Due to the low background noise of new energy vehicles, the high-frequency noise
will be relatively loud. The control of high-frequency noise, such as gear noise
and electromagnetic noise, is an important subject in the electrification
process of the automobile industry. While the influence of the powertrain, mount
bracket, and acoustic package on this type of noise has been studied for a long
time, as one of the advanced technologies for such high-frequency noise
reduction, the rubber high-frequency dynamic stiffness test and control method
has received the attention of many researchers in recent years. In this paper, a
more in-depth analysis of the method that calculates rubber high-frequency
dynamic stiffness using the mount system FRF (frequency response function)
hammering test result under real vehicle conditions is conducted. The applicable
frequency range of this method is above 200 Hz, and the corresponding accuracy
of each frequency is proposed. The influence of the FRF coherence on the rubber
high-frequency stiffness calculation result is discussed, and the calculation
result is not affected by the mount bracket resonance. Finally, the method is
applied in the reduction of gear noise of a specified vehicle. This vehicle has
a 1500 Hz frequency gear noise issue occurring at a constant speed of 60 km/h.
By reducing the rubber hardness from 52 to 48, the left-mount rubber X-direction
stiffness at 1500 Hz frequency is reduced from 3400 N/mm to 800 N/mm, the
passive side vibration of the mount is reduced from 0.8 m/s2 to 0.2
m/s2, and the interior gear noise is reduced from 33 dB(A) to 23
dB(A).