Issue 30

G. Belingardi et alii, Frattura ed Integrità Strutturale, 30 (2014) 469-477; DOI: 10.3221/IGF-ESIS.30.57 476 C ONCLUSIONS bject of the present paper is the simulation of the dynamic behaviour of an automotive transmission for electric vehicle by means a Multibody approach, performed with the software RecurDyn, so as to obtain some necessary information to be involved in the evaluation of the Internal Dynamic Factor. The results obtained are very helpful in the evaluation of the dynamic loads. Two different simulations have been done, the first has considered the two meshing gears as rigid bodies, the second one has been done with flexible rims and rigid webs. Forces values have been compared to the corresponding theoretical ones and a very good agreement has been obtained. Then, by processing force trends calculated with the Multibody approach, the dynamic factor K v , involved in a fatigue study following the ISO Standard 6336 [10], has been determined for the Gear 4. All obtained K v values match very well, emphasizing a similar dynamic behaviour of the system. It may be concluded that the Multibody approach provides a satisfactory information about the dynamic response of the system in both instantaneous and averaged condition. However, on the basis of the obtained results, it may be observed that the more efficiency in calculation doesn’t justify the corresponding increasing in computational time by shifting from rigid (at maximum 47 hours) to flexible-rigid (384 hours) simulation, for as concerns the transmission considered in the present work. A CKNOWLEDGEMENTS hanks to the Regione Piemonte for the financial support and Bitron s.p.a. for the assistance. N OMENCLATURE α= Pressure Angle, °; β= Helix Angle, °; m n = Normal module, mm; Z = Number of teeth; b = Face width, mm; K v = Internal Dynamic Factor; K v-A =Internal Dynamic Factor calculating with Method A of ISO Standard 6336-1 [7]; K v-B =Internal Dynamic Factor calculating with Method B of ISO Standard 6336-1 [7]; K v-C =Internal Dynamic Factor calculating with Method C of ISO Standard 6336-1 [7]; N = Resonance ratio; N s = Lower limit of the main resonance range; n 1 = Rotational speed of the pinion, rpm; n E1 = Running speed of the gear pair, rpm; F t , F r , F a = Tangential, radial, axial forces, N; K A = Application factor; t A F K / b  = Specific Load, N/mm; F x ,F y , F z = Forces in the main directions, N; v = Maximum tangential speed, m/s. R EFERENCES [1] Inc. FunctionBay. RecurDyn/ Solver Theoretical Manual, (2011). [2] Kahraman, A., Singh, R., Non-linear dynamics of a spur gear pair, J. Sound Vib., 142 (1990) 49–75. O T