Thermal Elastohydrodynamic Analysis of a Worm Gear

Abstract

This study explores the elastohydrodynamic lubrication (EHL) between the contacting tooth flanks of a worm gear with nonconjugate meshing action. The contact is characterized by a slender-like elliptical shape and high sliding. The geometry and contact conditions for the considered worm gear were obtained using tooth contact analysis. Based on that, the complete area of the worm gear contact was analyzed using a validated numerical EHL model considering non-Newtonian, thermal, and transient effects. The geometrical and kinematic design factors that influence EHL film formation in worm gears were identified and are discussed. The results show the specific characteristics of worm gear EHL contacts, such as the very slender contact in the tooth root flank area, which diminishes the effect of the entrainment speed on film thickness. EHL film formation could be supported by increasing conformity between the flanks to make the contact less slender. By comparing the film thickness results against analytically obtained ones, relatively large differences were observed except for one formula for minimum film thickness.

Performance improvement of set of worm gears used in soot blower through profile modification

“…Croccolo et al (2020) reviewed and gathered practical examples to provide valuable suggestions and guidelines for gear design, including dimensioning and lubrication. Tosic et al investigated the elasto-hydrodynamic lubrication (EHL) between the connecting tooth sides of a worm-type gear with meshing action of the non-conjugate; the connection type was a slender elliptical form with a rapid sliding rate, and the geometry and contact parameters for the worm-type gear were determined using toothtype contact analysis (Tosic et al, 2023).…”

Investigation of the Influence of Contact Patterns of Worm-Gear Sets on Friction Heat Generation during Meshing

“…This simulation model includes tooth contact analysis and tribological calculation to determine friction and wear. Tošić investigated the thermal effects of slender EHL contacts in the case of disc-disc contact [12] and contact of worm gears [13]. He introduced a numerical procedure for the investigation of the transient thermal EHL contact of worm gears with nonconjugated meshing action.…”