Elastohydrodynamic Lubrication Performance of Curvilinear Cylindrical Gears Based on Finite Element Method

The fixed-setting face-milled curvilinear cylindrical gear features teeth that are arc-shaped along the longitudinal direction. Some researchers hypothesize that this arc-tooth may enhance the lubrication conditions of the gear. This study focuses on this type of gear, employing both finite element analysis (FEA) and analytical methods to determine the input parameters required for elastohydrodynamic lubrication (EHL) analysis. The effects of assembly errors, tooth surface modifications, load, and face-milling cutter radius on the lubrication performance of these gears are systematically investigated. The finite element model (FEM) of the gear pair is utilized to calculate the coordinates of contact points on the tooth surface and the corresponding contact pressures at the tooth surface nodes throughout a meshing cycle. Subsequently, the normal load on specific gear teeth is determined using a gradient-based approach. Entrainment speed, slip-to-roll ratio, and effective radius near the contact points on the tooth surface are derived through analytical methods. The data obtained from FEA serve as input parameters for EHL simulations. The lubrication performance of the curvilinear cylindrical gear is evaluated through example studies. The findings indicate that using FEA to provide input parameters for EHL simulations can reveal the occurrence of edge contact phenomena during gear meshing, allowing for a more accurate representation of the gear's lubrication conditions. The lubrication performance of the curvilinear cylindrical gear is shown to be independent of the face-milling cutter radius but is significantly influenced by the size of the contact pattern on the tooth surface. Curvilinear gears with larger contact patterns demonstrate superior lubrication performance.