机械学专家温诗铸

(1)建立工程模型弹流润滑理论,奠定现代润滑设计的基础他相继在国际上提出以完备数值解为基础的考虑热效应的热弹流、考虑动态效应的非稳态弹流、考虑润滑剂非牛顿性的流变弹流以及分析粗糙表面的微观弹流等润滑理论,系统地建立了工程中各类弹流润滑问题的设计方法.在此基础上,导出当今普适性最高的润滑方程,并将上述各种实际因素全部纳入分析,建立了工程模型的弹流润滑理论,为现代润滑设计奠定基础.     

直齿轮啮合弹性流体动力润滑的非稳态效应的研究

分析了渐开线直齿轮啮合弹流润滑的非稳态参数,推导了其弹流润滑方程组,并沿整个啮合线上作了完全的数值解,指出了齿轮啮合弹流润滑应考虑非稳态效应。     

变位非对称聚合物行星齿轮的瞬态热弹流润滑

为探究非对称齿廓的内啮合齿轮在变位情况下的热弹流润滑特性,用多重网格法对采用变位设计的非对称聚合物齿轮进行了瞬态热弹流润滑分析,比较了不同传动类型的变位齿轮的弹流润滑特性,分析了不同变位系数分配形式以及齿廓修形对非对称聚合物齿轮在内啮合情况下的瞬态弹流润滑的影响。结果表明,非对称齿轮能改善变位齿轮的润滑性能,正传动的变位类型的齿轮润滑性能最优,内齿轮采用较大的变位系数对热弹流润滑更为有利,合理的修形能够改善非对称变位齿轮的润滑性能。     

渐开线斜齿轮瞬态弹流润滑数值分析

渐开线直齿圆柱齿轮的弹流润滑问题已经基本成熟,而对同样是线接触的渐开线斜齿圆柱齿轮的弹流润滑求解却研究甚少并颇有争议.建立了斜齿圆柱齿轮弹流润滑计算的数学模型,将斜齿圆柱齿轮的弹流润滑问题等效为2个反向圆台的弹流润滑问题,应用多重网格法求得了一对斜齿圆柱齿轮轮齿在不同啮合瞬时的弹流润滑完全数值解.结果表明:斜齿圆柱齿轮啮合线上各点的压力、膜厚均不相同,沿接触线方向上最大等效半径的位置对接触线上油膜颈缩的位置有较大影响;接触线最长时从动轮齿根部分和主动轮齿顶部分在啮出点位置的膜厚最小,压力最大,最容易早期失效.     

滚柱包络环面蜗杆传动弹流润滑特性分析

为了研究滚柱包络环面蜗杆传动的弹流润滑特性,在滚柱包络环面蜗杆传动啮合理论研究和弹性流体动力润滑理论的基础上,建立了线接触等温弹流润滑数学模型。利用直接迭代法对传动副的弹流润滑进行求解,得到了传动副的油膜压力和油膜厚度曲线,分析了传动副在齿根圆、分度圆、齿顶圆处的弹流润滑特性,最后,分析了喉径系数和滚柱半径对滚柱包络环面蜗杆传动润滑特性的影响。结果表明,该传动副具有良好的润滑特性,增大喉径系数和滚柱半径,能够有效改善传动副的润滑性能。     

电容分压器法测试弹流润滑状态的研究

本文介绍了一种弹流润滑过程的测试方法——电容分压器法,对该方法的测试原理、电路原理及提高测量分辨率等问题进行了详细的分析,并把该方法的测试曲线与电阻法的测试曲线进行了对比,认为电容分压器法既适合于全膜弹流润滑状态的测试,又适合于部分膜弹流润滑状态的测试,是较有前途的弹流润滑过程的测试方法。     

橡胶滑块与镀镍钢环的水润滑机理分析

对水润滑橡胶轴承在完全水润滑条件下的标准实验模型进行了弹流理论建模,应用多重网格技术对理论模型进行了数值计算和结果分析。结果表明:完全水润滑条件下,在高速轻载时形成了弹流润滑,而在低速重载时,即使在完全水润滑条件下橡胶滑块与镀镍钢环之间也较难形成稳定的弹流润滑。计算结果与实验结果基本一致。     

粘塑性流体弹流润滑的研究进展

介绍了粘塑性流体弹流润滑产生的背景、国内外的研究现状,阐述了粘塑性流体弹流润滑未来亟待解决的问题。     

渐开线斜齿圆柱齿轮弹流润滑模型的建立

渐开线直齿圆柱齿轮的弹流润滑问题已经基本成熟，而对同样是线接触的渐开线斜齿圆柱齿轮的弹流润滑求解却研究甚少并颇有争议。分析了斜齿轮齿廓曲面的形成及啮合特点，建立了研究渐开线斜齿圆柱齿轮弹流润滑的物理模型和数学模型．通过数学推导，得到了膜厚方程，通过多重网格法即可获得渐开线斜齿圆柱齿轮在某一瞬时的弹流润滑数值解。     

高副接触机械零件弹流动力润滑研究新进展

弹性流体动力润滑是润滑理论的一个重要分支,也是关系到高副接触机械零件使用耐久性和可靠性的关键技术问题。计算机模拟仿真技术、数值计算方法和弹流测试技术的发展,推动了弹流润滑理论的发展和该理论在高副零件摩擦副设计中的广泛应用。综述齿轮、凸轮、轴承3种高副接触零件基于表面粗糙纹理、轮齿修形、有限长接触、热效应、镀层等因素的弹流润滑研究发展概况。指出现代弹流润滑理论虽然在高副接触零件中的应用已逐渐接近工程实际要求,能够较可靠地解决实际工况下的润滑难题,但在非稳态效应和真实粗糙表面对高副零件弹流润滑的影响方面,高副零件弹流润滑的多重参数耦合、计算机仿真及相关实验验证方面,还须进一步深入研究。     

N次谐波凸轮-挺柱副的润滑特性分析

将线接触弹流润滑理论应用于发动机配气机构，计算了某N次谐波凸轮-挺柱副润滑的稳态最小膜厚、膜厚比等参数，分析了凸轮．挺柱副稳态润滑在设计转速下随凸轮转角的变化特征，比较和讨论了发动机转速变化对润滑性能的影响。结果表明，凸轮桃尖区多为部分弹流润滑状态和边界润滑，工作段其它部分多为部分弹流、完全弹流和动力润滑状态。曲轴转速提高一般情况下对增加稳态最小膜厚有利，但由此导致的载荷波动量增加对最小膜厚的稳定性不利，从而使表面摩擦和磨损的可能性增加。     

The Effect of the Electric Double Layer on Very Thin Thermal Elastohydrodynamic Lubricating Film

The effect of the electric double layer (EDL) of friction surface on lubrication is significant under the condition of very thin lubricating film. This article presents a theoretical evaluation concerning the effect of the EDL on the film thickness and the pressure distribution of the elastohydrodynamic lubricating water film. These numerical analyses are based on the modified Reynolds equation that considers the EDL. Owing to the temperature risen readily in elastohydrodynamic lubrication (EHL) contact area, the influence of the temperature rise on the EDL effect was also investigated. The analysis results show that the EDL leads to a noticeable increase in the film thickness but has few influences on the pressure. Further, the analytical comparisons between isothermal and thermal conditions reveal that the temperature rise in the contact area weakens the effect of the EDL on the EHL film. Overall, consideration of the EDL effect gives a thicker EHL film, but once the temperature rise in the EHL regime is taken into account, the film thickness is correspondingly decreased.     

虚拟弹性流体润滑实验台的研究

弹性流体动力润滑是摩擦学主要研究领域,由于弹流状态下润滑剂所处的特殊条件,其实验过程十分复杂,获取数据也非常困难。本文利用数值计算方法和计算机技术。在计算机上虚拟显示实验过程和结果,形象地表现出弹流实验的现象及特征,为弹流实验教学和研究提供了一种快速和有效的工具。     

A Review of Elasto-Hydrodynamic Lubrication Theory

The development and understanding of elastohydrodynamic lubrication (EHL) can be traced back to the beginning of the previous century. However, it was not until 1949 that the first real solution of the problem was published. Since then, the technology has evolved enormously. In the current article a summary of these developments is given. Smooth surface EHL has become well established. Numerical methods, analytical solutions, and experimental techniques have become mature. Focus areas of research today are thermal EHL, starved EHL, friction (non-Newtonian lubricants), roughness, and grease. The scope of EHL is so wide that the authors needed select the topics of focus in this article. Therefore, in addition to the general overview of the areas of friction, analytical methods, starved EHL, and grease EHL are highlighted in this article.     

表面凹槽对滚子链套筒-销轴摩擦副热弹流润滑影响的数值模拟

以工业滚子链为工程背景,研究表面沟槽对套筒-销轴铰链副在充分供油条件下的热弹流润滑问题的影响。分析基于长椭圆接触假设,建立稳态热弹流润滑的数学模型,采用纵向和横向2种凹槽的表面织构形式。结果表明:在椭圆接触区长轴两端布置2个对称的纵向凹槽时,可以起到储油的作用,增加局部油膜厚度;在椭圆接触区长轴两端各布置3个对称的横向凹槽时,会引起油膜厚度、压力与温度的急剧变化,增加了动压效应。在接触区端部设置横向凹槽的效果要好于设置纵向凹槽。     

Analyzing viscoelastic effects in piston skirts EHL at small radial clearances in initial engine start up

Non-Newtonian engine lubricant and EHL film enhance engine life at small clearance in normal engine operation. It is not so in initial engine startup. This study models 2-D Maxwell viscoelastic hydrodynamic and EHL of piston skirts in initial engine startup. The 2-D Reynolds equation and the inverse solution technique are used for EHL solutions. Numerical solutions predict viscoelastic effects on piston eccentricities, hydrodynamic pressures and EHL films at different small radial clearances. Results are compared with Newtonian model, which suggest that viscoelasticity is beneficial for skirts lubrication at small radial clearances. Outcomes optimize small radial clearance in initial engine startup.     

Measurements of Two-Dimensional Distribution of Refrigerant Concentration in EHL Film Using Micro FT-IR and Effect of Variation of Concentration on Oil Film Thickness

The dissolution of refrigerant into a lubricant causes a decrease in viscosity of the oil and it gives a large effect on the lubrication of sliding parts in a refrigerant compressor. This paper describes an application of micro FT-IR to measure the two-dimensional concentration distribution of refrigerant held in solution in the EHL film surrounded by the refrigerant gas and discusses the refrigerant concentration variation in the vicinity of the Hertzian contact area. In order to measure the concentration distribution, an apparatus which can observe the EHL film in a point contact in the refrigerant atmosphere was developed. The refrigerant concentration was measured using micro FT-IR through a CaF₂ window from outside of the apparatus with polyol ester as a base oil in an atmosphere pressurized with HFC-134a refrigerant gas. The results indicate that the concentration of HFC-134a refrigerant reduces in the inlet boost region of EHL contact and the Hertzian contact area but in the side region of Hertzian contact area it is greater than that in the bulk fluid. In addition, the effect of the variation on the oil film thickness is discussed.     

EHL simulation using the free-volume viscosity model

The free-volume viscosity model can accurately predict the temperature–pressure–viscosity relationship of lubricants. However, it is seldom used in elastohydrodynamic lubrication (EHL) simulation. This paper presents the application of the free-volume viscosity model in a Newtonian EHL simulation of a squalane-lubricated circular contact. Good agreement is observed between available experimental data and simulation results. The pressure–viscosity coefficients fit from viscometer data are also discussed. A recently developed definition of the coefficient is used to compare the coefficient value extracted from EHL film thickness interference measurements. Results indicate that the coefficient values from the curve fitting and EHL film thickness extraction agree well which has not been previously observed. Two factors help achieve this agreement: the new coefficient definition and smaller prediction error when using the Hamrock–Dowson formula in the cases studied. The effects of different pressure–viscosity relationships, including the exponential model, the Roelands model and the free-volume model, are investigated through an example with bright stock mineral oil. It is found that the real pressure–viscosity behavior predicted by the free-volume model yields a higher viscosity at the low-pressure area which results in a larger central film thickness. Therefore, due to use of the free-volume model, the present results are more consistent with experimental observations than previously reported numerical results.     

Abrasive Wear Behavior and Its Relation with the Macro-indentation Fracture Toughness of an Fe-Based Super-Hard Hardfacing Deposit

Tribology Letters - There is an ongoing debate concerning the best rheological model for liquid flows in elastohydrodynamic lubrication (EHL). Due to the small contact area and high relative...     

滚动轴承弹流油膜测试仪的研制与应用

利用阻容振荡原理,通过电路参数优化,研制出一台滚动轴承弹流油膜厚度测试仪。仪器的分辨率为３．５Ｈｚ／ｐＦ,测量范围为０￣２．２ｎＦ。仪器在全膜弹流润滑时可定量测量弹流膜厚;在部分膜时可根据振荡波形分析非金属时间接触率。利用仪器实测某惯性轮轴承的弹流油膜厚度,并考虑热和乏油的影响,对轴承的弹流油膜厚度进行理论计算,实测结果与理论计算结果基本一致。