碳纤维增强汽车摩擦材料的研究

利用D—MS摩擦试验机研究了碳纤维增强汽车库擦材料的摩擦磨损性能。结果表明：碳纤维含量对摩擦材料的摩擦磨损性能影响显著，摩擦材料的摩擦因数和磨损率都随碳纤维含量的增加而减小，碳纤维的质量分数不宜超过5％。SEM分析表明，其摩擦磨损机理亦与碳纤维含量密切相关。     

摩擦材料的研究现状

摩擦材料的质量直接影响着车辆和动力机械的速度，负荷以及安全性。文章概述了摩擦材料的发展历史，介绍了国内外摩擦材料的研究现状，指出无石棉摩擦材料是摩擦材料的发展方向，并简述了目前几种无石棉摩擦材料各自的优，缺点。     

汽车零件的摩擦机理研究

本文讨论了汽车零件的摩擦起因，重点介绍了摩擦的粘着理论和分子一机械理论，并对配合副的固体摩擦、流体摩擦、边界摩擦机理及影响因素进行了深入细致的研究。最后，通过Ｓｔｒｉｂｅｃｋ曲线给出了汽车零件各种摩擦状态之间的相互转化条件。     

机动车摩擦材料克劳斯摩擦试验机与惯性式制动台架试验机的比较

对德国克劳斯摩擦试验机与制动器惯性式台架试验机试验结果进行了对比分析，讨论了其配用试验程序间的关系和试验结果之可比性。用克劳斯摩擦试验机进行制动器实物试验，与其它摩擦试验机进行小试样测试相比，可免去尺寸模拟、几何形状模拟等环节，故能较好地模拟摩擦材料的使用条件。     

制动器摩擦副摩擦因数研究

以某EQ1208型车辆后桥鼓式制动器为例.对其三维热机耦合有限元模型进行了等速持续制动工况仿真.仿真结果与试验结果对比表明,仿真值和试验值在相同温度测量点的温升动态变化趋势相同,从而验证了仿真所利用摩擦因数温度特性的准确性.对该后桥鼓式制动器在连续15次循环制动工况下摩擦表面平均温度、摩擦副摩擦因数及制动管路压力的动态变化进行了计算分析.     

摩擦材料摩擦特性对轿车前,后制动力之比的影响

本研究了摩擦材料摩擦特性对轿车（盘式），后（鼓式）制动器制动力之比的影响。根据对前，后制动器部总成大量的测功器试结果，计算并绘出前，后制动之比值随制动管路压力，车速，制动温度的变化关系曲线，并与设计作了对比分析，讨论了它对轿车制动稳定性的影响，为制动性能计算，制动器设计和制动衬片摩擦材料的选配提供依据和参考，从而保证了轿车的制动稳定性。     

搅拌摩擦焊接技术在汽车制造中的应用研究

搅拌摩擦焊接是固相连接技术，焊接过程中形成精细的锻造组织，具有较高的接头性能。在介绍搅拌摩擦焊技术的基础上，对该技术在汽车制造业中的应用进行了探讨。对搅拌摩擦点焊技术进行了介绍。由于搅拌摩擦点焊具有成本低、耗能少等优势，可完全替代传统点焊方法用于汽车制造。     

湿式摩擦材料摩擦学性能研究

湿式摩擦材料它具有良好的摩擦磨损性能，广泛应用在汽车，摩托车和各类机械相，根据影响摩擦材料主要参数其压力（Ｐ）、湿度（Ｔ）、线速度（Ｖ）和润滑油工作特性这一情况，采用ＭＭ－１０００型摩擦试验机对一批国内，外具有代表性的湿式摩擦材料性能进行了测试，根据湿式摩擦材料使用工况，对湿式摩擦材料进行模拟试验。     

片式摩擦离合器的模糊优化设计

为保证离合器具有良好的工作性能，要求作用在摩擦片上的正压力和摩擦因数在离合器使用过程中变化要小。在传统的摩擦离合器设计中，摩擦因数和正压力均为未知的待定量，即具有模糊性。对摩擦离合器的模糊优化，就是希望摩擦因数和正压力都尽量小些，这是一个没有明确边界的模糊目标。文中以此为目标建立离合器模糊优化设计的数学模型，使设计结果更接近于客观实际。     

汽车制动摩擦材料的研究

７０年代中期，世界各发达国家开始禁止汽车使用石棉摩擦片，因此使新型汽车摩擦材料被推向市场。分析了汽车半金属摩擦材料的配方设计时所要注意的问题，并着重分析了汽车制动摩擦材料的摩擦磨损机理，以有其解决的基本方法。     

汽车摩擦材料的变革与非石棉摩擦材料的发展

回顾了全球汽车摩擦材料的变革进程,分析了非石棉摩擦材料的特点、性能要求及其关键技术,简介了非石棉摩擦材料的类型、组分及制造工艺,展望了汽车非石棉摩擦材料的发展趋势。     

双向自增力式制动器摩擦模型的研究

为了科学准确地描述双向自增力式制动器的摩擦系数和速度温度等因素间的关系。综合考虑静摩擦到动摩擦非线性阶段,动摩擦速度稳态阶段以及动摩擦随温度变化阶段,建立了制动器制动过程的摩擦模型,并用仿真曲线与制动过程曲线对比,验证了摩擦模型。     

Kalker's algorithm Fastsim solves tangential contact problems with slip-dependent friction and friction anisotropy

This paper presents two extensions of Kalker's algorithm Fastsim of the simplified theory of rolling contact. The first extension is for solving tangential contact problems with the coefficient of friction depending on slip velocity. Two friction laws have been considered: with and without recuperation of the static friction. According to the tribological hypothesis for metallic bodies shear failure, the friction law without recuperation of static friction is more suitable for wheel and rail than the other one. Sample results present local quantities inside the contact area (division to slip and adhesion, traction) as well as global ones (creep forces as functions of creepages and rolling velocity). For the coefficient of friction diminishing with slip, the creep forces decay after reaching the maximum and they depend on the rolling velocity. The second extension is for solving tangential contact problems with friction anisotropy characterised by a convex set of the permissible tangential tractions. The effect of the anisotropy has been shown on examples of rolling without spin and in the presence of pure spin for the elliptical set. The friction anisotropy influences tangential tractions and creep forces. Sample results present local and global quantities. Both extensions have been described with the same language of formulation and they may be merged into one, joint algorithm.     

Dynamic model for the wheel–rail contact friction

Accurately estimating the coefficient of friction (CoF) is essential in modelling railroad dynamics, reducing maintenance costs, and increasing safety in rail operations. The typical assumption of a constant CoF is widely used in theoretical studies; however, it has been noticed that the CoF is not constant, but rather depends on various dynamic parameters and instantaneous conditions. In this paper, we present a newly developed three-dimensional nonlinear CoF model for the dry rail condition and test the CoF variation using this model with estimated dynamic parameters. The wheel–rail is modelled as a mass–spring–damper system to simulate the basic wheel–rail dynamics. Although relatively simple, this model is considered sufficient for the purpose of this study. Simulations are performed at a train speed of 20 m/s using rail roughness as an excitation source. The model captures the CoF extremes and illustrates its nonlinear behaviour and instantaneous dependence on several structural and dynamic parameters.     

低摩擦低排放的发动机

Gomecsys公司发布了下一代的发动机技术，在这种新型的设计中，偏心轮和齿轮围绕曲柄销与曲轴做相同方向的转动，在减小摩擦的同时，提升了系统的效率     

Piston friction force with EGR activated

The piston friction force increases in the latter half of the compression stroke where the EGR system is activated, while the force is decreased at each stroke center. This is due to the soot contained in the EGR gas. Although tho reduction of piston friction force at the stroke center reduces the piston friction loss, the increase of friction force in the latter half of compression stroke is caused by the friction coefficient, which becomes higher at this point. Hence it can be anticipated that wear on the piston rings and cylinders would increase accordingly. The change in piston friction force characteristics with the mixture of soot is quite an interesting phenomenon, and further studies on this phenomenon, are expected.     

电动汽车摩擦制动器的轻量化设计

本文主要对制动器的性能要求,在某一附着条件下所需的制动器制动力,在制动过程中的能量负荷及约束条件进行了描述,并运用遗传算法对摩擦制动器轻量化进行计算和设计     

A study on the friction characteristics and durability of band brakes

A band brake is often used as a braking device in an automatic transmission because it fits around the clutch drum and does not require additional space. Its friction characteristics vary depending on the oil film between the brake band and the drum. Less friction force occurs under lower pressure and greater lubrication. In this study, the relationship between friction performance and the number of grooves in a brake lining was investigated experimentally and analytically. It was found that a reduction in the friction area resulted in a higher brake lining surface temperature. This relationship is thought to affect the durability of friction materials.     

Modelling the effects of friction modifiers on rail corrugation in cornering

A proposed solution to the problem of rail corrugation on curves of urban lines is the use of friction modifiers. Recent experimental research indicates this approach can be effective. This paper makes use of two theoretical models to study the effects of friction modifiers on corrugation in cornering. The first one is a nonlinear time-domain model that predicts corrugation growth from a series of simulated passes of a bogie. The second one is a frequency domain model of wheel–rail interaction, linearised about a steady cornering state, estimated from the nonlinear model. Both models predict reduction of growth of corrugation due to the use of friction modifiers. Friction modifiers can alter the steady cornering state to one with somewhat lower creeps and much lower tractions. Major reductions in corrugation growth rate have been shown to occur if a wheel can be prevented from reaching a state of full sliding when subject to oscillating creeps caused by existing rail corrugation.     

Experimental investigation of the valvetrain friction in actual engine operation conditions

Recently, the demands for improved fuel economy have been continually rising because of environmental protection policies, legislative pressures on emissions and increases in the price of oil. Reducing the friction power loss in a production engine may be regarded as one of the most effective technologies for improving fuel economy because the technology is cost effective and applicable to a great number of vehicles. This paper describes attempts to measure the torque needed to drive a camshaft and to examine the sources of the torque fluctuations in order to analyze the friction in valvetrains. The measurements were performed through a cam sprocket-type torquemeter, which was able to measure the torque of the valvetrain under actual engine operating conditions. In the cam torque measured, the fluctuations were mainly dependent on the primary oscillations caused by cam events and the secondary oscillations caused by the valvetrain natural frequency. The range of the fluctuations became greater at high speed because of the inertial mass. The resulting FMEP (friction mean effective pressure) of the valvetrain decreased, and the effective peak tension increased with an increase in the engine speed.