外文翻譯--磁軸承時(shí)代的來臨

1、<p><b>　　外文資料</b></p><p>　　Magnetic Bearings Come Of AgePrinter-friendly version</p><p>　　Magnetic-bearings, which support shafts with magnetic levitation rather than mechanical

2、 contact, have been in industrial use for decades. Magnetic bearings offer a host of advantages to users, including high-speed capabilities and the ability to operate lubrication-free and in vacuum environments. They gen

3、erate no friction, experience minimal wear, and operate contamination free with extremely low vibration. And the bearings can precisely control shaft position, measure external forces acting on</p><p>　　MAGN

4、ETIC-BEARING BASICS:</p><p>　　Magnetic-bearing systems electromagnetically suspend shafts by applying electric current to a bearing's ferromagnetic materials. The systems have three main elements: bearin

5、g actuators, position sensors, and controller and control algorithms. Typical units consist of two magnetic radial bearings and one magnetic thrust bearing. They control the shaft along five axes: two axes for each radia

6、l bearing and a fifth axis along the shaft. Magnetic bearings have stationary and rotating components — the</p><p>　　CONTROL SYSTEMS:</p><p>　　The control system regulates bearing current and, t

7、hus, the force of the bearings. During operation, radial and axial position sensors feed data on shaft location and movement to the controller. It compares actual and desired shaft position, calculates the force required

8、 to maintain the shaft in the preset position and, if necessary, commands the amplifier to adjust the electric current to raise or lower the level of magnetic flux. The main parts of the control system are the digital si

9、gnal-proc</p><p>　　DESIGN CONSIDERATIONS:</p><p>　　The ultimate goal of magnetic-bearing design is reliable, noncontacting rotation over the machine's entire speed range. It is also essentia

10、l to meet OEM and end-user cost targets without compromising performance. Reducing the size of digital-control systems means more cost-efficient solutions, and compact magnetic-bearing designs can lead to smaller, more-r

11、obust machines. When developing magnetic-bearing systems, main factors to consider are the speeds, loads, and operating environment. The mech</p><p>　　DIVERSE APPLICATIONS：</p><p>　　The unique d

12、esign and wide-ranging capabilities of magnetic bearings offer solutions in a host of diverse applications. One example is semiconductorfabrication, particularly front-end operationsinvolving the production of silicone w

13、afers. Magnetic bearings can improve yields in these operations, which are highly sensitive to contamination and vibration. For instance, magnetic bearings permit edge rotation of 300-mm wafers, allowing convenient acces

14、s to both wafer sides. Because magnetic bearings</p><p>　　Magnetic bearings operate without contact. This results in many unique characteristics that are valuable in a wide range of equipment. Applications t

15、hat require more than one of the following attributes are generally suitable for magnetic bearings.</p><p>　　Lubrication-free: Consider magnetic bearings when lubrication systems for other types of bearings

16、are expensive, unreliable, or unsafe; the lubricant contains environmentally unfriendly components and disposal becomes an issue; or the lubricant is incompatible with or contaminates the fluid or process. </p>&l

17、t;p>　　Reliability. The bearings offer superior reliability, comparable to that of electric motors, and it is reasonable to expect an operational life of 15 to 20 years. The control system has reliability typical of el

18、ectronic components with conservative mean time between failures of 5 years. </p><p>　　Operation in vacuum. High vacuums are difficult environments for lubricants. Many systems in high to ultrahigh vacuums (

19、to 10- 16 Torr) are sensitive to outgassing and contamination of volatile lubricants. </p><p>　　Low vibration: Magnetic bearings are suitable for applications sensitive to machine vibration. Typical casing v

20、ibration is 0.01 m m. </p><p>　　Force measurement: The controller can determine bearing load and force direction by measuring current and position within the bearings. This gives valuable information for mac

21、hine designers when developing magnetic-bearing systems. Forces can be measured with accuracy generally better than 5%. </p><p>　　Shaft-position control: Because sensors monitor shaft location, the control s

22、ystem can reposition or oscillate the shaft while it is rotating. For example, the control system can compensate for wear and adjust the shaft axial position during operation to optimize the grinding-plate gaps and impro

23、ve product quality in pulp refiners. </p><p>　　Precision: Tight control eliminates shaft runout caused by unbalance. This is accomplished with Adaptive Vibration Control. Shaft displacement at the running sp

24、eed can be reduced to about 1 m m, important for precision grinding and machine-tool cutting operations. </p><p>　　Contamination: Processes sensitive to microcontaminants benefit from magnetic bearings with

25、stainless-steel cans or barriers. With the advent of 300-mm wafers and 0.25-mm device sizes, it has become critically important to eliminate microcontaminants in all aspects of wafer processing. </p><p>　　Su

26、bmerged operation: Magnetic bearings can operate directly in the process fluid and eliminate the need for mechanical seals. This reduces emissions, machine cost, and operating maintenance costs. </p><p>　　Re

27、duced energy consumption: Magnetic bearings reduce frictional losses, resulting in higher overall mechanical efficiency. And the lack of a lubrication system eliminates the cost of operating pumps, cooling fans, reservoi

28、r ventilation fans, and so on. </p><p>　　Condition monitoring: Magnetic bearings have built-in condition-monitoring capabilities. This eliminates the need for devices like accelerometers and vibration sensor

29、s, as well as monitoring equipment and interface software. In addition, magnetic-bearing control systems directly observe shaft and process-fluid behavior with no need to interpret rolling-element and race frequencies. &

30、lt;/p><p>　　Air gap: Some applications simply benefit from noncontact operation. For example, in biotech applications, heart pumps or mixers benefit by not damaging cells with contacting surfaces. In textiles,

31、fibers can pass through the gap. Air gaps can be up to 2 mm. </p><p>　　High speed: Speed is limited by the mechanical strength of the shaft. Surface speeds on radial bearings are as high as 3.5 3 10 6 DN (di

32、ameter (mm) 3 rpm). This attribute becomes more valuable as lubrication becomes more difficult. </p><p>　　Phase control: Today's DSPs do more than just controlling the magnetic bearing, performing functi

33、ons that can easily reduce the cost of a system by more than the cost of the magnetic bearing. One example is phase control. This feature synchronizes shaft rotation with external timing signals. Synchronization position

34、s the shaft (phase) to within 0.05 of its reference mark while rotating at speeds to 36,000 rpm. Phase control is used in applications such as neutron choppers. </p><p><b>　　中文譯文</b></p>&

35、lt;p><b>　　磁軸承時(shí)代的來臨</b></p><p>　　磁懸浮軸承不是靠機(jī)械觸點(diǎn)而是利用磁懸浮的支撐軸，它已經(jīng)在工業(yè)中使用了幾十年。磁懸浮軸承給使用者帶來了包括高速運(yùn)轉(zhuǎn)，無潤滑和真空環(huán)境運(yùn)作的能力等諸多方便和好處。磁懸浮的機(jī)械磨損小，能耗低，無油污染并且可以精確控制軸的位置，以及精確測量外部干擾力，從而可以監(jiān)控機(jī)器的運(yùn)轉(zhuǎn)狀況。隨著近年來數(shù)字處理和控制技術(shù)的發(fā)展，磁軸承也相繼

36、成為一種比以前更加強(qiáng)健和劃算的設(shè)計(jì)解決方案。今天的磁軸承從半導(dǎo)體到微渦輪機(jī)，從制冷壓縮機(jī)到真空泵等方面得到了更加廣泛的應(yīng)用。 </p><p>　　磁懸浮軸承基礎(chǔ)知識:</p><p>　　磁軸承系統(tǒng)是通過電勵(lì)磁使軸懸浮。該系統(tǒng)有三個(gè)主要元素：軸承制動器，位置傳感器和控制器。機(jī)械系統(tǒng)包括兩個(gè)磁徑向軸承和一個(gè)磁推力軸承。他們從六個(gè)自由度來控制軸承。磁懸浮軸承有固定部分和旋轉(zhuǎn)部分?！ㄗ樱D(zhuǎn)

37、子。徑向定子是由疊片堆積形成的，疊片堆積在一起形成極點(diǎn)。每一個(gè)極點(diǎn)上都繞有線圈?？刂齐娏魍ㄟ^線圈，同時(shí)產(chǎn)生電勵(lì)磁，電勵(lì)磁對鐵磁轉(zhuǎn)子產(chǎn)生吸引力，并使其在氣隙內(nèi)懸浮?？諝忾g隙通常約為0.5毫米，在某些應(yīng)用里可以是大于兩毫米。轉(zhuǎn)子疊片裝在氣隙里的軸上。這在一些要彌補(bǔ)磨損的實(shí)例中得到了很大的應(yīng)用，或如果軸擺動。例如在機(jī)床磨削過程中磨輪的磨損會隨著時(shí)間增加而增多。磁推力軸承是提供軸向控制。推力軸承轉(zhuǎn)子是固體銅磁盤，從定子一側(cè)或兩側(cè)連接到軸，并定位

38、在一個(gè)預(yù)定的距離。在操作時(shí)，有定子產(chǎn)生的電磁力作用在轉(zhuǎn)子上并控制軸向運(yùn)動。磁軸承配置還包括輔助軸承，其主要功能是當(dāng)支撐軸處于空載時(shí)和在電流中斷或失敗的情況下保護(hù)機(jī)件。著陸軸承外圈內(nèi)徑小于磁軸承空氣間隙主要是為了防止對軸承潛在損害。</p><p><b>　　控制系統(tǒng)：</b></p><p>　　控制系統(tǒng)是控制磁軸承的電流，從而控制軸承的電磁力。在操作期間，徑向和軸

39、向位置傳感器把軸位置和動態(tài)數(shù)據(jù)傳給控制器它比較實(shí)際和理想的軸的位置，計(jì)算使軸保持在預(yù)設(shè)位置處的力，如果有必要，控制器將控制電流的大小來改變電勵(lì)磁磁通量。電子信號處理，電源和放大器是控制系統(tǒng)的三個(gè)主要部分。一般情況下，機(jī)器越大放大器就越大?？刂破鞯拇笮∪Q于動態(tài)負(fù)載能力的需求，這在重機(jī)應(yīng)用中尤為明顯?？赏ㄟ^適應(yīng)于高速和更苛刻的應(yīng)用程序，如單輸入/單輸出或者多輸入/輸出算法控制軸?？刂破魍ǔＲ?0千赫的頻率來測量和處理位置信號。使旋轉(zhuǎn)速度精

40、確的控制在100000rpm或者更快的速度。磁懸浮技術(shù)的一個(gè)重要優(yōu)點(diǎn)是控制器作為內(nèi)置的監(jiān)測系統(tǒng)提供廣泛的實(shí)時(shí)信息，并使其不需要其他監(jiān)控設(shè)備。像來自SKF的MBScope軟件可以提供有關(guān)機(jī)器健康的詳細(xì)診斷信息并且可以更加有效地定期監(jiān)測。該軟件包括調(diào)整輸入?yún)?shù)和在啟動前檢測空襲配置裝置，其工具包括對位置，電流和力的實(shí)時(shí)監(jiān)控器。記錄在發(fā)生不正常情況前后的所有系統(tǒng)產(chǎn)量以及短期或長期趨勢分析的警報(bào)日志。這使用戶可以以不同的形式來查看軸承的信息以及

41、機(jī)器診斷程序。自適應(yīng)振動控制是另一個(gè)重要的工具。A</p><p><b>　　設(shè)計(jì)考慮事項(xiàng)：</b></p><p>　　磁懸浮軸承設(shè)計(jì)的最終目標(biāo)是讓機(jī)器在整個(gè)速度范圍內(nèi)可靠無接觸運(yùn)轉(zhuǎn)。在不影響性能的情況下滿足OEM和終端用戶的成本目標(biāo)也是非常重要的。減少控制系統(tǒng)的大小可以實(shí)現(xiàn)更合算的解決方案，緊密的磁性軸承的設(shè)計(jì)可以使機(jī)器變得更小更強(qiáng)大。發(fā)展磁懸浮軸承系統(tǒng)時(shí)，要考

42、慮的主要因素是速度，荷載和操作環(huán)境。機(jī)械強(qiáng)度的軸通常限制速度。3.5 X 10 的表面速度6 DN (mm 3 rpm 的直徑) 是可能的。靜態(tài)能力——磁懸浮軸承產(chǎn)生的最大力量，它是一個(gè)函數(shù)變量。如放大器電流表面面積磁極，線圈繞組和氣隙尺寸。動態(tài)能力——磁懸浮軸承改變外加力的速率，由放大器電壓這一單一變量決定。例如，考慮將連接在2A.40V的150N的磁懸浮軸承控制系統(tǒng)，轉(zhuǎn)換到更大線圈砸數(shù)的200N或更大磁極范圍等等，如果控制器不變則靜

43、態(tài)能力將會增大，但不會影響動態(tài)能力——在操作過程中處理軸的失衡狀態(tài)和其他動態(tài)力量的能力。相反，保持150N的磁性軸承但切換到3A，50V，系統(tǒng)將增加該軸的動態(tài)能力，但對靜態(tài)能力沒有影響。</p><p><b>　　不同的應(yīng)用程序：</b></p><p>　　磁懸浮軸承獨(dú)特的設(shè)計(jì)和廣泛應(yīng)用的能力為不同應(yīng)用程序提供了解決方案。其中一個(gè)例子是半導(dǎo)體制造，尤其是前端的生產(chǎn)

44、包括有機(jī)硅生產(chǎn)。磁懸浮軸承可以提高生產(chǎn)產(chǎn)量，這些對振動和污染高度敏感。例如，磁性軸承允許 300 毫米晶片的旋轉(zhuǎn)，允許方便地訪問到雙方晶圓片邊緣。因?yàn)榇艖腋≥S承有氣隙，所以他們是某些生物制藥應(yīng)用的理想選擇。血液細(xì)胞或其它液體可以安然無恙的通過空氣隙。制冷壓縮機(jī)是另一個(gè)重要的應(yīng)用。磁懸浮軸承可以以新一代制冷劑所需的的高速度運(yùn)行，與常規(guī)油潤滑軸承不同的是，它們構(gòu)成污染風(fēng)險(xiǎn)降至最低。磁懸浮軸承也可以密封，因此對處理會腐蝕線圈與疊片的流體很有吸

45、引力。</p><p><b>　　磁懸浮軸承原理：</b></p><p>　　磁懸浮軸承的運(yùn)作無接觸。這會帶來許多獨(dú)特的特性，這些特性在很多的設(shè)備中很有價(jià)值。適合磁懸浮軸承的應(yīng)用程序通常需要多個(gè)以下屬性:</p><p>　　無潤滑：考慮磁懸浮軸承當(dāng)其他類型的軸承潤滑系統(tǒng)是昂貴、 不可靠的或不安全的 ；潤滑劑包含不環(huán)保的成分和支配成為一個(gè)問

46、題 ；或潤滑劑與流體不兼容或可以造成污染。</p><p>　　可靠性：軸承提供優(yōu)異的可靠性的電動馬達(dá)，合理期望壽命15至20年?？刂葡到y(tǒng)具有典型的保守平均 5 年故障時(shí)間與電子元器件的可靠性。</p><p>　　真空操作：高真空對潤滑劑是種挑戰(zhàn)。許多系統(tǒng)在高到超高真空系統(tǒng) (10- 16 托爾) 對排氣和揮發(fā)性潤滑劑污染很敏感。</p><p>　　測力：控制器

47、可以通過測量電流和軸承內(nèi)的位置確定軸承負(fù)荷和力方向。這給開發(fā)磁懸浮軸承系統(tǒng)的設(shè)計(jì)師提供了有價(jià)值的信息。可以測量的力的精度一般優(yōu)于 5%。</p><p>　　軸位置控制：因?yàn)閭鞲衅鞅O(jiān)測軸的位置，控制系統(tǒng)可以重新定位或擺動軸轉(zhuǎn)動。例如，控制系統(tǒng)可以彌補(bǔ)磨損和調(diào)整軸向位置以優(yōu)化間隙和提高紙漿煉油廠的產(chǎn)品質(zhì)量。</p><p>　　精密：嚴(yán)格控制消除了不平衡所致的軸徑向跳動。這是有自適應(yīng)振動控制

48、來完成的。軸位移在運(yùn)行速度可以減至約 1 m m，對精密磨削加工和機(jī)床切割操作很重要。</p><p>　　污染：對微污染物敏感的操作可以從有不銹鋼罐或障礙的磁懸浮軸承中受益。在晶元加工的所有方面，伴隨著300毫米晶片和0.25毫米設(shè)備尺寸的出現(xiàn)，這些工序?qū)p少微污染物來說已經(jīng)變得尤為重要。</p><p>　　淹沒操作：磁軸承可在工序中直接操作流體而不需用機(jī)械密封，這將減少排放，降低機(jī)器

49、成本以及運(yùn)營維護(hù)成本。</p><p>　　降低能耗：磁軸承可減少摩擦損耗，進(jìn)而提高整體機(jī)械效率。而且摩擦損耗的減少可以部分省卻潤滑系統(tǒng)，進(jìn)一步節(jié)省對于水泵、冷卻風(fēng)扇以及水庫通風(fēng)風(fēng)扇等的操作費(fèi)用。</p><p>　　狀態(tài)監(jiān)測。磁力軸承具有內(nèi)置的狀態(tài)監(jiān)測能力，這消除了對一些設(shè)備的需求，比如加速表和振動傳感器，以及監(jiān)測設(shè)備和接口軟件。此外，磁軸承控制系統(tǒng)直接觀察軸和過程流體而無需解釋轉(zhuǎn)動體與

50、運(yùn)行頻率。</p><p>　　氣隙：某些應(yīng)用程序受益于非接觸式操作。例如，在生物技術(shù)應(yīng)用中，心臟泵或攪拌機(jī)在不破壞細(xì)胞的接觸面情況下可以受益。在紡織業(yè)， 纖維可以通過差距。氣隙可以到 2 毫米。</p><p>　　高速：軸的機(jī)械強(qiáng)度可以限制速度。徑向軸承的表面速度高達(dá) 3.5 3 10 6 DN （直徑 (mm) 3 rpm）。隨著潤滑變得更加困難，此屬性將變得更有價(jià)值。</p&