Generating standard 20° involute pinions with increased fillet strength by using 25° rack cutters with non-standard module

Abstract

According to all prevailing standards for gear design, a strict guideline is that the individual gears of a gear pair must be of the same module and pressure angle in order to mesh properly and the compatibility of the remaining geometrical parameters is determined under this assumption. However, in this article, the fundamental meshing principles of a generating rack and pinion are reinterpreted, and a more insightful form of the compatibility equations for involute gears is presented. In this context, stronger tooth forms with thicker root fillets can be produced using 25° rack cutters and still be able to mesh with standard 20° involute gears indiscriminately. The increased strength of pinions of the proposed design versus their standard counterparts is verified with finite element analysis.

Keywords

involute pressure angle non-standard module gear generation interchangeable gears fillet strength finite element analysis (FEA)

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