Programs for the Preliminary Design of Nonstandard Gear Teeth 891931
Programs for personal computers or programmable calculators for the preliminary design of gears having external involute teeth with nonstandard proportions are described along with the formulas involved. They include the formulas necessary to produce an involute profile, a program to calculate the addendum radius for a given top land thickness and to solve a transcendental equation involved in that calculation, a program to calculate the contact ratio for two external gears in mesh, a formulation in terms of involute parameters of the Heywood-Cornell (modified Heywood) relation for tooth stress at the fillet, a program to evaluate this formulation, and a program to estimate the life of each of two gears in mesh as formulated at the NASA Lewis Research Center.
These relations are applied to the design of a gear pair to provide a 3:1 speed ratio for pressure angles of 14.5°, 20°, and 25°.