商用车传动轴的振动及噪声直接影响了整车传动的平稳性与乘坐的舒适性，甚至影响到整车的可靠性。作为商用车制造厂，必须对传动轴的振动情况进行研究并对传动轴系进行合理的布置与设计，从根本上控制产生振动与噪声的因素。为了尽快解决某车型传动系振动带来的汽车传动轴中间支承横梁开裂的问题，本文应用了国内外的一些研究成果，从理论和试验两方面分析了某重型商用车传动系振动的原因和机理，提出解决措施，并对传动系进行了优化设计。同时，本文还从系统论的观点出发，对传动系振动问题寻求最优解决方案。本文主要对车架和传动轴中间支承进行了有限元分析、对传动轴系进行了振动加速度测试、振动频率测试、试验模态分析、传动轴横梁应力测试，最终找出了造成传动轴支承横梁开裂的主要原因，一是发动机引起的动力传动系一阶弯曲共振，二是中间支承位置不在模态振型节点上，三是中间支承隔振性能不良。针对问题的起因，本文从设计角度提出了具体的改进方案。同时，根据隔振理论，采用了变刚度的传动轴中间支承，使得传动轴中间支承具有低频大阻尼、高频低刚度的变参数性能，在低频率范围内能提供较大的阻尼，对传动系大幅值振动起到迅速衰减的作用，中高频时具有较低的动刚度，能有效吸收振动能量，起到很好的隔振效果。验证试验表明，本文提出的解决传动轴振动问题的各项措施和方法正确，振动明显减小，彻底解决由传动轴振动引起的传动轴中间支承横梁开裂的问题。本课题紧密结合企业工程实际问题，具有较强的针对性和现实意义。
The NVH of commercial-vehicle driveline directly affects easiness and safety of the whole vehicle. In order to reduce the vibration and noise, it is necessary for the vehicle manufacture to research the NVH of driveline and to carry out rational layout and design to the driveline which is the fundamental ways of all.In this paper, some research results of the domestic and foreign have been applied to analyze the vibration of driveline theoretically and experimentally. Furthermore, the vehicle chassis intermediate mounting cross member abruption problem due to the vibration of driveline has been resolved by optimizing the driveline layout. Based on system theory, this thesis gives out the optimal solution to the driveline vibration.This article mainly carried on the finite element analysis to the frame and the driveline intermediate mounting, the vibration acceleration test, the vibration frequency test, the experimental modality analysis, the stress test of the driveline crossbeam, and finally found the primary causes to the cracks of driveline’s mounting cross member: The first cause is driveline’s first order flexural resonance which caused by the engine. The second one is intermediate mounting’s position does not locate in the node of vibration mode. The last one is that the intermediate mounting vibration isolation function is not good. In view of the question causes, this article proposed the concrete improvement program. At the same time, according to the vibration isolation theory, this paper adopts the driveline intermediate mounting which is dynamic stiffness, this enables the shaft intermediate mounting to have variable element at low frequency, it has big damping to reduce the driveline’s vibration rapidly, or else lower rigidity with good vibration isolation effect.The verification result indicates that the solution of driveline vibration is effective. It reduced the vibration obviously, and resolved the cracks questions of driveline’s intermediate mounting cross member fundamentally.This thesis connected with practical project in our company, has the characteristic of just pertinence and realistic meaning.
