PhD. Transactions of Machine Elements Division. Lund 1973

Abstract:

Internal involute spur gears are studied. Geometrical conditions are given. Non-dimensional quantities are derived and calculated for maximum contact pressure and maximum fillet tensile stress. The results are shown in diagrams.

To verify the calculations, photoelastic test and gear driving tests have been made. The agreement between calculation s and tests is satisfactory.

An optimum analysis is made, which show how to design internal involute spur gears considering gear strength. The comparison between different gears are based upon equal gear ratio, equal torque on the gear face, and either equal centre distance or equal radius of the gear root cylinder. The last comparison is dependent on whether centre distance or available extension is suitable.

The optimum gears show considerable modification factors, which implies that designer often must determine a minimum allowed toothe tip thickness in proportion to the module.