Design of new sound metric and its application for quantification of an axle gear whine sound by utilizing artificial neural network

The gear whine sound of an axle system is one of the most important sound qualities in a sport utility vehicle (SUV). Previous work has shown that, because of masking effects, it is difficult to evaluate the gear whine sound objectively by using only the A-weighted sound pressure level. In this paper, a new objective evaluation method for this sound was developed by using new sound metrics, which are developed based on the increment of signal to noise ration and the psychoacoustic parameters in the paper, and the artificial neural network (ANN) used for the modeling of the correlation between objective and subjective evaluation. This model developed by using ANN was applied to the objective evaluation of the axle-gear whine sound for real SUVs and the output of the model was compared with subjective evaluation. The results indicate a good correlation of over 90 percent between the subjective and objective evaluations. This paper was recommended for publication in revised form by Associate Editor Yeon June Kang Professor Sang-Kwon Lee received a Ph.D. degree in ISVR (Institute of Sound and Vibration Research) from Southampton University in 1998. He joined Hyundai Motor Research Center in Korea, working with the Automotive Noise and Vibration Control Group from 1985 to 1994. He has been the Professor at the Department of Mechanical Engineering, Inha University, Inchon, Korea, since March 1999. His research interests are the digital signal processing, NVH (noise vibration harahness), condition monitoring, product sound quality design and active control.     

基于MASTA的齿轮变速箱啸叫研究

为了降低变速箱啸叫,以MASTA为平台,建立了变速箱啸叫分析模型,对引起啸叫的主要激励进行了分析。在充分考虑变速箱壳体、轴承、轴及齿轮等零部件柔性变形叠加对齿轮传递误差影响的基础上,对变速箱齿轮重合度、传递误差、齿面接触应力及变速箱振动响应等相关参数进行了数值计算,分析了各参数对变速箱啸叫的影响,并通过对齿轮宏观参数及微观参数进行优化,降低了变速箱啸叫。研究结果表明,通过适当提高齿轮端面重合度,以及进行轮齿修形,可较明显减小变速箱振动响应,为改善变速箱啸叫提供了依据。     

齿轮精度与变速器啸叫声控制的定量分析

齿轮的精度对变速器齿轮副啸叫噪声有重要影响,提高齿轮精度是控制啸叫声的一个重要手段。以452AMT变速器主减齿轮为研究对象,把其传统的剃齿工艺更改为热后磨齿工艺,使齿轮精度提高3个等级,齿轮微观参数的正态分布标准差σ提高1倍以上,且更符合设计要求。最后把两种状态下各5台变速器先后通过下线台架EOL振动和1台整车NVH客观测试的单因素和正交试验的对比分析,变速器壳体振动强度下降1/2左右,车内主减齿轮副啮合阶次啸叫声加速和滑行时分别降低3 dB(A)和6 dB(A)左右。研究揭示齿轮精度对齿轮啸叫影响的机理,对变速器NVH的理论与应用具有一定的学术和工程意义。     

基于阶次跟踪的变速箱啸叫噪声分析

运用阶次跟踪的分析方法,研究了某车型手动变速箱的二挡啸叫噪声现象。首先,在阶次跟踪的等角度间隔重采样算法中,提出用分段三次埃尔米特（Hermite）多项式代替传统的最小二乘法多项式拟合变速箱输入轴转速曲线,再分段对其积分得到变速箱输入轴转角表达式,提高了转速拟合与阶次跟踪分析的精度;然后,把短时傅里叶变换（STFT）用于阶次跟踪分析;最后开展了啸叫噪声的实车实验,结合变速箱噪声实验的主观评价经验,定量地分析和研究了变速箱的二挡啸叫现象。     

圆锥滚子轴承预紧力对变速器啸叫噪声的影响分析

基于仿真分析和实验方法研究了轴承预紧力对汽车变速器啸叫噪声的影响,建立了六挡机械式变速器动力学仿真模型,分析了副轴-后轴承采用不同的预紧力对系统动力学性能的影响,主要考察了传动误差激励、动态啮合力和轴承力变化,获得了不同的箱体动态响应。利用阶次跟踪方法进行实验,分析了不同预紧条件下的振动加速度和声压级水平。结果表明：采用合理的预紧力时,增大轴承刚度有助于抑制变速器啸叫噪声的产生,仿真分析与实验结论一致。     

国产轿车变速器啸叫噪声源的识别与控制

对一款国产轿车变速器存在的啸叫问题进行了研究。首先进行了车内噪声实验和NVH半消声室台架实验,利用阶次分析找到了主要的阶次,然后利用声贡献量分析最终确定了啸叫特征阶次。计算发现该问题较为特殊,由于设计不当出现了不同传动部件阶次一致的情况。针对阶次一致的传动部件,通过接触斑点分析,最终确定了啸叫的噪声源。最后以实际接触斑点的位置和形状为依据,对齿轮进行了齿向修形设计,啸叫声降低约5dB（A）。     

发动机平衡轴剪刀齿机构啸叫试验和计算方法研究

基于多体动力学理论，采用AVL EXCITE建立了2.0 L发动机平衡轴剪刀齿机构啸叫计算模型，并进行了模型验证，通过振动色谱图和齿轮谐次噪声与总谐次噪声差值综合评价啸叫。针对4缸机平衡轴齿轮系统，分析了平衡轴剪刀齿机构啸叫产生原因，同时分析了剪刀齿机构弹簧刚度和正、反旋向剪刀齿机构对啸叫的影响。研究结果表明：驱动齿轮与剪刀齿机构浮动齿轮传递误差最大，是引起空载啸叫的主要原因；弹簧预紧力矩相同时，弹簧刚度为0.5 N·m/（°）时的传递误差比弹簧刚度为1.0 N·m/（°）时降低约7.2%；反旋向剪刀齿机构为一个减振系统，在2 500~4 000 r/min工况浮动齿轮角加速度相对正旋向剪刀齿机构降低约25%，在空载加速工况啸叫的改善效果明显。