Abstract
A pinion and a gear of a pair of spur gears usually have different the maximum root bending stresses because of using profile-shifted gears or thin-rimmed gears or internal gears. Because of inequality of the maximum root bending stresses, load-carrying capacity of the gear with smaller root bending stress is limited by the gear with larger one. If this limit can be removed, this pair of the gears can have greater load-carrying capacity than it has before. So, this paper presents an idea to remove this limit through designing a pair of spur gears with uniform maximum root bending stresses. It is realized through changing the tooth thickness of the racks on the pitch lines from a standard tooth thickness into a non-standard one. Tooth root stresses and surface contact stresses of a pair of spur gears with standard and non-standard tooth thicknesses are analyzed by loaded tooth contact analysis using the finite element method (FEM). Calculation results show that the load-carry capacity of the pair of the gears become greater when the pinion and the gear have the same maximum root bending stresses.
