nvh_noise vibration harshness_噪声和振动控制工程(福特汽车).pptVIP

NVH(noise vibration harshness)噪声和振动控制工程 Summary Flow Chart流程总图 Background背景 Issues 问题 -Sound-Loudness/speech interference -声音-响度/语音 干涉 -Sound quality on as needed basis during development 在改善音质的过程中依据的原理 -Vibration-velocity or acceleration 振动-速度或者加速度 Trends:competition is steadily improving 趋向：竞争越来越激烈 Customer Concerns顾客关心的问题 General -P/T NVH is defined as the NVH the customer ascribes to powertrain sources, usually because of Operating condition(e.g..idle or wot) P/T振动和噪声的协调性被如此定义的原因，用户认为是由于噪声和振动是动力装置所产生，而噪声与振动通常是与运行工况密切相关的（例如…空转） Engineering Definition 工程上的解释 Vehicle powertrain NVH is any vehicle noise or vibration due to powertrain excitation including induction, exhaust and tailpipe sources 车辆动力装置的噪声和振动问题是由于动力装置的激励产生的包括进排气和排气管的激励。 P/T NVH Phenomena P/T噪声和振动表现出的一些现象 Shake,Roughness,Boom,Moan振动，工作粗暴，轰隆，呼啸声 Why worry about low frequency problems -Shake, roughness and boom problems are hard to fix late in a problem—they must be deal with early 振动，工作粗暴，噪声很大的问题很难放到程序里头—他们应该被提前处理掉 -Sever problems may lead to buy-backs严重的问题可能导致招回 Column shake gives the impression of “rough idle” 轴的振动给人以很粗暴的印象 -Customer wonder if engine will stall 用户想知道发动机是否会停下来 Body Mode Issue车身样式问题 -Shake,roughness and boom problems tend to involve the same low frequency body models 振动，工作粗暴，噪声很大的问题往往与同样的低频车身形状有关 -Same structure involved有关的同样的结构 -Excitations may be quite different 激励源可能大不相同 Target Consistency物体的组成 -Modal/component targets must be consist 组成的物体之间要相容 -Example:Steering Column Shake例如：操纵轴振动 Mode frequency must be 25Hz for wheel/tire 对于车轮或是轮胎的形状频率必须25Hz Must avoid primary firing frequency 必须避开最初的点火频率 Main Operation Conditions for Evaluation P/T NVH用主要的运行工况来评估P/T噪声和振动 Source 来源 Frequency Alignment of Forces StructuralModes受力与结构样式的频率表 Target Setting Cascade物体位置的重叠 General process 一般的方法 -VOC-QFD rates of importance VOC-QFD 重要性 -Functiona