Influence of long wavelength gearing errors due to production and assembly on the excitation behaviour of spur gears in the high speed range

 

Starting Situation

Due to the increasing use of electric motors, gear noise is no longer masked to the extent that it is in vehicles with combustion engines. Low noise development is an important design objective in transmission development and represents an important quality criterion. The tolerances in production are often narrowed down as the manipulated variable for achieving the design criteria, since the effects of manufacturing and assembly deviations varying over the gearwheel circumference on the characteristics for describing the application behaviour are unknown in many cases. Usually, analyses and tolerances of defects are not carried out on all teeth, but on the individual tooth. However, the contact geometry in the tooth engagement during wheel rotation, which changes as a result of the deviations, has a decisive influence on the excitation behaviour. The influence of production and assembly-related deviations from the ideal tooth engagement, which do not only refer to a single tooth but to the entirety of all teeth of a toothing and are variable via these, has not been taken into account in the tooth contact analysis up to now.

Research Objective

The aim of the project is a method for the consideration of variable contact conditions due to manufacturing and assembly errors in the tooth contact analysis for the realistic description of the application behaviour of gears. This requires a novel procedure for controlling and evaluating a tooth contact analysis, which is carried out using the example of the "FE spur gear chain". With this method, an analysis of the influence of different types of faults, such as wobble, concentricity and pitch faults, for different IT qualities on the resulting application behaviour in comparison to an ideal gear set should be made possible. The evaluation is based on the rotation error spectrum. This creates a possibility to identify, for example, noise-critical excitation cases with regard to gear acoustics. Based on this, corrections can be designed and tested in a defined way to optimize the application behavior.