學(xué)習(xí)機械設(shè)計制造與測試心得體會(編輯修改稿)
2024-11-09 03:16 本頁面
【文章內(nèi)容簡介】 insufficient squareness of the bearing mounting site．Misalignment of more than 1/4can cause an early failure．Contaminated lubricant is often more difficult to detect than misalignment or creep．Contamination shows as premature wear．Solid contaminants bee an abrasive in the lubricant．In addition。tolerate only minimal deflections to maintain precision cuts．Consequently, bearings are manufactured with low NRR just for machinetool applications．Contamination is unavoidable in many industrial products，and shields and seals are monly used to protect bearings from dust and dirt．However，a perfect bearing seal is not possible because of the movement between inner and outer races．Consequently，lubrication migration and contamination are always problems．Once a bearing is contaminated, its lubricant deteriorates and operation bees noisier．If it overheats，the bearing can seize．At the very least，contamination causes wear as it works between balls and the raceway，being imbedded in the races and acting as an abrasive between metal surfaces．Fending off dirt with seals and shields illustrates some methods for controlling contamination．Noise is as an indicator of bearing quality．Various noise grades have been developed to classify bearing performance capabilities．Noise analysis is done with an Anderonmeter, which is used for quality control in bearing production and also when failed bearings are returned for transducer is attached to the outer ring and the inner race is turned at 1,800rpm on an air is measured in andirons, which represent ball displacement in μm/ experience, inspectors can identify the smallest flaw from their , for example, makes an irregular scratches make a consistent popping and are the most difficult to damage is normally a constant highpitched noise, while a damaged outer race makes an intermittent sound as it defects are further identified by their , defects are separated into low, medium, and high are also referenced to the number of irregularities per revolution.事后的調(diào)查分析提供出寶貴的信息時，最好首先通過正確地選定軸承來完全避免失效的發(fā)生。為了做到這一點，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是非常重要的。同樣重要的是噪聲的研究要求,轉(zhuǎn)矩,跳動,以及可能的暴露于污染物,敵對的液體,和極端溫度。這可以提供進一步的線索軸承是否適合工作。軸承失效的原因大約40%的球軸承故障是由污染引起的灰塵、污垢,刨花和腐蝕。污染也導(dǎo)致轉(zhuǎn)矩和噪聲問題,往往是由于操作不當或應(yīng)用程序。由環(huán)境和污染所產(chǎn)生的軸承失效是可以預(yù)防的，而且通過簡單的肉眼觀察是可以確定產(chǎn)生這類失效的原因。進行后期給出了尋找失敗或失敗的軸承,然后理解失敗背后的機制,如滲碳硬化或疲勞,有助于消除問題的根源。只要使用和安裝合理，軸承的剝蝕是容易避免的。剝蝕的特征是在軸承圈滾道上留有由沖擊載荷或不正確的安裝產(chǎn)生的壓痕。剝蝕通常是在載荷超過材料屈服極限時發(fā)生的。如果安裝不正確從而使某一載荷橫穿軸承圈也會產(chǎn)生剝蝕。軸承圈上的壓坑還會產(chǎn)生噪聲、振動和附加扭矩。類似的一種缺陷是當軸承不旋轉(zhuǎn)時由于滾珠在軸承圈間振動而產(chǎn)生的橢圓形壓痕。這種破壞稱為低荷振蝕。這種破壞在運輸中的設(shè)備和不工作時仍振動的設(shè)備中都會產(chǎn)生。此外，低荷振蝕產(chǎn)生的碎屑的作用就象磨粒一樣，會進一步損害軸承。與剝蝕不同，低荷振蝕的特征通常是由于微振磨損腐蝕在潤滑劑中會產(chǎn)生淡紅色。扭矩要求是由潤滑劑、保持架、軸承圈質(zhì)量（彎曲部分的圓度和表面加工質(zhì)量）以及是否使用密封或遮護裝置來決定。潤滑劑的粘度必須認真加以選擇，因為不適宜
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