Anregungsgerechte Auslegung und Tolerierung schnelllaufender Getriebe unter Berücksichtigung kurz- und langwelliger Verzahnungsabweichungen

• Excitation-oriented design and tolerancing of high-speed gearboxes considering short and long-wave tooth deviations

Ahmad, Mubarik; Brecher, Christian (Thesis advisor); Gold, Peter Werner (Thesis advisor)

1. Auflage. - Aachen : Apprimus Verlag (2023)
Book, Dissertation / PhD Thesis

In: Ergebnisse aus der Produktionstechnik 41/2022
Page(s)/Article-Nr.: 1 Online-Ressource : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2022

Abstract

High-speed gearboxes are becoming increasingly important because of the rising electrification of drive components in the automotive industry. Current concepts show the trend towards electric drives with higher speeds than internal combustion engines. While the disturbing noise of the transmission is largely masked by the combustion engine, this is not the case when electric motors are used. Up to now, the focus in excitation optimization has been on the tolerance-related analysis of standardized modifications of the single tooth. Modifications that go beyond these standardized geometries, such as the flank twist, are rarely considered. In addition, the current design is based on the assumption of the same geometry (deviation) for each tooth. With the system of IT gear qualities used in this context, tolerances are defined primarily on the basis of manufacturing and not on the basis of functionality. The objective of this dissertation is the development of a method for the excitation-oriented design of high-speed gears. Both short-wave and long-wave excitation characteristics of cylindrical gears are considered. The main focus of the work is on the detailed understanding of the contact conditions due to the flank twists, eccentricities, wobble and pitch deviations and the resulting excitation and noise behavior. The first part deals with the verification of the functional potential of the flank twist. For this purpose, the modification of a series gear set is extended by a targeted flank twist as a variation parameter for the optimization of the excitation behavior. The second part deals with the effects of long-wave deviations on the meshing conditions and the acoustics of the gears. For these investigations, eccentricities, wobble and pitch deviations are specifically introduced into the gearing .In the third and fourth parts of the dissertation, the findings are applied to a vehicle gearbox. In addition, a deeper understanding of the contact conditions resulting from the deviations is developed and, based on this, analytical correlations are derived which can be used to directly determine the contact distances and the transmission error. The correlations verified with a tooth contact analysis can finally be used to derive functional parameters for the excitation-oriented tolerancing of long-wave deviations. In summary, the developed method can be used to determine deviation limits that must be followed in order to achieve a defined excitation for a given gear geometry. Conversely, it is also possible to determine the resulting excitation behavior for the specific gear case when a deviation occurs. These findings can support the design process with little knowledge and experience in the definition of assembly and manufacturing deviations and effectively save costs.

Institutions

• Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University [417200]
• Chair of Machine Tools [417310]