基于JFO理论滑动轴承性能研究

利用Vijayaraghavan-Keith算法对径向滑动轴承的承载能力和稳定性进行定量分析。根据Vijayaraghavan-Keith算法推导径向滑动轴承的无量纲控制方程和数值离散结果。分别利用Vijayaraghavan-Keith算法和Elrod模型对一个轴承实例的性能参数进行对比,发现两种模型下承载力、偏位角和气穴区比率都比较接近。最后,分别讨论轴承长径比、偏心率、气穴压力对径向滑动轴承的承载能力和稳定性的影响。结果表明:适当增大偏心率,可以提高轴承承载能力和稳定性;相同工况下,气穴压力越低,承载能力越大,偏位角越大。     

卧式水电机组局部多油楔径向滑动轴承研究

针对卧式水电机组用径向滑动轴承载荷日益提高的现状,设计一种局部多油楔瓦面结构的径向滑动轴承。通过联立求解膜厚方程、雷诺方程、密度方程、黏度方程、能量方程和固体热传导方程等,获得轴承的热流润滑特性,并与椭圆径向滑动轴承的热流特性进行对比。结果表明,局部多油楔径向滑动轴承具有较大的动压承载区域和较小的油膜压力梯度以及较低的油膜温升,可以大幅度提高轴承的承载能力。     

基于进化算法的液体动力润滑轴承优化设计

采用Matlab语言,分别运用改进型粒子群算法和基本粒子群算法,在最大限度满足液体动力润滑径向滑动轴承的承载量系数值,以达到滑动轴承承载能力的条件下,对内燃机径向滑动轴承进行了优化设计,计算机仿真结果表明:采用改进型粒子群算法优化的轴承孔直径、轴径直径、轴承宽度、承载量系数等优化参数效果最好,符合实际工艺要求,且滑动轴承承载能力最强。改进型粒子群算法优化结果明显优于基本粒子群算法的优化结果,从而表明了改进型粒子群算法应用于内燃机问题的优化求解切实可行。     

高速高压圆弧螺旋齿轮泵径向力补偿方法研究

针对普通径向力补偿方法难以解决圆弧螺旋齿轮泵在高速高压下径向力剧增的问题,建立了齿轮轴受力数学模型,设计出一种新型滑动轴承,对剧增的径向力进行补偿,即圆弧螺旋齿轮泵压油腔内的高压油通过滑动轴承进油口流入滑动轴承的静压槽内,作用在齿轮轴上,以补偿径向力;然后利用Fluent软件对高速高压工况下新型滑动轴承与普通滑动轴承的承载特性进行对比分析,并通过实验进行验证。研究结果表明：新型滑动轴承静压槽内的油液压力与负载压力变化一致,且静压槽内油液压力未产生压降,补偿不平衡径向力效果显著,大大降低了轴承磨损;在额定压力为25 MPa工况下,相对于普通滑动轴承,新型滑动轴承承载能力提升了约4倍,温升降低了10℃。     

表面纹理对径向滑动轴承油膜承载能力的影响

为研究表面纹理对径向滑动轴承油膜承载能力的影响机制,利用不重叠区域分解法建立针对径向滑动轴承表面纹理润滑计算的有效方法,通过数值计算得到不同纹理分布模式和纹理几何参数条件下的轴承润滑油膜承载力。计算结果表明:合理的表面纹理分布模式和纹理几何尺寸对提高轴承油膜承载能力有一定作用。     

聚四氟乙稀软带贴面轴承的研制与应用

介绍了一种新型滑动轴承－PTFE（聚四氟乙烯）软带贴面轴承的加工工艺，分析摩擦材料的性能特点，并通过实验和应用证明此轴承的设计是成功的。     

无油轴承带动模具行业革命

金属基镶嵌式固体自润滑轴承（简称JDB）是一种兼有金属轴承特点和自润滑轴承特点的新颖润滑轴承,由金属基体承受载荷,特殊配方的固体润滑材料起润滑作用.它具有承载能力高、耐冲击、耐高温、自润滑能力强等特点,特别适用于重载、低速、往复或摆动等难以润滑和形成油膜的场合,也不怕水冲和其它酸液的浸蚀和冲刷.广大用户普遍反映镶嵌轴承不仅节油、节能,而且其工作寿命也比普通滑动轴承长.目前产品已广泛应用在冶金连铸机、轧刚设备、矿山机械、船舶、汽轮机、水轮机、注塑机及设备生产流水线中。     

对具有可倾瓦块和固定瓦块的混合型径向滑动轴承性能分析

本分析计算了顶部瓦块固定的可倾瓦径向滑动轴承（简称混合型轴承）的性能参数,与相同尺寸的可倾瓦径向滑动轴承相比,该种混合型轴承在承载能力,流量,摩擦功耗,平均温升等方面都发生了变化,具有明显的特点,最后的验测试验证了本所采用的分析计算方法是可行的。     

EMP径向滑动轴承温度场和压力场测试研究

弹性金属塑料瓦(EMP)径向滑动轴承是一种新型的轴承,由于轴瓦所采用的复合材料的特殊特性使得其油膜温度场和压力场分布情况与传统金属瓦轴承的油膜温度场和压力场分布情况有所不同。本文对呻径向滑动轴承油膜温度场和压力场进行了实验研究,为从理论上揭示EMP径向滑动轴承的流体动压润滑机理并进而进行型面设计提供实验依据。     

齿轮泵轴的挠曲变形对其轴承承载能力的影响

一、引言高压齿轮泵设计中,由于齿轮承受较大的液压径向力,其滑动轴承往往是决定齿轮泵寿命的重要环节。按照传统的滑动轴承设计方法,轴被认为是绝对刚性的,即轴和轴承始终平行。可是由于径向力的作用,轴总要产生一定的挠曲变形。这个变形改变了油膜的形状,因而改变了油膜中的压力分布,使油膜的承载能力发生变化。为了提高轴承的承载能力,往往加宽轴承的宽度以降低轴承比压。但由于宽度增加,轴加长,使其变形更多。故有时这样做并不一定带来好的结果。现代有限元理论的发展为计算带有挠曲变形轴的滑动轴承的计算提     

Comparison of tribological characteristics between aluminum alloys and polytetrafluoroethylene composites journal bearings under mineral oil lubrication

This study examined the tribological behavior of journal bearings made from polytetrafluoroethylene (PTFE) composites and aluminum (Al) alloys. The PTFE composite journal bearings consisted of a steel backing with a thickness of 1.6 mm, a middle layer of sintered porous bronze with a thickness of 0.24～0.27 mm, and a surface layer of PTFE filled with fluorinated ethylene propylene (FEP) powder and carbon fibers with a thickness 0.06～0.14 mm. The other was an aluminum alloy journal bearing consisted of a steel backing with a thickness of 1.5 mm and a surface layer of an Al-6Sn-6Si alloy with a thickness 0.35～0.75 mm. A series of lubrication tests were performed using a journal bearing tester under various normal loads. The tribological properties for each journal bearing were evaluated by measuring the lubricant oil temperature and friction coefficient as a function of the applied normal load. In addition, the chemical compositions and microstructures of the journal bearing materials used in this study was analyzed by inductively coupled plasma (ICP), optical microscopy (OM), and scanning electron microscopy (SEM), respectively. The experimental results showed that the Al alloy journal bearings reduce the friction coefficient by 28 % compared to the PTFE composites bearings. In addition, the Al alloy journal bearing worked properly at the maximum load of ～ 8,000 N without adhesion. However, the PTFE composite journal bearings exhibited strong adhesion at the loads ranging from 6300 to 8000 N. This suggests that the Al alloy is a more promising material in journal bearings than PTFE composites.     

Boundary slip surface design for high speed water lubricated journal bearings

This paper presents the development of a numerical model for high speed and water lubricated journal bearings with different boundary slip arrangements. The effect of boundary slip and its possible mechanism are analyzed and discussed. The results suggest that a suitable combination of slip/no-slip surfaces on the sleeve of a journal bearing enables improvement of the tribological performance through (i) suppressing the occurrence of cavitation, (ii) enhancing the load bearing capacity, and (iii) reducing the interfacial friction between bearing sleeve and shaft. Such improvement becomes more significant for the bearings with smaller eccentricity ratio, smaller width and larger diameter.     

Evaluation of Ball-Bearing Performance in Liquid Hydrogen at DN Values to 1.6 Million

Experimental data were obtained in liquid hydrogen (?423 F) on two series of 40-mm-bore ball bearings utilizing various retainer materials. Effects of diametral clearance and retainer material on limiting DN value (product of bearing bore in mm and shaft speed in rpm) were investigated at thrust loads to 500 lb and at speeds to 41,200 rpm. An analysis was made to determine the effect of ball size and race curvatures on the heat generated in bearings of both series as a result of ball spin. The results, supported experimentally, indicate that higher limiting DN values at a specific thrust load could be obtained with an extremely light series (1908) bearing with open-race curvatures than with a light series (108) bearing. Successful operation to a DN value of 1.6 million was obtained with 1908 bearings (at 110 lb thrust load) using two different retainer materials. The glass-fiber-filled PTFE (polytetrafluoroethylene) retainer exhibited much less wear than the MoS₂-filled phenolic retainer at these test conditions.     

径向螺旋槽空气轴承起飞速度与承载能力试验研究

起飞转速是空气轴承的重要性能指标。以螺旋槽空气轴承为研究对象,运用摄动法求解等温可压缩条件下螺旋槽气体润滑轴承压力分布的微分方程,得到空气轴承压力分布及承载力等特性;以最大承载力为目标,计算螺旋槽空气轴承的结构参数,并对设计的空气轴承进行试验,探究其不同载荷下的起飞速度。试验结果表明：空载状态下,转速约为1 200 r/min时空气轴承的转子与轴承套脱离接触,达到起飞速度;螺旋槽空气轴承的起飞速度与起飞转矩均随着的载荷的增加而逐渐升高,随着转速的升高,轴承的承载能力也越来越大。研究表明所设计的螺旋槽空气轴承具有良好的性能,为后续螺旋槽轴承设计优化及实际应用提供了理论与实践基础。     

向心透平发电膨胀机静压气体轴承设计与承载特性分析

为提升有机朗肯循环（organic Rankine cycle,ORC）系统向心透平发电膨胀机静压气体轴承的承载力与刚度,采用表压比法设计了以R245fa为润滑工质的静压气体轴承,分析转子偏心率、供气孔尺寸、进气压力对静压气体轴承承载力与刚度的影响。实验结果表明：在相同供气压力下,轴承承载力与刚度随着转速的增大而增大;在相同转速下,0.7 MPa供气压力相对于其他气体供气压力轴承的承载力与刚度略高;静压气体轴承的偏心率越大承载力越大;相同供气孔直径下,静压气体轴承的承载力与刚度随着转速的升高而升高;随供气孔直径增大,静压气体轴承的承载力和刚度也随之增大。     

润滑介质种类对气浮轴承性能的影响*

为研究润滑介质种类对于气浮轴承性能的影响,通过FLUENT对采用空气、二氧化碳、氢气与氦气作为润滑介质的气浮轴承进行数值计算,分别对静压轴承承载力随供气压力的变化趋势以及动压轴承承载力随转速的变化趋势进行分析;并对不同环境压力和温度下的二氧化碳润滑动压气浮轴承承载力变化趋势进行研究。数值计算结果表明:润滑介质种类对于静压、动压气浮轴承的承载特性均具有明显影响;不同润滑介质润滑下静压气浮轴承的承载力由大到小排序大致为空气、氦气、氢气、二氧化碳;不同润滑介质动压气浮轴承承载力变化趋势基本与润滑介质黏度变化趋势保持一致;二氧化碳润滑动压气浮径向轴承的承载力受环境温度与压力的影响主要体现在其工质黏度(随温度与压力)变化,二氧化碳润滑动压止推轴承的承载力随环境压力的增大近似呈线性增大。     

Simulation of tribological functionality of heterogeneous tribomaterials

We simulated the tribological functionality of two heterogeneous tribomaterials used in conformal contacts by means of a FEM-based approach: journal bearing material AlSn20 and polymeric sealing material PTFE with bronze filler particles. For AlSn20, the emergency running capability, which is based on the activation (melting) of the soft phase tin, was simulated taking into account thermo-elasto-plastic behaviour of the material. For the PTFE bronze compound, we analysed the load bearing capacity of the particle-structured surface with varying volumetric fraction of particles, temperature, load and creep behaviour of the PTFE Matrix. The results show benefit of heterogeneous designs over homogeneous materials.     

均压槽与静压气体轴颈轴承承载特性的关系研究

主要研究通过开设不同结构形式的均压槽来提高静压气体轴颈轴承的承载能力和刚度,利用加权余量法和有限元离散化方法求解雷诺方程进行数值计算和仿真,针对单排孔和双排孔轴颈轴承,分析不同长度的周向均压槽,以及不同数量、不同位置和不同长度的轴向均压槽对轴承承载能力和刚度的影响规律。结果发现:开设周向均压槽和轴向均压槽都可以提高轴承的承载能力,相比开设周向均压槽,开设轴向均压槽对提高轴承的承载能力更为有效,而且只开设一条或两条轴向均压槽就能显著提高轴承的承载能力,通常将轴向均压槽置于气膜间隙较小的位置时能使轴承的承载能力和刚度最大。数值仿真结果通过试验进行验证,研究结果可用以指导高承载和高刚性静压气体轴颈轴承的设计。     

The Role of Radial Clearance on the Performance of Foil Air Bearings

Load capacity tests were conducted to determine how radial clearance variations affect the load capacity coefficient of foil air bearings. Two Generation III foil air bearings with the same design but possessing different initial radial clearances were tested at room temperature against an as-ground PS304 coated journal operating at 30000 rpm. Increases in radial clearance were accomplished by reducing the journal's outside diameter via an in-place grinding system. From each load capacity test the bearing load capacity coefficient was calculated from the rule-of-thumb (ROT) model developed for foil air bearings.

The test results indicate that, in terms of the load capacity coefficient, radial clearance has a direct impact on the performance of the foil air bearing. Each test bearing exhibited an optimum radial clearance that resulted in a maximum load capacity coefficient. Relative to this optimum value are two separate operating regimes that are governed by different modes of failure. Bearings operating with radial clearances less than the optimum exhibit load capacity coefficients that are a strong function of radial clearance and are prone to a thermal runaway failure mechanism and bearing seizure. Conversely, a bearing operating with a radial clearance twice the optimum suffered only a 20% decline in its maximum load capacity coefficient and did not experience any thermal management problems. However, it is unknown to what degree these changes in radial clearance had on other performance parameters, such as the stiffness and damping properties of the bearings.     

Effects of fine‐dispersed PTFE on load carrying capacity of PEEK

Poly(tetrafluoroethylene) (PTFE)‐blended poly(ether‐etherketone) (PEEK)‐based materials for bearings was evaluated by ring‐on‐disc test equipment. The role of PTFE on load carrying capacities was studied from the viewpoint of tribochemistry. The load carrying capacities of PEEK‐based materials were improved by the addition of PTFE. The dispersion degree of PTFE in PEEK strongly affected the tribological properties. Time‐of‐flight secondary ion mass spectroscopy and X‐ray photoelectron spectroscopy were employed to study the surface chemistry of the rubbed surface. The results indicate that the formation of boundary film composed of PTFE is beneficial to improve load carrying capacities. Copyright © 2008 John Wiley & Sons, Ltd.