Formula derived from particle swarm optimization (PSO) for optimum design of cylindrical roller profile under EHL regime

•Evaluation of a simple geometry for roller profiling.•Multi-objective optimization of thermal EHL problems including edge effects.•Analysis assumes optimal profile corrections assure uniform contact pressure.•Analysis included slenderness, load, and three mineral oil ISO grades.•The final formulas offer a rapid design tool for optimal roller profiles.

Roller profile corrections play an important role in EHL load capacity of cylindrical contacts. Recently, the authors published a 3D thermal EHL model and demonstrated that when considering pressure distribution uniformity, crowning modifications combined with rounded corners offer similar performances to that of logarithmic profiles, while conceivably being less difficult to manufacture. This paper develops formulas establishing crowning and corner rounding radii for rapid design of optimal roller. These formulas amalgamate results obtained from multi-objective particle swarm optimizations (PSOs) completed over a five-level dimensionless factorial design, with the factors being the slenderness, the load and the lubricant viscosity. The PSO optimizations integrated three concurrent objective functions: the contact pressure uniformity, the film thickness stability, and the maximum load capacity.

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