轴承寿命外文翻译参考文献(共13页).doc

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1、精选优质文档-倾情为你奉上外文文献翻译 (含：英文原文及中文译文) 英文原文 EXTENDING BEARING LIFEAbstractNature works hard to destroy bearings, but their chances of survival can be improved by following a few simple guidelines. Extreme neglect in a bearing leads to overheating and possibly seizure or, at worst, an explosion. But even

2、a failed bearing leaves clues as to what went wrong. After a little detective work, action can be taken to avoid a repeat performance.Keywords: bearings failures lifeThere are many causes of bearing failure, but common ones are improper use, contamination, improper use of lubricants, damage during i

3、nstallation or handling, and mounting errors. It is not difficult to diagnose the cause of the failure because the traces left on the bearings can determine the cause of the bearing failure.However, when post-hoc investigations provide valuable information, it is best to avoid failures completely by

4、 properly selecting the bearings first. In order to do this, it is important to review the manufacturers dimensional positioning guidelines and the use characteristics of the selected bearings.1 Cause of bearing failureAbout 40% of ball bearing failures are caused by dust, dirt, debris, and corrosio

5、n. Contamination is usually caused by incorrect use and poor use of the environment. It also causes problems with torque and noise. Bearing failures caused by the environment and contamination are preventable, and simple visual inspection can determine the cause of such failures.Through post-failure

6、 analysis, you can find out what aspects of bearings that have failed or are about to fail should be viewed. Understanding the mechanisms of failure such as erosion and fatigue failure can help eliminate the root cause of the problem.As long as it is used and installed properly, erosion of the beari

7、ng is easily avoided. Erosion is characterized by the presence of indentations on the raceways of the bearing ring caused by impact loads or incorrect installation. Erosion usually occurs when the load exceeds the yield limit of the material. If the installation is incorrect so that a load traversin

8、g the bearing ring can also produce erosion. The pits on the bearing rings also produce noise, vibration and additional torque.A similar defect is the elliptical indentation that occurs when the bearing does not rotate due to the ball oscillating between the bearing rings. This kind of damage is cal

9、led low erosion. This type of damage occurs in both the equipment in transit and the equipment that is still vibrating when not in use. In addition, the debris generated by low-frequency chattering act like abrasive particles and further damage the bearing. Unlike denudation, low charge erosion is o

10、ften characterized by fretting corrosion that produces a reddish color in the lubricant.Eliminating the source of vibration and maintaining good bearing lubrication can prevent low load chatter. Isolating the device or isolating the base can reduce the vibration of the environment. In addition, addi

11、ng a small preload on the bearing not only helps the ball and the bearing ring to maintain close contact, but also helps to prevent the low load eroding generated during the transportation of the equipment.Causes of bearing seizures are due to lack of internal clearance, improper lubrication and exc

12、essive loads. Before it gets stuck, excessive friction and heat soften the bearing steel. Overheated bearings usually change color and generally turn blue-black or yellowish. Friction also forces the cage, which can damage the support frame and accelerate bearing failure.Premature fatigue failure of

13、 materials is caused by excessive preload after heavy load. If these conditions are unavoidable, the bearing life should be carefully calculated to develop a maintenance plan.Another solution is to change the material. If standard bearing materials do not guarantee adequate bearing life, special mat

14、erials should be used. In addition, if this problem is caused by excessive loads, bearings with stronger load carrying capacity or other structures should be used.Creep is not as common as premature fatigue. The creep of the bearing is caused by the excessive clearance between the shaft and the inne

15、r ring. The harm caused by creep is very large. It not only damages the bearings but also destroys other parts.The obvious features of peristaltic motion are scratches, scratches, or changes in the color of the shaft and the inner ring. In order to prevent creep, the components of the bearing housin

16、g and the shaft should be visually inspected first.Creep is related to improper installation. If the bearing ring is not correct or tilted, the ball will move along a non-circular orbit. This problem is caused by incorrect installation or incorrect tolerances or insufficient verticality at the beari

17、ng installation site. If the deflection is more than 0.25, the bearing will prematurely fail.It is much more difficult to check the contamination of the lubricant than to check for improper assembly or creep. Contamination is characterized by premature bearing wear. Solid impurities in lubricants ac

18、t like abrasive particles. Poor lubrication between the ball and cage can also wear and weaken the cage. In this case, lubrication is critical to a fully processed form of cage. In contrast, ribbon or crown cages make it easier to get the lubricant to the entire surface.Rust is a form of moisture po

19、llution, and its presence often indicates that the material is not properly selected. If a material is tested to meet the requirements of the job, the easiest way to prevent rust is to package the bearings until the package opens.2 methods to avoid failureThe best way to solve the bearing failure pr

20、oblem is to avoid failure. This can be achieved by considering key performance features during the selection process. These characteristics include noise, starting and running torque, stiffness, non-repetitive runout, and radial and axial clearances.The torque requirement is determined by the qualit

21、y of the lubricant, cage, bearing ring (roundness of the bend and surface finish) and whether seals or shields are used. The viscosity of the lubricant must be carefully chosen because unsuitable lubricants generate excessive torque, especially in small bearings. In addition, different lubricants ha

22、ve different noise characteristics. For example, grease generates more noise than oil. Therefore, lubricants should be selected according to different uses. During the rotation of the bearing, if there is a random eccentricity between the inner ring and the outer ring, a non-repetitive oscillation (

23、NRR) very similar to that of the cam motion occurs. NRR is caused by the size error of the cage and the eccentricity of the bearing ring and the ball. Unlike repetitive vibration, NRR is not compensated.In the industry, bearings of different types and accuracy levels are generally selected according

24、 to the specific application. For example, when the minimum vibration is required, the non-repetitive oscillation of the bearing cannot exceed 0.3 m. Similarly, the machine tool spindle can only tolerate minimal runout to ensure cutting accuracy. Therefore, non-repetitively-oscillating bearings shou

25、ld be used in machine tool applications.In many industrial products, contamination is unavoidable, so seals or shields are often used to protect the bearings from dust or dirt. However, due to the movement of the inner and outer rings of the bearing, the sealing of the bearing cannot reach a perfect

26、 level. Therefore, leakage and contamination of the lubricating oil is always an unsolved problem.Once the bearing is contaminated, the lubricant deteriorates and the operating noise increases. If the bearing overheats, it will get stuck. When the contaminant is between the ball and the bearing ring

27、, its effect is the same as that between the metal surface, which can cause the bearing to wear. The use of seals and shields to stop dirt is a method of controlling contamination.Noise is an indicator of bearing quality. Bearing performance can be expressed in different noise levels.The analysis of

28、 noise was performed using Anderson meters, which can be used to control the quality of the bearings, as well as to analyze the failed bearings. A sensor is attached to the outer ring of the bearing while the inner ring rotates at a spindle speed of 1800r/min. The unit of measurement noise is andero

29、n. That is, bearing displacement expressed by um/rad.According to experience, observers can identify minor defects based on sound. For example, dust produces irregular hum; ball scratches create a continuous blasting sound that is most difficult to determine; inner ring damage usually produces conti

30、nuous high-frequency noise, and outer ring damage creates a kind of Intermittent sounds.Bearing defects can be further identified by their frequency characteristics. Bearing defects are usually divided into three bands: low, medium and high. Defects can also be identified based on the number of irre

31、gular changes that occur each rotation of the bearing.Low-frequency noise is a result of irregular changes in the long-wavelength band. This irregular change in bearing rotation can occur 1.6 to 10 times per revolution, and they are caused by various interferences (such as pits in bearing ring racew

32、ays). A perceptible pit is a manufacturing defect that is formed during the manufacturing process due to the too tight grip of the multi-jaw chuck.IF noise is characterized by an irregular change of 10 to 60 times per rotation of the bearing. This defect is caused by vibrations that occur in the gri

33、nding of bearing rings and balls. The high-frequency irregular changes of the bearing occur every 60 to 300 times, which indicates that there are dense vibration marks or a large area of roughness on the bearing.Bearings are categorized using the noise characteristics of the bearings. Users can dete

34、rmine the noise level of the bearings in addition to the ABEC standards used by most manufacturers. The ABEC standard only defines dimensional tolerances such as hole, outside diameter, and runout. As the ABEC level increases (from 3 to 9), the tolerance becomes smaller. However, the ABEC rating doe

35、s not reflect other bearing characteristics such as bearing ring quality, roughness, noise, etc. Therefore, the classification of noise levels contributes to the improvement of industry standards.中文译文如何延长轴承寿命摘要自然界苛刻的工作条件会导致轴承的失效,但是如果遵循一些简单的规则,轴 承正常运转的机会是能够被提高的。在轴承的使用过程当中,过分的忽视会导致轴承的过 热现象,也可能使轴承不能够再被

36、使用,甚至完全的破坏。但是一个被损坏的轴承,会留下它为什么被损坏的线索。通过一些细致的侦察工作,我们可以采取行动来避免轴承的再 次失效。关键词 :轴承 失效 寿命导致轴承失效的原因很多,但常见的是不正确的使用、污染、润滑剂使用不当、装卸 或搬运时的损伤及安装误差等。诊断失效的原因并不困难,因为根据轴承上留下的痕迹可 以确定轴承失效的原因。然而,当事后的调查分析提供出宝贵的信息时,最好首先通过正确地选定轴承来完全 避免失效的发生。为了做到这一点,再考察一下制造厂商的尺寸定位指南和所选轴承的使 用特点是非常重要的。1 轴承失效的原因在球轴承的失效中约有 40%是由灰尘、 脏物、 碎屑的污染以及腐蚀

37、造成的。 污染通常是 由不正确的使用和不良的使用环境造成的,它还会引起扭矩和噪声的问题。由环境和污染 所产生的轴承失效是可以预防的,而且通过简单的肉眼观察是可以确定产生这类失效的原 因。通过失效后的分析可以得知对已经失效的或将要失效的轴承应该在哪些方面进行查 看。弄清诸如剥蚀和疲劳破坏一类失效的机理,有助于消除问题的根源。只要使用和安装合理,轴承的剥蚀是容易避免的。剥蚀的特征是在轴承圈滚道上留有 由冲击载荷或不正确的安装产生的压痕。剥蚀通常是在载荷超过材料屈服极限时发生的。 如果安装不正确从而使某一载荷横穿轴承圈也会产生剥蚀。轴承圈上的压坑还会产生噪声、 振动和附加扭矩。类似的一种缺陷是当轴承

38、不旋转时由于滚珠在轴承圈间振动而产生的椭圆形压痕。这 种破坏称为低荷振蚀。这种破坏在运输中的设备和不工作时仍振动的设备中都会产生。此 外,低荷振蚀产生的碎屑的作用就象磨粒一样,会进一步损害轴承。与剥蚀不同,低荷振 蚀的特征通常是由于微振磨损腐蚀在润滑剂中会产生淡红色。消除振动源并保持良好的轴承润滑可以防止低荷振蚀。给设备加隔离垫或对底座进行 隔离可以减轻环境的振动。另外在轴承上加一个较小的预载荷不仅有助于滚珠和轴承圈保 持紧密的接触,并且对防止在设备运输中产生的低荷振蚀也有帮助。造成轴承卡住的原因是缺少内隙、润滑不当和载荷过大。在卡住之前,过大的摩擦和 热量使轴承钢软化。过热的轴承通常会改变颜

39、色,一般会变成蓝黑色或淡黄色。摩擦还会 使保持架受力,这会破坏支承架,并加速轴承的失效。材料过早出现疲劳破坏是由重载后过大的预载引起的。如果这些条件不可避免,就应 仔细计算轴承寿命,以制定一个维护计划。另一个解决办法是更换材料。若标准的轴承材料不能保证足够的轴承寿命,就应当采 用特殊的材料。另外,如果这个问题是由于载荷过大造成的,就应该采用抗载能力更强或 其他结构的轴承。蠕动不象过早疲劳那样普遍。轴承的蠕动是由于轴和内圈之间的间隙过大造成的。蠕 动的害处很大,它不仅损害轴承,也破坏其他零件。蠕动的明显特征是划痕、擦痕或轴与内圈的颜色变化。为了防止蠕动,应该先用肉 眼检查一下轴承箱件和轴的配件。

40、蠕动与安装不正有关。如果轴承圈不正或翘起,滚珠将沿着一个非圆周轨道运动。这 个问题是由于安装不正确或公差不正确或轴承安装现场的垂直度不够造成的。如果偏斜超 过 0.25,轴承就会过早地失效。检查润滑剂的污染比检查装配不正或蠕动要困难得多。污染的特征是使轴承过早的出 现磨损。润滑剂中的固体杂质就象磨粒一样。如果滚珠和保持架之间润滑不良也会磨损并 削弱保持架。在这种情况下,润滑对于完全加工形式的保持架来说是至关重要的。相比之 下,带状或冠状保持架能较容易地使润滑剂到达全部表面。锈是湿气污染的一种形式,它的出现常常表明材料选择不当。如果某一材料经检验适 合工作要求,那么防止生锈的最简单的方法是给轴承

41、包装起来,直到安装使用时才打开包 装。2 避免失效的方法解决轴承失效问题的最好办法就是避免失效发生。这可以在选用过程中通过考虑关键 性能特征来实现。这些特征包括噪声、起动和运转扭矩、刚性、非重复性振摆以及径向和 轴向间隙。扭矩要求是由润滑剂、保持架、轴承圈质量(弯曲部分的圆度和表面加工质量)以及 是否使用密封或遮护装置来决定。润滑剂的粘度必须认真加以选择,因为不适宜的润滑剂会产生过大的扭矩,这在小型轴承中尤其如此。另外,不同的润滑剂的噪声特性也不一样。 举例来说,润滑脂产生的噪声比润滑油大一些。因此,要根据不同的用途来选用润滑剂。 在轴承转动过程中,如果内圈和外圈之间存在一个随机的偏心距,就会

42、产生与凸轮运 动非常相似的非重复性振摆 (NRR ) 。 保持架的尺寸误差和轴承圈与滚珠的偏心都会引起 NRR 。 和重复性振摆不同的是, NRR 是没有办法进行补偿的。在工业中一般是根据具体的应用来选择不同类型和精度等级的轴承。例如,当要求振 摆最小时,轴承的非重复性振摆不能超过 0.3微米。同样,机床主轴只能容许最小的振摆, 以保证切削精度。因此在机床的应用中应该使用非重复性振摆较小的轴承。在许多工业产品中,污染是不可避免的,因此常用密封或遮护装置来保护轴承,使其 免受灰尘或脏物的侵蚀。但是,由于轴承内外圈的运动,使轴承的密封不可能达到完美的 程度,因此润滑油的泄漏和污染始终是一个未能解决

43、的问题。一旦轴承受到污染,润滑剂就要变质,运行噪声也随之变大。如果轴承过热,它将会 卡住。当污染物处于滚珠和轴承圈之间时,其作用和金属表面之间的磨粒一样,会使轴承 磨损。采用密封和遮护装置来挡开脏物是控制污染的一种方法。噪声是反映轴承质量的一个指标。轴承的性能可以用不同的噪声等级来表示。噪声的分析是用安德逊计进行的,该仪器在轴承生产中可用来控制质量,也可对失效 的轴承进行分析。将一传感器连接在轴承外圈上,而内圈在心轴以 1800r/min的转速旋转。 测量噪声的单位为 anderon 。即用 um/rad表示的轴承位移。根据经验,观察者可以根据声音辨别出微小的缺陷。例如,灰尘产生的是不规则的劈

44、 啪声;滚珠划痕产生一种连续的爆破声,确定这种划痕最困难;内圈损伤通常产生连续的 高频噪声,而外圈损伤则产生一种间歇的声音。轴承缺陷可以通过其频率特性进一步加以鉴定。通常轴承缺陷被分为低、中、高三个 波段。缺陷还可以根据轴承每转动一周出现的不规则变化的次数加以鉴定。低频噪声是长波段不规则变化的结果。 轴承每转一周这种不规则变化可出现 1.610次, 它们是由各种干涉(例如 轴承圈滚道上的凹坑)引起的。可察觉的凹坑是一种制造缺陷, 它是在制造过程中由于多爪卡盘夹的太紧而形成的。中频噪声的特征是轴承每旋转一周不规则变化出现 1060次。这种缺陷是由在轴承圈 和滚珠的磨削加工中出现的振动引起的。轴承每旋转一周高频不规则变化出现 60300次, 它表明轴承上存在着密集的振痕或大面积的粗糙不平。利用轴承的噪声特性对轴承进行分类,用户除了可以确定大多数厂商所使用的 ABEC 标 准外,还可确定轴承的噪声等级。 ABEC 标准只定义了诸如孔、外径、振摆等尺寸公差。随 着 ABEC 级别的增加 (从 3增到 9) , 公差逐渐变小。 但 ABEC 等级并不能反映其他轴承特性, 如轴承圈质量、粗糙度、噪声等。因此,噪声等级的划分有助于工业标准的改进。专心-专注-专业