Thermal elastohydrodynamic lubrication analysis of nutation face gear transmission

Purpose The purpose of this paper is to analyze the influence of basic design parameters of nutation face gear transmission on the thermal elastohydrodynamic lubrication characteristics of grease lubrication, considering the influence of heat generated by frictional power loss between meshing tooth surfaces on the viscosity and density of lubricating grease in the flow and film thickness directions. Design/methodology/approach Based on the velocity separation method, the Reynolds equation corresponding to the constitutive equation of the Herschel Bulkley rheological model is given, and then the numerical calculation model of thermal elastohydrodynamic lubrication is established. Considering the influence of temperature rise between meshing tooth surfaces on the viscosity and density of lubricating grease in the direction of flow and film thickness, the multi-grid method is used to numerically solve the thermal elastohydrodynamic lubrication calculation model. Findings By comparing the thermal elastohydrodynamic numerical calculation results with the isothermal elastohydrodynamic numerical calculation results, the influence of the temperature rise between the meshing tooth surfaces on the film thickness and pressure in the lubrication area of the nutation gear transmission is obtained. Originality/value Based on specific working conditions and performance parameters of the face gear and lubricating grease, the influence of basic design parameters of the face gear transmission on the thickness and pressure of the film in the thermal elastohydrodynamic lubrication area is obtained, which establishes a more reasonable basis for judging the gear failure of nutation face gear transmission.