Internal involute spur gear pairs with improved efficiency

Eliminating all toothing non-geometrical parameters from the formula for the calculation of the sliding mechanical power loss in the spur gear teeth mesh, the geometrical friction loss function has been got. The minimum of this function for a gear pair with fixed module, number of teeth and centre distance corresponds to the optimal addendum modification coefficients, which results in minimal frictional losses. An experimental verification has also been made. II call be seen that an improper choice of the addendum modification coefficients can even double the mechanical losses and lead to high energy consumption. As the integral gear pairs are used most often in planetary gear trains, an optimization regarding their efficiency has also to be made. Practical approximative formulae for the determination of the optimal x-values will be proposed enabling their simple use in internal gear pairs calculation.