Compensatory Capability Analysis of Gears Made up of Individual Discs

Abstract

Incomplete tooth edge contact, caused by manufacturinginaccuracy and gearbox partdeformation, isone of the reasons that limits gearload capacity. The uniform distribution of tooth contact over the entire crown width is providedby the gear wheels made up of separate toothed discs. Gear ring adaptability of a compound gear is achieved by overcoming friction forces or elastic flexibility of special elements. The article presents basic designs of compound gear wheels both with extra friction discs and toothed discs with spokes. The aim of the study is to quantify the compensatory capabilities of compound gear wheels. The most essential parameter determining the adaptability of a gear is the thickness of its toothed disccomponents. The influence of thin toothed discson the load capacity was considered: the edge effect in the contact stressdistribution; the tooth stability as a cantilever beam. The study was performed using the apparatusofstrength ofmaterials and the finite element method. It has been established that tooth stability isthe limiting factor. Toothed disc thickness can be reduced up to 0.1 modulewithout the risk of reducing the relative load capacity of the engagement. Multi-disc gears are hardly subjected to tooth failurecaused by uneven load distribution along its axis. Contact load uneven distribution decreases inversely to the number of toothed discs. Compound gear designs with elastic elements, in particular with spokes, are somewhat inferior to systems using friction elements in terms of the maximum angle of tooth axis misalignment. Nevertheless, their compensatory capabilities are an order of magnitude higher than those of solid gears.