壳体开裂是变速器进行钢改铝轻量化设计后经常遇到的问题。变速器壳体开裂的原因复杂、多样。为对某轻型货车变速器壳体的开裂故障进行有效地诊断，从轻型货车动力总成的静、动态测试出发，对九种实际工况下动力总成各测点振动信号、应变信号、声信号进行工作模态拟合及PSD三维谱分析，结合变速器壳体各激励频率分析结果，从多种途径找到影响变速器壳体开裂的根本原因并提出设计改进思路。研究方法全面、完整，且不同方法的所获得结果达到互相验证，因此准确率高，该方法对类似工程问题的诊断也有一定的借鉴作用。%Cracking is a common issue in transmission cases in the lightweight design of replacing steel by aluminum due to its complicated and diverse causes. This paper attempts to develop an effective diagnostic method for identifying the transmission case cracking in a light-duty truck. Under the static and dynamic conditions of the powertrain, the operational modal analysis (OMA) and power spectrum density (PSD) three-dimensional spectral analysis were applied to the vibration signals, strain signals and acoustic signals for nine actual working conditions. Through integrating the results of excitation frequency analysis for the transmission cases, the fundamental causes of the transmission case cracking were identified and the improvement design was proposed. The results obtained from various methods were examined by one another comparison, which could significantly improve the accuracy in the diagnoses. This work has a potential application to similar problems in engineering.
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