Study on the meshing evolving mechanism of a novel self-evolution hourglass worm drive

Abstract

To satisfy the increasing unique characteristics of high precision and heavy-load performance in industrial equipment, a novel self-evolution hourglass worm drive is proposed in this paper. It is consisted of an involute helical beveloid (IHB) gear and an oblique planar enveloping (OPE) hourglass worm, and this worm drive gradually evolves from a local conjugate hourglass worm drive with point contact in the initial meshing state, and a middle meshing state (MES) hourglass worm drive with short-line contact with continuous operation and wear, as well as the finally evolves into a toroidal involute (TI) hourglass worm drive with line contact. According to the differential geometry theory and the spatial meshing principle, the mathematical models of this novel self-evolution hourglass worm drive are established in each evolution stage, the theory of backlash-adjustable is confirmed with introducing a pair of transition tooth surfaces, and the meshing contact area evolution mechanism was defined and elaborated. In addition, the meshing performance evolution of the contact area and the bearing capacity are simulated by numerical analysis including tooth contact analysis and finite element analysis. The analysis results show that with the continuous evolution, the contact area keeps increasing, and the bearing capacity also keeps improving. This study will provide a theoretical basis for the industrial application of this novel hourglass worm drive.