Research Article
Analysis on the Noise for the Different Gearboxes of the Heavy Truck
Table 2
The speed-ratio of the three gearboxes.
| Speed-ratio | 3-speed | 4-speed | 5-speed | 6-speed | 7-speed | 8-speed | 9-speed |
| Types I and III | 7.31 | 5.71 | 4.46 | 3.48 | 2.71 | 2.11 | 1.64 | Type II | 9.39 | 7.33 | 5.73 | 4.46 | 3.48 | 2.71 | 2.10 |
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