滚动轴承故障诊断的基本方法及故障诊断理论毕业设计
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英文翻译学生姓名：学 号：专业班级：学 部：指导教师：第一章 绪论1.1 本课题研究的主要意义机械故障诊断技术是近40年来发展起来的识别机器或机组运行状态的科学。它是适应工程实际需要而形成的多学科交叉的综合学科。它研究的是机器或机组运行状态的变化在诊断信息中的反映，它是由机器运行中的物理现象（声音、振动、声发射、热现象等）出发来推断机器内含故障的技术，是一种典型的反向工程。从20世纪60年代开始，机械故障诊断技术随着机器的不断完善、复杂化和自动化组建发展起来，并与当代科技的前沿科学结合，取得了令人瞩目的成绩。滚动轴承是各种旋转机械中应用最广泛的一种通用部件，也是机械设备中的易损零件，许多机械的故障都与滚动轴承的状态有关。据统计，在使用滚动轴承的旋转机械中，大约30的机械故障是由于滚动轴承的损坏造成的。可见，滚动轴承的好坏对机械系统工作状况的影响极大。由于设计不当和安装工艺不好或轴承的使用条件不佳，或突发载荷的影响，使轴承运转一段时间后会产生各种各样的缺陷，并且在继续运行中进一步扩大，使轴承运行状态发生变化。因此，滚动轴承的故障诊断一直是研究的热点。而与其它零部件相比，滚动轴承有一个很大的特点，这就是其寿命离散性很大。由于在材料、加工精度、热处理及装配质量等各方面不可能完全相同，使得一批类型、尺寸相同的轴承，即使在相同条件下工作，各个轴承的寿命也是不同的，寿命最大相差可达几十倍。由于轴承的这个特点，在实际使用中就出现这种情况：有的轴承已大大超过设计寿命却依然完好地工作；有的轴承远未达到设计寿命就出现故障。所以，如果按照设计寿命对轴承进行定时维修，则出现以下情形：一方面，对超过设计寿命而完好工作的轴承拆下来作为报废处理，造成浪费；另一方面，未达到设计寿命而出现故障的轴承坚持到定时维修时拆下来报废，使得机械在轴承出现故障后和拆下来这段时间内工作精度下降，未到维修时间就出现故障，导致整个机械出现严重事故。由此看来，对重要用途的轴承来说定时维修是很不科学的，要进行工况监测与故障诊断，改传统的定期维修为预知性维修，这样既能经常保持设备的完好状态，又能充分利用轴承的使用寿命，从而延长大修时间，缩短大修时间，减少故障停机损失。因此，滚动轴承的工况监测与故障诊断引起国内外许多科技人员的重视。1.2 滚动轴承故障诊断方法滚动轴承的工况监测与故障诊断就是通过对滚动轴承在各种工况下表现出来的振动、噪声、温度、工作参数、气味、泄漏等信息的监测和综合分析来对其工作状态、故障类型和故障严重程度进行综合评价的过程，主要包括检测试验技术、信号处理技术、模式识别技术和预测评估技术4项基本技术，从而实现检测和发现异常、诊断故障状态和部位、分析故障类型、提出诊断方案和诊断结论的目的。目前，根据故障监测和诊断技术机理的不同，滚动轴承的故障诊断技术主要包括：1. 振动信号监测诊断技术在各种轴承故障诊断方法中，振动检测是最常用的一种方法。轴承元件的工作表面出现疲劳剥落、压痕或局部腐蚀时，轴承运行中会出现周期性的脉冲信号。这种周期性信号可由安装在轴承座上的传感器(速度型或加速度型)来接收，通过对振动信号的分析就可以实现对滚动轴承运行状态的监测与诊断。2. 噪声信号监测诊断技术这种方法是通过滚动轴承在运行过程中的噪声来判断其故障。用噪声法进行轴承的故障检测，优点是不必接触受测轴承就可得到检测信号；其弊端就是很难从周围环境的各种杂音中分离出轴承异常的声音信号。所以，噪声法一般很少被采用。但成功的例子也是有的，就是在方向性强的抛物线型音响器上安装传声器，收集轴承发出的声音信号，并用反向滤波器排除其它杂音，检测出轴承异音。3. 温度信号监测诊断技术通过安装在轴承座(或箱体)处的温度传感器监测温度，判断轴承工作是否正常。温度监测对轴承载荷、速度和润滑情况的变化反映比较敏感，尤其是对润滑不良而引起的轴承过热现象很敏感。所以，由于这种场合比较有效。但是，当轴承出现诸如早期点蚀、剥落、轻微磨损等比较微小的故障时，温度监测基本上没有反映，只是当故障达到一定的严重程度时，用这种方法才能监测到。所以，温度监测不适用于点蚀、局部剥落等所谓的局部损伤类故障。4. 油样分析监测诊断技术油样分析法油样分析法有光谱分析与铁谱分析两大类。轴承磨损颗粒与其工作状况有密切的联系。光谱分析方法有多种，但共同点是利用光谱分析，测定油液中所含各种金属元素的成分和含量，以判断含有被测元素的零部件的磨损状况和程度。铁谱分析方法是将带有磨损颗粒的润滑油通过一强磁场，在强磁场的作用下，磨粒按一定的规律沉淀在铁谱片上，铁谱片可在铁谱显微镜上做定性观察或在定量仪器上测试，据此判断轴承的工作状况。油样分析法适合于用润滑油润滑的轴承的故障诊断，对使用脂润滑的轴承较困难。另外，这种方法易受其它非轴承损坏掉下的颗粒的影响；多用于离线监测方式，这样会导致一定信息丢失；信息量大且杂，即有图像又有数字，依靠人力来管理是十分困难的。所以，这种方法具有很大的局限性。5. 油膜电阻监测诊断技术润滑良好的轴承，由于油膜的作用，内、外圈之间有很大的电阻。故通过测量轴承内、外圈之间的电阻，可对轴承的异常作出判断。其特点是对不同的工况条件可使用同一评判标准，适用于旋转轴外露的场合，对表面剥落、压痕、裂纹等异常的诊断效果比较差。随着科学技术的不断发展，一些新的监测技术不断出现并应用于滚动轴承的工况监测与诊断中，例如：声发射技术、光纤技术等。但是由于种种原因和局限性，这些技术真正普及应用于实际的滚动轴承故障诊断还有一段距离。1.3 滚动轴承故障诊断技术的发展概况滚动轴承的故障诊断技术大概开始于20世纪60年代。最原始的轴承故障诊断方法是将听音棒接触轴承部位，依靠听觉来判断有无故障。后来逐步采用各式测振仪器、仪表并利用振动位移、速度或加速度的均方根值来判断轴承有无故障。随着对滚动轴承的运动学、动力学的深入研究，对于轴承振动信号中频率成分和轴承零件的几何尺寸及缺陷类型的关系有了比较清楚的了解，加之快速傅立叶变换(FFT)技术的发展，开创了用频域分析法来检测和诊断轴承故障的有效途径。在几十年的发展时间里，各种方法与技巧不断产生、发展和完善，应用的领域不断扩大，诊断的有效性不断提高.总的来说，滚动轴承故障诊断的发展经历了以下几个阶段：第一阶段：利用低频信号接收法诊断阶段20世纪60年代中期，由于快速傅立叶变换(FFT)技术的出现(1965年)和发展，低频信号接收法得到了很大的发展。低频信号接收法是将轴承上由传感器检测到的宽频信号直接进行频谱分析，或者信号经过低通滤波，去除高频成分后在作频谱分析，从频谱上观察主要谱峰。如果某一谱峰对应的频率与理论计算轴承元件的间隔频率相一致，则表示该元件上存在故障。这种方法对于低频成分能量较大，外来干扰较小的信号，理论上说应该是可行的，但实际运行中的轴承，因为故障冲击的能量很小，而轴承、齿轮的工艺误差诱发的振动能量比它要大得多。因此，直接利用低频信号接收法得到的谱图往往谱线密集，模糊不清，很难鉴别出故障信号。目前很少直接用这种方法去识别轴承故障，有些仅是用这种频谱来确定轴承元件的固有频率。第二阶段：利用冲击脉冲法诊断阶段在60年代末期，首先由瑞典SPM仪器公司开发出冲击脉冲计，根据冲击脉冲的最大幅值来诊断轴承故障。滚动轴承在运转中，如果滚动体接触点进入表面缺陷区（剥落、裂纹、凹坑和高低不平的粗糙区），就将发生低频冲击，并且以不连续的冲击脉冲波形式传递到轴承座上。虽然冲击脉冲波形很快被衰减下去，累积的能量很小。然而，在这个冲击力作用下，轴承元件或结构的某一部分可能被激发起它的固有频率。尽管冲击脉冲的重复频率远低于轴承的固有频率，但只要这个冲击产生的高阶频率落在轴承固有频率的通带内，也会激起轴承系统的共振现象。共振的高频波中包含了低频冲击和随机干扰的幅值调制波，经过窄带滤波和包络检波后的信号幅值大小就反映了冲击力的大小，也就反应了滚动轴承工作表面的故障状况。第三阶段：利用共振解调法诊断阶段共振解调法也称为包络检波频谱分析法。1974年，美国波音公司的DR Harting发明了一项叫做“共振解调分析系统”的专利，这就是我国现在统称的“共振解调技术”的雏形。共振解调法与冲击脉冲法的基本原理类似，但能做到更精确的诊断。冲击脉冲法只能给出轴承损伤程度的指标，一般来说并不能判断轴承的损伤部位；而共振解调法不仅能判断轴承的损伤程度，还可以通过频谱分析指示出轴承的损伤部位。共振解调法也是利用轴承或检波系统作为谐振体，把故障冲击产生的高频共振响应波放大，通过包络检测方法变为具有故障特征信息的低频波形，然后采用频谱分析法找出故障的特征频率（间隔频率），从而确定故障的类型以及故障发生在轴承的哪一元件上。共振解调法适用于轴承故障的早期诊断。因为早期故障非常轻微，它引起的冲击脉冲强度非常小，所以其振动响应信号的故障特征很不明显，用一般方法很难辨别出来。采用共振解调技术由于放大(谐振)和分离(带通滤波)了故障特征信号，极大地提高了信噪比，所以能比较容易地诊断出故障来。第四阶段：开发以微机为中心的滚动轴承故障诊断系统阶段20世纪90年代以来，随着微机技术迅猛发展，开发以微机为中心的滚动轴承故障诊断系统引起了国内外研究者的重视。微机信号分析和故障诊断系统不但具有灵活性高，适应性强，易于维护和升级的特点，而且易于推广和应用。1.4 滚动轴承故障诊断技术的发展方向近些年，故障诊断的新技术和新方法层出不穷，人工智能和计算机在轴承故障诊断中的应用越来越广泛，今后的发展方向主要体现在以下方面：1. 时域分析和频谱分析在轴承故障诊断中的应用将日趋完善；2. 对于轴承故障诊断的理论和方法进一步深入研究，并且各种研究成果将会逐步应用到实际生产；3. 故障诊断智能系统进一步的深入研究，多种轴承故障分析方法相结合，如小波神经网络、模糊识别与小波分析相结合等新分析方法应用智能专家系统，提高诊断的效率和准确率；4. 随着计算机和网络技术的发展，远程故障诊断将是现代故障诊断发展的一个重要的方向。1.5 本课题主要研究内容本文分析研究了滚动轴承的常见失效形式及其特征，总结滚动轴承的振动机理和振动信号特点，研究了滚动轴承信号处理及故障诊断的方法，搭建了滚动轴承故障诊断系统，采用较为先进、成熟的故障诊断方法，对滚动轴承进行故障诊断。本文的主要内容如下:第一章：绪论。简要介绍了本课题研究的意义、滚动轴承故障诊断方法、滚动轴承故障诊断技术发展概况、发展方向。第二章：滚动轴承的故障特征分析。分析滚动轴承的主要失效形式和原因，分析计算滚动轴承的理论特征频率和固有振动频率，研究滚动轴承的故障信号特征。第三章：滚动轴承故障诊断方法研究。包括时域方法、频域方法，对各种方法的特点进行了比较。第四章：滚动轴承故障诊断系统总体设计。在滚动轴承故障诊断方法理论的基础上搭建基于Matlab的滚动轴承故障诊断系统，对软件系统进行总体设计。第五章：滚动轴承实测信号分析。通过对采集的滚动轴承实测信号分析，验证各种诊断方法的优劣和滚动轴承的故障特征。- 19 -第二章 滚动轴承的故障特征分析2.1 概述滚动轴承是旋转机械中的重要零件，它在各个机械部门中的应用最为广泛。它的运行质量直接影响整台设备的工作性能（包括精度，可靠性，寿命等）。一般来说对滚动轴承采用以设计寿命为限的定时进行维修。但是，如前文所述这种维修制度会对设备的连续运行带来一定的影响。一方面，对超过设计寿命而运行完好的滚动轴承拆下来作报废处理，造成浪费；另一方面，已处于失效状态的轴承继续使用会造成整机运行性能的下降，甚至会酿成严重的事故。因此必须加强滚动轴承的监测工作，改传统的定期维修为预知性维修，最大限度地发挥轴承的工作潜力，提高设备的运行效率。2.2 滚动轴承的典型结构滚动轴承是有内圈、外圈、滚动体和保持架等元件组成。内圈、外圈分别与轴颈及轴承座孔装备在一起。在大多数情况下外圈不动，而内圈随轴回转。滚动体是滚动轴承的核心元件，它使相对运动表面间的滑动摩擦变为滚动摩擦。滚动体的形式有球形、圆形、锥柱形和鼓形等。滚动体可在内、外圈滚道上进行滚动。2.3 滚动轴承的主要失效形式及原因由于滚动轴承的材料缺陷，加工或装配不当，润滑不良，水份和异物侵入，腐蚀以及过载等原因都可能导致早期损坏。当然，即使在安装、润滑和使用维护都正常的情况下，经过一段时间的运转，轴承也会出现疲劳剥落和磨损等现象影响机器的正常工作。概括起来滚动轴承的主要故障形式有:1. 塑性变形轴承转速时，其损坏形式主要失效形式是塑性变形，这与接触表面的最大挤压应力有关（如工作负荷过重，热变形影响，过大的冲击载荷等）。按弹性理论分析，接触表面的最大挤压应力发生在受力最大的一个滚动体与轴承内圈的接触点处，其损坏的特征是滚道上形成一个个小圆穴（凹痕），使轴承在运转时产生很大的振动和噪声。2. 疲劳剥落滚动体在滚道上由于反复承受载荷，工作到一定时间后，首先在接触表面一定深度处形成裂纹（该处的切应力最大），然后逐渐发展到接触表面，使表层金属呈片状剥落下来，形成剥落凹坑，即形成疲劳剥落。疲劳剥落使轴承在工作时发生冲击性振动。在正常工作条件下，疲劳剥落是轴承的主要失效形式。3. 磨损或擦伤滚动体与滚道之间的相对运动以及外界污物的侵入，是轴承工作表面产生磨损的直接原因。润滑不良，装配不正确均会加剧磨损或擦伤。磨损量较大时，轴承游隙增大，不仅降低了轴承的运转精度，也会带来机器的振动和噪声，对精密机械用的轴承，磨损量就成为决定轴承使用寿命的主要因素。4. 锈蚀和电蚀锈蚀是由于空气中或外界的水分带入轴承中，或者机器在腐蚀性介质中工作，轴承密封不严，从而引起化学腐蚀。锈蚀产生的锈斑使轴承工作表面产生早期剥落，而端面生锈则会引起保持架磨损。电蚀主要是转子带电，在一定条件下，电流击穿油膜产生电火花放电，使轴承工作表面形成密集的电流凹坑。5. 断裂轴承零件的裂纹和断裂是最危险的一种失效形式，这主要是由于轴承超负荷运行、金属材料有缺陷和热处理不良引起的。转速越高，润滑不良，轴承在轴上压配过盈量太大以及过大的热应力会引起裂纹和断裂。6. 胶合胶合指滚道和滚动体表面由于受热而局部融合在一起的现象。常发生在润滑不良、高速、重载、高温、起动加速度过大等情况下。由于摩擦发热，轴承零件可以在极短时间内达到很高的温度，导致表面灼伤，或某处表面上的金属粘附到另一表面上。7. 保持架损坏通常，由于装配或使用不当而引起保持架发生变形，从而就可能增加保持架与滚动体之间的摩擦，甚至使某些滚动体卡死而不能滚动，或者由于保持架与内外滚道发生摩擦等均可能引发保持架损坏，导致振动、噪声与发热增加。Chapter I Introduction1.1 The main significance of this researchMachinery fault diagnosis technology has developed to identify scientific machine or running state in nearly 40 years. It is to adapt to the need of the actual engineering and the formation of interdisciplinary comprehensive discipline. What it studies is the machine or the unit running status change in the diagnostic message reflection. It is the technology by the machine run in physical phenomenon (sound, vibration, sound launch, hot phenomenon and so on) embarks infers the machine content breakdown and is one kind of typical reverse engineering. Started from the 1960s, along with the machine consummates, the complication and the automation unceasingly the mechanical fault diagnosis technology has developed, and with the contemporary sciences and technologys front science union, has made the amazing progress.The rolling bearing is one kind of general part in each kind of revolving machinery applies. Rolling element bearing is one of the most widely used general part of rotating machinery,and one of the most easily damaged parts of mechanical equipment. A lot of mechanical failure is relevant to the state of rolling element bearings. It is estimated that about 30 percent of mechanical failure is caused by its fault in the rotating machine with rolling element bearings. It is obvious that the quality of rolling element bearings has a great impact on the working condition of electromechanical systems. Because of wrong design, poor working condition or a jump heavy load, bearing will be damaged and worse during the running time. So at present, the fault diagnosis of rolling element bearings is a research hotspot.But compares with other spare parts, the rolling bearing has a very major characteristic, this is its life leaves the divergence to be very big. Because in the material, the working accuracy, the heat treatment and the assembly quality and so on various aspects is impossible identical, causes one batch of types, the size same bearing, even if works under the same condition, life is different for each bearing, and difference up dozens of times. As a result of bearings this characteristic, it has this kind of situation in the actual use: Some bearings have significantly exceeded design life and work is still intact; some bearings have not achieved the design life to present the breakdown. Therefore, if carries on according to the design life to the bearing fixed time services, then has the following situation: On the one hand, the bearing surpasses the design life, but works complete the bearing opens down takes abandonment processing, creates the waste; On the other hand, the bearing has not achieved the design life to present the breakdown to insist fixed time services when dismantles the incoming telegram to be waste, causes the machinery after the bearing presents the breakdown and opens down in this period of time to work the precision to drop, has not presented the breakdown to the maintenance time, causes the entire machinery to present the serious accident. Therefore, to the important uses bearing settled when the service is very unscientific, must carry on the operating mode monitor and the failure diagnosis, changes traditional the regular service is the forecasting service, like this both can maintain equipments sound condition frequently, and can use bearings service life fully, thus the extension overhaul time, reduces the overhaul time, reduces the disaster dump to lose. Therefore, rolling bearings operating mode monitor and the failure diagnosis bring to the domestic and foreign many technical personnels attention.1.2 Rolling bearing failure diagnosis methodRolling bearings operating mode monitor and the failure diagnosis are through to the rolling bearing information and so on vibration which, noise, temperature, operational parameter, smell, divulging displays under each kind of operating mode monitors and the generalized analysis to its active status, the breakdown type and the breakdown order of severity carry on the quality synthetic evaluation the process, mainly includes the examination experiment technology, the signal processing technology, the pattern recognition technology and the forecast appraisal technology 4 basic strokes, thus realizes the examination and the discovery exceptionally, the diagnosis malfunction and the spot, the analysis breakdown type, proposes the diagnosis plan and the diagnosis conclusion goal.At present, according to the breakdown monitor and the diagnosis technology mechanisms difference, rolling bearings failure diagnosis technology mainly includes:1. Vibration signal monitor diagnosis technologyIn each bearing failure diagnosis method, the vibration examination is the most commonly used one method. When the bearing parts active face presents weary flaking, the indentation or the localized corrosion, in the bearing movement will present the periodic signal impulse. This kind of periodic signal may by install the sensor (speed or acceleration) receives on the bearing seat, through to vibrates the signal the analysis to be possible to realize to the roll axis undertakes to transport the row state the monitor and the diagnosis.2. Noise signal monitor diagnosis technologyThis method is judges its breakdown through rolling bearings in movement process noise. Carries on bearings failure detection with the noise law, the merit does not need to contact was measured that the bearing may obtain the detection signal; its malpractice is separates the bearing unusual sound signal very difficultly from environment each kind of static. Therefore, the noise laws are very generally few are used. But the success example also has, is installs the microphone on the directive strong parabola sounder, collects sound signal which the bearing sends out, and removes other static with the reverse filter, examines the bearing different sound.3. Temperature signal monitor diagnosis technologyThrough installs in the bearing seat (or box body) place temperature sensor monitor temperature, judges the bearing to work whether normally. The temperature monitoring to the bearing load, the speed and the lubrication situations change reflection is quite sensitive, particularly the bearing overheated phenomenon which causes to the insufficient lubrication is very sensitive. Therefore, because this kind of situation is quite effective. But, when the bearing presents such as the early pitting, flaking, the slight attrition and so on quite small breakdown, the temperature monitoring basically had not reflected that is only when the breakdown achieves certain order of severity, can monitor with this method. Therefore, the temperature monitoring is not suitable for the pitting, partial flaking and so on so-called partial damage class breakdown.4. Oil type analysis monitor diagnosis technologyThe oil type analytic method oil type analytic method has the spectral analysis and the hard spectrum analyzes two broad headings. The bearing attrition pellet has close contacting with its working condition. The spectral analysis method has many kinds, but the common ground uses the spectral analysis, determines in the fat liquor to contain each metallic element ingredient and the content, judges includes is measured the element the spare part wear condition and the degree. The hard spectrum analysis method has the attrition pellet lubricating oil through a strong magnetic field, under the strong magnetic fields function, the abrasive precipitates according to certain rule on the hard spectrum piece, the hard spectrum piece may make the qualitative observation or on the hard spectrum microscope tests on the quota instrument, according to the above judges bearings working condition.The oil type analytic method suits in using the lubrication oil lubrication bearings failure diagnosis, for uses the bearing which the fat lubricates to be difficult. Moreover, this method easily the pellet influence which falls down other non-bearing failure; Uses in the off-line monitor way, like this will cause certain bit drop-out; The information content is big and is mixed, namely has the image also to have the digit, depends upon the manpower to manage is very difficult. Therefore, this method has the very big limitation.5. Lubricant film resistance monitor diagnosis technologyThe bearing has the good lubricates, as a result of the lubricant film function, between the addendum circle has the very big resistance. Therefore through surveys between the bearings, the addendum circle resistance may exceptionally make the judgment to the bearing. Its characteristic is may use the identical judgment standard to the different operating mode condition, is suitable situation which appears externally in the rotation axis, to the surface scaling, the indentation, the crack and so on unusual diagnosis effect is quite bad. Along with sciences and technologys unceasing development, some new monitor technology appears unceasingly and applies in rolling bearings operating mode monitor and the diagnosis, for example: Sound launch technology, optical fiber technology and so on. But with the limitation, this technical true popularization applies for various reasons in the actual rolling bearing failure diagnosis also has section of distances.1.3 Rolling bearing failure diagnosis technology development surveyRolling bearings failure diagnosis technology started probably in the 1960s. The most primitive bearing failure diagnosis method is listens the stick contact bearing portion, whether there is depends upon the sense of hearing to judge the breakdown. Afterward used various types vibration meter gradually, the measuring appliance and using the vibration displacement, whether there is the speed or the acceleration root-mean-square value judges the bearing breakdown. Along with to rolling bearings kinematics, the dynamics deep research, vibrated the signal medium frequency ingredient and the bearing part geometry size and the flaw type relations regarding the bearing had the quite clear understanding, in addition the fast Fournier transformation (FFT) technologys development, founded examined and the diagnosis bearing breakdown efficient path with the frequency range analytic method. In several dozens year development time, each method and the skill have, the development and the consummation unceasingly, the application domain expand unceasingly, the diagnosis validity enhances unceasingly. Generally speaking, the rolling bearing failure diagnosiss development has experienced the following several stages:The first stage: Uses the low-frequency signal reception diagnosis stageIn the mid-1960s, because the fast Fournier transformation (FFT) technologys appearance (in 1965) and the development, the low-frequency signal reception obtained the very big development. The low-frequency signal reception is the broadband signal which examines from the sensor carries on directly the bearing on the spectral analysis, or signal after low-pass filtering, after elimination high-frequency component, in makes the spectral analysis, observes the main spectrum peak from the frequency spectrum. If some spectrum peak correspondence frequency with theoretical calculation bearing parts spacing frequency consistent, then expresses on this part to have the breakdown. This method is big regarding the low frequency ingredient energy, the external disturbance small signal, should be theoretically speaking feasible, but actual moves the bearing, is very small because of the breakdown impacts energy, but the bearing, gears craft error suggestions vibrational energy must be much bigger than it. Therefore, the direct use low-frequency signal reception obtains the spectrogram the spectral line is often crowded, slurred, very difficult to distinguish crashes the signal. At present are very few distinguishes the bearing breakdown directly with this method, some is only determines the bearing parts natural frequency with this kind of frequency spectrum.The second stage: Using shock pulse law diagnosis stageIn the late 60s, first develops the shock pulse idea by Sweden SPM Instrument Company, diagnoses the bearing breakdown according to shock pulses greatest peak-to-peak value. Rolling bearing in revolution, if the rolling body contact point enters the surface defect area (flaking, crack, pit and uneven rough area), will have the low frequency impact, and transmits on the bearing seat by not the continual impact pulse wave form. Although the shock pulse profile weakens very quickly, the accumulation energy is very small. However, under this impact action of force, the bearing part or structure some part is possibly stimulated its natural frequency. Although shock pulses recurrence rate is lower than bearings natural frequency far, but the higher order frequency which, so long as this impact produces falls on the bearing natural frequency pass band, also will arouse the bearing systems resonance effect. In the resonating high-frequency wave has contained the low frequency impact and the random disturbance peak-to-peak value modulating wave, has reflected the impulse size after the narrow band filtering and envelope detections signal peak-to-peak value size, also responded the rolling bearing active face breakdown condition.The third stage: Using resonating demodulation law diagnosis stageThe resonating demodulation law is also called the envelope detection frequency spectrum analytic method. in 1974, US Boeings DR Harting has invented a named “the resonating demodulation analysis system” the patent, this is our country is called now “the resonating demodulation technology” the embryonic form. The resonating demodulation law and shock pulses method basic principle is similar, but can achieve a more precise diagnosis. The shock pulse law can only give the bearing extent of damage the target, generally speaking cannot judge bearings damage spot; But resonates the demodulation law not only to be able to judge bearings extent of damage, but may also instruct bearings damage spot through the spectral analysis. The resonating demodulation law is also takes the resonant body using the bearing or the detection system, has the high frequency resonating response wave the breakdown impact on enlarge, becomes through the enveloping examination method has the breakdown characteristic information low frequency profile, then uses the frequency spectrum analytic method to discover the breakdown the eigen frequency (spacing frequency), thus which part does the determination breakdowns type as well as the breakdown occur on bearings.The resonating demodulation law is suitable for the bearing breakdown early diagnosis. Because the incipient failure is slight, it causes the shock pulse intensity is small, therefore its vibration response signals breakdown characteristic is not very obvious, is very difficult with the general method to distinguish. Uses the resonating demodulation technology, because enlarged (resonance) and the separation (bandpass filter) the breakdown characteristic signal, enhanced the signal-to-noise ratio enormously, therefore could diagnose quite easily crashes.The fourth stage: Development take microcomputer as central rolling bearing failure diagnosis system stageSince the 1990s, along with the microcomputer technology rapid development, has developed take the microcomputer has brought to the domestic and foreign researchers attention as the central rolling bearing failure diagnosis system. Not only the microcomputer signal analysis and the failure diagnosis system has the flexibility to be high, compatible, easy to maintain and the promotion characteristic, moreover easy to promote and applicate.1.4 Rolling bearing failure diagnosis technology development directionThe recent years, failure diagnosiss new technology and the new method emerge one after another incessantly, the artificial intelligence and computers is getting more and more widespread in bearing failure diagnosis application, presents development direction will mainly manifest in the below aspect:1. The time domain analysis and the spectral analysis will consummate day by day in the bearing failure diagnosiss application;2. Regarding bearing failure diagnosis theory and method further deep research, and each kind of research results will apply the actual production gradually;3. The failure diagnosis intelligent system further deep research, many kinds of bearing fault analysis method unifies, like the wavelet neural network, the fuzzy recognition and the wavelet analysis unify and so on new analysis method application intelligence expert system, enhances the diagnosis the efficiency and the rate of accuracy;4. Along with the computer and networkings development, the long-distance failure diagnosis will be a modern failure diagnosis development important direction.1.5 This topic main research contentThis article analytical study rolling bearings common failure mode and the characteristic, summarized rolling bearings vibration mechanism and the vibration signal characteristic, has studied the rolling bearing signal processing and the failure diagnosis method, has built the rolling bearing failure diagnosis system, used advanced, the mature failure diagnosis method, carried on the failure diagnosis to the rolling bearing. This article primary coverage is as follows:The first chapter: Introduction. Introduced this topic research significance, the rolling bearing failure diagnosis method, the rolling bearing failure diagnosis technological development survey, the development direction brieflyThe second chapter: Rolling bearings breakdown characteristic analysis. Analysis rolling bearings main failure mode and reason, analysis computation rolling bearings theory eigen frequency and natural vibration frequency, research rolling bearings fault signal characteristic.The third chapter: Rolling bearing failure diagnosis method study. Including the time domain method, the frequency range method, have carried on the comparison to each methods characteristic.The fourth chapter: Rolling bearing failure diagnosis system design. Builds in the rolling bearing failure diagnosis method theorys foundation based on the Matlab rolling bearing failure diagnosis system, carries on the system design to the software system.The fifth chapter: Rolling bearing actual signal analysis. Through to the gathering rolling bearing actual signal analysis, confirms each diagnosis method the fit and unfit quality and rolling bearings breakdown characteristic.Chapter II Rolling bearing fault feature analysis2.1 OutlineThe rolling bearing is in the revolving machinerys important components, it is most widespread in each mechanical departments application. Its riding quality immediate influence puts in order the Taiwan equipments operating performance (including precision, reliability, life and so on). Generally speaking uses to the rolling bearing designs the life to be limited to fixed time carries on the service. But, if the preamble will state this kind of service system to bring certain influence to equipments continuous running. At the same time, to surpasses the design life to move the complete rolling bearing to open down makes abandonment processing, creates the waste; On the other hand, has been at the mode of failure the bearing to continue to use can create the complete machine performance characteristic the drop, will breed the serious accident. Must therefore strengthen rolling bearings monitor work, changes traditional the regular service is the forecasting service, maximum limit displays bearings operating potential, raises equipments operating efficiency. 2.2 Rolling bearings modular designThe rolling bearing has part compositions and so on inner loop, addendum circle, rolling body and retainer. The inner loop, the addendum circle separately with the journal and the bearing seat hole equip in together. The addendum circle is motionless in the majority situations, but inner loop along with axis rotation. The rolling body is rolling bearings core part, it causes the sliding friction between the relative motion surface to become the rolling friction. The rolling body form has the sphere, the circular, the awl to be cylindrical and drum shape and so on. The rolling body may, on the addendum circle roller conveyer carry on the trundle.2.3 Rolling bearings main failure mode and reasonAs a result of rolling bearings material flaw, the processing or assembles improper, the insufficient lubrication, the moisture and the foreign matter invasion, reasons and so on corrosion as well as overload possibly cause the early damage. Certainly, even if in the installment, the lubrication and in the use maintenance normal situation, will pass through period of time the revolution, the bearing will also present weary phenomena and so on flaking and attrition interferes with machines normal work. Summarizes rolling bearings major failure form to include:1. Plastic deformationWhen bearing rotational speed, its damage form main failure mode is the plastic deformation, this and faying surfaces biggest crushing stress related (for example working load is overweight, thermal deformation influence, oversized impact load and so on). According to the theory of elasticity analysis, faying surfaces biggest crushing stress occurs in a stress biggest rolling body and the bearing inner loop contact point, its damages characteristic is on the roller conveyer forms each one small circle hole (dent), causes the bearing when the revolution has the very big vibration and the noise.2. Weary flaking The rolling body on the roller conveyer as a result of repeat
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