考虑真实粗糙表面的燃机球轴承磨损与混合润滑耦合机理

船舰燃机轴承服役环境苛刻,工作界面难以建立全膜润滑状态,局部粗糙峰接触发生磨损,而磨损又会通过影响表面形貌反作用于界面混合润滑状态,影响轴承摩擦学特性。目前,面向燃气轮机滚动轴承,开展考虑真实表面粗糙度的磨损与混合润滑状态耦合作用的研究仍然很少。因此,以燃气轮机涡轮端球轴承为对象,综合考虑接触界面磨损、弹性变形与实测机械表面粗糙度影响,建立滚动体与内滚道三维磨损区域下的润滑-接触数值分析模型,研究低速、重载及滑滚苛刻条件下轴承摩擦磨损特性。     

多轴承支承主轴系统轴承磨损研究

为了明晰不同工况参数对主轴系统中轴承磨损的影响规律,定量各参数对轴承磨损的影响程度,开展了多轴承支承的主轴系统轴承磨损研究.首先介绍了考虑润滑状态的磨损系数计算方法,推导了角接触球轴承磨损深度计算模型;其次,基于系统模型获得的轴承滚动体的运动参数与接触参数计算了轴承内外滚道的磨损深度;最后,讨论了主轴转速、轴承安装角偏移、外载荷和轴承表面粗糙度对轴承磨损的影响.结果 表明,主轴转速对轴承磨损影响显著,转速改变导致了轴承磨损规律的较大差异;轴承不存在安装角偏移时,主轴系统中各轴承内外滚道磨损深度之和最小;外载荷的变化对轴承磨损影响微弱;表面粗糙度的增大能够显著增大轴承的磨损深度.     

滚动轴承最佳工作游隙的确定及分析

滚动轴承的工作游隙与载荷分布系数之间存在关联,当载荷分布系数为0.7~0.8时,轴承能够获得较长的疲劳寿命,因此使轴承载荷分布系数在最佳范围时的工作游隙为最佳状态。分析了影响工作游隙的重要因素(配合、温度、材料等),基于上述分析,根据6σ准则建立了计算轴承工作游隙的理论计算模型。最后,结合实例介绍了轴承工作游隙的计算方法。     

一种考虑轴承缺陷影响的机构动力学分析方法

为有效地揭示轴承滚道缺陷特征对高速机构动态响应特性的影响规律,在多体动力学理论框架下提出一种考虑轴承缺陷影响的机构动力学分析方法。该理论采用力约束方法构建机构中滚动轴承转动副模型,通过分析轴承中各滚动体与滚道缺陷几何特征之间的接触关系,计算滚动体接触载荷并获取轴承转动副等效约束反力,探讨轴承缺陷激励对高速机构动态性能的影响规律。在此基础上,以含深沟球轴承的曲柄滑块机构为例,分析轴承滚道表面局部式缺陷和分布式波纹度缺陷对机构动力学特性的影响。研究表明,轴承滚道缺陷将引发轴承各滚动体接触动载荷突变。这种突变载荷经传播后,直接影响着机构中各构件的运动状态,对高速机构运动平稳性将产生严重影响。此外,该理论方法具有一般性,具有不同滚道几何缺陷特征的滚动轴承均可嵌入到本方法中,分析轴承转动副缺陷对各类机构动力学特性的影响。     

基于非理想Hertz线接触特性的圆柱滚子轴承局部故障动力学建模

传统方法对圆柱滚子轴承局部故障动力学的分析都是基于Hertz线接触理论,然而当轴承的滚子为凸度形状时,滚子素线不为直线,滚子与滚道之间的接触问题已经超出Hertz线接触理论的范畴。针对这个问题,以滚道表面存在局部故障的圆柱滚子轴承为研究对象,提出考虑滚动体与内外圈滚道之间非理想Hertz线接触特性和时变位移激励的圆柱滚子轴承局部故障动力学模型,研究位移激励形式和局部故障尺寸对圆柱滚子轴承振动特性的影响规律。研究表明,该模型能克服传统的线接触经验公式无法考虑滚子与滚道曲率的缺点,能更加准确反映圆柱滚子轴承滚道表面局部故障与滚动体接触的实际情况,为滚动轴承早期局部故障动力学分析和诊断工作提供新的计算方法和一些有价值的结论。     

基于动力学的行星齿轮传动系统的轴承磨损寿命预测

轴承磨损寿命与系统动力学特性密切相关,为了准确预测行星齿轮传动系统的轴承磨损寿命,提出了基于动力学模型的行星齿轮传动系统的轴承磨损寿命预测。首先运用集中参数理论,建立了一个考虑轴承磨损的行星齿轮传动系统平移-扭转动力学模型;然后运用摩擦学理论,建立滚动轴承单周接触的磨损量计算模型,结合行星齿轮传动系统动力学模型,建立轴承磨损寿命预测模型;最后分析了轴承磨损对轴承动态载荷和轴承磨损寿命的影响规律,并提出了提高轴承磨损寿命的方法。分析表明,轴承磨损对行星轮轴承动态载荷影响最大,并且行星轮轴承的磨损寿命与其刚度成正比,因此可通过轴承径向间隙补偿或轴向预紧等方法来提高行星轮轴承磨损寿命。     

转子-轴承系统动态特性与轴承磨损演化研究

以角接触球轴承支承的转子-轴承系统为研究对象,应用拉格朗日方程,推导建立了转子-轴承系统动力学模型,基于Archard模型,建立了包含润滑影响的轴承磨损深度计算模型,磨损深度以轴承游隙的形式引入到系统动力学模型中。分析了转子转速、轴承预紧和转盘位置等参数影响下,转子系统的动态特性与轴承磨损的演化规律。结果表明,轴承磨损对转子动态特性的影响与转子转速和轴承预紧密切相关;转盘位置的改变没有导致转子动态特性随轴承磨损深度的显著变化;转子转速显著影响轴承的磨损,轴承预紧对轴承磨损影响较小,转盘位置变化引起各轴承磨损深度的微弱差异。     

径向游隙对圆柱滚子轴承疲劳寿命的影响

应用经典的滚动轴承理论和“切片法”的基本思想,以某大兆瓦风电机组齿轮箱输出轴轴承为例,采用Romax Designer工程分析软件,计算了圆柱滚子轴承不同径向游隙时的轴承内部载荷分布、接触应力、套圈滚道当量动载荷和寿命,分析径向游隙对轴承ISO/TS 16281寿命的影响。研究结果表明：径向游隙不仅通过对轴承内部载荷分布、接触应力和套圈滚道当量动载荷的影响而对寿命产生影响,还通过对寿命修正系数等因素的影响而对寿命产生影响。研究结果可为滚子类轴承的优化设计提供参考。     

滚动轴承局部损伤故障动力学建模及仿真

针对实际齿轮箱轴承系统,建立了转子-故障滚动轴承-轴承座系统非线性振动模型,在模型中充分考虑了轴承间隙、滚珠与滚道的非线性接触力及变柔度VC振动.在此基础上,进一步建立了轴承外圈、内圈、滚动体局部损伤故障非线性动力学模型,并运用数值积分的方法进行了动力学仿真与分析.仿真分析结果验证了滚动轴承存在局部故障时的动力学特性,表明轴承局部损伤故障动力学模型的正确性.     

游隙及载荷对滚动轴承载荷分布的影响

基于滚动轴承动力学、Hertz弹性接触理论和轴承宏观几何学,建立了滚动轴承的分析模型。分析游隙及载荷对滚动轴承载荷分布的影响。分析结果表明:随着径向游隙的减小,轴承的接触分布范围角增大;随着径向载荷的减小,轴承接触分布范围角减小;当轴承出现负游隙时,轴承内、外圈相对变形量较小,但轴承中滚动体的平均载荷增加,会导致轴承寿命降低。     

深井、超深井套管磨损机理及预测技术研究

概述了近年来深井、超深井套管磨损机理及预测技术的研究动态，讨论了套管磨损主导机理及其影响因素的几种观点，重点分析了磨损效率模型的特点，明确了深井、超深井套管磨损研究的主要发展方向。     

Characterization of wear scar surfaces using combined three-dimensional topographic analysis and contact resistance measurements

In this paper, a technique for the quantitative characterization of wear scar surfaces, using combined three-dimensional topographical analysis and contact resistance measurements, is introduced. Parameters for the characterization of wear surfaces, developed during sliding of pin-on-disk specimens in oxygen at high temperature, such as wear volume, roughness, average wear depth on the disk specimen, surface coverage by wear-protective oxide layers and their distributions over the wear surface, are presented and calculated. Such analyses provide more effective data for the analysis of wear processes and wear mechanisms.This method has been applied to the analysis of dry reciprocating sliding wear of a nickel-base alloy, N80A, at temperatures to 600°C. It was found that there was usually a difference between the wear rates of the pin and the disk. This difference increased with increase in temperature, the wear of the pin being much less than that of the disk at the higher temperatures. Although the total wear of both the pin and the disk decreased considerably with increase in temperature, the damage to the disk, judged by the wear depth of the scar, was much higher at elevated temperatures than at low temperatures. The roughnesses of the wear surfaces generally increased with increase in temperature. Less than 50% coverage of the scar surfaces by wear-protective oxide layers was sufficient for the severe-to-mild wear transition. However, the distribution of the wear-protective layers over the wear surfaces was non-uniform. Most of them were concentrated near the centre of the scar, along the sliding direction, under the present conditions. These features of the wear scar surfaces were mainly related to the adhesion and compaction of wear debris particles onto the wear surfaces, leading to development of the wear-protective layers at the various temperatures.     

ZTA陶瓷刀具连续切削淬硬T10A时的切削性能研究

研究两种自主研制的新型ZTA(Al2O3/Zr O2)陶瓷刀具切削淬硬T10A时的切削性能。刀具后刀面磨损量随切削深度和切削速度的增加而增大;刀具的主要磨损形态为后刀面磨损;主要磨损机理为后刀面磨粒磨损和部分粘结磨损。     

GCr15微动磨损转向往复滑动磨损特性的研究

对GCr15金属球和平面试块在300N的法向力作用下作了从微动磨损向往复滑动磨损转变的试验研究，对摩擦磨损过程中的磨损系数、摩擦力变化特性、磨痕的轮廓进行了分析研究。结果表明，在微动磨同往复滑动磨损转变前后，除磨损系数出现突变外，摩擦系数和磨痕的轮廓形貌也发生了比较大的变化，磨损转变过渡区的范围为70－100μm。     

陶瓷材料磨损机制及磨损程度评价方法综述

综合分析陶瓷材料摩擦磨损的机制和影响摩擦磨损的各种因素,如表面加工状况、载荷、速度、时间、温度、润滑等。介绍几种陶瓷材料摩擦磨损程度的评定方法,如用量纲一化参数(最大赫兹接触压力、最大表面粗糙度和断裂韧性的函数Sc,硬度、最大表面粗糙度和断裂韧性的函数S*)大小评价磨损程度,用磨损表面的粗糙度Ry与平均粒径Dg的比值评价陶瓷材料磨损程度,用磨损率评价陶瓷材料磨损程度等。以期指导人们进一步认识陶瓷摩擦磨损的本质规律,有目的地调整材料的性能以提高其耐磨性。     

组装式滑板对地铁接触线犁削磨损的影响

在弓网载流摩擦磨损实验台上,用直流恒流电源对组装式浸金属碳滑板以及银铜合金接触线进行摩擦磨损试验,研究组装式碳滑板的接缝间隙和滑板间高度差对地铁接触线犁削磨损及滑板异常磨耗现象的影响。试验结果表明:组装式碳滑板高度差会严重刮伤接触线,是接触线犁削磨损的主要原因,而接缝间隙仅会轻微划伤接触线;80 N以上的法向力会显著减小滑板的磨损率;接缝间隙较小时更容易刮伤接触线,造成犁削磨损。分析滑板磨损表面形貌发现:存在滑板间高度差时滑板会出现机械划痕,电气磨耗和接触线材料转移也比较严重。     

Wear reducing effects and temperature dependence of tribolayer formation in harsh environment

Certain materials show a tribolayer formation especially at enhanced temperatures in abrasive environment, building a wear protection layer with the abrasive on the surface. Three materials with different microstructures were tested in three-body abrasive and impact/abrasive environments at temperatures up to 700 °C to investigate tribolayer formation. Optical and electron microscopical methods were used for wear qualification. Furthermore, hot hardness tests were performed up to 700 °C to investigate the influence of hardness drop on tribolayer formation.It was shown that no significant tribolayer formation occurs on grey cast iron, whereas other materials form tribolayers. Generally, tribolayer formation increases with increasing testing temperature, especially for austenitic and ferritic materials. This entails a self-protecting effect and thus superior wear resistance in abrasive environment.     

Analysis of wear mechanism and influence factors of drum segment of hot rolling coiler

Because the work environment of segment is complex, and the wear failures usually happen, the wear mechanism corresponding to the load is a key factor for the solution of this problem. At present, many researchers have investigated the failure of segment, but have not taken into account the compositive influences of matching and coiling process. To investigate the wear failure of the drum segment of the hot rolling coiler, the MMU-5G abrasion tester is applied to simulate the wear behavior under different temperatures, different loads and different stages, and the friction coefficients and wear rates are acquired. Scanning electron microscopy(SEM) is used to observe the micro-morphology of worn surface, X-ray energy dispersive spectroscopy(EDS) is used to analyze the chemical composition of worn surface, finally the wear mechanism of segment in working process is judged and the influence regulars of the environmental factors on the material wear behaviors are found. The test and analysis results show that under certain load, the wear of the segment changes into oxidation wear from abrasive wear step by step with the temperature increases, and the wear degree reduces; under certain temperature, the main wear mechanism of segment changes into spalling wear from abrasive wear with the load increases, and the wear degree slightly increases. The proposed research provides a theoretical foundation and a practical reference for optimizing the wear behavior and extending the working life of segment.     

A Finite Element Approach to Modeling Abrasive Wear Modes

Machine components operating in sandy environments will wear because of the abrasive interaction with sand particles. In this work, a method is derived to predict the amount of wear caused by such abrasive action, in order to improve the maintenance concept of the components. A finite element model is used to simulate various tips scratching a smooth surface. The model is verified by comparing the obtained results with a set of experiments performed earlier (M. Woldman, et al., 2013, Wear, 301(1–2), pp 76–81).     

TC4合金冲击磨损性能与机制的研究

固定冲击频率,在3组大小不同的冲击力下,在自制的小载荷冲击磨损实验机上对TC4合金进行了系列周次的冲击试验,研究了TC4合金的冲击磨损性能与磨损机制.结果表明:试样的整个冲击磨损过程可分为3个阶段,即无磨损阶段、微量磨损阶段和严重磨损阶段,增加冲击力将缩小前2个阶段的进程,加速材料的磨损;在各冲击力下磨痕轮廓及形貌的变化规律基本一致.TC4合金的磨损过程是接触表面硬化、启裂、疲劳剥落的过程,其磨损机制主要表现为塑性变形和疲劳剥落.