Purpose
Agricultural tractors have various noise sources, such as engines, transmissions, and hydraulic systems, with engines generally being the largest noise sources. Nonetheless, with the development of engine design technology, transmission gear noise, which was relatively unknown, has become an issue. However, research on the evaluation and analysis of transmission gear noise in agricultural tractors is insufficient.
Method
In this study, a method for evaluating the gear rattle and gear whine noise level of an agricultural transmission was presented. Also gear rattle noise and gear whine noise levels were evaluated and compared for domestic and imported tractors available in South Korea.
Results
The rotational speed fluctuation that determines the gear rattle noise level of domestic and imported tractors was 29.9 and 21.5 rpm, respectively. Moreover, comparing the acceleration response of the PTO housing, the average of domestic tractors was 21.9 g and that of imported tractors was 7.7 g, 35% of that of domestic tractors. The overall noise level inside the domestic and imported tractors was measured to be 80 and 72 dBA, respectively, indicating a difference of 8 dBA based on the engine-rated rotational speed.
Conclusion
When the noise level of the gear harmonic component was compared through order tracking analysis, it was experimentally confirmed that the engine noise contributed the most to the cabin noise of the imported tractor, while the noise of several gear noise contributed more than the engine noise in the domestic tractor.