A novel tooth contact analysis method for conical worm drives: An enhanced ease-off topography-based approach with conforming grid and TE-clearance assessment

Abstract

This paper focuses on the ease-off based tooth contact analysis (e-TCA) of conical worm gearing with twisted pinion tooth flanks. Existing methods have two significant drawbacks: 1) The calculation of ease-off values employs non-conforming grids, leading to errors, and 2) the determination of contact path boundaries lacks detailed research, resulting in contact patterns that do not reflect variations in the contact ratio. To address the first issue, a conforming discrete grid partitioning method is proposed, which ensures that corresponding nodes lie in the same tangent direction and uses tangent deviation to express ease-off, thereby eliminating errors. To solve the second issue, the TE-clearance formula is introduced, which reflects changes in the contact path length and boundaries under different preset clearance thresholds (PCT), capturing variations in the contact ratio. Additionally, the method for determining the working area has been optimized, making the e-TCA more reliable and enhancing the overall consistency and integrity of the contact curve calculation method. Finally, numerical examples and rolling tests verify the accuracy and advancement of the proposed algorithm, which is expected to replace rolling inspections and finite element analysis.