A novel method to study the long period three-dimensional vibration characteristics of herringbone gear with asymmetry pitch deviation

Most of the existing dynamic models of herringbone gear assume that the three major internal excitations, namely, the comprehensive mesh stiffness (CMS), the comprehensive mesh error (CME), and the meshing impact force (MIF), are the same at each meshing period. However, due to the inevitable asymmetric pitch deviation in the machining and installation process, the three internal excitations are coupled with each other and vary in a long period. In addition, since the driving gear usually adopts an axially floating support, this in turn gives rise to a unique axial displacement (AD) excitation of the herringbone gear. Firstly, an improved loaded tooth contact analysis (LTCA) model of herringbone gear with asymmetric pitch deviation is established, and the coupling relationship between multi-source excitation is explored. Secondly, a nonlinear dynamic model of herringbone gear with asymmetric pitch deviation is proposed, and the above multi-source excitation is introduced into the model to study the effects of load, speed, and asymmetric MIF on the long period three-dimensional (3-D) vibration characteristics of herringbone gear. Finally, the correctness of the theoretical simulation results is verified by experiments. The proposed novel method can predict the 3-D vibration characteristics of herringbone gear more realistically and effectively.