Shuting Li

Contact Stress and Root Stress Analyses of Thin-Rimmed Spur Gears With Inclined Webs

Loaded tooth contact analysis (LTCA), deformation, and stress calculations of three types of thin-rimmed spur gears with inclined webs at the left side, the center, and the right side of the tooth are conducted in this paper with finite element methods (FEM) combined with a mathematical programming method when these gears are engaged with a solid mating gear. The contact stresses on the tooth surfaces, the bending stresses at the tooth roots, and the joint stresses of the rim and the web are analyzed as the web position and the web angle are changed. It was found that the web position and the web angle of the thin-rimmed gears have a significant effect on the tooth contact stresses, the root bending stresses, and the joint stresses. The maximum contact stress of the right web gear becomes very small when the web is inclined from 0 to 30 deg, and it increases again when the web angles are changed from 45 to 60 deg. This interesting r-elationship between the web angle and the tooth contact stresses of thin-rimmed right inclined web gears is used to absorb the misalignment errors in the gears and improve the partial tooth contact pattern i-esultingfi-om the misalignment errors. A calculation example is provided to illustrate how to improve the partial tooth contact patterns in gears with misalignment errors.

A Challenge to Design of a New Harmonic Drive Device

A new silk-hat type of harmonic drive device (HDD) with arc flexspline (FS) structure is developed. Loaded gear contact analysis (LGCA) and stress calculations are made for it with three-dimensional, finite element method (3D-FEM). Basic performances and strengths tests are also made. It is found that the new structure almost has the same performances and strength as the old one.

The latest design technologies for gear devices with great transmission ratios

Four types of gear devices with great transmission ratios (simply called great ratio gears or GRG) are discussed in this paper. They are strain wave gearing device (SWG), trochoidal gear reducer (TGR), hipocyclic gear reducer (HGR) and James Ferguson type of planetary drive (JFD). Structures, advantages and basic performances of these four devices are compared. The latest design and strength analysis methods are also introduced. Finally, the future tendencies of the GRG are predicted.