Troubleshooting Gear Whine with Hyundai Motor Company at VDI Transmissions in Vehicles 2012

Romax Technology, global leaders in the design and analysis of the complete transmission will present a technical paper, jointly written with Hyundai Motor Company, at the international VDI Transmissions in Vehicles 2012 conference.

Romax’s Director of Simulation Technology, Younsu Park will be presenting the paper titled, “8 Speed Automatic Transmission NVH Improvements – Asymmetric Sideband Whine Noise Troubleshooting”, will discuss a trouble shooting process for resolving a typical noise problem of an 8 speed automatic transmission developed for a luxury passenger vehicle, when the common methods of micro-geometry optimization and modal tuning techniques were not able to deliver a satisfactory outcome.

Gear whine noise is a high frequency tonal noise which is perceived as highly unpleasant to passengers of a vehicle. Gear mesh excitation, called transmission error, is the source of gear whine noise. Minimizing transmission error by performing gear micro geometry optimisation is often the preferred solution, because it addresses the source of vibration directly. Modal tuning techniques can be adopted if the problematic noise is caused by particular vibration modes of the transmission system.

Although the noise problem to be presented was that of gear whine, it could not be resolved by either of the above methods. Measurements showed that the noise was caused by modulation of transmission error at sideband frequency rather than at the gear mesh frequency.

We will highlight the various design changes that were proposed as a result of this study including gear macro geometry, support bearing position and manufacturing tolerance tightening. Prototype test results are presented, including successful correlation with the simulated vibration results.

“We are looking forward to presenting at such a prestigious event”, said Romax’s Younsu Park. “The conference gives us an opportunity to discuss aspects of our advanced gear whine technology with leading specialists in the transmissions industry and highlight the latest developments in our portfolio of NVH solutions. Our joint paper with Hyundai Motor Company is a great case study showing the applicability of our NVH solutions in practice.”

Romax who are Gold Sponsors of the event will also be exhibiting at booth 96. Please be sure to visit the Romax booth where a panel of experts will be available to discuss further our NVH solutions and provide software demonstrations.