一种低噪声齿轮室盖板的设计方法

A Design Method of Low Noise Gearbox Cover

采用仿真预测与试验测量相结合的方法对某款直列四缸柴油机前端齿轮室盖板结构响应及噪声辐射进行研究。结合噪声测试、声源识别及模态分析提出一种板面结构低噪声优化思路:噪声测试得到关注频带,声源识别得出关注频带辐射具体位置,模态分析判断辐射噪声位置与模态振型是否重合,若重合则进行结构优化。同时,提出一种通过开孔破坏整体刚度耦合与更换高阻尼材料相结合的低结构噪声优化方法。通过这种方法,使关注频带噪声降低了1.95dB(A),发动机前端整体噪声降低了0.96dB(A)。提出一种简单模拟齿轮室盖板安装状态边界条件的方法:对比齿轮室盖板计算与试验模态振型来调整约束节点位置,对比其固有频率来调整约束节点数。并通过对比优化后齿轮室盖板的试验模态与计算模态,固有频率相对误差为6.97%,验证了边界条件的可行性。

A method of integrated simulation prediction and experimental test was used to study the gearbox cover＇s structural response and noise radiation of an engine. A low structural noise optimization idea was proposed by the combination of noise test, noise source identification and modal analysis. This allowed use to the noise test to get the attention band, the noise identification to get the location of the attention band noise, and the modal analysis to judge whether the location of radiation noise is coincident with the modal shape for further structure optimization. Meanwhile, a low noise structure optimization method was proposed by opening a hole to destroy the overall stiffness and replacing with the high damping materials. Using this method, could reduce the band noise of the band by 1.95 dB（A） and the engine front end noise by 0. 96 dB（A）. Furthermore a simple method for simulation of the boundary conditions of gearbox cover in the installation state was put forward in order to compare the calculated modal shape of gearbox cover with the measured value to adjust the position of constraint nodes and to compare the natural frequency to adjust the number of constraint nodes. Compared the calculated modal with the measured value of the optimized gearbox cover, the relative error of the nature frequency was 6.97~, which Verified the feasibility of boundary conditions.