共查询到19条相似文献,搜索用时 140 毫秒
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通过噪声、振动自功率谱分析和相干函数分析技术,应用杭州亿恒公司的8通道动态信号测试分析系统,对一台内燃叉车的液力变速箱进行了噪声振动分析,从而得出了该台变速箱产生噪声的主要原因在于Z6-Z7齿轮轴的啮合激励。 相似文献
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液力变矩器是一种以液体为工作介质的扭矩变换器,通常与动力换挡变速箱组成液力传动变速器,作为大、中吨位内燃叉车液力机械式传动系统的一个重要组成部件,具有液力传动输出的自适应性,能够随叉车行驶阻力的变化而相应改变其输出扭矩和转速;能吸收和消除发动机和外载对传动系统带来的冲击振动; 相似文献
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本文概述了内燃叉车声辐射机理,讨论了噪声源的识别方法和叉车结构外表面按其辐射声功率的大小评定主次的方法。通过对带驾驶室CPCD5型内燃叉车的噪声与振动的频谱分析,提出了降低该机整机噪声的有效措施。同时指出,控制辐射源与控制激振源同样重要,两者都是机械噪声控制技术的关键。 相似文献
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基于传统内燃机汽车发动机引起振动噪声阶次特征明显的特点,运用短时傅里叶变换(short-time Fourier transform,简称STFT)进行转速估计,结合阶次追踪法,对汽车加速工况变速器振动信号进行阶次分析。首先,利用STFT对加速工况变速箱振动信号进行时频分析;其次,利用改进型峰值搜索法提取特征阶次所对应的瞬时频率值,进一步计算得到发动机转速信号表达式;然后,根据发动机转速信号表达式对振动信号在角域重采样,进行阶次分析;最后,利用本研究方法对变速箱加速过程振动信号进行阶次分析,并与商用软件LMS.Test.lab分析结果进行对比。结果表明,本研究方法无需布置转速传感器即可对变速箱振动信号进行阶次分析,为整车振动噪声试验分析提供参考。 相似文献
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《机械科学与技术》2016,(9):1396-1401
对152QMI单缸汽油机进行噪声及振动以及曲轴转角等信号的采集,在LMS Test.Lab软件中利用频谱分析和小波变换计算得出了该单缸汽油机噪声能量的主要分布范围,并以此作为噪声源识别的对象,利用阶次分析和小波变换筛选出该机噪声信号中频率不随转速变化的共振因素,随后在角度域内对信号进行小波变换,结合发动机配气机构等部件的运动特征研究识别相对于各频率带的发动机噪声源。研究结果表明,该发动机主要噪声频率带为800 Hz以下、2 000 Hz和4 000 Hz~5 000 Hz,各频率带噪声源分别为进排气噪声、缸盖共振和顶杆对摇臂的冲击以及气门落座冲击。 相似文献
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分析了某变速箱试验时的异常振动和噪声原因。先对一台样机测试其各挡稳定过程的振动和噪声信号,再对测得的信号进行功率谱密度分析。之后,运用Pro/Engineer建立了变速箱壳体的实体模型,并用OptiStruct软件进行了壳体前端面加零位移约束的模态分析;计算了各挡齿轮的啮合频率,分析了壳体的模态频率与齿轮啮合频率对振动和噪声信号功率谱中峰值的影响。最后根据分析结果,提出对壳体的改进建议,以达到变速箱减振降噪的目的。 相似文献
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往复压缩机噪声诊断及降噪研究 总被引:3,自引:0,他引:3
对全封闭往复压缩机进行了声功率、声压级、壳体振动和壳体模态试验,分析了压缩机主要振动和噪声源.确定了壳体的振动模态,指出了进一步降低压缩机噪声的途径。确定2500Hz和3150Hz的峰值噪声主要是壳体的辐射噪声,并且采取了两种降噪措施,经试验比较,降噪效果明显。 相似文献
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B. A. Gordeev V. P. Gorskov A. N. Osmekhin S. N. Okhulkov 《Journal of Machinery Manufacture and Reliability》2012,41(2):178-182
Problems of improving damping characteristics of hydraulic vibration mounts are considered. It is shown that, when there are
nondissolved air bubbles present in a working fluid, damping characteristics are not weakened but improved significantly in
a number of cases. Testing of a hydraulic vibration mount was carried out at a vibration test stand within a frequency range
from 20 to 55 Hz. The vibration frequency of the vibration test stand platform was measured discretely with a step of 5 Hz.
As soon as the stand’s input vibration signal was not a purely harmonic one, harmonic components from 0.5 to 100 Hz were present
in its spectrum. This frequency range was exposed to spectral and cepstral processing. It was determined that efficient vibration
suppression with presence of gas cavities with a total volume of 5 mL occurs in the whole range of harmonic change. 相似文献
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我们每天都会受到音频噪音的影响,原始信息会受到周围环境噪声信号的污染。为此,本文研究了一个多抽头自适应去噪实时硬件系统,它利用TMS320C6713上实现的最小均方算法(LMs)来去除与音频相关的应用程序中接收到的不期望出现的噪声信号。文章首先介绍了最小均方算法的c语言实现并在CodeComposerStudio上进行仿真,最后在C6713上实现。考虑不同的音频输入,进行了三项实验来测试所设计的自适应去噪系统的效率。实验采用300、500、800、1000和3000Hz的音频信号及男性语音信号为输入的参考信号,持续检测信号中的噪声,直至将它全部去除。此外,还研究了与自适应去噪系统性能相关的收敛速度、滤波器安排顺序以及信噪比。实验结果表明,所设计系统其信噪比有很大的改善。 相似文献
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提出了内螺纹冷挤压振动信号的时频分析新方法:Hilbert—Huang变换。将内螺纹冷挤压振动信号分成了开机未挤压、挤压、挤压与校正、校正阶段,对4个阶段的信号进行了EMD分解,并对分解结果做了Hilbert变换,得到Hilbert谱和边际谱。分析结果表明,在内螺纹冷挤压过程中,由于丝锥与工件间产生了高频摩擦,高频成分在挤压阶段出现,并在之后的过程中高频能量出现变化,揭示了内螺纹冷挤压过程中高频摩擦的变化规律。 相似文献
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PT fuel injector is one of the most important parts of modern diesel engine.To satisfy the requirements of the rapid and accurate test of PT fuel injector,the self-adaptive floating clamping mechanism was developed and used in the relevant bench.Its dynamic characteristics directly influence the test efficiency and accuracy.However,due to its special structure and complex oil pressure signal,related documents for evaluating dynamic characteristics of this mechanism are lack and some dynamic characteristics of this mechanism can’t be extracted and recognized effectively by traditional methods.Aiming at the problem above-mentioned,a new method based on Hilbert-Huang transform(HHT) is presented.Firstly,combining with the actual working process,the dynamic liquid pressure signal of the mechanism is acquired.By analyzing the pressure fluctuation during the whole working process in time domain,oil leakage and hydraulic shock in the clamping chamber are discovered.Secondly,owing to the nonlinearity and nonstationarity of pressure signal,empirical mode decomposition is used,and the signal is decomposed and reconstructed into forced vibration,free vibration and noise.By analyzing forced vibration in the time domain,machining error and installation error of cam are revealed.Finally,free vibration component is analyzed in time-frequency domain with HHT,the traits of free vibration in the time-frequency domain are revealed.Compared with traditional methods,Hilbert spectrum has higher time-frequency resolutions and higher credibility.The improved mechanism based on the above analyses can guarantee the test accuracy of injector injection.This new method based on the analyses of the pressure signal and combined with HHT can provide scientific basis for evaluation,design improvement of the mechanism,and give references for dynamic characteristics analysis of the hydraulic system in the interrelated fields. 相似文献
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基于自适应时变滤波阶比跟踪的齿轮箱故障诊断 总被引:4,自引:0,他引:4
针对多输入多输出齿轮箱传动系统和齿轮箱集群的振动信号中各啮合频率阶次相互干扰,从而导致故障诊断困难的问题,研究提出一种基于自适应时变滤波阶比跟踪的齿轮箱故障诊断方法。该方法利用基于多尺度线调频基稀疏信号分解提取各对传动齿轮的啮合频率,以各啮合频率为中心频率,对应转频的倍频为滤波带宽分别设计自适应时变滤波器对信号进行滤波,逐个提取振动信号中的啮合频率调制分量,再分别对提取的啮合频率调制分量单独进行阶比分析,有效地抑制其他无关联轴上齿轮啮合振动信号和其他非阶比噪声信号对阶比谱的影响,较好地解决阶比信号相互干扰的问题,提高阶比谱的调制识别效果,为多输入多输出齿轮箱系统和齿轮箱集群的故障诊断提供一条有效途径。仿真算例和应用实例说明方法的有效性。 相似文献
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Prism Signal Processing is a new recursive FIR technique offering rapid filter design and calculation. It has previously been applied to Coriolis mass flow metering to generate fast (48 kHz) flow measurement updates, facilitating for the first time the direct mass flow measurement of individual fuel pulses injected into a laboratory diesel fuel injection test bench. In this paper we describe an augmented sensor signal filtering scheme which enables rapid tracking of the desired mode of flow tube vibration while notching out undesired modes. The new scheme is applied to a gasoline injection test bench where the vibrational interference is greater than for the previously described diesel system due to increased hydraulic shock. The paper presents experimental findings which illustrate the further challenges to be overcome in order to achieve the goal of traceable direct mass flow measurement of individual fuel injection pulses. For example, when a fuel pulse is shorter than the resonant period of the flow tube, the observed phase difference appears to show dependence on the instantaneous phase of the flow tube vibration. 相似文献
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为了研究工程机械混合动力系统的机电耦合特性和轴系的振动特性,研制了由柴油机、电动机和液压泵共轴连接组成的工程机械混合动力系统实验台.设计了由工控机、PCI总线控制卡和组态软件组成的实验台测控系统,分析测控系统输入信号和控制信号的数量与类型,确定测控系统控制策略的设计原则和开发过程.通过在柴油机输出轴的端面布置3个加速度传感器实现柴油机工作时曲轴的振动特性,对不同负载功率下柴油机曲轴的振动特性进行试验测试.测试结果表明,柴油机曲轴的振动能量集中在径向,轴向的振动能量可忽略不计;设计的测控系统能实现混合动力系统轴系振动性能测试. 相似文献