聚合物及其改性材料润滑与密封转移膜形成与密封机理分析

文章运用现代摩擦学理论，固体物理学理论和高分子材料科学，从物质内在结构和本质上分析了聚合物及其改性密封材料的润滑与密封转移膜形成机理，对进一步研究润滑与密封技术，开发高性能润滑与密封复合功能材料具有一定的指导意义。     

非对称聚合物齿轮的瞬态弹流润滑分析

聚合物齿轮质轻而耐腐蚀,可降低噪声,提高经济效益.相对地,聚合物轮齿强度低于金属轮齿,故采用非对称设计提高聚合物齿轮的强度.为探究非对称聚合物齿轮的弹流润滑特性,在水润滑条件下,采用多重网格法对非对称聚合物齿轮进行了瞬态弹流润滑分析:对比非对称齿轮与传统对称齿轮的水膜压力与厚度;改变齿轮运行工况及考虑轮齿的表面粗糙度,研究其对齿轮弹流润滑分析的影响.结果表明,非对称齿轮可有效改善弹流润滑,润滑膜的压力和膜厚受齿轮转速和载荷影响较大,表面粗糙度对于非对称聚合物齿轮的弹流润滑有着不利影响,在应用中应保证齿面加工质量.     

二硫化钼基润滑涂层在润滑油中的作用机理及实际应用

讨论了在几种液体润滑介质(液体石蜡、10^#机油、HM46液压油)中，涂敷FM-510二硫化钼基润滑涂层的摩擦副的摩擦磨损性能和润滑机理。试验机评价和台架考核结果表明，在润滑油中，涂敷FM-510涂层的摩擦偶对能够协助流体润滑膜的形成并维持流体润滑状态。扫描电镜观察涂层和对偶的微观表面，用能谱分析表面元素组成，揭示了其作用机理：干摩擦条件下，二硫化钼基润滑涂层与金属对偶表面的相对滑动，形成了以Mo、S、Sb为主的转移膜，但在润滑油介质中没有形成这类转移膜；二硫化钼基润滑涂层的表面有大量的、均匀分布的、直径小于3μm的孔穴，起到了蓄油作用，更易于建立流体润滑条件，形成均匀分布的油膜。     

表面织构水润滑聚合物轴承承载性能有限元分析

应用ADINA有限元方法,对无织构和有织构水润滑聚合物轴承的承载性能进行流固耦合有限元仿真分析,探讨不同内衬材料轴承在不同转速下的水膜压力分布及承载力变化状况,以及材料弹性模量、转速、水膜压力对凹坑表面织构变形的影响规律。仿真结果表明:内衬材料弹性模量对凹坑变形及水膜压力有重要影响,在相同条件下,弹性模量越大,水膜压力及承载力也越大,因此内衬材料应选弹性模量较大的聚合物材料;在相同条件下,有织构轴承的水膜压力和承载力均高于无织构轴承;轴承发散区的织构布置初始角对轴承承载力分布状况有一定影响,随初始角的增大轴承承载力呈现先升高后降低的变化趋势。     

润滑油添加剂对聚合物材料摩擦磨损性能的影响研究

利用MM－200型磨损试验机考察了ZDDP对聚合物材料（PTFE、PI及MCPA）－GCr15轴承钢摩擦副摩擦磨损性能的影响。研究发现，液体石蜡及含ZDDP的液体石蜡润滑均可大幅度改善聚合物材料的摩擦磨损性能，且使其摩擦系数比干摩擦时降低一个数量级，摩擦副表面的ZDDP吸附膜均在不同程度上提高聚合物材料的耐磨性，但其对聚合物材料的摩擦性能影响不大。     

弹流膜厚的测试方法述评

论述了弹性流体动力润滑油膜工测试方法的进展，分析了各种膜厚测试方法的特点及应用范围。     

类金刚石膜在水环境下的摩擦学行为

测试了 CoCrMo合金表面沉积类金刚石薄膜与CoCrMo在水溶液润滑下的摩擦磨损行为。结果表明：摩擦副在不同浓度牛血清白蛋白溶液润滑下的平均摩擦因数均在0.10左右,CoCrMo合金销磨损量最小值为1.69×10-5 mm3;相同条件下,生理盐水溶液润滑的磨损量为1.38×10-5 mm3,且销表面有转移膜生成;牛血清白蛋白溶液润滑时,界面蛋白吸附层屏蔽了转移膜的形成。根据结果可知,转移膜的形成经历了磨屑附着、连续转移、局部脱落的过程。     

固体润滑轴承的寿命分析

通过对固体润滑寿命理论和试验分析，得出要获得固化润滑轴承更长的寿命，则需使轴承实现转移膜润滑，而合适转移膜润滑的实现与保持架的稳定性，材料的磨损及工况条件等有着密切关系。     

PTFE粉末颗粒流润滑方式下的润滑性能*

为探究颗粒流润滑方式下聚四氟乙烯（PTFE）粉末的润滑减磨性能,在不同载荷及干摩擦和PTFE粉末润滑条件下进行氮化硅摩擦副摩擦磨损实验,分析不同载荷下PTFE粉末润滑对试样摩擦学特性的影响,通过扫描电子显微镜（SEM）和能量色散X射线能谱仪（EDS）分析试样在不同润滑条件下的磨损及润滑机制。结果表明：PTFE粉末润滑条件下的摩擦因数要明显低于干摩擦条件下的摩擦因数,且在实验时间内PTFE粉末保持润滑持续稳定;在滑动摩擦过程中,PTFE粉末由于压力作用,形成一层转移膜粘附在试样表面,使摩擦因数处于一个持续较低的状态,对试样起到良好的润滑和保护作用;随着载荷增加,转移膜的覆盖面积和连续性先变好后变差,导致在PTFE粉末润滑条件下的摩擦因数也先降低后升高。因此,颗粒流润滑方式下PTFE粉末具有良好的润滑和减磨效果,具有十分广泛的应用前景。     

弹性流体润滑状态图的研讨与改进

本文研讨并提出一种新的弹流润滑状态图。新图不仅能直观地反映出油膜厚度随载荷和速度的变化,而且能与道森所提供的油膜厚度图统一起来。若将道森所提供的膜厚图坐标换成为新润滑图的坐标,膜厚图的应用范围就不再受无量纲载荷参数G等于5000的限制,当G值不等于5000时,本文提供的系数K可对膜厚进行修正。     

Self-lubricating polymer composites and polymer transfer film lubrication for space applications

The use of self-lubricating polymers and polymer composites in space is somewhat limited at present. In general, they are only used when other methods are inadequate. There is potential, however, for these materials to make a significant impact on future space missions, if properly utilized. This paper surveys some of the different polymers and fillers used to make self-lubricating composites. It delves into the mechanisms of composite lubrication and wear, the theory behind transfer film lubricating mechanisms, and some factors which affect polymer composite wear and transfer. In addition, some of the current space tribology application areas for self-lubricating polymer composites and polymer transfer are mentioned.     

Large‐scale specimen testing on friction and wear of pure and internally lubricated cast polyamides

Due to the casting process for nylons, their composition can easily be modified to cover a wide range of mechanical properties and applications, especially as large wear surfaces in, for example, crane guidances. Presently, selection tests for working conditions up to 40MPa are presented on pure Na‐catalysed polyamides, oil‐filled polyamides with homogeneous oil dispersions and holes in the surface containing oil lubricant and two types of thermoplastic solid‐lubricated polyamides. Pure polyamides are, however, prone to high and unstable sliding at pressures as low as 10MPa with brittle fracture and lumpy transfer. Oil lubrication is not able to remove the sliding instabilities as oil supply to the sliding interface is controlled by migration effects that are restricted by deformation and thermal softening or melting of the polyamide matrix. Although friction and wear are lower and more stable for samples with oil supplied through lubricating holes, additional running‐in phenomena are attributed to a relatively thick transfer film that is brittle and easily peels off. A continuous thick molten film or island‐like deposition occurs on the polyamide surface. Solid lubricants are able to stabilize friction and lower wear down to the formation of a thin and coherent transfer film. However, increasing the amount of lubricants induces lower mechanical properties and higher deformation of the test samples. The differences in transfer behaviour are discussed with reference to optical microscopy and calculations of bulk and flash temperatures. Copyright © 2006 John Wiley & Sons, Ltd.     

Modelling of non-laminar phenomena in high reliability hydrostatic seals operating in extreme conditions

A numerical study of hydrostatic seals is presented. The theoretical model takes account of the transition to turbulence and inertia effects in the lubricant fluid film. The thermo-elastic deformations of the seal faces and heat transfer are considered using influence coefficient matrices. To obtain a good correlation between numerical simulations and measurements taken in French nuclear power stations, it is necessary to deal with entrance and exit pressure losses. It is shown that the seal operates in a laminar or near turbulent flow regime, depending on the inlet temperature.     

固体润滑谐波减速器真空运行性能的试验

根据谐波减速器在空间机械精密传动中的工作条件 ,研制出真空环境模拟试验装置 ;并使用该装置对XB3- 6 0扁平式谐波减速器所采用的几种物理气相沉积 (PVD)薄膜润滑方案进行了系统考核。试验结果表明 ,研制出的真空运行试验装置结构合理 ,性能稳定 ,可以保证环境模拟试验的可靠性 ;对几种薄膜润滑系统的考核结果 ,为确定谐波减速器的固体润滑方案提供了实验依据     

Full film lubrication of deep drawing

An analytical model for full film lubrication of deep drawing is developed, combining the elastic–plastic membrane finite element code of deep drawing together with full film lubrication theory. In full film lubrication, the surfaces are not in contact, and the gap in between includes two types of lubrication: the thick film lubrication regime and the thin film lubrication regime. The film thickness and the strain distribution of full film lubrication are predicted here. The theoretical results show excellent agreement with the experiment data.     

三种固液复合润滑系统的真空边界润滑特性

为研究MoS2/815Z、MoS2/RP4751和MoS2/RIPP4758三种固液复合润滑体系在真空边界润滑工况下的润滑特性,对三种固液复合润滑体系进行了真空往复滑动摩擦试验和真空螺旋轨道摩擦(SOT)试验研究,并对SOT试验后的球盘摩擦副平盘表面进行扫描电镜(SEM)和X射线能量色散谱仪(EDS)分析.试验结果表明...     

Solid lubrication of ball bearings for spacecraft mechanisms

The advantages of solid lubricants over oils and greases for the lubrication of ball bearings in spacecraft are briefly discussed. The techniques of transfer film, of ion plating and of sputtering are well suited to such bearing lubrication. Three specific lubricants, which account for the majority of applications: ptfe-composite, rf-sputtered MoS₂ and ionplated lead film, are first discussed and then compared in terms of durability and torque characteristics. It is concluded that any of these solid films may be acceptable, depending upon the required bearing duty. The limitations of each lubricant are considered and compared     

Non-newtonian thermal analysis of an EHD contact lubricated with MIL-L-23699 oil

A thermal and non-Newtonian fluid model under elastohydrodynamic lubrication conditions is proposed, integrating some particularities, such as the separation between hydrodynamic and dissipative phenomena inside the contact. The concept of apparent viscosity is used to introduce the non-Newtonian behaviour of the lubricant and the thermal behaviour of the contact into the Reynolds equation, acting as a link element between the hydrodynamic and dissipative components of the EHD film, independently of the rheological and thermal models considered. The apparent viscosity enables the application of the rheological model better adapted to each lubricant, without appealing to special formulations of the EHD problem.The Newton–Raphson technique is used to obtain the lubricant film geometry and the pressure distribution inside the EHD contact. The shear stresses developed in the fluid film are evaluated assuming the non-linear Maxwell rheological model. The surfaces and lubricant temperature distributions are determined using the simplified Houpert's method, applied to the inlet contact zone, and the thermal method proposed by Tevaarwerk is applied in the high pressure contact zone.The non-Newtonian thermal EHD model is applied to the analysis of a contact lubricated with MIL-L-23699 oil. Significant results are obtained for the centre and minimum film thickness, for the inlet shear heating and film thickness reduction factor (φ_T), for the temperature rise of the lubricant and of the surfaces and for the friction coefficient inside the contact, considering wide ranges of the operating conditions (maximum Hertzian pressure, inlet oil temperature, rolling speed and slide-to-roll ratio).Finally, the numerical traction curves determined are compared with the corresponding experimental results, showing very good correlation.     

环面接触复层多孔轴承热流体动压润滑性能及生/传热机制分析

为分析热效应对多孔环面接触复层含油轴承流体润滑性能的影响,建立环面接触复层含油轴承系统的热流体动压润滑模型,数值分析轴承系统的温度场及速度场分布,讨论考虑热效应时的复层含油轴承流体润滑问题及其生热、传热机制。结果表明：从轴承底面到摩擦对偶面,温度呈先升高后降低趋势,径向上温度随着半径增加而升高,系统的最高温度位于油膜区外环面上的最小膜厚处;轴承系统中的热量主要由油膜相对剪切发生,周向相对运动速度是系统生热的主要影响因素,温度与周向速度的分布形态相似,油膜产生的热量通过对流换热逐渐向多孔轴承中传导,轴承表层厚度或渗透率降低,对流换热效果变差,轴承系统中温度升高,热效应对润滑性能的影响变大;考虑热效应后,油膜润滑性能变差,但数值分析精度提高,数值结果更接近试验实测值。