2nd ICAI 2022

International Conference on Automotive Industry 2022

Mladá Boleslav, Czech Republic

Analysis of the Effect of Gearbox Design on Gear Meshing Josef Bradáč 1 , Vojtěch Dynybyl 2 , Martin Hrdlička 3 , Bohuslav Novotný 4 , Jaroslav Prokop 5 , František Starý 6 ŠKODA AUTO University 1,2,6 Department of Mechanical and Electrical Engineering Na Karmeli 1457, Mladá Boleslav, 293 01 ŠKODA AUTO a.s. 3,4,5 tř. Václava Klementa 869, Mladá Boleslav, 293 01 Czech Republic e-mail: josef.bradac@savs.cz 1 , vojtech.dynybyl@savs.cz 2 , martin.hrdlicka@skoda-auto.cz 3 , ext.bohuslav.novotny@skoda-auto.cz 4 , jaroslav.prokop2@skoda-auto.cz 5 , frantisek.stary@savs.cz 6 Abstract The transmission is an integral part of every car and contributes to its operating efficiency and driving acoustics. The design and construction of the transmission must therefore keep in mind the basic requirements of trouble-free functionality, long service life, high efficiency, and low noise. In this context, the aim of this paper is to present some design elements of gearboxes that affect the gear mesh. This in turn affects the gear mesh of the gearing and its acoustics. The structural elements that affect the gear meshing are not always included in the design of the gear set. Therefore, the influence of the applied bearings and the effect of the shifting mechanism are analyzed in detail in this paper. Keywords: gearbox, gear meshing, acoustics, bearings, shifting mechanism JEL Classification: L74, Q55, R41 1. Introduction The gear tooth contact pattern influences the pressure distribution during power transmission and transformation (Moravec, 2009). The contact pattern is the area of the tooth flank that is used during the real shot. It is therefore the area created by the mutual contact of the individual teeth during the mesh (Pavlík, 2020). We must distinguish the one path contact pattern when two specific teeth are engaged, i.e., one contact of two teeth during engagement (one tooth path) under specific load, speed and part temperature conditions. And then the total contact pattern, which can be defined as the contact pattern appearing on one tooth after contact with all teeth of the mating gear under constant conditions of load, speed, and temperature of the parts (sum of individual contacts), see Figure 1. The size of the contact pattern is then directly influenced by the size of the instantaneous actual contact ration coefficients ε α and ε β (and therefore ε γ ), which can be very different from the calculated ones, when only the ideal geometry of the gearing without any deformations and micro-corrections is considered, i.e., with mutual full contact of the teeth (Graf, 2017). Again, a distinction can be made between the actual contact ratio of two specific teeth and the actual contact ratio after mesh with all teeth (Pavlík, 2017). The contact pattern indicates the

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