Abstract: A series of vehicle tests are conducted to address the issue of poor noise, vibration, harshness (NVH) performance of the 9.5-ton drive axle assembly of a certain passenger car. The root causes of the problem are ultimately determined, including insufficient isolation rate of the lower thrust rod and design and manufacturing errors in the main reducer gear. In order to reduce the noise of the drive axle assembly, improvements and optimizations have been made, including tooth surface modification of the hypoid gear of the main reducer and design improvements of the lower thrust rod structure. In order to verify the rationality of the two optimization schemes, bench tests are conducted in the laboratory and whole vehicle tests are conducted in actual driving environments. The effects of gear modification of the main reducer and optimization of the lower thrust rod structure on the noise of the drive axle assembly are analyzed. The results show that both optimization schemes reduce the noise of the drive axle assembly by about 10 dB(A), with a significant reduction in the noise values of the 9th order and its harmonics. Therefore, both optimization schemes have played a certain role in vibration reduction and noise reduction, providing a reference for improving the NVH performance of the bus drive axle assembly.

Key words: Drive axle; Optimization of noise; Gear; Lower thrust rod

摘要： 针对某客车 9.5 吨驱动桥总成的噪声、振动与声振粗糙度（NVH）性能不佳的问题， 进行了一系列整车测试，最终确定导致该问题的原因，即下推力杆隔振率不足、主减速器齿 轮设计制造误差等因素。为了降低驱动桥总成的噪声，对其进行了改进和优化，包括对主减 速器的准双曲面齿轮进行齿面修形，以及对下推力杆结构进行设计改进。为了验证两种优化 方案的合理性，在实验室进行了台架试验，并在实际行驶环境中进行了整车测试，分别分析 了主减速器齿轮修形与下推力杆结构优化对驱动桥总成噪声的影响，结果表明两种优化方案 均使驱动桥总成噪声降低了大约 10 dB(A)，其中第 9 阶次及其倍频的噪声值明显降低。因此， 两种优化方案均起到了一定的减振降噪作用，为提高客车驱动桥总成的 NVH 性能提供了参 考。

关键词: 驱动桥；噪声优化；齿轮；下推力杆