6 Speed Automatic Transmission Vibration Magnitude Prediction and Whine Noise Improvement through Transmission System Modeling 2011-01-1553
As automotive technology has been developed, gear whine has
become a prominent contributor for cabin noise as the masking has
been decreased. Whine is not the loudest source, but it is of high
tonal noise which is often highly unpleasant. The gear noise
originates at gear mesh. Transmission Error acts as an excitation
source and these vibrations pass through gears, shafts and bearings
to the housing which vibrates to produce noise on surrounding air.
As microgeometry optimization target to reduce the fundamental
excitation source of the noise, it has been favored method to
tackle gear whine noise, especially for manual transmission.
However, practicality of microgeometry optimization for the
planetary gear system has been still in question, because of
complex system structure and interaction among multi mesh gear sets
make it hard to predict and even harder to improve.
In this paper, successful case of whine noise improvement by
microgeometry is presented. System level simulation model with
accurate details of actual test system condition such as
clearances, measured microgeometry and test rig condition were
constructed. The vibration at the accelerometer location at the
housing was predicted using the model. The comparison of the result
to test result showed very good correlation. Especially, the
absolute housing vibration level matched very well, which allowed
engineers to use the simulation result during optimization process
to make decision quickly without having to run the actual test to
know if the improvement was sufficient enough to meet the vibration
target. Microgeometry optimization was done for all gear sets in
the rear planetary. The predicted result of vibration showed 3 m/s₂
reduction at the target speed range under target torque condition.
The noise test result confirmed that the noise was reduced by 5~6
dBA and the design target could be satisfied.
Citation: Shin, W., Kanase, A., Hwang, S., Baek, S. et al., "6 Speed Automatic Transmission Vibration Magnitude Prediction and Whine Noise Improvement through Transmission System Modeling," SAE Technical Paper 2011-01-1553, 2011, https://doi.org/10.4271/2011-01-1553. Download Citation