Analysis and Improvement of External Noise of a Loader.

In response to the problem that the external noise of 106.7 dB(A) of a new loader prototype to be sold in the international market fails to meet the noise requirement of 105 dB(A) in the target sales destination, after analyzing the noise data of the original loader, it is found that the main noise sources of the external noise are the cooling fan and the silencer assembly, with a main noise frequency band of 280 Hz to 8 700 Hz. By analyzing the noise data of two states of removing acoustic wool wrapping the cooling fan and silencer and introducing exhaust outside, it is found that the noise of the cooling fan is mainly in the frequency band of 90 Hz to 2 800 Hz, the noise of the silencer assembly is mainly in the frequency band above 2 800 Hz, and both overlaps with the main noise reduction frequency band, so the optimization of noise of the cooling fan and the silencer assembly becomes two important directions for overall noise reduction. Finally, by reducing the rotational speed of the cooling fan from 2 400 r/min to 2 200 r/min, installing the silencer inside the rear cover, pasting acoustic wool inside the rear cover and introducing exhaust outside, the external noise of the loader is reduced from the original 106.7 dB(A) to 104.84 dB(A) to achieve the purpose of noise reduction. [ABSTRACT FROM AUTHOR]