Robust Design of Gears With Material and Load Uncertainties

Traditionally gears are designed using design standards such as AGMA, ISO, etc. These design standards include a large number of “design factors” accounting for various uncertainties related to geometry, load and material uncertainties. As the knowledge about these uncertainties increases, it becomes possible to include them systematically in the gear design procedure, thereby reducing the number of empirical design factors. In this paper a method is proposed to eliminate two design factors (viz., factor of safety in contact and reliability factor) used in standard AGMA-based design procedures through the formal introduction of uncertainty in the magnitude of load and material properties. The proposed method is illustrated via the design of an automotive gear with a desired reliability, cost, and robustness. The solutions obtained are encouraging and in-line with the existing knowledge about gear design, and thus reinforces the possibility of schematically reducing the aforementioned design factors.