Operational Vibration Analysis of Automotive Transmissions 2011-01-0147
On the last years with automotive evolution, the vehicle internal noise became an important item for all automakers. Vehicles have many source of noise like tires running on road, engine intake and exhaust flows, wind and transmission gear rattle noise focus of this paper.
With all noise reduction improvements and new high compression engines, due to high usage of ethanol fuel; transmission gear rattle noise became more evident and it has taken attention from auto companies in the world.
Options to improve the transmission gear rattle noise were created focus on reduce the driveline torsional vibration and focus on improve the gears behaviors. The torsional vibration of driveline can be improved applying a clutch disc with torsional damper or applying a dual mass flywheel on engines.
A clutch disc with torsional damper has some limitations mailing for a drive maneuvers where the clutch disc torsional stiffness and the torsional hysteresis are the main limit, dual mass flywheel (DMF) is a better solution to improve a torsional vibration but your piece cost and mass impact create a roadblock to use in all vehicle applications.
Improve gear design parameters, e. g. backlash, can improve gear rattle noise, but in general it is always linked to high investments in gear manufacturing line.
Considering all items above the focus of this paper is to understand the housing behavior during the vehicle operation and recognize the noise propagation on transmission structure.