【正文】 的爆破聲，確定這種劃痕最困難；內(nèi)圈損傷通常產(chǎn)生連續(xù)的高頻噪聲，而外圈損傷則產(chǎn)生一種間歇的聲音。這種缺陷是由在軸承圈和滾珠的磨削加工中出現(xiàn)的振動引起的。 however, the results of an endurance test series are only meanin gful when the test bearings fail by fatiguerelated mechanisms. The experimenter must control the test process to ensure that this occurs. S ome of the other failure modes that can be experienced are discussed in detail by Tallian [19. 2]. The followin g paragraphs deal with a few specific failure types that can affect the conduct of a life test sequence. In Chapter 23, the influence of lubricat ion on contact fatigue life is discussed from the standpoint of EHL film generation. There are also other lubrication related effects that can affect the oute of the test series. T he first is particulate contaminants in the lubricant. Depending on bearin g size, operating speed, and lubricant rheolo gy, the overall thickness of the lubricant film developed at the rollin g element raceway contacts may fall between 0. 05 and ? m . Solid partic les and damage the raceway and rollin g e lement surfaces, leadin g to substantially shortened endurances. T his has been amply demonstrated by Sayles and MacPherson [] and others. Therefore, filtration of the lubricant to the desired level is necessary to ensure meaningfu l test result. The desired level is determined by the application which the testing purports to approximate. If this degree of filtration is not provided, effects of contamination must be considered when evaluatin g test results. Chapter 23 discusses the effect of various degrees of particulate contamination, and hence filtration, on bearing fatigue life. T he moisture content in the lubricant is another important consideration. It has long been apparent that quantit ies of free water in the oil cause corrosion of the rolling cont act surfaces and thus have a detrimental effect on bearing life. It has been further shown by Fitch [19. 7] and others, however, that water levels as low as 50100 parts per million(ppm) may also have a detrimental effect, even with no evidence of corrosion . T his is due to hydrogen embrittlement of the rollin g element and raceway material. See also Chapter 23. Moisture control in 河南科技大學(xué)外文 翻譯 8 test lubrication systems is thus a major concern, and the effect of moisture needs to be considered during the evaluation of life test results. A maximum of 40 ppm is considered necessary to minimize life reduction effects. The chemical position of the test lubricant also requires consideration. Most mercial lubricants contain a number of proprietary addit ives developed for specif ic purposes。 利用軸承的噪聲特性對軸承進行分類，用戶除了可以確定大多數(shù)廠商所使用的 A BEC 標準外，還可確定軸承的噪聲等級。通常軸承缺陷被分為低、中、高三個波段。軸承的性能可以用不同的噪聲等級來表示。因此在機床的應(yīng)用中應(yīng)該使用非重復(fù)性振擺較小的軸承。舉例來說，潤滑脂產(chǎn)生的噪聲比潤滑油大一些。 最后的 4 張圖片不是用正確的實驗方法得到的有效的失效模式。 元素 金相實驗可以提供一個精確的證據(jù)，使實驗結(jié)果處于可控制情況下，同時檢測有疑點和爭議的地方。有的也不一定，比如一些表面硬度不同的鋼材或是專為實驗用生產(chǎn)的鋼材。可以在系統(tǒng)中應(yīng)用這些技術(shù)方法來檢驗缺陷。腐蝕是由于震動產(chǎn)生的微粒被氧化而產(chǎn)生的。因此對于軸承壽命試驗時 177。 一般的對潤滑劑做化學(xué)檢測時是不會檢測添加劑的成分的。因此一個軸承的壽命試驗需很長的時間。 為了降低對壽命減少的影響，潮氣的含量最多不能超過 40P PM。潤滑劑的選擇由工況決定，實驗時也如此。 關(guān)鍵詞 ： 軸承 失效 壽命河南科技大學(xué)外文 翻譯 2 1 .軸承失效的原因 軸承失效有以下多種原因，然而軸承的壽命實驗卻是所有機械實驗中最有意義的。通過一些細致的 觀 察工作，我們可以采取行動來避免軸承的再次失效。 因此，為了 確保實驗結(jié)果我們必須 選用合適等級的潤滑 劑。因此在軸承壽命 的 試驗 結(jié)果中 必須考慮到潮氣的影響。 為了得到一個合理的結(jié)果，統(tǒng)計學(xué)要求做很多組壽命試驗。這些易退化的添加劑會影響軸承表面的潤滑條件，從而影響軸承的壽命。因此為了保證實驗數(shù)據(jù)的連貫性，必須監(jiān)控并實時調(diào)節(jié)每個軸承的使用溫度。軸外徑和軸承內(nèi)徑都會受腐蝕的影響。比如說噪音，溫度，震動等缺陷。而且這個遞增還不是主要因素，考慮到有代表性的耐久性實驗的數(shù)據(jù)都是經(jīng)統(tǒng)計學(xué)分析后得到的。現(xiàn)在 Tallian 已經(jīng)將其更新為【 】，其中加入了彩色圖片。圖 是一個由于熱變形造成的內(nèi)圈游隙變化的圖片。另外，不同的潤滑劑的噪聲特性也不一樣。同樣，機床主軸只能容許最小的振擺，以保證切削精度。 噪聲是反映軸承質(zhì)量的一個指標。 軸承缺陷可以通過其頻率特性進一步加以鑒定。軸承每旋轉(zhuǎn)一周高頻不規(guī)則變化出現(xiàn) 60~300 次，它表明軸承上存在著密集的振痕或大面積的粗糙不平。 for example, to provide antiwear properties, to achieve extreme pressure and/or thermal stability, and to provide boundary lubrication in case of marginal lubricant films. T hese addit ives can also affect the endurance of rollin g bearin gs, e ither immediately or after experiencin g timerelated degradation. Care must be taken to ensure that the addit ives included in the test lubricant will not suffer excessive