh stiffness of the modified double-helical gear pair and impact dynamic model, the calculation formula of meshing impact force (MIF) is proposed, and the effects of helix angle and modification parameters on MIF are discussed. The calculation methods of TVMS, TVFE and MIF proposed in this paper will be useful for accurate prediction about vibration and noise of the double-helical gear system.