機械設(shè)計與制造總結(jié)(編輯修改稿)
2024-11-09 06:25 本頁面
【文章內(nèi)容簡介】 ing or different configuration may be used．Creep is less mon than premature fatigue．In bearings．it is caused by excessive clearance between bore and shaft that allows the bore to rotate on the shaft．Creep can be expensive because it causes damage to other ponents in addition to the bearing．0ther more likely creep indicators are scratches，scuff marks，or discoloration to shaft and bore．To prevent creep damage，the bearing housing and shaft fittings should be visually checked．Misalignment is related to creep in that it is mounting related．If races are misaligned or cocked．The balls track in a noncircumferencial path．The problem is incorrect mounting or tolerancing，or 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
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