Experimental and theoretical assessment methods of mesh excitation in mechanical drive trains

Gearboxes are essential components in mechanical drive trains for power transmission. Besides a sufficient load capacity, design for a low noise emission is more than a convenience aspect, but for many applications, it is a substantial design objective. Especially for gearboxes with high rotational speeds, for example in the field of battery electric vehicles (BEV), wind turbines or aircraft engines, a design for low excitation is mandatory in terms of comfort and operational safety. The mesh excitation forms one of the main causes of noise generation in gearboxes. For the assessment of mesh excitation, there do exist both, experimental as well as computational methods. Common measurement strategies are airborne noise or structure borne noise measurement, whereas high frequency acceleration measurements directly at the gear wheel body represent a more direct method. With additional measurement of the absolute angle positions at the in- and output shaft of the gearbox, it is possible to determine the loaded transmission error experimentally (LTE). For the computational investigation of the mesh excitation there exist various programs, such as the software Dynamic Tooth Force Program (DZP), to calculate characteristic values like LTE or force excitation. Because of the wide variety of different numerical and experimental methods, an efficient application of those methods is essential. Thus, after a description of the basic principles of numerical and experimental assessment possibilities a recommendation for scope of application is given in this paper.