Loaded and Unloaded Tooth Contact Analysis of Spiral Bevel Gear in Consideration of Misalignments

Bevel gear pairs are employed extensively in transmission systems, such as vehicle transmissions (rear axle drive), aircraft engines/turbines, and helicopter gears, for transferring power between non-parallel shafts at high speed or torque. The most complex form of bevel gear is the spiral bevel gear (SBG). SBGpairs are commonly used in applications that require high load capacity at higher operating speeds than are typically possible with other types of bevel gears. Spiral bevel gears, when manufactured in a metal-cutting process, can either be produced in single indexing (face milling method, which is considered in this study), or continuous indexing (face hobbing method). Due to manufacturing imperfections and flexibility of components, the system might experience misalignments that intensify or exert a destructive effect on the gear vibration, which causes disruption in the stress distribution, thereby decreasing the lifetime of the gearbox. The main purpose of this study is to carry out the loaded and unloaded tooth contact analyses (LTCA and UTCA, respectively) for an SBG pair in the presence of two types of misalignments, axial and radial misalignments, and represent their effects on the mesh stiffness (MS). To calculate MS, it is essential to determine the geometrical mismatch between two mating tooth profiles, by means of UTCA. To conduct LTCA, three main approaches could be utilized: the finite element method (FEM), experimental, and analytical approaches. Thanks to the development of software packages during the last decade, in this study, Transmission3D-Calyx, a FEM-based software, is used to carry out LTCA and UTCA. Finally, the mesh stiffness for different misalignment cases are compared to represent the effect of misalignment on the SBGpairs.