美孚工业润滑脂助力轴承行业“提质增效”

正2016年9月,在中国轴承工业协会主办的2016中国国际轴承及其专用装备展览会期间,埃克森美孚举办了主题为"升级您的润滑脂,提升设备生产力"润滑脂技术研讨会,集中展示了其专为各类轴承打造的领先润滑解决方案。在此次研讨会上,美孚的技术专家与前来参与活动的客户及经销商伙伴介绍了美孚滑脂在轴承行业的应用,并分享了滑脂选择、失效分析和风机用润滑脂简介等话题。     

润滑状态对轧机圆锥滚子轴承接触特性的影响

针对梅钢五机架连轧六辊轧机工作辊的圆锥滚子轴承磨损和烧损问题,介绍了脂润滑滚动轴承的润滑机制;为了选择合适的轴承润滑脂,建立了面向润滑分析的4列圆锥滚子轴承有限元模型,并对3组不同润滑脂润滑后的轴承进行了有限元仿真;通过不同润滑状态下轴承接触特性模拟结果的比较,发现聚脲脂可明显改善轧机轴承的接触特性。现场使用结果表明,聚脲脂润滑可大大降低轧机轴承的磨损和烧损失效发生概率。     

脂润滑轴承静置状态下漏油机理及对策

脂润滑轴承在静置状态下的漏油问题一直是一个难题。枯文旨在地润滑脂的分油及基础油在固体壁面的迁移分析，来探求脂润滑轴承润滑剂泄漏机理；同时介绍了在润滑脂中加入氟表面活性剂、改善轴承壁面结构设计两项措施来降低脂润滑轴承在静置状态下的漏油。     

导向滑轮轴承极压润滑脂的研究及应用

以导向滑轮轴承实际工况和用脂需求为基础,参考现用进口极压润滑脂性能分析结果,制定了国产极压润滑脂产品技术指标,并进行了新型润滑脂的制备及理化性能分析。对进口润滑脂和新研润滑脂分别进行高转速、大载荷轴承台架试验,对比了使用2种润滑脂时试验轴承的最大转速、温度、典型载荷曲线和典型转速曲线,并定期检测轴承游隙、轴承表面质量、剩余润滑脂量及加脂量,同时定期对进口和新研润滑脂取样,进行红外光谱分析与理化性能测试。结果表明:新研润滑脂的各项指标均达到技术指标要求,在台架试验轴承中未发生失效和故障,表现出比进口润滑脂更强的稳定性和可靠性,满足装备的使用要求。     

福建福清核电有限公司

为探讨某发电机组球面滚子轴承失效原因，采用发射光谱、铁谱、电镜能谱及模拟试验等方法，对新脂、在用脂以及损毁的轴承进行检测与分析。分析发现球面滚子轴承失效原因为，新脂在贮存过程中抗磨性能有所下降；轴承运行过程中，润滑脂受到水分污染失效，又未能定期添加，导致摩擦副表面发生高温氧化，最终烧伤轴承。提出选用满足要求的润滑脂和采用少量多次的定期加脂方式等改进措施，改进后球面滚子轴承运行正常。     

航空电机轴承故障分析与改进措施

针对某型航空交流发电机轴承故障形貌特征,分别从结构参数、材料、润滑脂性能及填脂量等4个方面对轴承损坏的原因进行了排查和分析。结果表明,润滑不良是导致轴承失效的主要原因。通过采取相应的改进措施,取得了良好效果。     

脂润滑滚动轴承润滑机理探讨

轴承的润滑已成为影响轴承寿命的一个重要因素。润滑脂对轴承的作用是显而易见的，但脂润滑轴承的润滑机理如何，目前还没有共识。通过分析各国学者研究成果的基础上，提出了对脂润滑轴承润滑机理的一些看法。附图1幅，参考文献7篇。     

某航空电机脂润滑轴承失效分析与改进措施

针对某航空电机用脂润滑密封轴承试验器试验失效问题,分别从轴承外观、材料、硬度、金相组织、润滑脂等5个方面进行检测和分析,发现密封圈磨损产生的磨屑掉入轴承内部使润滑脂变质是导致轴承失效的主要原因。提出将密封圈材料由聚四氟乙烯更换为硬度较低的氟橡胶,同时降低密封圈接触唇与内圈挡边过盈量等改进措施,取得了良好的效果。     

全合成复合锂皂润滑脂的润滑寿命试验分析

从理论上分析了润滑脂的失效机理及影响因素,指出温度、转速、载荷与填脂量是影响轴承润滑脂寿命的主要因素,通过模拟特定工况对某全合成锂皂润滑脂的润滑寿命进行了试验。结果表明:温度升高20℃,润滑脂的50%可靠度寿命降低约60%;转速增加50%,润滑脂可靠度寿命降低40%以上。     

采用不同结构冷却系统时电主轴脂润滑轴承温度场仿真分析

针对高速电主轴采用脂润滑时发热量大且散热困难，极易导致润滑脂过热失效和轴承寿命缩短的问题，以B7009C轴承为研究对象，基于摩擦学和传热学理论，建立了不同转速下轴承发热量的数学模型，通过有限元软件仿真计算了无冷却结构下轴承和轴承座的温度场分布，结果表明高速下发生了润滑失效，需要设计针对性的冷却结构。分别设计了“一进一出单环形槽”“三进三出单环形槽”及“三进三出双环形槽”冷却模型对轴承外圈进行冷却，并对相同工况下3种冷却模型的温度场进行仿真分析，结果表明，达到稳态后，“三进三出双环形槽”冷却模型整体温度较低，温度分布均匀，有助于提高润滑脂的润滑性能，延长轴承寿命，减小冷却水道对轴承座支承刚度的影响。     

Grease Degradation in Rolling Element Bearings

Grease is degraded during use in rolling element bearings and as a result the lubrication performance can deteriorate. Under severe conditions this can result in lubrication failure and, thus, the grease life will effectively limit the bearing life. At present there is a lack of detailed information regarding the changes that occur in the grease and the way in which this degradation affects lubrication performance and failure.

This paper reports an initial study into grease degradation in bearings. The aim of the work was to characterize the changes that occur to the chemical and physical properties during use. A series of bearing tests using the modified DIN 51 806 test designated R2F(M) have been carried out using two greases: additized and non-additized. The tests have been run for different temperature and speed conditions for up to 300 hours. The aim was to examine the grease during normal running rather than after failure. At the end of the tests the bearings were dismantled and grease taken from different parts of the bearing for infrared spectroscopic analysis. This technique can characterize the degree of oxidation or degradation of the grease both in the bulk sample and from thin grease layers remaining on the bearing surfaces.

The analysis has shown that the condition of the grease varies depending on the distribution within the bearing. The lubricant remaining in the cage pocket region was heavily degraded and contained very little thickener. The grease on the seals contained different amounts of thickener depending on the seal position. The lubricant remaining on the inner raceway surface was predominately base oil although there was some thickener present. These results are discussed in the light of proposed bearing lubrication mechanisms.     

送风机电机滚动轴承磨损失效分析

采用扫描电镜、光电直读谱分析仪、红外光谱仪等分析测试手段,对YKK630-6型电动机滚动轴承磨损失效原因进行了分析。结果表明,引起滚动轴承过度磨损的主要原因是润滑脂失效导致金属摩擦副之间的直接对磨。另外,轴承滚动过程中产生放电现象,使轴承内圈表面烧伤、剥离,加速了轴承的磨损。     

汽车水泵轴承润滑脂的选用

在对国产汽车水泵轴承用脂调研的基础上，选用3类典型轴承用润滑脂进行高温耐久性寿命、抗水能力、防锈性及与尼龙材料相容等性能的评价试验和分析，考察了汽车水泵轴承用润滑脂选择的基本要求、相关技术指标及试验方法。对比分析认为，聚脲脂是一种效果理想的可作为汽车水泵轴承用的润滑脂品种。     

Fracture of polymeric materials under tensile loads

The frictional mechanism in a journal bearing lubricated with grease containing powdered PTFE was examined by infrared spectroscopy and by scanning electron microscopy. An explanation of the modifying action of grease containing powdered PTFE is presented in terms of the mechanically induced physico-chemical interactions between PTFE, grease, environment and the metallic substrate of the bearing.     

Mapping of Grease Migration in High-Speed Bearings Using a Technique Based on Fluorescence Spectroscopy

A novel approach that allowed the identification of (in) active grease reservoirs in high-speed superprecision angular contact ball bearings for spindle applications is described. To improve the design of these grease-lubricated bearings it is necessary to measure grease migration and determine the lubrication role of internal grease reservoirs. Hence, a technique based on fluorescence spectroscopy is successfully applied that allowed the identification of grease migration in such a bearing. Therefore, this technique provides a new way to further improve grease migration in critical bearing locations with the ultimate goal of attaining even higher speeds and longer life.     

一种耐轴承腐蚀和磨损的复合锂基润滑脂的研制

研究不同类型极压抗磨剂、抗氧剂和防锈剂等对复合锂基润滑脂性能的影响,并复配一种多功能复合添加剂制备出复合锂基润滑脂。所研制复合锂基润滑脂的梯姆肯值为266 N、高温下氧化诱导期为761 min、滴点大于330℃,且通过了FE 8轴承磨损和EMCOR轴承腐蚀台架的检测。研究结果表明:所研制的复合锂基脂具有优异的极压抗磨、高温抗氧及耐轴承腐蚀和磨损等性能,应用效果良好。     

Grease lubrication of rolling element bearings — role of the grease thickener

The contribution of grease thickener to lubricant film formation was examined in this paper. Lubricant film thickness and friction were measured for different grease thickener types in a bearing simulation device. The results showed that the greases formed thick (20–80nm), low friction surface layers at low speeds, which were much greater than the corresponding base oil film. These films appeared to be formed by the physical deposition of thickener in the track during overrolling of the grease. This was confirmed by infrared reflection analysis, which showed the deposited films to have increased thickener content. The ability of grease to form renewable physically deposited solid films has significant implications for optimising lubricant formulation for certain applications, e.g. bearings operating at high temperatures and low speeds where a conventional elastohydrodynamic lubricating film would be inadequate. Copyright © 2007 John Wiley & Sons, Ltd.     

Optimum grease quantity for roller bearing lubrication

This paper presents the results of an experimental study of the effect of the amount of lubricating grease on both temperature and frictional characteristics of rolling bearings. The test rig allows experimental work to be conducted on rolling bearings of various types and sizes with controlled quantities of grease being injected into them. Applied load, rotational speed, frictional torque, and bearing operating temperature are measured. For the rolling bearing tested, the bearing temperature rises with increase in the amount of grease supplied, rotational journal speed, and applied load: frictional drag displays a minimum value which corresponds to the optimum quantity of grease in the bearing     

Grease degradation in a bearing simulation device

In this study, a ball-on-disc traction (MTM) device has been used to degrade grease under controlled thermal and shear conditions over an extended period. The tests were run under both fully flooded and semi-starved conditions to simulate the lubricant supply levels found in bearings. A simple lithium hydroxystearate grease with and without an additive package was used. At the end of the test Infrared micro-reflection spectra were taken from the track and surrounding grease to determine lubricant film composition. These results were compared to IR reflection analysis of lubricant films in used bearings. The MTM results show that in the semi-starved tests the grease “runs-in” during the first few cycles as the friction coefficient drops giving a low, stable value comparable to the fully flooded condition. During initial overolling the grease is shear degraded releasing mobile lubricant, which replenishes the contact and reduces starvation. IR analysis of the lubricant film in and around the track has shown evidence of the local degradation, the formation of thickener-rich layers and new chemical species. The unadditised grease failed towards the end of the test due to incipient starvation, which was exacerbated by the formation of oxidised thickener deposits in the track. The IR spectrum from this film was very similar to that found in some bearing samples.     

滚动轴承保持器磨损对轴承失效的影响

针对滚动轴承运行特点,采用XRF技术调查和分析铜、铁及尼龙为主体材料的保持器在脂润滑条件下的磨损,研究保持器磨损与轴承滚动体磨损之间的相关性及对轴承磨损失效过程的影响,并对不同材料保持器所产生的磨损颗粒对轴承及润滑脂的影响进行初步分析和探讨。统计数据分析结果表明,不同结构或材料构成的保持器在脂润滑轴承运转过程中始终存在着一定程度的磨损,且与轴承滚动体的磨损在磨损相对数量上显著相关;高聚物尼龙保持器所形成的磨损颗粒的影响,更多地反映为保持器材料中硬质填料的机械作用,而钢制保持器因其磨损颗粒具有金属活性和催化性,磨损颗粒同时还加速润滑脂的化学氧化过程及对脂稠化剂网状结构的破坏。