1　前言拖拉机的噪声不仅危害驾驶员的身心健康 ,而且污染环境 ,成为一种公害。因此 ,拖拉机的噪声是衡量拖拉机优劣的主要指标之一。目前国产拖拉机噪声水平与国外拖拉机相比还存在一定差距 ,如国外拖拉机的驾驶室内噪声普遍在 80ｄＢ(Ａ)以下 ,而国产拖拉机室内噪声一般在 90 1 Introduction Tractor noise not only endanger the driver’s physical and mental health, but also pollute the environment and become a public hazard. Therefore, the tractor noise is one of the main indicators to measure the pros and cons of tractors. At present, the domestic tractor noise level still lags behind that of foreign tractors. For example, the noise in the driver’s cab of foreign tractors is generally below 80dB (A), while the domestic noise of domestic tractors is generally at 90