Investigations on effects of lubrication environments on performance of spur gear hobbing

Abstract

Gears are the toothed mechanical components used for transmission of torque and/or motion between two shafts. They are classified according to relation of their mounting shafts. Cylindrical gears (i.e. spur and helical) are used for parallel shafts, straight and spiral bevel gears are used for intersecting shafts, whereas hypoid, crossed helical, worm, and spiral helical gears are used for non-parallel non-intersecting shafts. Spur gears are most commonly used in a wide range of domestic, industrial, commercial, and scientific applications. Quality of a gear is determined by its microgeometry parameters, flank surface roughness, and subsurface hardness as shown in Fig. 1. Gear microgeometry deviation parameters are categorized in form and location parameters. Form parameters include deviations in pitch (Fa) and lead (Fβ) of a gear. They significantly affect load carrying capacity and noise generation characteristics of a gear. Location parameters involve deviations in pitch (Fp) and runout (Fr) and are responsible for transmission efficiency and motion transfer characteristics of a gear. Tooth flank surface roughness parameters such as average roughness (Ra) and maximum roughness (Rmax) significantly affect the performance and service life of gears. A gear with minimum flank roughness and better surface integrity i.e. higher subsurface hardness enhance its fatigue strength, corrosion resistance, and tribology performance (Petare and Jain, 2018)