Locus of lubricating weak point for the toroidal surface enveloping cylindrical worm drive

Based on the lubrication angle field and the locus of lubricating weak point, the lubricating characteristic of the toroidal surface enveloping cylindrical worm drive is globally investigated. The nonlinear equation system to determine the lubricating weak point is established by utilising the lubrication angle. Generally speaking, the weak locus always exists roughly in the middle of the tooth surface of cylindrical wormgear and a zone with worse lubricating behaviour is around the locus. By increasing the number of worm thread, the locus of lubricating weak point can be completely removed from the wormgear tooth surface, and the locus approximately is in the shape of the inverse capital letter L. On this occasion, the entire wormgear tooth surface is half surrounded by the locus, and the overall lubrication performance of the worm drive is improved. The current research is an application of elastohydrodynamic lubrication (EHL) on worm drive.