ABSTRACT

In order to be able to carry out an optimal gear design with the aim of cost reduction and the careful handling of resources, load capacity is an important criterion for the evaluation of a gear. Standardized procedures, such as ISO 6336 for cylindrical gears and ISO 10300 for bevel gears, are widely used and established in the design and evaluation of gears. In such procedures, the gear meshing is simplified to a single reference point and a comparative stress is derived. This simplification is based on experience and validation, but the influence of flank modifications is only approximated via factors.

Detailed flank modification design with consideration of all possible types of damage for bevel gears is only possible with the aid of local load capacity analyses. Depending on the load, the location of the maximum stress or damage can occur at different points on the tooth. When calculating load spectra, the minimum safety and the accumulated damage can be determined more precisely with local consideration of stresses, lubrication coefficients such as friction and film thickness, and geometry coefficients like sliding speeds. In addition, the local load distribution includes the interaction of the overall system with all of its components and their associated loads. For example, bearing stiffness and clearances, shaft bending and torsion, housing deformation, load-dependent center distance or gravity may be considered. This provides a more accurate picture of the stresses and quickly gives an overview of the possible resulting relevant damage forms.

In this paper, the currently available local methods for bevel gears are applied to cylindrical gears. This will demonstrate the benefits of local methods and how they can assist in the design of flank modifications. To validate the accuracy of the calculation methods, a well-documented series of tests from the literature is recalculated and evaluated.

Author(s): Dennis Tazir, Frederik Mieth

ISBN: 978-1-64353-163-2