【文章內(nèi)容簡介】 e Bearings(陳鵬文，有錯包含)A machine tool spindle must provide rotational speed, transfer torque and power to the cutting tool, and have reasonable load carrying capacity and life. （機床主軸必須提供轉(zhuǎn)速、傳遞力矩和公路到切削工具上，而且具有一個合理的負載承受能力和壽命。）The bearing system, one of the most critical ponents of any highspeed spindle design, must be able to meet these demands or the spindle won’t perform.（軸承系統(tǒng)，是任何高速主軸設計中最需要主要考慮的部件之一，它必須能夠滿足這些需要或者是主軸不能實現(xiàn)的需要。）Highspeed spindle bearing available today include roller, taper roller, and angular contact ball bearings.（當今可以用的高速主軸軸承包括滾珠軸承、錐型滾柱軸承和徑向止推滾珠軸承。） Selection criteria depend on the spindle specifications and the speed needed for metalcutting.（選擇標準依靠主軸規(guī)格和金屬切削所需的速度。）Angular contact bearings are the type most monly used in very highspeed spindle design. （徑向止推軸承在超高速主軸設計中是用得最普遍的。）These bearings provide precision, load carrying capacity, and the speed needed for metalcutting.（這些軸承提供精確度，伏在承受能力和金屬切削所需的速度。） Angular contact ball bearings have a number of precision balls fitted into a precision steel race, and provide both axial and radial load carrying capacity when properly preloaded.（徑向止推軸承有許多安裝在精確鋼槽里的精確滾珠，在正確安裝下提供軸向和徑向的負載承受能力。）In some cases, tapered roller bearings are used because they offer higher load carrying capacity and greater stiffness than ball bearings. （在某些情況下，錐型滾珠軸承被用是因為它能提供較滾珠軸承更大的負載承受能力和更大的剛度。）However, tapered roller bearings do not allow the high speeds required by many spindles.（然而，錐型滾柱軸承不能保證許多主軸需要的高的速度。）Angular contact ball bearings are available with a choice of preloading magnitude, typically designated as light, medium, and heavy.（徑向止推滾珠軸承可以選擇預裝載大小，典型的有輕載型，種載型和重載型。） Light preloaded bearings allow maximum speed and less stiffness. These bearings are often used for very highspeed applications, where cutting loads are light.（輕載型軸承能保證最大速度和較小的剛度。這些軸承通常在超高速，切削力小的的情形下應用。）Heavy preloading allows less speed, but higher stiffness.（重載型軸承可以保證較低速度，較高剛度。） To provide the required load carrying capacity for a metalcutting machine tool spindle, several angular contact ball bearings are used together. （為了給機床提供金屬切削所需要的負載承受能力，一些徑向止推滾珠軸承被結(jié)合使用。）In this way, the bearings share the loads, and increase overall spindle stiffness.（用這種方法，軸承分擔負載，而且提高了整個主軸的剛度。）Hybrid ceramic bearings are a recent development in bearing technology that uses ceramic (silicon nitride) material to make precision balls.（混合的陶瓷軸承是在軸承科技中最近發(fā)展起來的，是利用陶瓷（氮化硅）材料制做精確的滾珠。） The ceramic balls, when used in an angularcontact ball bearing, offer distinct advantages over typical bearingsteel balls（應用于徑向止推滾珠軸承中的陶瓷滾珠提供了較鋼珠軸承中鋼珠明顯的優(yōu)點。）.Ceramic balls have 60% less mass than steel balls.（陶瓷滾珠質(zhì)量不到鋼珠的60%。） This is significant because as a ball bearing is operating, particularly at high rotational speeds, shape of the ball. （這是有意義的，因為一個轉(zhuǎn)動的滾珠軸承尤其是在高速旋轉(zhuǎn)中，滾珠的形狀會發(fā)生變化。）This deformation leads to rapid wear and bearing deterioration.（ 這種變形會導致快速的磨損和軸承的破會。）Ceramic balls, with less mass, will not be affected as much at the same speed. （陶瓷滾珠具有較小的質(zhì)量，在相同速度下陶瓷滾珠受到影響不如鋼珠大。）In fact, the use of ceramic balls allows up to 30% higher speed for a given ball bearing size, without sacrificing bearing life.（事實上，利用陶瓷滾珠可以保證給定尺寸的滾珠在超過30%速度上工作而不犧牲軸承壽命。） Due to the nearly perfect roundness of the ceramic balls, hybrid ceramic bearings operate at much lower temperatures than steel ball bearings, which results in longer life for the bearing lubricant. （由于幾近完美圓度的陶瓷滾珠，混合的陶瓷軸承工作在較鋼珠軸承低得溫度，這些導致在軸承潤滑中有較長的壽命。）Tests show that spindles utilizing hybrid ceramic bearings exhibit higher rigidity and have higher natural frequencies, making them less sensitive to vibration.（實驗表明主軸利用混合陶瓷軸承體現(xiàn)出更高的剛度個更高的固有頻率，使主軸對振動不那么敏感。）Bearing lubricant is necessary for angular contact ball bearing to operate properly.（軸承潤滑在徑向止推軸承正確工作中是必要的。） The lubricant provides a microscopic film between the rolling elements to prevent abrasion. （潤滑劑在轉(zhuǎn)動零件間提供了一層微觀模來防止磨損。）In addition, it protects surfaces from corrosion, and protects the contact area from particle contamination.（另外，它還防止平面腐蝕，保護接觸平面受磨粒影響。）Grease is the most mon and most easily applied type of lubricant.（潤滑油脂是在潤滑劑中最普遍最簡單的應用方式。） It is injected into the space between the balls and the races, and is permanent. （它被注射到滾珠和滾槽之間的縫隙中，是永久的。）Grease requires minimal maintenance.（潤滑油脂需要最小的維護。） Generally, highspeed spindles utilizing grease lubrication do not allow replacement of the grease between bearing replacements. （通常情況下，高速主軸應用油脂潤滑不能保證潤滑油脂在軸承替換件中的替換。）During a bearing replacement, clean grease is carefully injected into the bearing.（在軸承替換中，情節(jié)的油脂是小心地注射到軸承中。）Often at high rotational speeds, lubrication with grease is not sufficient. （通常在高轉(zhuǎn)速中，油脂潤滑是不夠的。）Oil is then used as a lubricant, and delivered in a variety of ways.（那么油液就用作為潤滑劑，以多種方式傳遞。） Maintenance of the lubrication system is vital, and must be closely monitored to ensure that proper bearing conditions are maintained. （潤滑維護系統(tǒng)式非常重要的，而且必須嚴密檢測來保證維護中正確的軸承維護條件。）Also, use of the correct type, quantity, and cleanliness of lubricating oil is ，正確的用法，用量和潤滑油清潔度也重要。How much life can be expected?（預測壽命是多長呢？） All bearings will have a useful life, defined as operation time until the bearing specifications are lost, or a plete failure of the bearing occurs. （所有的軸承都將有一個使用壽命，被定義為從工作開始時間到軸承規(guī)格破壞時間或者到軸承完全地實效。）The most mon cause of bearing failure is fatigue, in which the races bee rough, leading to heating, and eventual mechanical failure. （導致軸承失效的最普遍的原因是疲勞，在疲勞狀態(tài)下滾槽變得粗糙導致摩擦熱和最終的機械故障。）Bearing life, in general, is affected by axial and radial bearing loads, vibration levels, lubrication quality and quantity, maximum speed, and average bearing temperature. （通常情況下，軸承的壽命受軸向和徑向的負載、振動程度、潤滑質(zhì)量、最高速度和平均軸承溫度影響。）From these influences, bearing life can be calculated from standard equations. （由于這些影響，軸承壽命能通過標準方程來計算。）Today, puter models are often used to forecast bearing life.（現(xiàn)在，計算機模型經(jīng)常用于預測軸承壽命。）1機構的基本概念一些有關聯(lián)的部分綜合起來能夠?qū)崿F(xiàn)一定運動并能完成有用的工作叫做機器。一個機構是一個由兩個以上的部分裝配成的機器的一個組件以實現(xiàn)一個部件的運動帶動其他部分運動。運動學是研究機構的運動而不涉及施加在機構上的力。動力學是研究運動的部分和受力和力矩影響的機構。研究靜止系統(tǒng)的力和力矩叫做靜力學（或者說是慣性影響對系統(tǒng)是微不足道的）。 綜合分析是設計產(chǎn)品以滿足一定的性能需求的一個步驟，如果一個產(chǎn)品配置先