An efficient dynamics model of spur gear drive with curved path of contact in mixed elastohydrodynamic lubrication

Abstract

Design of new tooth shapes have been the focus of gear researchers aimed at overcoming the defects of involute gears. For the spur gear drive with curved path of contact, normal contact loads between engaged teeth vary in direction and magnitude, which makes it difficult to build the dynamics model of the gear drive. The current models treat the curved path of contact as an equivalent straight line without considering directional variation of normal tooth loads. This paper presents an efficient tribo-dynamics integrated model for this type of gear drive including effects of alternate meshing of single-double tooth pairs. Directional variation of normal tooth loads is considered by invoking geometric parameters of meshing points instantly. And the transient lubrication properties in mixed elastohydrodynamic lubrication are also taken into account without extensive numerical simulations. The dynamics model of a gear drive with constant relative curvature (CRC gear drive) is given as an example. The model is verified with the results of the finite element model. The results indicate that the CRC gear drive has advantages over the involute gear drive in terms of lubrication performance and mechanical efficiency. The proposed model can be used to analyze dynamics features of gear drives with curved path of contact comprehensively.