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总结了自润滑轴瓦不同制备工艺的优缺点,指出涂料喷涂工艺是高性能轴瓦的最佳制备工艺之一,并介绍了内燃机轴瓦喷涂工艺。针对喷涂轴瓦使用老旧的检测工具且结合强度检测无国标参考的缺点,采用轮廓仪检测轴瓦轮廓度,影像壁厚分选机检测壁厚、涂层外观缺陷,热震后划格法检测结合强度,提高了内燃机轴瓦的检测精度。 相似文献
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船用内燃机中轴瓦及曲轴工作时接触界面受力复杂,若润滑不当极易造成轴颈的黏着、擦伤、裂纹等。为改善船用内燃机轴瓦的使用寿命,在轴瓦表面制备聚酰胺酰亚胺和聚四氟乙烯(PAI/PTFE)聚合物涂层,并探讨MoS2颗粒对PAI/PTFE复合涂层摩擦性能的影响。通过喷涂-烧结法在轴瓦材料铝锡铜合金表面制备不同MoS2质量分数的复合涂层,并以轴承钢球作为摩擦配副,在3、4、5 N载荷以及干摩擦和油润滑下考察复合涂层的摩擦学性能。结果表明:在干摩擦下,MoS2质量分数为2%的复合涂层摩擦因数降低了80%以上,磨损降低了90%以上;油润滑下摩擦因数最大降低了67%。SEM和EDS分析表明,5 N载荷下,MoS2质量分数低于2%时,长时间摩擦会导致复合涂层破裂,进而产生大的摩擦磨损;而含有2% MoS2的涂层会在钢球接触表面上产生均匀的硫化物层,可以保护涂层提高其稳定性。通过对不同MoS2含量涂层的摩擦因数、磨损及磨痕形貌对比,得出较优的涂层配比。研究表明,适量的MoS2能够提高涂层摩擦膜的稳定性,减小摩擦磨损。 相似文献
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利用超音速等离子喷涂技术制备了不同喷涂功率条件下的NiCr-Cr3C2涂层,结合表面自由能理论研究了其表面摩擦学性能。利用Owens-Wendt几何平均法计算了涂层的表面自由能及其分量。对比发现,涂层孔隙率、显微硬度和摩擦因数均随着喷涂功率的变化而变化,且其变化趋势与极性分量均表现出一定的相似性。分析表明,受喷涂功率的影响,喷涂粒子的温度和速度对涂层表面分子间作用力产生影响,从而间接改变了涂层表面的自由能,并且自由能及其分量的改变,会直接影响NiCr-Cr3C2涂层表面的摩擦学特性。 相似文献
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针对铝合金硬度低、耐磨性差的问题,采用电弧喷涂分别在6061铝合金基体表面喷涂Al和Al-Ni-Mm-Co涂层,采用显微硬度计、扫描电子显微镜、X射线衍射仪分别对涂层硬度、涂层显微结构、涂层成分进行分析。采用球-盘式往复摩擦试验机考察涂层在脂润滑下的摩擦学性能,并对磨痕形貌和表面主要元素进行观察。结果表明,Al-Ni-Mm-Co涂层的减摩性和抗磨性能均优于6061铝合金和Al涂层,其优异的摩擦学性能归结为摩擦表面形成的Al2O3、NiO、CoO等氧化保护层,主要的磨损形式为疲劳磨损。 相似文献
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内燃机活塞环陶瓷涂层摩擦性能研究 总被引:1,自引:0,他引:1
采用等离子喷涂陶瓷涂层的方法对某活塞环表面进行了强化处理.探讨了活塞环表面涂层的材料种类、结构及喷涂工艺流程,研究了陶瓷涂层活塞环的机械性能和摩擦学性能,并探讨了其摩擦磨损机制.结果表明:与镀铬活塞环相比,陶瓷涂层活塞环具有较低的摩擦因数和较高的耐磨性和耐腐蚀性;陶瓷涂层同基体有很高的结合强度,涂层不易脱落,并使活塞环整体具有较好的韧性和弹性;陶瓷涂层表面磨损机制主要表现为脆性剥落、挤压剥落和疲劳磨损. 相似文献
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超声深滚法提高电弧喷涂3Cr13涂层性能 总被引:1,自引:0,他引:1
利用超声深滚(Ultrasonic deeprolling,UDR)技术对钢基体电弧喷涂3Cr13涂层进行表面复合强化处理,旨在改善涂层的综合性能。采用扫描电镜、应力仪及球—盘式摩擦磨损试验机等设备检测和分析UDR工艺对该涂层孔隙率、表面粗糙度、残余应力、显微硬度、摩擦学性能等的影响。结果表明,UDR工艺使该涂层的孔隙率从5.1%降为2.3%;表面粗糙度Ra由40μm以上降为2.4μm;表面残余压应力由8MPa提高到257MPa;涂层显微硬度提高约45%,涂层摩擦学性能得到了明显提高。且Bragg衍射峰明显宽化、左移、峰强增大,这表明涂层晶粒明显细化、晶格畸变,且形成晶向平行表面的板织构。同时分析和讨论UDR工艺对提高3Cr13涂层性能的影响机理。 相似文献
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《现代制造技术与装备》2019,(10)
在20钢表面运用等离子喷涂技术分别制备了Cu-Al_2O_3涂层和Cu-AT13涂层,并测试了涂层显微硬度、结合强度以及摩擦学性能。结果表明,Cu-Al_2O_3涂层较Cu-AT13涂层,平均显微硬度提高,结合强度减小,摩擦系数降低,磨损率降低,两种复合涂层的主要磨损机制均为剥落。 相似文献
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The effect of journal and bearing surface roughness on the performance of a capillary compensated hole-entry hybrid journal bearing system has been theoretically studied. The analysis considers the average Reynold’s equation for the solution of lubricant flow field in the clearance space of a rough surface journal bearing system. The finite element method and Galarkin’s technique has been used to derive the system equation for the lubricant flow field. The non-dimensional parameters Λ (surface roughness parameter) and γ (surface pattern parameter) have been defined to represent the magnitude of height distribution of surface irregularities and their orientation, respectively. The influence of surface roughness on the bearing performance has been studied for the transverse, isotropic and longitudinal surface patterns. The bearing performance characteristics have been computed for both symmetric and asymmetric capillary compensated hole-entry journal bearing configurations for the various values of surface roughness parameter (Λ), surface pattern parameter (γ) and restrictor design parameter (
). The computed results indicate that the inclusion of surface roughness effects in the analysis affects the performance of a bearing quite significantly vis-à-vis smooth surface bearing. The study indicates that for generation of accurate bearing characteristic data, the inclusion of surface roughness effects in the analysis is essential. 相似文献
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T. V. V. L. N. Rao 《摩擦学汇刊》2013,56(6):750-758
Journal bearing performance depends on the boundary conditions at the interfaces between the fluid and the solid surfaces. In the derivation of the Reynolds equation used to predict the bearing performance, the no-slip boundary conditions of the fluid and the solid interfaces are used. Recent research has shown that a slip can occur on specially made surfaces, the conventional no-slip boundary conditions are not valid, and the Reynolds equation is no longer applicable. If the slip is allowed to occur in certain regions, the fluid flow in the bearing can be altered, and the bearing stability characteristics can be improved. In this article, the numerical stability analysis of a journal bearing based on the extent of the slip region on the bearing surface is analyzed. An extended Reynolds equation is derived based on the slip length model, using a no-slip boundary condition against the journal surface and the slip against the bearing surface. A linearized perturbation method is used to determine the stability limit of a rigid rotor supported on two symmetrical journal bearings. Using the linear stability analysis, the linearized stiffness and damping coefficients, the threshold speed, and the critical whirl ratio are evaluated. The effects of the slip parameter on the bearing stability performance are discussed. The results show that with a critical shear stress of zero, an increase in the stability threshold can be achieved with a higher value of the nondimensional slip length and a smaller extent of the slip region on the bearing surface. 相似文献
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The provision of helical grooves on the surface of a plain journal bearing should, in principle, improve the overall performance of the bearing. This improvement, however, depends on a number of parameters such as the arrangement of the grooves along the axial length of the bearing. In order to verify this supposition, two types of helical groove bearing with different groove arrangements and a reference plain journal bearing were studied to assess their steady-state performance when lubricated with an oil. It was found that the steady-state performance of both types of helical groove bearing is not as good as that of the plain bearing. Of the two helical groove bearings tested, the asymmetrical bearing proved to be a more energy efficient than the symmetrical bearing. 相似文献
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为研究油气润滑状态下表面织构对角接触球轴承润滑性能的影响,在角接触球轴承的内圈滚道上设计表面织构,基于气液两相流理论,采用多重参考坐标系(MRF)模型和流体体积(VOF)法,对高速角接触球轴承腔内润滑油流动特性进行数值分析,对比分析长沟槽、短沟槽、矩形、圆柱形4种表面织构对角接触球轴承润滑性能的影响,发现长沟槽形的表面织构对改善角接触球轴承的润滑性能效果最为显著,并进一步分析长沟槽形表面织构结构参数对轴承润滑性能的影响。结果表明:轴承腔内油相体积分数随着沟槽深度和面积率的增大先增大后减小,随着沟槽宽度的增加逐渐增大,存在最佳织构参数使得轴承腔内油相体积分数最大。因此,合理地设计织构参数能有效提高角接触球轴承润滑性能,该研究结果对角接触球轴承表面织构设计具有一定的参考价值。 相似文献
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To improve the tribological performance of mating surfaces such as journal bearings, dimples with different shapes were introduced through laser surface texturing. In laser surface texturing processes, bulges are always induced around the dimples and may influence the tribological performance of the surface. In this article, the influence of the bulges on the tribological performance of a journal bearing is numerically investigated. Variations in both the friction coefficient and the eccentricity ratio of a journal bearing with the width and height of the bulges are studied. The influence of the radius of the dimples on the tribological performance of a journal bearing is also investigated. Results show that the friction coefficient increases with both the width and the height of bulges in the case of journal bearing under light and moderate loading conditions, which is in accord with the experimental results in previous works. The linear variation in the friction coefficient with the height of the bulges indicates that the wear rate of the bulges may be investigated by monitoring the friction coefficient. The abnormality of friction coefficient variation with the width of the bulges in the case of heavy loading condition indicates that introducing the bulges is an effective approach for reasonable tribological performance. From the results for the influence of the dimple radius, it can be concluded that although the introduction of dimples can improve the tribological performance, it also has some disadvantages such as decreasing the load-carrying capacity. 相似文献
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Numerical and experimental analysis of aerostatic thrust bearings with porous restrictors 总被引:4,自引:0,他引:4
T. S. Luong W. Potze J. B. Post R. A. J. van Ostayen A. van Beek 《Tribology International》2004,37(10):825-832
The finite element method is used to predict the performance of aerostatic thrust bearings with a complete porous surface. Results obtained by a 1D and 3D source flow model derived from D’Arcy’s law are compared for rectangular porous bearings having an infinite width. It turns out that the 1D source flow model is adequate for practical design parameters. For a circular aerostatic porous thrust bearing results calculated with several mathematical models for the source flow and slip flow are compared with experimental results. A relatively simple model incorporating unflatness and deformation of the bearing surface correlates well with the experimentally determined bearing performance. 相似文献
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The effect of surface roughness on the performance of hydrodynamic slider bearings is studied. A generalized form of surface roughness characterized by a stochastic random variable with non-zero mean, variance and skewness is assumed to define the bearing surface topography. Various film shapes such as: plane slider, exponential, secant and hyperbolic are considered. The results are obtained for the general lubricant film shape in integral form which are numerically computed for the shapes under consideration. The results are presented both graphically as well as in tabular form. The performance of a rough bearing can be considered in terms of an identical smooth bearing with an equivalent film thickness. It is observed, for the lubricant film shapes under consideration, that the increasing positive values of α, σ and ε decrease the load carrying capacity, frictional force and temperature rise while it increases the coefficient of friction. Increasing positive values of α and ε shift the center of pressure towards the outlet edge. For negative values of α, the increasing value reverses the trend of the effect on performance characteristics which is in conformity with the physical aspects of the problem. A similar trend is observed in case of the effect of negative values of ε. Thus, a negatively skewed surface roughness modifies the performance of the slider bearings whereas the performance of a bearing suffers on account of positively skewed surface roughness. Moreover, it is noticed that in the case of exponential and hyperbolic slider bearings the effect of increasing values of σ is more pronounced whereas in case of plane slider and secant shaped slider this effect is marginal. 相似文献