【作者】 张华伟；

【导师】 符永宏；

【作者基本信息】 江苏大学 ， 机械制造及其自动化， 2009， 硕士

【摘要】 活塞环-缸套摩擦副是发动机中最为关键的摩擦副之一。随着发动机越来越向高速、重载方向发展,如何使活塞环-缸套系统保持良好的润滑状况,对减小该摩擦副的摩擦磨损,延长发动机的使用寿命,提高经济性、动力性和耐久性具有非常重要的意义。近年来,作为改善摩擦副摩擦性能的激光表面微造型技术(LST),以其易控制、无污染、加工质量稳定等独特优点得到广泛关注。为改善活塞环-缸套摩擦副的摩擦状况,本文将激光表面微造型技术应用于活塞环表面处理中,具有重要的理论研究价值和工程实用意义。本文基于流体动压润滑理论,对外圆表面具有规则微凹腔结构的活塞环进行数值分析,并进行了模拟试验研究。首先,以激光微造型活塞环轴向4个凹腔为数值分析对象,建立活塞环表面具有规则抛物面微凹腔结构的流体动压润滑数学模型,结合雷诺空化边界条件,利用变异多重网格法,采用Matlab语言编程,数值求解离散后的数学模型。以流体膜无量纲平均压力作为衡量激光微造型活塞环动压润滑性能的标准,主要分析微凹腔面积占有率、深度和半径对流体动压润滑性能的影响规律,得到最优的微观凹腔几何参数组合。其次,采用“单脉冲同点间隔多次”激光微加工工艺,在淬火45钢试样表面进行激光微造型工艺试验,确定合理的激光微造型工艺参数。最后,在UMT-2摩擦磨损试验机上,对激光微造型试样进行摩擦磨损试验,试验结果表明:试样经激光微造型处理,明显改善了润滑效果,并且与理论研究结果有着较好的吻合性。本文的研究成果对于进一步拓展激光表面微造型技术(LST)在发动机其它摩擦副中的运用,具有非常重要的借鉴作用。更多还原

【Abstract】 The tribopairs of piston ring-cylinder liner are one of the most important tribopairs in an internal combustion.With the development of engine aiming at high-speed and heavy-load,how to make the piston ring-cylinder liner system maintain a good lubrication condition has great importance in terms of reducing the friction and wear,prolonging the engine’s longevity,improving economy/power/durability.In recent years, laser surface micro-texturing(LST),a technology to improve friction performance,has won extensive attention because of it’s unique advantage such as easy to control,environment-friendly,stable processing quality.In order to improve the friction conditions of piston ring-cylinder liner,we apply the LST to piston ring surface modifying,which has important theoretic value and practical significance.Based on hydrodynamic lubrication theory,the content carries out numerical analysis on the lubrication performance of piston ring which surface has regular micropores structure and simulation experimental study. Firstly,take four pores in the axis direction of LST piston ring as the study object,establish a hydrodynamic lubrication mathematical model with regular paraboloid structure micropores on the surface of piston ring,along with Reynolds cavitation boundary condition,by way of modified multi-grid method and Matlab language,figure out the discrete mathematical model.Take the dimensionless average pressure of the fluid film as the criterion to estimate the LST piston ring’s hydrodynamic lubrication performance,and mainly analyze the micropores’ area density, depth and radius on piston ring’s lubrication characteristics,then finally gain the optimized parameters of micropores.Secondly,adopt the technology of LST and use the "single pulse at the same point,interval more times" processing technics,an experimental study on quenching 45 steel sample is carried out and determining the rational laser micro-texturing technological parameters.Finally,carry out the friction and wear test on LST samples with the help of an experimental device which named UMT-2.The results show that the samples after laser micro-texturing can improve lubrication performance obviously,and the experimental results has well with the theoretical results.The achievements of this study has greatly important reference at the aspects of expanding LST applied in the other tribopairs of engines.更多还原