【正文】 因此，噪聲等級(jí)的劃分有助于工業(yè)標(biāo)準(zhǔn)的改進(jìn)。隨著 ABEC 級(jí)別的增加（從 3 增到 9），公差逐漸變小。 利用軸承的噪聲特性對(duì)軸承進(jìn)行分類(lèi)，用戶除了可以確定大多數(shù)廠商所使用的ABEC標(biāo)準(zhǔn)外，還可確定軸承的噪聲等級(jí)。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(dòng)引起的?？刹煊X(jué)的凹坑是一種制造缺陷，它是在制造過(guò)程中由于多爪卡盤(pán)夾的太緊而形成的。 低頻噪聲是長(zhǎng)波段不規(guī)則變化的結(jié)果。通常軸承缺陷被分為低、中、高三個(gè)波段。例如，灰塵產(chǎn)生的是不規(guī)則的劈啪聲；滾珠劃痕產(chǎn)生一種連續(xù)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。即用 um/rad 表示的軸承位移。將一傳感器連接在軸承外圈上，而內(nèi)圈在心軸以 1800r/min的轉(zhuǎn)速旋轉(zhuǎn)。軸承的性能可以用不同的噪聲等級(jí)來(lái)表示。采用密封和遮護(hù)裝置來(lái)?yè)蹰_(kāi)臟物是控制污染的一種方法。如果軸承過(guò)熱，它將會(huì)卡住。但是，由于軸承內(nèi)外圈的運(yùn)動(dòng)，使軸承的密封不可能達(dá)到完美的程 度，因此潤(rùn)滑油的泄漏和污染始終是一個(gè)未能解決的問(wèn)題。因此在機(jī)床的應(yīng)用中應(yīng)該使用非重復(fù)性振擺較小的軸承。例如，當(dāng)要求振擺最小時(shí)，軸承的非重復(fù)性振擺不能超過(guò) 微米。和重復(fù)性振擺不同的是， NRR 是沒(méi)有辦法進(jìn)行補(bǔ)償?shù)摹? 在軸承轉(zhuǎn)動(dòng)過(guò)程中，如果內(nèi)圈和外圈之間存在一個(gè)隨機(jī)的偏心距，就會(huì)產(chǎn)生與凸輪運(yùn)動(dòng)非常 相似的非重復(fù)性振擺（ NRR）。舉例來(lái)說(shuō)，潤(rùn)滑脂產(chǎn)生的噪聲比潤(rùn)滑油大一些。潤(rùn)滑劑的粘度必須認(rèn)真加以選擇，因?yàn)椴贿m宜的潤(rùn)滑劑會(huì)產(chǎn)生過(guò)大的扭矩，這在小型軸承中尤其如此。這些特征包括噪聲、起動(dòng)和運(yùn)轉(zhuǎn)扭矩、剛性、非重復(fù)性振擺以及徑向和軸向間隙。 避免失效的方法 16 解決軸承失效問(wèn)題的最好辦法就是避免失效發(fā)生。 銹是濕氣污染的一種形式，它的出現(xiàn)常常表明材料選擇不當(dāng)。在這種情況下，潤(rùn)滑對(duì)于完全加工形式的保持架來(lái)說(shuō)是至關(guān)重要的。潤(rùn)滑劑中的固體雜質(zhì)就象磨粒一樣。 檢查潤(rùn)滑劑的污染比檢查裝配不正或蠕動(dòng)要困難得多。如果偏斜超過(guò) 176。如果軸承圈不正或翹起，滾珠將沿著一個(gè)非圓周軌道運(yùn)動(dòng)。為了防止蠕動(dòng)，應(yīng)該先用肉眼檢查一下軸承箱件和軸的配件。蠕動(dòng)的害處很大，它不僅損害軸承，也破壞其他零件。 蠕動(dòng)不象過(guò)早疲勞那樣普遍。若標(biāo)準(zhǔn)的軸承材料不能保證足夠的軸承壽命，就應(yīng)當(dāng)采用特殊的材料。如果這些條件不可避免，就應(yīng)仔細(xì)計(jì)算軸承壽命，以制定一個(gè)維護(hù)計(jì)劃。摩擦還會(huì)使保持架受力，這會(huì)破 壞支承架，并加速軸承的失效。在卡住之前，過(guò)大的摩擦和熱量使軸承鋼軟化。另外在軸承 上加一個(gè)較小的預(yù)載荷不僅有助于滾珠和軸 承圈保持緊密的接觸，并且對(duì)防止在設(shè)備運(yùn)輸 中產(chǎn)生的低荷振蝕也有幫助。 消除振動(dòng)源并保持良好的軸承潤(rùn)滑可以防止低 荷振蝕。此外，低荷振蝕產(chǎn)生的碎屑的作用就象磨粒一樣，會(huì)進(jìn)一步損害軸承。這種破壞稱(chēng)為低荷振蝕。軸承圈上的壓坑還會(huì)產(chǎn)生噪聲、振動(dòng)和附加扭矩。剝蝕通常是在載荷超過(guò)材料屈服極限時(shí)發(fā)生的。 只要使用和安裝合理，軸承的剝蝕是容易避免的。 通過(guò)失效后的分析可以得知對(duì)已經(jīng)失效的或?qū)⒁У妮S承應(yīng)該在哪些方面進(jìn)行查看。污染通常是由不正確的使用和不良的使用環(huán)境造成的，它還會(huì)引起扭矩和噪聲的問(wèn)題。為了做到這一點(diǎn)，再考察一下制造廠商的尺寸定位指南和所選軸承的使用特點(diǎn)是非常重要的。診斷失效的原因并不困難，因?yàn)楦鶕?jù)軸承上留下的痕跡可以確定軸承失效的原因。通過(guò)一些細(xì)致的偵察工作，我們可以采取行動(dòng)來(lái)避免軸承的再次失效。在軸承的使用過(guò)程當(dāng)中，過(guò)分的忽視會(huì)導(dǎo)致軸承的過(guò)熱現(xiàn)象，也可能使軸承不能夠再被使用，甚至完全的破壞。 Utilize faulttolerant technology, adopt and design the important part redundantly , in order to realize the trouble resumes by oneself。 One hundred sheets of storehouses adds the manipulator and adds one pair of main shafts to transfer to the tower machining center. 10 Development trend of the current numerical control lathe At present, the advanced manufacturing technology in the world is rising constantly, such application of technology as ultrafast cutting , ultraprecision processing ,etc., the rapid development of the flexible manufacturing system and integrated system of the puter one is constant and ripe, have put forward higher demand to the process technology of numerical control. Nowadays the numerical control lathe is being developed in several following directions. （ 1） . The speed and precision at a high speed , high accuracy are two important indexes of the numerical control lathe , it concerns directly that processes efficiency and product quality. At present, numerical control system adoptfigure number, frequency high processor, in order to raise basic operation speed of system. Meanwhile , adopt the super largescale integrated circuit and many microprocessors structure, in order to improve systematic data processing ability , namely improve and insert the speed and precision of mending operation. Adopt the straight line motor and urge the straight line of the lathe workingbench to be servo to enter to the way directly, it is quite superior that its responds the characteristic at a high speed and dynamically. Adopt feedforward control technology , make it lag behind error reduce greatly , thus improve the machining accuracy cut in corner not to track. For meet ultrafast demand that process, numerical control lathe adopt main shaft motor and lathe structure form that main shaft unite two into one, realize frequency conversion motor and lathe main shaft integrate , bearing , main shaft of electrical machinery adopt magism float the bearing , liquid sound pigeonhole such forms as the bearing or the ceramic rolling bearing ,etc.. At present, ceramic cutter and diamond coating cutter have already begun to get application. （ 2） . Multifunctional to is it change all kinds of machining centers of anization (a of capacity of storehouse can up to 100 of the above ) automatically to furnished with, can realize milling paring , boring and pares , bores such many kinds of processes as paring , turning , reaming , reaming , attacking whorl ,etc. to process at the same time on the same lathe , modern numerical control lathe adopt many main shaft , polyhedron cut also , carry on different cutting of way process to one different 11 position of part at the same time. The numerical control system has because adopted many CPU structure and cuts off the control method in grades, can work out part processing and procedure at the same time on a lathe , realize socalled the front desk processes , the backstage supporter is an editor . In order to meet the needs of integrating the systematic one in flexible manufacturing system and puter, numerical control system have remote serial interface , can work , realize data munication , numerical control of lathe, can control many numerical control lathes directly too. （ 3） . Intelligent modern numerical control lathe introduce the adaptive control technology, according to cutting the change of the condition, automatic working parameter, make the processing course can keep the best working state , thus get the higher machining accuracy and roughness of smaller surface , can improve the service life of the cutter and production efficiency of the equipment at the same time . Diagnose by oneself , repair the function by oneself, among the whole working state, the system is diagnosed, checked by oneself to CNC system and various kinds of equipment linking to each other with it at any time. While breaking down , adopt the measure of shutting down etc. immediately , carry on the fault alarm, brief on position , reason to break down ,etc.. Can also make trouble module person who take off automatically , put through reserve module , so as to ensure nobody demand of working environment. For realize high trouble diagnose that requires , its development trend adopts the artificial intellige