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往复式发动机里使用的滑动轴承在某些工作条件下有可能受到穴蚀的影响。由于小气泡的产生和随即破灭引起高压脉冲,所以轴承表面易局部受损。这种现象主要发生在当对现有发动机进行强化或改变轴承设计及其周围环境时。受环保法规的推动,发动机设计师进一步提高了甚至更小型和更轻量化发动机的效率和功率密度。结果,整个曲轴机构及其轴承座的弹性变形增大,从而恶化了轴承的工作条件。虽然现在通过广泛使用计算流体动力学(CFD)方法能够成功地模拟某些型式的穴蚀,但是轴承内的机油流动情况仍然太复杂以致其不可能被一个全尺寸模型所涵盖。适用于标准轴承评价的最普通的方法是采用基于雷诺方程数值解的弹性流体动力学程序。与此同时,还扩展采用了可使机油平衡更为精确的质量守恒定律。通过结合使用某种观察曲轴机构机油流动定时的工具,可以分析大多数轴承穴蚀现象。本文论及与引起轴承穴蚀有关的主要因素。通过给出若干实例,描述最常见的轴承穴蚀现象,并展示了其与模拟结果之间的相互关系。接着,编制了一个各种影响因素的结构矩阵,并推导出一个关于防止穴蚀的轴承设计工作流程。为了证明所介绍方法的优点,对一新设计的发动机进行了预防连杆大端轴承穴蚀的分析。在文章的最后进行了总结并对未来发展进行了展望。
Slide bearings used in reciprocating engines may be subject to cavitation under certain operating conditions. Due to the generation of small bubbles and the subsequent burst caused by high-pressure pulse, so the bearing surface is easily damaged locally. This phenomenon mainly occurs when the existing engine to strengthen or change the bearing design and its surrounding environment. Driven by environmental regulations, engine designers have further increased the efficiency and power density of even smaller and lighter-weight engines. As a result, the entire crankshaft mechanism and its housing elastomeric deformation increases, thereby deteriorating the bearing operating conditions. Although some types of cavitation can now be successfully simulated by the widely used computational fluid dynamics (CFD) method, the flow of oil within the bearing is still so complex that it can not be covered by a full-scale model. The most common method that is suitable for standard bearing evaluation is to use elastohydrodynamic procedures based on numerical solutions of the Reynolds equation. At the same time, it is also extended to adopt a more accurate mass conservation law that balances the oil. By combining the use of some kind of tool for observing crankshaft oil flow timing, most bearing cavitation can be analyzed. This article addresses the main factors that contribute to bearing cavitation. By giving several examples, the most common phenomenon of bearing cavitation is described and the correlation between them and the simulation results is shown. Then, a structural matrix of various influencing factors was compiled and a working procedure of bearing design to prevent cavitation was deduced. In order to prove the advantages of the presented method, a newly designed engine was used to prevent cavitation of connecting rod big end bearing. The article concludes with a summary of the future development prospects.