ABSTRACT

In order to meet the increasing demand for high-performance applications in the area of power density, new material alloys and heat treatment processes for gears are continuously developed and investigated. The investigation of various combinations of materials and heat treatments are usually carried out by the evaluation of S-N curves. However, when generating S-N curves for the tooth bending strength, the influence of deviations in the area of the tooth root contour is often not considered and an identical tooth root contour is assumed for all investigated variants. An evaluation of the tooth quality of the test gears is usually only carried out for the area of the tooth flank by means of ISO 1328-1:2013 due to the lack of a uniform evaluation standard for the area of the tooth root. Accordingly, stress-increasing effects, such as changes in the tooth root radius due to deformations from heat treatments, are often not considered. Especially when investigating gears with an unground tooth root area, shape deviations from the heat treatment have a direct effect on the test results.

Therefore, in this study, the influence of tooth contour deviations on the tooth bending strength is investigated using different combinations of heat treatments and material alloys. With the aid of a tactile precision measuring system, the tooth root contours of different combinations are measured. The tooth bending strength of the measured tooth root contours are evaluated using both FE-based and standard-based (ISO 6336-3:2019) stress calculations. Finally, the effect of considering the measured tooth root contours on the determination of the tooth bending strength is demonstrated by an experimental investigation of the measured test gears.

Author(s): Christian Eggert, Dieter Mevissen, Jens Brimmers, Christian Brecher

ISBN: 978-1-64353-159-5