2nd ICAI 2022

International Conference on Automotive Industry 2022

Mladá Boleslav, Czech Republic

Tram Gearbox Optimization in order to reduce Noise Emission Jan Křepela 1 , Miroslav Vintera 2 Wikov MGI 1, 2 Research and Development Zbečník 356, Hronov CZ-549 31 Czech Republic e-mail: jkrepela@wikov.com 1 Abstract The first part of this paper deals with optimization steps on the tram gearbox in order to reduce noise emission. The company Wikov MGI, within the project TAČR CKVD, has run experimental noise measuring on geometry and micro-geometry of helical gears. The results of those experimental measurements were used to reduce excitation from the gear mesh frequency. The second part of the paper deals with optimization of the gearbox as with a complex kinematic dynamic and acoustic model. This was done with help of the software Romax by the company Hexagon. This approach of the prediction of noise emitted from gearbox surfaces focuses on the noise caused by the gear mesh excitation which is further transmitted through the gearbox to its housing. The authors verified those methods on a gearbox prototype using test equipment. The prototype was custom-built for this purpose. Keywords: reduction of noise, geometry and micro-geometry of helical gears, noise emitting JEL Classification: Z 1. Introduction At present, there are more and more demands to reduce the noise emission of rolling stock gearboxes, but at the same time, there are also demands to reduce the weight of gearboxes to reduce energy consumption. Both of these requirements for rolling stock must not have the effect of reducing the required service life of a component such as a gearbox. Reducing noise emissions is a complex process that starts with reducing excitation sources, where the main source is the gear mesh frequency and harmonics. This excitation can be further amplified by various resonance frequencies, which can occur both in the torsional system, where are the rotating components of the transmission, and on the housing of the gearbox. There are also cases when the excitation from the gears is transferred to other components of the rolling stock chassis. Nowadays, not only the total sound pressure level or acoustic power in the entire speed range of the gearbox operating speed but also the tonality is limited in the technical specifications according to which the gearbox design is processed. All these requirements can only be met if both of these conditions are fulfilled. Firstly, attention must be paid to the detailed optimization of the macro-geometry and micro-geometry of the gears. Secondly, the designer can control the resonance of the torsional system as well as the gearbox housing. The use of comprehensive Romax gearbox design software allows Wikov MGI to meet these requirements. Over the past five years, Wikov MGI

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