Practical methods for managing the gear whine phenomena

Unprecedented competition among the worldwide automotive manufacturers has benefited the consumer, resulting in higher levels of overall quality while simultaneously reducing the time-to-market for new models. One subjective differentiator of automotive quality is the noise and vibration performance, as evident by the quieter interiors even in vehicles not typically associated with the luxury banner, such a large trucks. In essence, passenger compartments devoid of objectionable road and wind noise have become a fundamental customer requirement expected in all vehicles regardless of cost, thereby reducing the broadband masking content of the interior. This reduction of masking has the potential to make tonal noise more prominent and annoying, by increasing the tone-to-noise ratio, and as result, the perception of quality may suffer. Gear whine is one such tonal noise phenomena that must be diligently managed by automotive engineers in order to avoid objectionable passenger compartment noise. This can be quite challenging, since many gear design features implemented for increased durability are often counter productive for noise. Sources of gear whine include powertrain components such as automatic and manuals transmissions, axles, transfer cases, power-take of units, engine accessory drives, and an assortment of other potential noise makers. This paper will attempt a technology review of various practical methods for managing the gear whine phenomena, including the use of Quality Function Deployment charts, dynamic transmission error with parametric gear models, and response surface modeling for gear design optimization.