内燃机滑动轴承润滑研究的现状及进展

曲轴-轴承系统是内燃机的关键部件,其摩擦学、动力学性能直接影响到内燃机工作的可靠性和耐久性,对其进行流体动力润滑和弹性流体动力润滑研究具有重要的意义。本文从流体动力润滑理论出发论述了内燃机滑动轴承润滑研究的现状和进展,讨论了近年来曲轴润滑研究的意义。     

Tribological Behaviors of 52100 Steel in Carbon Dioxide Atmosphere

The tribological behavior of 52100 steel in a carbon dioxide (CO₂) atmosphere was investigated using a reciprocating ball-on-disk tribometer. X-ray photoelectron spectroscopy (XPS) was used to identify the adsorbed surface layers and tribochemical products. We found that CO₂can substantially reduce friction and wear of the steel. Adsorbed and reacted surface layers containing iron carbonate and/or bicarbonate play an important role in reducing friction. A disk, exposed once to CO₂atmosphere, also shows a low friction for a long time even in a vacuum environment. An optimum CO₂pressure exists for effectively reducing friction and wear. A low-pressure CO₂atmosphere is insufficient to produce iron carbonate. In contrast, high pressure engenders serious chemical wear.     

无油润滑压缩机导向环轴向宽度设计的研究

无油润滑压缩机导向环轴向宽度的传统设计方法将活塞组件的重量作为导向环所承受的载荷,忽略了数倍于活塞组件重量的侧压力的影响,造成轴向宽度过短,缩短使用寿命;另外,承压表面许用比压的取值过小,导致轴向宽度过长,不利于活塞和气缸的加工。对轴向宽度设计方法进行了改进,把侧压力和活塞组件的重量共同作为导向环承受的载荷,比压控制在0.06～0.10MPa以下,所设计的导向环应用在SW-2.5/7型全无油润滑压缩机上寿命达8000h以上。     

机油换油周期对机车设备润滑的影响

阐述内燃机车机油换油周期对设备润滑的影响,介绍用取样目测法确定换油周期具体操作过程,该方法简单实用,可操作性强.     

Developments in engine bearing design

Some of the important recent developments in engine bearing design techniques are highlighted. The availability of increased computing power has enabled more realistic assumptions about bearing conditions to be considered; these include oil feed features, oil film history, non-circular bearings, inertia effects due to journal centre movement, improved prediction of main bearing loads, flexible housings and special bearings. References to these advances are made, together with illustrations of how they affect predicted bearing performance. Experimental evidence is also being obtained, which helps to verify and give confidence in the analytical predictions     

SiAlON–epoxy nanocomposite coatings: Corrosion and wear behavior

In this study, epoxy powder as a matrix was combined with different contents of silicon–aluminum–oxygen–nitrogen (SiAlON) nanoparticles using a planetary ball mill. Pure epoxy and nanocomposite powders were applied on the surface of plain carbon steel components by the electrostatic spraying method. Curing of the coatings was done in an oven or microwave for the appropriate time. The coating structure and morphology of the SiAlON nanoparticles were studied by scanning electron microscopy and transmission electron microscopy, respectively. The corrosion properties of the coatings were assessed by immersion, Tafel polarization, and electrochemical impedance spectroscopy tests in 3.5% NaCl solution. The results show that addition of 10 wt % SiAlON nanoparticles markedly increases the corrosion resistance of epoxy coatings. Thus, it can be inferred that the corrosion rate of these coatings is 15 to 18 times lower than that of pure epoxy samples and 8 to 11 times lower than coatings with 20 wt % SiAlON. The higher corrosion resistance of nanocomposite coatings can be attributed to the barrier properties of SiAlON nanoparticles. The tribological performance of the coatings was studied with the pin‐on‐disk test. The results of wear testing show that the samples containing 10 wt % SiAlON provide about five times more wear resistance than pure ones and about two times more than coatings with 20 wt % SiAlON. However, the coefficient of friction for nanocomposite coatings is reduced about 50% compared to the pure sample. Also, the curing process in either regime (oven or microwave) has the same effect on the corrosion and wear properties, and the coatings are completely crosslinked. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43855.     

不同工况下丁腈橡胶的摩擦磨损机理

为了合理选择螺杆泵定子橡胶材料以提高螺杆泵的使用寿命,分析了不同工况下丁腈橡胶与金属配副的摩擦磨损机理.采用MPV-600环块式摩擦磨损试验机对不同炭黑质量分数的丁腈橡胶在变载荷情况下进行摩擦磨损试验,利用体视显微镜观察橡胶磨损后的表面形貌,使用红外光谱仪分析表面官能团变化.试验结果表明:干摩擦情况下,磨损量在一定炭黑质量分数范围内随其增加而减小,磨损机制为黏着磨损和磨粒磨损;水润滑情况下,由于水的润滑及冷却作用,炭黑质量分数适中的橡胶耐磨性最好,磨损机制为磨粒磨损;原油润滑低载荷情况下,磨损量几乎不受炭黑质量分数的影响,而高载荷情况下,炭黑质量分数越高,磨损量越小,其磨损机制以腐蚀磨损为主.     

钣金V形折弯回弹影响因素的有限元分析

在钣金V形折弯成形过程中,回弹对成形精度的影响很大,为此,针对板材的成形和弹复过程进行有限元仿真试验,分析材料性能参数（弹性模量,硬化指数）、板料厚度、模具几何参数（下模具开口宽度,上模具圆角半径）和润滑条件对折弯回弹的影响.仿真结果表明：回弹随弹性模量、硬化指数和板料厚度的增大而显著减小,随下模具开口宽度的增大而增大;上模具圆角半径和润滑条件对折弯回弹的影响较小,回弹随上模具圆角半径与摩擦系数的增大而缓慢减小.研究揭示了影响回弹的主要规律,为提高V形折弯成形精度提供了可靠的依据.     

增效浸渗砂轮的增效机理及其效果

增效浸渗砂轮处理技术是用于解决干式磨削时，磨削精度和磨削质量差，砂轮消耗大等不足的一项应用技术。通过实验研究，分析了增效浸渗砂轮在提高磨削质量和磨削精度，提高砂轮的磨削能力及降低砂轮消耗等方面的增效机理及其效果。     

Additive Manufacturing of Polymer-Based Lubrication

The fast growth of 3D printing technology gives designers many ways to make structures that are hard to see. 3D printing lets you customize complex structures in any way you want and make rapid prototypes of materials. It enables you to simulate things more effectively. So far, experiments with polymer-based lubrication have been done on atomically smooth surfaces, under dynamic conditions, and on the nano- or micro-scale. Polymer-based lubrication in 3D printing has been studied in depth, which has made it possible to make significant, multifunctional 3D structures with microscale accuracy. It is a crucial way to approach lubrication and has sparked much scientific interest. A thorough literature review is done to keep track of the latest advances in 3D printing for structural polymer-based lubrication simulation. The design and lubrication performance quality of bio-inspired, different-sized simulation structures is given much attention. The material requirements, skills, and representative applications of various 3D printing technologies are summarized. The efficient directions for future research in designing and making 3D-printed lubrication structures are also pointed out.