精密机床静压转台轴承-转子摩擦副材料选型

静压转台由于其刚度大、阻尼性能较好及运转平稳等优点,特别适用于精密磨床及铣床。针对精密机床静压转台轴承-转子摩擦副的材料选型问题,通过对其使用工况的分析,获得了对轴承-转子摩擦副的材料选型方案,该方案重点考察摩擦副的摩擦磨损性能及润滑油的粘-温特性。根据选型方案,对几种备选的摩擦副材料(转子材料、轴承材料及润滑油)进行了摩擦磨损实验及润滑油粘-温特性实验,并对实验的结果进行了分析和评价,获得了一组最佳的轴承-转子摩擦副材料搭配。研究结果可为精密机床静压转台摩擦副设计及材料选型提供参考。     

核主泵电机轴承润滑故障分析

调查了核主泵电机轴承结构及材质。分析了核主泵电机在用润滑油的理化指标、元素含量及磨损颗粒，探讨了核主泵电机滑润油铅含量偏高的原因。结果表明：在本案例中，核主泵电机润滑油铅含量升高与润滑油本身以及电机轴承的机械磨损无关，可能来源于电化学腐蚀电机轴承或者由于加油工艺偏离，换热器、密封等破损导致的外界污染。     

重型汽车中桥减速器润滑油中磨损颗粒分析

重型汽车中桥减速器在工作过程中其摩擦副接触表面因相对运动而产生的磨损颗粒进入润滑油中,导致润滑油性能下降;磨损颗粒随润滑油进入摩擦副接触表面,摩擦副磨损加剧。根据重型汽车的运行特点,每隔一定里程数对减速器润滑油进行取样,综合分析在用润滑油中磨损颗粒物的大小、形貌及成分。结果表明：减速器在用润滑油中磨损颗粒主要成分是铁屑和铜屑,磨损颗粒主要来自于球面垫片（铜）及其配副的摩擦以及齿轮副间的摩擦。具体分析磨损颗粒产生过程及形成机制,为重型汽车中桥减速器中运动摩擦副的设计及制造提供理论依据。     

凹槽缺陷对径向轴承润滑影响的模拟研究

径向轴承在运行过程中由于磨损、疲劳裂纹、烧蚀、开有油槽等,可能会出现沟槽缺陷而影响轴承的润滑状态。基于Reynolds方程对表面有沟槽的径向轴承进行理论建模并进行数值模拟,得到表面有凹槽缺陷的径向轴承在润滑过程中油膜厚度、压力的分布,研究不同形状、周向宽度、深度和周向间距的凹槽对轴承润滑状态的影响。研究结果表明,矩形凹槽对轴承润滑的影响最大;凹槽参数对轴承润滑的影响在润滑油入口区和出口区各不相同,在润滑油入口区,随着凹槽周向宽度、周向间距的增加,承载力减小、摩擦因数增大;在润滑油出口区,随着凹槽周向宽度、周向间距的增加,承载力增大、摩擦因数减小;在润滑油出口区,凹槽深度对轴承润滑影响不大,而在润滑油入口区,凹槽深度增加将导致承载力减小、摩擦因数增大。     

风力机变桨轴承热力学分析

变桨轴承是确保风力机变桨机构正常稳定运行的关键部件。针对风力机变桨轴承的因摩擦升温而导致的轴承老化和磨损问题,建立风力机变桨轴承的三维模型,并对轴承模型进行热力学仿真分析。仿真结果显示,风力机稳态运行时,变桨轴承的下滚道比上滚道平均温度要高;当摩擦系数从0.02增长到0.1时,轴承的最高温度大幅度上升;在温度场和载荷同时存在的情况下,对比只施加载荷的情况,轴承所受最大应力大了约三倍。该研究对于提高风力机变桨轴承的可靠性、完善变桨轴承设计方法具有参考价值。     

空间合成碳氢润滑油的真空边界润滑寿命评估

为评估空间润滑油能否满足处于边界润滑工况下的扫描机构8年长寿命要求,分析润滑油在空间环境下的摩擦磨损和长寿命润滑性能。以空间合成碳氢润滑油RP4751为研究对象,分别采用真空螺旋摩擦试验系统(SOT)和滑动摩擦试验系统(SRV)测试润滑油的名义润滑寿命(每消耗1μg润滑油时钢球转动的圈数)、磨斑直径和滑动摩擦因数,结合扫描电子显微镜和X射线能量色散谱仪进行微观分析。结果表明:RP4751润滑油在真空环境下滑动摩擦因数较小、耐磨寿命较长,具有良好的真空边界润滑性能和较高的名义寿命;红外透过率分析结果表明,SRV试验前后润滑油未发生质变。利用2台RP4751润滑油润滑的扫描电机开展1∶1真空寿命试验,结果表明:RP4751润滑油润滑时电机寿命满足红外地球敏感器运动机构的8年在轨运行寿命需求;试验得到的电机轴承中的钢球润滑寿命大于等于2 943 r/μg,该结果与SOT试验的润滑油名义寿命3 598 r/μg有较好的一致性,为其他空间运动机构润滑油的选用及长寿命润滑设计提供重要试验依据。     

基于有限元分析和油液监测的轴承疲劳磨损寿命研究

提出有限元分析和油液监测相结合的方法来预测风电机组轴承疲劳磨损寿命。通过ABAQUS有限元分析,结合某风力发电机的实际运行工况,获得风机发电机后轴承的应力分布和应力时间历程曲线,通过雨流计数法和Miner准则,计算出轴承出现疲劳磨损的寿命时间;运用油液检测和铁谱分析实验,得到该风机轴承的润滑脂性能信息和磨损颗粒信息,从而判断出该轴承的润滑和磨损状态。通过结合分析仿真计算和实验的结果,可以更准确地预测和诊断轴承的疲劳磨损寿命和故障,从而提高风电机组运行的可靠性。     

液压往复密封件磨损失效概率研究

根据摩擦副系统可靠性理论,对液压往复密封件的磨损失效概率进行研究,提出了一种检测密封件磨损失效的方法。以液压缸杆密封Y形密封件为研究对象,通过ANSYS仿真分析密封件在不同磨损程度下摩擦应力和失效概率变化规律,计算密封件在运行过程中磨损失效概率,并通过试验验证有限元计算结果的有效性。结果表明:Y形液压往复密封件唇口处摩擦应力较大,因此其磨损部位主要发生在唇口;随着磨损程度的增加,Y形密封件受到的摩擦应力增加,失效概率也随之变大。研究表明,提出的方法可对液压缸实际运行过程中往复密封件的磨损进行检测。     

镀银膜轴承在油和脂润滑下的摩擦性能

试验研究镀银膜轴承在干摩擦、润滑油和润滑脂复合润滑下的摩擦性能。试验结果显示:在中低转速下,镀银膜轴承在银膜和液体润滑剂(油和脂)复合润滑下的摩擦因数仅相当于银膜干摩擦下摩擦因数的10%左右,且变化平稳;在高转速下,试验轴承在银膜和液体润滑剂复合润滑下的摩擦因数随转速增加而增加,且银膜与润滑脂复合润滑条件下的摩擦因数随转速增加得更快,但仍小于银膜干摩擦下的摩擦因数;镀银膜轴承在银膜和液体润滑剂(油和脂)的复合润滑下的磨损小于银膜干摩擦时的磨损;中低转速下,镀银膜轴承在液体润滑剂(油和脂)复合润滑下的摩擦磨损性能远优于银膜干摩擦时的摩擦磨损性能。     

煤矿提升机滑动轴承的磨损失效分析

运用油液分析和铁谱分析技术手段,探讨了煤矿提升机滑动轴承的磨损失效机制,分析了巴氏合金摩擦聚合物的成因、结构与形貌特征;讨论了提升机滑动轴承的润滑方式和润滑油的选择.滑动轴承巴氏合金轴承衬偶合副磨损失效的主要形式是粘着磨损,巴氏合金轴承衬产生的磨屑是以巴氏合金为载体和粘和剂的多种材料成分的微粒共存的聚合物,在对提升机滑动轴承进行润滑磨损状态监测时,要同时分析巴氏合金摩擦聚合物的尺寸及其在润滑油中的含量.     

BN-硅油复合胶体润滑特性的研究

采用二甲基硅油作为研磨介质,加入少量表面活性剂,研磨出分散均匀的超微米级BN粒子体和硅油的复合胶体。在XP-5型数控销盘式摩擦磨损试验机上研究了其摩擦学性能,并探讨了超微BN对硅油润滑性能改善的作用机制。结果表明无论在常温还是在高温下,超微米BN的添加均能有效地改善硅油的边界润滑性能和承载能力。在摩擦过程中,由于BN超微粒子体对摩擦表面的修复作用以及对硅油在钢表面粘附作用的改善,BN-硅油胶体能在钢的摩擦表面形成较厚的润滑膜,从而提高了其润滑性能。     

海水对油品混合物老化及其摩擦学性能的影响*

为探究海水对油品混合物老化及其摩擦学性能的影响，使用烘箱对含盐水（模拟海水）油品混合物进行老化测试，分析含典型基础油及极压抗磨剂的油品混合物在老化过程中的物理化学性能；使用光学显微镜表征油品混合物老化过程中对滚子表面形貌的影响，采用球盘试验机研究老化后油品混合物的摩擦学行为，并利用X射线电子光谱仪（XPS）对摩擦试验后的摩擦副表面进行化学分析。结果表明：添加盐水的油品混合物中老化后，其黏度和总酸值不会发生明显变化（酯基系列油品混合物除外），但其润滑下的磨损会高于没有添加盐水的油品混合物；随着老化时间的增加油品混合物润滑下的磨损会降低，原因在于老化后摩擦副表面磨痕上氧（氧化物）含量降低，在磨合期间能给摩擦副表面提供的保护较少。     

大型内燃机组润滑油换型方案制定与实施方法

为实现某进口关键大型机组润滑油国产化改造,制定润滑油换型方案与实施方法。首先通过现场调研、原润滑油和替代润滑油的混容试验,确定替代的润滑油品种;然后提出详细的换油方案包括油品更换的方式和更换时间、油样取样周期等;最后对机组换油后润滑油各项指标进行监测,在运行4 000 h后进行对机组摩擦副进行磨损情况检测。油液监测结果表明,油品各项指标(黏度、闪点、水分、碱值等)及元素含量均处于正常范围,拆机检测表明,气缸内部、连杆轴瓦、活塞磨损均处于正常水平,验证了该润滑油换型方案的可行性。     

The Influence of Lead Suspension in Oil Lubricant on the Sliding Wear Behaviour of Cast Iron

This investigation pertains to the analysis of the sliding wear response of a cast iron over a range of applied pressures in the presence of an oil lubricant. The effect of varying concentrations of lead particles suspended in the oil lubricant on the wear behaviour of the cast iron was also examined. The wear rate increased with pressure initially at a lower rate followed by a higher rate of increase beyond a specific pressure. Furthermore, the presence of suspended lead particles up to a specific concentration in the oil proved beneficial while the trend reversed at still higher concentrations. The extent of frictional heating increased with test duration at a high rate in the beginning of the tests. This was followed by a reduced rate of temperature increase at longer test durations. In some cases, the rate of temperature rise increased once again while it reduced in one case towards the end of the tests. The severity and extent of frictional heating also increased with pressure. Lead addition to the oil lubricant up to a specific concentration led to a reduced degree of heating while the trend reversed at still higher lead contents. Specimen seizure caused significantly high wear rate and frictional heating. The observed wear response of the samples has been explained in terms of specific characteristics like cracking tendency and lubricating and load bearing capacity of various microconstituents of the specimen material. Another important factor of concern affecting wear characteristics was observed to be lubricating film formation and its stability during sliding. The wear behaviour has also been substantiated through the characteristics of wear surfaces and subsurface regions.     

压裂泵滑动轴承流体动压润滑性能研究*

压裂泵的十字头滑履与导板间隙、供油流量和油压等关键参数,目前主要通过工程经验进行调节,缺乏科学依据,易致导板磨损和烧瓦,严重影响压裂泵服役寿命。针对以上问题,建立3500HP压裂泵的轴瓦、轴承间隙及润滑油组成的流体力学系统,利用计算流体力学软件Fluent进行滑动轴承的流场分析,考察润滑油黏度、轴瓦间隙、润滑流量、润滑油压对压裂泵用滑动轴承的影响。结果表明：随着滑履与导板间隙的减小,导板的形变与应力会增大,最优导板间隙为0.5 mm左右;增大供油流量会使导板的形变与应力降低,供油流量最好不低于2.2 L/min;增大供油黏度会使导板的形变与应力变大,在0.2~0.4 Pa·s范围内供油黏度越小越好;随着供油油压的增大,导板的形变与应力增加显著,当油压大于4 MPa时,导板的应变与应力呈现指数级增大,当供油油压为3 MPa时,导板的形变与应力达到最小值。     

Sliding wear response of a cast iron under varying test environments and traversal speed and pressure conditions

This study pertains to the examination of sliding wear behaviour of a gray cast iron over a range of sliding speeds and applied pressures in dry and (oil and oil plus graphite) lubricated conditions. Wear properties characterized were wear rate and frictional heating. The cast iron revealed various forms and sizes of graphite particles in a matrix of pearlite and limited quantity of free ferrite. Different solidification patterns, as controlled by the chemical composition and/or carbon equivalent of the alloy and rate of cooling, were thought to be responsible for the varying morphology of the graphite phase formed in the material matrix. Occasional decohesion of graphite at ferrite/graphite interfacial regions was also observed.The wear rate of the cast iron increased with the speed and pressure of sliding due to increasing severity of wear condition. The specimens tended to lose proper contact with the disc at larger pressures when slid dry. This was attributed to severe cracking tendency of the material. On the contrary, specimen seizure was noticed in the oil and oil plus graphite lubricated conditions; the seizure resistance (pressure) decreased with sliding speed in presence of the lubricants. The wear rate versus pressure plots attained different slopes, i.e. the rate of increase in wear rate with pressure, depending on the test environment. One slope and inappreciable effect of pressure on wear rate were noticed due to substantial cracking tendency of the cast iron when tested in dry condition. In the oil lubricated condition also, virtually one slope was observed but it was higher than that in dry condition indicating greater sensitivity of wear rate towards the applied pressure. Also, the samples attained lower wear rate in oil than in dry condition in view of suppressed cracking tendency causing more stable lubricating film formation in presence of the oil lubricant. Addition of graphite particles to the oil lubricant caused a further reduction in wear rate because of the enhanced possibility of a more stable lubricant film formation due to smearing of the graphite particles. In this case, the slope of the wear rate versus pressure plots was the least in the intermediate range of pressures irrespective of the sliding speed owing to more stable lubricating film formation.A higher rate of temperature increase with test duration (intermediate sliding distance) in the beginning was attributed to the abrasive action of the hard debris generated through the fragmentation of the initially contacting asperities. A subsequently observed lower rate of increase at longer durations could be owing to the occurrence of mild wear condition in view of less stressing of the contacting asperities and increased stability of the lubricant film formed. Increase in the rate of frictional heating at still longer durations resulted from destabilization of the lubricating film.Frictional heating increased with applied pressure and sliding speed in view of increasing severity of wear condition. The rate of increase in frictional heating was low initially up to a specific pressure followed by a higher rate of increase at still larger pressures when the tests were conducted in oil plus graphite at both the sliding speeds and in the oil lubricant at the lower speed. A constant (high) rate of increase in frictional heating with pressure was noticed in the dry condition at both the sliding speeds and in the oil lubricant at the higher speed. Low rate of frictional heating with pressure was attributed to the occurrence of mild wear condition while a higher rate of frictional heating with pressure resulted from the occurrence of severe wear condition. As far as the influence of test environment on frictional heating is concerned, least frictional heat was generated in the oil plus graphite lubricant mixture while the maximum was noticed in dry condition, intermediate response of the samples being observed in oil. Formation of more stable lubricating film was thought to be responsible for lower frictional heating in the lubricated conditions; the presence of graphite in the oil lubricant increased the extent of lubricating film formation and stability of the film so formed.The wear response of the samples has been explained in terms of cracking tendency and lubricating effects of graphite, predominance of the counteracting effects of the two parameters over each other, and lubricating film formation by the external oil (plus graphite) lubricant on the sliding surfaces in specific test conditions. Characterization of wear surfaces, subsurface regions and debris particles of the material enabled to further substantiate the observed wear performance of the samples.     

考虑混合润滑的飞机燃油泵径向滑动轴承静特性分析

针对飞机燃油泵径向滑动轴承润滑油黏度极低、润滑油膜形成难、表面易磨损等问题,通过综合考虑紊流、热效应、质量守恒、温黏效应及混合润滑边界等因素,建立轴承的热流体动力学润滑分析模型,采用有限元方法联立求解雷诺方程、能量方程、接触方程得到轴承的静态特性,研究轴承间隙比、宽径比、转速、载荷、进油温度等对轴承静态润滑性能如油膜厚度和油膜压力的影响规律。结果表明：由于航空煤油动力黏度低,造成轴承的浮起转速高（大于5 500 r/min）,极限承载力低（小于37 N）、油膜厚度过低;降低进油温度、适当减小间隙,增加轴瓦宽度有利于增加油膜厚度,提高轴承可靠性。研究结果对飞机燃油泵径向滑动轴承设计与运行维护具有一定的工程借鉴价值。     

润滑油黏度对全陶瓷球轴承腔体温度场分布规律的影响

为揭示全陶瓷球轴承在油润滑条件下内部温度场分布及变化情况,提高全陶瓷球轴承的运转性能与使用寿命,以7007C氮化硅全陶瓷角接触球轴承为研究对象,利用仿真软件模拟分析不同工况和润滑油黏度条件下全陶瓷球轴承腔体内部温度场及润滑油的分布状态;在轴承寿命试验机上进行相同条件下全陶瓷球轴承的动态特性试验,研究在油润滑工况下全陶瓷球轴承的温升特性。结果表明：随着轴承转速的提高,全陶瓷球轴承腔体内温度呈增大趋势,腔体内润滑油体积分数呈减小趋势;更换不同黏度润滑油发现随着润滑油黏度的增大,全陶瓷球轴承腔体内温度场呈现先减小后增大的趋势,存在最优黏度值使全陶瓷球轴承腔体温度达到最小值,轴承服役性能表现最佳。研究成果为实际生产中全陶瓷球轴承最优润滑油的选择提供了技术参考。     

航空发动机主轴轴承失效模式分析

航空发动机圆柱滚子主轴承常常因为工作条件恶劣,发生失效。采用光学显微镜、扫描电镜、能谱仪、X射线光电子能谱等对服役后的圆柱滚子轴承进行失效分析。结果表明:根据失效机制与微观形貌对失效模式,可以将圆柱滚子轴承的失效模式分为8种不同的失效模式,包括划伤和擦伤、打滑蹭伤、压坑凹坑、疲劳剥落、振纹、受热变色、内圈烧伤、保持架镀银层磨损。对打滑蹭伤、烧伤和保持架镀银层磨损等失效模式的轴承进行分析,结果表明:在打滑蹭伤的轴承表面发现O元素,表明打滑蹭伤过程中发生了氧化磨损;在烧伤轴承表面发现了Fe的氧化物FeO和Fe2O3,表明轴承在烧伤时温度较高,润滑油膜被破坏,滚子和内圈互相接触发生剧烈磨损;保持架表面银层脱落,部分磨损区域露出铜表面,表明保持架在服役过程中发生了摩擦磨损。     

柴油机滑动轴承磨损试验系统的开发与研制

针对柴油机轴瓦磨损问题,为了研究滑动轴承磨损影响机理且由于现有设备无法满足试验要求,开发研制了一套滑动轴承磨损试验系统。利用该系统可进行主轴瓦和连杆瓦两种滑动轴承在结构、转速、载荷、磨粒、润滑油状态不同条件下磨损状态的模拟试验研究。在完成试验方法研究的基础上,着重介绍了该试验系统的液压模块、机械承载模块、润滑模块、试验控制模块等子系统的开发设计。该系统采用液压伺服的加载方式对模拟轴进行了拉压加载,采用变频器控制驱动电机转速,润滑油的压力及温度可以自由调节,并利用基于美国NI公司的LabVIEW环境的软件实现了对试验系统的自动控制以及试验数据实时显示和存储,实现了不同工况下的轴瓦磨损的模拟试验。研究结果表明,该试验系统可以实现试验功能,具有良好的试验性能,达到了试验系统开发的预期目标。