复合磷化膜的耐磨性

研究了经复合磷化液磷化处理后、钢铁表面磷化膜的摩擦学特性及其影响因素，主要探讨了摩擦零件表面状态及摩擦时润滑状况对复合磷化膜耐磨性的影响，分析了复合磷亿膜能够提高耐磨性的原因。     

角接触球轴承摩擦力矩波动性分析

针对低摩擦力矩角接触球轴承,利用能量守恒定律,研究角接触球轴承零件工作表面的波纹度对轴承摩擦力矩波动性的影响,从理论上对角接触球轴承零件工作接触表面的波纹度幅值、谐波阶次与轴承摩擦力矩波动性的关系进行分析,给出影响角接触球轴承摩擦力矩波动性的内、外滚道和钢球工作表面的主要波纹度谐波阶次和相应的激振频率,并试验验证.研究...     

表面波纹度在磨损过程中变化机理的研究

通过对摩擦过程的大量实验研究，总结出表面波纹度对耐磨性的影响规律：摩擦件的耐磨性不仅与粗糙度有关，而且与波纹度也有联系。并提出控制表面波纹度可以提高零件耐磨性的观点。     

轴向柱塞泵摩擦副磨损及改进探讨

通过受力分析，结合制造材质的特性，分析研究轴向柱塞泵摩擦副过早磨损和烧伤的机理，从设计、制造和使用等方面给出了改善柱塞泵摩擦性能，延长摩擦副使用寿命的建议，并得出结论：研究开发抗咬合性好且高耐磨性的新材料来制造摩擦副零件，是解决柱塞泵摩擦副过早磨损和烧伤问题的根本途径。     

发动机零部件的光整加工

光整加工技术对发动机整机性能的影响 发动机是各种汽车、工程机械、农机等的主要动力源，不断提高发动机整机性能的研究与实践是一个永恒的主题。其中，发动机摩擦副零件的表面质量，是影响发动机整机性能的重要因素之一。在传统制造水平相对较低的情况下，大量生产的摩擦副零件的一些技术要求如去毛刺、棱边倒圆等形同虚设，对表面加工纹理、表面物理力学、化学、光学性能、     

点磨削纹理特征及对零件摩擦学性能的影响

由于存在点磨削变量角度,点磨削纹理特征不同于常规外圆磨削。采用简化方法对点磨削表面纹理进行表征与分析;分析表面纹理方向对流体动压润滑效果的影响。在流体润滑条件下,对不同点磨削表面纹理方向的零件进行摩擦磨损试验,研究点磨削纹理方向对零件摩擦学性能的影响。结果表明:点磨削表面纹理方向的改变,会影响流体动压油膜的形成以及形成的油膜厚度的大小;在不同载荷作用下,不同纹理方向的零件的摩擦因数也不同,流体动压油膜的形成需要适当的载荷;在一定的工况下,存在使零件摩擦学性能最优的表面纹理方向,在生产中可以通过控制点磨削纹理方向来优化零件的摩擦学性能。     

金属陶瓷硬质覆层零件在磨损载荷作用下的界面最大剪切应力分析

金属陶瓷硬质覆层材料是一种具有高耐磨损性能的新型层状复合材料,尤其适应于耐磨损零件的制造.文中选择板类金属陶瓷硬质覆层零件为研究对象,首先把该零件等效为均质零件,把该均质零件与圆柱体零件在一定压力作用下的摩擦过程简化为平面应变问题,根据赫兹接触理论建立覆层零件界面处最大剪切应力理论模型.根据理论模型进行实例研究,并进行有限元分析.理论研究结果与有限元分析结果相符.二者均表明,覆层零件界面处最大剪切应力随覆层厚度的增大而减小,随磨损载荷的增大而增大.同时研究摩擦副材料对覆层零件界面最大剪切应力的影响规律.提出覆层零件在磨损载荷作用下应满足其界面最大剪切应力不超出相应覆层材料的界面剪切强度的设计准则.文中的研究结果对金属陶瓷硬质覆层零件的设计、优化以及金属陶瓷硬质覆层材料的进一步推广应用具有重要的理论指导意义.     

机床铸铁材料耐磨性能及其分析

一．概述机床导轨与拖权类零件是在摩擦状态下工作的，它们在工作过程中，主要受到机械作用，化学作用以及热作用而使零件受到不同形式的破坏，如均匀缓慢的逐层磨损，摩擦表面产生擦伤，划痕和剥落等等，而机床导轨等的耐磨性能是影响机床精度保持性和机床使用性能寿命的重要因素，其它类产品也如此，因此，研究材料的耐磨性能，使这类零件在工作中减少磨损，并且有较小的摩擦系数以减少动力消耗，就有着十分重要的意义。实际上，影响零件磨损的因素是多方面的，其中包括零件的材质，结构形式，表面质量，装配质量，润滑条件、负荷、运动速…     

陶瓷磨削残余应力对表面性能的影响

陶瓷零件的磨削表面必然要附加一层残余压应力 ,其对零件的使用性能影响较大。本文主要针对陶瓷材料磨削表面残余应力对疲劳磨损和表面硬度的影响进行实验研究。试验结果表明 :与金属材料相比 ,Zr O2 陶瓷材料的磨削残余应力对零件的摩擦磨损性能的影响要小得多。磨削、研磨及加热三个试件组的磨损量随摩擦时间呈现一定的变化规律。残余拉应力在一定程度上加速陶瓷零件的磨损 ,残余压应力可适当减缓陶瓷零件的磨损 ,其数值变化对零件性能的影响很小。随着残余压应力值的增加 ,表面硬度值也在逐渐增加 ,当残余压应力增加到一定值后表面硬度值开始下降。     

应用数值模拟技术研究摩擦对板料拉深成形的影响

本文论述了摩擦对板料成形的特点和重要性,应用数值模拟技术研究摩擦对板料拉深成形的影响。结果表明：模拟某复杂零件成形性能与摩擦系数关系密切;当摩擦系数为μ3时,冲压方向最大应力最小。研究结果表明采用数值模拟技术便于研究摩擦与板料冲压成形之间的相互关系。     

On the shear stress of elastohydrodynamic lubrication in elliptical contacts

Results of mathematical modelling of elastohydrodynamic lubrication of rolling contacts are presented. Effects of dimensionless parameters such as speed, normal load, elliptical parameters and coefficient of limiting shear stress on shear stress distributions have been studied. Moreover, profiles on hydrodynamic pressure and film thickness in EHD contacts have been studied. It has been found that shear stress profiles on two contact surfaces in entraining direction are similar with each other in some way. Shear stresses of fluid film on contact surfaces vary with many factors, which reveals the mechanism of traction in elastohydrodynamically lubricated contacts.     

Implementation of Hertz theory and validation of a finite element model for stress analysis of gear drives with localized bearing contact

An analytical approach for stress analysis of gear drives with localized bearing contact based on the Hertz theory is proposed. The proposed approach provides a complete and effective solution of the contact problem but satisfaction of the hypotheses for application of the Hertz theory is its main drawback. On the other hand, a finite element model has been developed and validated in terms of the contact area, maximum contact pressure, pressure distribution, maximum Tresca stress, and Tresca stress distribution underneath the contacting surfaces. Validation of the finite element model is provided for those cases wherein the Hertz theory can be applied. The obtained results confirm the applicability of the proposed approach for gear drives with localized bearing contact wherein edge contact is avoided by surface modifications and whole crowning of tooth surfaces is provided.     

Effect of peak radius on design of W-type donut shaped laser textured surfaces

Friction/stiction behavior of ultra high density magnetic disk drives can be controlled by controlling the size and shape of the laser bumps using a laser texturing tool. Different laser bump parameters like rim radius, rim height, peak radius and number of bumps (under the slider) play an important role in the design of laser textured disk surfaces. In the present study, an algorithm is developed for generation of W-type laser bumps on the computer. W-type laser surfaces with a Gaussian height distribution have been generated and contact analyses of these surfaces have been carried out. Design curves have been generated to calculate critical number of asperities required to minimize wear and stiction. Effect of the coefficient of friction on the number of bumps has also been studied.     

大功率电力机车牵引扭矩过盈接触分析及可靠性寿命校验

新型大功率电力机车牵引电动机采用过盈配合传递牵引扭矩。为验证设计可靠性,首先计算完全理想状态下该过盈配合的接触状态,然后利用非线性有限元手段对过盈装配应力进行数值仿真。比较两种方法的计算结果之后,又对过盈装配进行疲劳寿命预测。结果验证了这种新型传力方式的可靠性。     

Recent research on tribology in Japan

Recent research on tribology in Japan is outlined. There have been many papers on the following problems.

In fluid film lubrication, the effects of surface irregularities on the lubricating performance and increase in friction in high speed bearings due to turbulent flow are highlighted to date. Elastohydrodynamic lubrication and its related problems such as traction play an important role in the lubrication of cams and followers, rolling contact bearings and traction drives. The rheology of lubricants at high pressures is one of the most important properties governing lubricated concentrated contacts. Regarding basic studies on wear, the mechanism of the adhesive wear process is being studied. It is interesting to investigate the deformation behaviours of materials and structures by finite element methods. The friction and wear characteristics of plastics and their composites have been studied in basic terms.

The chemical reactions of lubricating oil additives with frictional surfaces play important roles in lubricated concentrated contacts. Recently there have been many studies on the correlation between the lubricating properties and the chemical reactivity of lubricant additives. It is very interesting that there are many papers on the mutual effects between lubricant additives.     

The nature of the logarithmic traction gradient

Great significance has been attached to the logarithmic traction gradient in elastohydrodynamic lubrication. It has been used to justify the assumption of logarithmic constitutive behavior.We have calculated viscous traction curves from the viscous shear response that is observable by simulation or experiment out of contact. This response includes Newtonian, shear-thinning of the ordinary power-law type, and rate independent behavior. The calculated traction curves can be reasonably described by a sinh law using fictitious viscosity and Newtonian limit. These system model parameters behave as expected from cases where the same system model was applied to measured traction.We conclude that for point contact, the logarithmic gradient results from rate-independent (limiting stress) behavior combined with greater than exponential pressure-viscosity behavior. Shear-thinning has little effect on this gradient in point contact. On the other hand for line contact, shear-thinning of the ordinary type (Carreau) is essential for the appearance of a logarithmic gradient.     

Mapping Shear Stress in Elastohydrodynamic Contacts

A new method has been, devised for investigating the theological properties of lubricant films in two-dimensional EHD contacts. A lubricated, sliding contact is produced between a sapphire flat and a steel ball. Thermal infrared emission microscopy is then employed to obtain 2-D maps of the variation of temperature rise due to friction across the contact. These maps are then used in conjunction with moving heal source theory to produce maps of energy dissipation and thus shear strength, of the lubricant film across the contact.

A series of mixtures of two lubricants, one giving high traction and one with low traction, have been studied using this technique to investigate the influence of lubricant, blending on shear stress and traction.     

Contact Stiffness of Machine Components and the Influence of the Microgeometry of the Contact Surfaces on It

The use of characteristics of the contact stiffness in the scientific literature to describe a discrete contact between machine components under normal and tangential loading has been analyzed. The application of a model of the discrete contact of rough surfaces, as well as the influence of the parameters of the contact surface microgeometry on the contact stiffness under normal and tangential loadings and shear has been studied.     

Rolling contact fatigue of case-hardened chromium steel

The rolling contact fatigue of case-hardened steel surfaces in lubricated heavily loaded contact was studied. Three different case-hardening treatments were tested with a ratio of slide to roll of ?5%. Other ratios of slide to roll were used to determine the effect of tangential traction on the rolling contact fatigue endurance. When the actual contact width was measured after testing, the scatter of the fatigue results was reduced. The depth of the maximum plastic strain was determined by measuring the hardness before and after testing and was found to correspond to the occurrence of the lowest ratio of the critical shear stress to the amplitude of the load-induced orthogonal shear stress. The role of residual stresses in rolling contact fatigue is discussed. It was found that a more detailed knowledge of lubricant behaviour in heavily loaded contacts is needed to reveal the true distribution of tangential traction on the contact surface. This affects the angle of the plane and the value of the maximum amplitude of the shear stress beneath the contact zone.     

Contact Problems for Rolling with Slip for Viscoelastic Solids

The three-dimensional contact problem for rolling of a rigid sphere over a base, which consists of viscoelastic layer bonded to a rigid half-space has been considered. The thin viscoelastic layer simulates the action of a friction modifier. The Kelvin model has been used to describe the layer properties. The method of calculating the distribution of normal and shear stresses within the contact interaction area has been presented, the boundaries of traction have been determined, and the slip subareas have been studied. In addition, the influence of the viscoelastic layer properties on the distributions of contact stresses has been analyzed.