A multi-body dynamics model of 7 speed transmission (6 forward plus reverse) for a front wheel drive vehicle is reported. It includes the modal behaviour of the transmission casing, while the input shaft motion is kinematic with engine order vibrations. These are measured from an experimental rig and fed into the model. The resulting lubricated impact/contact forces acting on the loose gear wheels are calculated. These forces transmit through to the transmission and their support bearings onto the casing. They excite a host of structural modes of the thin casing with a large modal density. The paper shows that some of these are high frequency flexural and effective radiators of noise; breathing modes. Rattle is a rather annoying sound which is broadband with structural content, as well as airborne from impact sites. It is important to include in the model the engine order vibrations, resident on the transmission input shaft. These are seen as playing an important role in transmission rattle, particularly under idle condition. The velocity variation of the input shaft was, therefore, measured from an engine/transmission test-bed rig, using a two beam laser vibrometer, directed to the transmission input shaft.
Elastodynamic response of automotive transmissions to impact induced vibrations
2010
8 Seiten, 4 Bilder, 4 Tabellen, 11 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
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