【作者】 马晨波；

【导师】 朱华；

【作者基本信息】 中国矿业大学 ， 机械设计及理论， 2010， 博士

【摘要】 表面织构是指通过一定的加工技术在材料表面上加工出具有一定尺寸、形状和排列的图案。为了系统全面地研究表面织构的减摩规律,寻求具体工况和润滑条件下的最优织构参数,论文分别对流体润滑状态和考虑粗糙度影响时的混合润滑状态下不同形状、尺寸和面积比织构表面的润滑减摩性能开展了相关的理论和试验研究,并对较复杂织构表面(包括变面积比织构表面和双织构表面)进行了探索性试验研究,得到了对摩擦副表面织构的减摩设计具有借鉴意义的研究结果。首先,通过应用Fluent软件对Navier-Stokes(N-S)方程的计算流体动力学(CFD)求解,研究了织构表面在流体润滑状态下的摩擦学特性。结果表明:惯性项作用对表面织构区域流动的求解具有重大的影响;流体域中压力变化曲线的幅值与织构的动压性能存在一定的对应关系,一般幅值越大,其动压性能越好;流体域中涡流的出现不利于动压性能的提高,其中,涡流开始出现时的织构深度与最优织构深度相对应;当流体域典型长度尺寸与摩擦副间隙尺寸比值L/h0≥46时,可以采用Reynolds方程代替N-S方程进行表面织构问题的理论求解,但此时必须考虑空化现象对压力分布的影响。其次,采用Visual Fortran语言编程对Reynolds方程数值求解的方法,研究了当L/h0≥46时织构表面在流体润滑状态下的摩擦学特性。研究发现:最优织构直径和最优织构深度之间存在一定的对应关系,最优织构直径越大,其对应的最优织构深度也越大;深径比参数不能作为织构尺寸参数对摩擦系数影响的唯一表征,但不论织构深度和直径如何,当织构深径比在0.005-0.01之间时,其对应的摩擦系数均较小。在仿真结果的基础上,建立了椭圆形截面织构的最优参数设计模型,并对其进行了试验验证和机理分析。通过引入Patir和Cheng的平均流量模型,考察了当考虑粗糙度影响时的混合润滑状态下织构表面的摩擦学特性。研究发现:织构最优参数不随方向参数的变化而变化;最优织构直径随综合粗糙度σ的增大而增大;当σ≥0.5μm时,最优织构深度随综合粗糙度的增大而增大;最优织构面积比与综合粗糙度之间不相关。基于理论分析的结果,提出了考虑粗糙度影响时的最优织构参数设计模型,并通过试验对其进行了验证和机理分析。论文最后还对较复杂的变面积比织构表面以及双织构表面进行了试验研究。结果表明:变面积比织构表面在重载高速的场合能够有效提高往复运动摩擦副的减摩性能;同时,其设计应遵循从中间到两端面积比逐渐增大的原则,而且面积比的大小与数量都应该处于一个合适的范围;在富油、乏油和不同试验载荷条件下,双织构表面与无织构表面下的摩擦系数相比差别不大,其并不能有效提高摩擦副的减摩性能。更多还原

【Abstract】 Surface textures are certain patterns machined with defined sizes, shapes and arrays on frictional surfaces. In order to research the antifriction behavior systematically and to look for the optimum parameters of surface texture in connected with the specific condition and lubrication state, the paper launched tribology properties of surface texture with different shapes, sizes and area ratios under hydrodynamic and mixed lubrication state considering the influence of surface roughness theoretically and experimentally. And more complicated including variable area ratios and double textured surface were also studied experimentally. The results have important implications on improving tribololgy theory and guiding design and application of surface texture.The tribology performance of surface texture under hydrodynamic lubrication was studied by solving the Navier-Stokes(N-S)equation by means of computational fluid dynamics (CFD) primarily, where the Fluent software was used. The importance of inertia was indicated, and it was found that there is certain relationship between amplitude of pressure variation curve and performance of surface texture. The larger the magnitude, the better of the performance of the dynamic pressure generally. In addition, it is not conducive to improving the performance of surface texture when swirl appears in fluid region. The depth of surface texture when the swirl begins to appear is corresponding with the optimal depth of surface texture. The Reynolds equation is suitable for the theoretical study on surface texture instead of the N-S equation when L/h0 is not larger than 46, while the cavatition must be considered.On the basis of the scope of application of Reynolds equation, the tribology performance of surface texture under hydrodynamic lubrication when L/h0 is not less than 46 was studied by solving Reynolds equation with Visual Fortran. Studies show that there are certain relationships between the optimal depth and diameter of surface texture, that is, the larger the optimal depth, the larger the optimal diameter; The depth to diameter ratio cannot be used as the only characterization size parameter on the effect of friction coefficient, but when the aspect ratio is between 0.005-0.01, the corresponding friction coefficient will be smaller. The design model of optimal parameters of the oval cross-section texture was developed and the correctness of the model was verified through experiment.The tribology performance of surface texture under mixed lubrication considering the surface roughness effect was investigated with the introduction of the average Reynolds equation developed by Patir and Cheng. It was found that, the optimum parameters of surface texture do not vary with the direction parameter changes; the optimum diameter of surface texture increased with the composite root-mean-square (rms), which is the same as the optimum depth whenσis not less than 0.5μm; while the optimum area ratio is not related to the composite rms. The design model of optimal parameters considering the surface roughness was developed and the correctness of the model was verified through experiment.A series of experimental research were carried on complicated including variable area ratios and double textured surface in the final part of the paper. The results show that, the texture with various area ratios has a great potential on improving the antifriction properties under the reciprocating motion, especially in the situation with heavy load and high speed, the design of which should be in accordance with the principle that the area ratio increasing from the middle to the ends of the region. While the double textured surface can not improve the properties of frictional pairs under various loads and lubrication states with rich or lean oil.更多还原