本文叙述了东风-50拖拉机变速箱的噪声随负荷与转速的变化关系,利用频谱分析和拆装零件的方法,确定了四档齿轮为其变速箱的主要噪声源。据此,在该齿轮上粘贴阻尼材料,使整机噪声级下降2.7dB(A)、齿轮啮合频率处声压级下降15.19dB。此外根据箱体振动和辐射噪声的关系,认为提高箱体刚度可能是降低变速箱噪声的有效途径之一。 This paper describes the noise of Dongfeng -50 tractor transmission with load and speed changes, the use of spectrum analysis and disassembly parts method to determine the fourth gear gearbox for the main noise source. According to this, the damping material is pasted on the gear so that the noise level of the whole machine drops by 2.7dB (A) and the sound pressure level at the gear meshing frequency drops by 15.19dB. In addition, according to the relationship between tank vibration and radiation noise, it is considered that increasing the stiffness of the tank may be an effective way to reduce the transmission noise.