Gears are one of the most important elements of any power transmission system. Among all types of gears, helical gears are more common due to their high capacity in power transmission as well as lower level of noise. The aim of this study is to present a model for analyzing the contact of teeth of helical gears considering thermal effects and surface roughness. In the present model, each helical gear is divided to several narrow spur gears in which each of the spur gears have a small rotation angle relative to the previous one. Also each contact point of gears is replaced with contact of two equivalent cylinders. Considering the fact that the governing regime for gears lubrication is the mixed-elastohydrodynamic regime, the total load is carried by lubricant and asperities' contact. Meshing and lubrication analysis of a pair of helical gears is conducted based on the load-sharing concept and parameters such as film thickness, friction coefficient and temperature rise are predicted. The predictions based on the load-sharing concept are compared to other published results Acceptable accuracy, short execution time along with considering thermal and roughness effects are some of the major characteristics of this study.

Keywords: Helical gear, Lubrication, Surface roughness, Friction coefficient, Film thickness of lubricant

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