A Deterministic Elastohydrodynamic Lubrication Model of High-Speed Rotorcraft Transmission Components

Abstract

Abstract This paper describes a deterministic approach to analyze elastohydrodynamic lubrication (EHL) of helicopter transmission gear surfaces with asperities. A thermal, non-Newtonian, model, accompanied by three specialized models is used to study the mechanisms of film generation, pressure distribution and temperature distributions within the fluid and on the surface, in an EHL line contact. A two-slope viscosity-pressure model is used to avoid overestimation of the viscosity of the lubricant under heavy loads. The three-dimensional roughness description of an actual gear tooth surface is measured using a non-contact surface profiler. The pressure distribution, film thickness distribution and the temperature rise at the contact surface are predicted as a function of the gear operating conditions including normal load, lubricant temperature and rolling/sliding speed. Presented at the 57th Annual Meeting in Houston, Texas May 19–23, 2002 KEY WORDS: Elastohydrodynamic Lubrication (EHL)Non-Newtonian LubricantsSurface Roughness EffectsThermal Effects Notes Presented at the 57th Annual Meeting in Houston, Texas May 19–23, 2002