锂基润滑脂屈服应力测定方法的探讨

选用旋转流变仪测定了锂基润滑脂的屈服应力。根据锂基润滑脂的流变性质,采用稳态、瞬态和动态实验等方法测定了屈服应力值。实验结果表明,不同测定方法对屈服应力值的影响较大,稳态、瞬态和动态实验测得的屈服应力值依次逐渐增大;稳态和动态实验的测定值为确定的值,而瞬态实验得到的应力值为一个范围。     

Impact of Water on the Rheology of Lubricating Greases

The operational life of bearings is often determined by the performance of the lubricating grease. The consistency of the grease prevents it from leaking out of the bearing and provides good sealing properties. The possible ingress of water into the bearing will have a considerable impact not only on this consistency but also on the lubricating ability of the grease. There are numerous applications where water ingress may occur, such as in the steel, food, pulp, and paper industries. Some greases are less sensitive to water than others. No specific guidelines are available to select the proper grease for bearings subjected to water ingress. The goal of the article is to contribute to the development of such guidelines for greases subjected to water ingress by studying the impact of water on grease rheology. Fully formulated, commercially available greases with the most common thickeners and base oils are used as model greases. It will be shown that water strongly influences rheological properties such as zero-shear viscosity, yield stress, and storage modulus. Calcium sulfonate greases were found to become stiffer after absorbing a considerable amount of water, leading to an increase in zero-shear viscosity and yield stress. However, lithium, lithium complex, and polyurea greases were found to soften, with appreciable changes in measured rheological properties.     

磷酸酯离子液体润滑脂的摩擦学性能研究

用腐蚀性较低、简单易合成的磷酸酯离子液体为基础油,聚四氟乙烯微粉为稠化剂制备一种新型的离子液体润滑脂,在Optimol SRV摩擦试验机上考察其对钢/钢摩擦副的摩擦学性能。结果表明,磷酸酯离子液体润滑脂在室温和高温(100℃)下都表现出优异的减摩抗磨性,并且其减摩抗磨性与离子液体阳离子和阴离子的烷基链长密切相关。磨斑表面扫描电镜和XPS的分析结果表明:摩擦表面既存在离子液体润滑脂与摩擦表面发生摩擦化学反应生成的含有Fe F2、Fe PO4和氮的氧化物的化学反应膜,又存在稠化剂聚四氟乙烯的物理吸附膜。     

高碱值磺酸钙对润滑脂性能的影响

高碱值磺酸盐是生产复合磺酸钙基润滑脂的重要原料,其质量是决定复合磺酸钙基润滑脂产品品质的关键因素之一.为选择合适的高碱值磺酸盐,考察不同高碱值磺酸盐从无定型碳酸钙转化为方解石型碳酸钙的转相时间、稠化能力,以及不同高碱值磺酸盐制备的润滑脂的滴点、锥入度、钢网分油和滚筒安定性能;筛选出的高碱值磺酸盐制备的复合磺酸钙基润滑脂...     

润滑脂的溶解及铁谱分析试验研究

针对润滑脂由于流动性差而无法直接采用铁谱技术进行磨粒分析的问题,探讨适合溶解不同润滑脂的有机溶剂。选择锂基、钙基和铝基3种目前设备润滑常用的润滑脂,通过水浴加热与超声波震荡的溶解方法,对比研究8种有机溶剂对润滑脂的溶解效果;通过摩擦试验制备带有磨粒的润滑脂试样,通过旋转式铁谱仪进行制谱试验,并结合显微镜分析谱片磨粒沉积效果。结果表明:正己烷溶液、体积分数30%二甲苯和70%正己烷混合溶液适合溶解锂基润滑脂,二甲苯和四氯乙烯适合溶解钙基润滑脂和铝基润滑脂;将润滑脂试样溶液的黏度稀释到4 mm~2/s以下时,在旋转式铁谱仪上能够获得良好的制谱效果。     

汽车发动机系滚动轴承润滑脂动态可靠性测试及评价

介绍了汽车发动机系滚动轴承润滑脂动态可靠性的测试及评价方法,包括SKF Emcor润滑脂动态抗腐蚀测试,FAG FE8润滑脂动态抗极压和磨损性能测试以及FAG FE9润滑脂动态润滑寿命测试,对正确选用润滑脂以及汽车发动机系滚动轴承可靠度设计等提供参考.     

大型立式水泵油轴承改水轴承的应用研究

分析了护管式清水润滑导轴承的结构原理,并与传统水润滑轴承进行了比较,介绍了护管式清水润滑导轴承在大型立式水泵中替代油轴承的应用情况,并指出水润滑轴承用于大型立式水泵时应注意的问题。     

锂基润滑脂流变性及摩擦学性能相关性研究

以锂基润滑脂为例,通过 R／S 锥板式流变仪和四球摩擦磨损试验机,对其流变性能及摩擦磨损性能进行研究,探讨润滑脂流变性能与摩擦磨损性能的相关性。结果表明：润滑脂表观黏度随剪切速率的增大逐渐减小,随锥板间隙的增大逐渐增大,随温度的升高逐渐下降,最后均趋于稳定值。润滑脂的平均摩擦因数和磨斑直径随速度的增大先增大后减小,随载荷的增大逐渐增大,随温度的升高先增大后减小。润滑脂的流变性能和摩擦磨损性能随速度、载荷、温度变化的趋势大体一致,表明锂基润滑脂流变性能与其摩擦磨损性能有一定的相关性,为进一步研究润滑脂流变性能与使用性能之间的关系打下了基础。     

滚动轴承润滑脂耐高温性能的试验及评价

比较了润滑脂耐高温性能的静态和动态试验方法,说明润滑脂的耐高温性能应该采用动态试验方法,以试验后润滑脂润滑功能的劣化程度即轴承摩擦力矩的升高程度或手感的加重程度来评价,强调试验后润滑脂色变与否及色变程度与其润滑功能没有必然联系,不宜作为润滑脂耐高温性能的评价依据.     

Studies of the Synthesis and Utilisation of Schiff's Bases: I. Schiff's Bases as Antioxidants for Lubricating Greases

Three Schiff's bases have been prepared as antioxidants for three grades of lubricating grease. The following Schiff's base compounds were synthesised: 3‐[(p‐chlorophenyl)iminomethylenyl]‐4‐hydroxy‐8‐methyl‐2(1H)‐quinolinone and its bromo and iodo analogues. The structures of these compounds have been confirmed using elemental analysis, nuclear magnetic resonance, and infrared spectroscopy. The quinolinone compounds were added to the lubricating greases in different concentrations. The antioxidant efficiency of these bases have been determined using infrared spectroscopy and total acid number. The results indicate that the oxidation stability of the lubricating greases is affected by the type of fatty acid they contain. It was found that the three types of grease resist oxidation in the presence of the Schiff's bases; the efficiency of these compounds as antioxidants decreases in the order: p‐chloro > p‐bromo > p‐iodo derivative. The mechanisms of operation of the quinolinone derivatives as scavengers for free radicals are suggested.     

Optical Attenuation Characterization of Water Contaminated Lubricating Grease

Water-contaminated grease samples are investigated with attenuation spectra in the visible and near-infrared (NIR) regions in this article. The purpose of this investigation was to identify a model with optical attenuation spectra such that the water content of grease samples could be characterized with a simple measurement setup using common methodology from the field of instrumental chemistry. The ratio between two chosen wavelengths of light appears to approximate the water content of grease samples with an acceptable coefficient of determination using a methodology to show what can potentially be done to develop condition monitoring tools. To illustrate the outlined method, a prestudy of grease aging and oxidation levels is also investigated to show that other variables do not significantly change the measurement.     

基础油组成对润滑脂抗磨性能的影响

采用液固吸附色谱、红外光谱和X射线荧光光谱对2种润滑脂基础油进行了分离和分析,用SRV摩擦性能实验考察基础油和润滑脂的抗磨性能。实验结果表明,增加基础油的芳烃和硫化物含量能够提高基础油的抗磨性能,基础油的抗磨性与润滑脂的抗磨性具有一致性,可以通过改变基础油的组成来改善润滑脂的抗磨性能。     

改性复合磺酸钙基润滑脂的研究

高碱值复合磺酸钙基润滑脂综合性能优异,被称为全新理念的润滑脂,但容易产生硬化问题。对复合磺酸钙基润滑脂进行了改性处理,并且对其硬化机制作了初步分析。结果表明:改性后的复合磺酸钙基润滑脂综合了复合锂基脂、聚脲基脂和复合磺酸钙基脂的性能优势,不仅解决了硬化问题,且该润滑脂具有特殊的纤维结构,从而赋予其极高的滴点、良好的高温极压润滑性能和低的摩擦因数。     

The influence of graphite solid additives,MoS2 and PTFE on changes in shear stress values in lubricating greases

The paper deals with the influence of graphite solid additives, bisulphide of molybdenum and polytetrafluoroethylene on changes in shear stress values in lubricating greases. The research was done on lithium and bentonite greases. They were ‘pure’ greases — without any additives — and the compositions of these greases were with different amounts of thickeners. The results of the experiments showed that both the kind of grease and the kind of thickener applied have a significant influence on rheological properties, which result in different grease composites. The research was carried out by means of a rotary rheometer with coaxial cylinders. Copyright © 2006 John Wiley & Sons, Ltd.     

修正的T-J模型分析高速航空润滑脂7018的拖动特性

在自行研制的高速润滑剂拖动特性试验台上对高速航空润滑脂7018进行拖动特性的试验,得出了该润滑脂的拖动系数随速度、温度、负载的变化规律;根据试验数据推导出润滑脂的流变参数;基于修正的T-J模型,求出高速航空润滑脂7018拖动力的大小。结果表明:根据修正的T-J模型计算出的高速航空润滑脂7018的拖动系数和试验值非常接近;高速航空润滑脂7018在试验条件下表现为弹塑性,拖动系数随着滚动速度的增大而减小;当载荷小于转折载荷时,随载荷的增加拖动系数增加,当载荷大于转折载荷时,随载荷的增加拖动系数减小。     

The influence of lubricating greases on rolling bearing failure

Significant savings can be made by the correct use of lubricants in terms of energy consumption, replacement parts, maintenance costs and the reduction of machinery downtime, because the service life of machines is one of the most important aspects of engineering. Planned preventive maintenance means the minimisation of failures and of maintenance costs; the technology should allow identification of the tribomechanical systems in all operating conditions and of the tribological regime and duration of operation. Despite the enormous advances that have been made over the last thirty years in the theory of rolling bearing lubrication, the successful operation of rolling bearings remains highly dependent on empirical knowledge. The aim of the present study is to investigate the influence of lubricating grease on rolling bearing failure; the experimental work was carried out at a metalworking factory.     

Impact of polyurea structure on grease properties

The thickener structure of polyurea grease has a crucial effect on its properties. Therefore, it is very important to study the relationship between a thickener structure and physical and performance properties. In this study, polyurea greases were synthesised, having a different number of urea groups in per polyurea thickener molecule. Properties such as dropping point, penetration, oil separation, shear stability and four‐ball wear and extreme pressure (EP) were evaluated. The result shows that properties of polyurea grease vary with the number of urea group per polyurea molecule. Based on molecular theory, the mechanisms explaining these effects are briefly discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

热氧老化对阀门用二硫化钼润滑脂摩擦性能的影响

利用时温等效原理,制定阀门用二硫化钼润滑脂的加速老化试验条件,并进行等效25℃条件下6年和10年的加速老化试验。在自行设计的模拟阀门试验件力传递效率测试装置上,研究不同条件热氧老化后二硫化钼润滑脂润滑下阀门螺纹的拧紧力矩系数。研究结果表明,在新型手动阀门中使用的二硫化钼润滑脂具有良好的耐老化性能,等效10年自然老化的润滑脂的摩擦性能与新润滑脂的摩擦性能相当,可以满足10年的使用要求。     

角接触球轴承摩擦力矩波动性分析

针对低摩擦力矩角接触球轴承,利用能量守恒定律,研究角接触球轴承零件工作表面的波纹度对轴承摩擦力矩波动性的影响,从理论上对角接触球轴承零件工作接触表面的波纹度幅值、谐波阶次与轴承摩擦力矩波动性的关系进行分析,给出影响角接触球轴承摩擦力矩波动性的内、外滚道和钢球工作表面的主要波纹度谐波阶次和相应的激振频率,并试验验证.研究...