摩擦制动噪声防治研究进展

回顾了汽车摩擦制动噪声抑制和防治的理论研究与工程措施，分析和评述了目前的制动噪声研究现状与进展，提出了发展新型摩擦制动材料,结合系统动力学和摩擦学特点从根源上抑制或消除摩擦噪声的思路。     

水润滑引起摩擦噪声的机制及实验研究

水润滑摩擦噪声是一种较为常见的现象,会影响产品性能和环境舒适性.分析水润滑引起的摩擦因数一速度特性与摩擦振动系统稳定性的关系,对橡胶块与玻璃片的水润滑摩擦噪声进行实验研究.结果表明:水润滑引起的摩擦特性对系统具有负阻尼作用,当系统等效阻尼为负时,系统失稳,形成摩擦自激振动,是产生水润滑摩擦噪声的根源;摩擦元件的固有频率决定摩擦噪声频率,不同的支撑方式会改变系统模态频率,从而影响摩擦噪声频率.     

摩擦磨损机理现代概念及磨损计算探讨

本阐述材料摩擦磨损机理的现代概念，认为由于摩擦时进行的物理，物理化学和机械过程的综合结果，使摩擦表面磨合过程的作用导致二次组织的产生，二次组织的特征和性能对摩擦副的耐磨性有着决定性的影响。根据现代概念建立的零件磨损率一般公式及其简化公式与根据粘着理论模型建立的Archard公式比较，指出了过去的理论与计算的弊端。     

基于盘-销系统的摩擦尖叫条件下的动态时滞摩擦特性分析

为研究摩擦副间摩擦特性,建立盘-销模型台架试验系统,采用三向力传感器在发生和不发生摩擦尖叫条件下测量摩擦接触作用力,并利用小波分解方法将摩擦接触力分解为准静态分量和动态分量;在此基础上提出摩擦因数传递函数的概念,进行传统摩擦因数和新摩擦因数传递函数的计算与分析.对比分析发现:在系统发生摩擦振动或者噪声的条件下,采用摩擦因数传递函数评价摩擦特性更加合理.研究结论有助于深化摩擦因数特性的认识以及摩擦振动和噪声发生机理的研究.     

机械设备润滑工作浅析

摩擦是能量流失的主要根源，磨损是造成材料消耗的主要原因，润滑则是控制两者的主要手段。笔者阐述了机械设备润滑的方法，润滑材料的选择及润滑油的回收与再生，对实际操作具有一定的指导作用。     

微机械电子系统中的摩擦磨损及研究方向

介绍了微机械电子系统的概念,分析了微机电系统的摩擦磨损机理。结合近年来研究成果,根据微机电与传统机械摩擦磨损的不同,总结出了微机械电子系统摩擦磨损设计中的研究方向。     

摩擦焊技术的研究

本项研究包括了当前推动磨擦焊技术进一步发展和应用的三方面内容。分别简介如下：1．摩擦焊接头焊后余热处理的研究摩擦焊接头韧性低。目前各国都是通过常规焊后热处理改善它的韧性，但也只能提高到（调质）母材韧性的一半左右。本项成果针对摩擦焊接过程同时存在相变与形变的特点，引入形变热处理概念，增强摩擦扭矩作用使接头形变区覆盖热影响区，并利用余热进行淬火，使接头得到相变与形变双重强韧化作用，实现了在不降低接头强度的前提下使其韧性接近或达到（调质）母材的韧性水平，同时消除了常规局部热处理时热处理热影响区边缘的强…     

微机电系统中微摩擦特性及控制研究

针对微机电系统设计中存在的微摩擦问题，论述了开展微观摩擦研究的意义和必要性。全面总结了微摩擦基本特性研究的进展，包括微观摩擦与宏观摩擦的对比，微观摩擦与表面形貌的相关性，以及粘滑现象等。提出了控制微摩擦特性的一些主要研究方向。     

液压和润滑系统的主动预防性维护

提出了“主动预防性维护”的概念，阐述了液压和润滑系统失效的根源，并提供了防止失效和延长元件寿命的方法。主动预防性维护是检测和校正导致机器失效的根源性异常工况的维护活动，可以大大延长系统和元件的使用寿命。     

普通导轨润滑机理探讨

本文在对导轨滑动表面润滑机理进行研究中，首次提出了微观表面动压润滑的概念，在此基础上深入探讨了导轨滑动表面的润滑机理，从而指出导轨滑动表面润滑状态不应是介于边界润滑与干摩擦之间，而应是介于边界润滑与动压润滑之间。     

基于修正黏性摩擦LuGre模型的比例多路阀摩擦补偿

为减小摩擦对比例多路阀性能的影响,提出基于修正黏性摩擦LuGre模型的比例多路阀摩擦特性分析、模型参数辨识以及摩擦补偿方法。通过实验测试间接得出摩擦数据,运用数据拟合方法辨识出修正黏性摩擦LuGre模型的静态和动态参数。基于辨识参数设计出修正黏性摩擦LuGre模型摩擦状态观测器,将观测器摩擦信号输出量反馈到控制模型输入端,减小摩擦对比例多路阀性能的不良影响。仿真结果表明,基于辨识参数的修正黏性摩擦LuGre模型摩擦补偿方法可提高比例多路阀的位置跟踪精度。     

离合器摩擦副表面温度对摩擦因数的影响

通过对某型离合器摩擦副的摩擦学小样试验,研究了离合器在结合的滑动摩擦过程中,摩擦面温度对离合器摩擦材料摩擦因数的影响.采用扫描电子显微镜(SEM),分析了样件的摩擦表面形貌,探讨了产生影响的机制,并从摩擦因数角度探讨了微车离合器起步发抖和烧蚀的主要原因.微车离合器摩擦材料摩擦因数随着摩擦面温度先升高,然后趋于稳定,最后再降低,其稳定工作的温度区间为130～220℃;在摩擦面温度较低的工况下,摩擦因数较低,微车起步时,离合器传递的扭矩不足以克服道路阻力,引起微车起步发抖的现象;而在摩擦面温度过高的工况下,离合过程中,摩擦因数较低,传递扭矩效率低,导致离合器滑磨时间过长,引起烧蚀现象.     

[成形过程仿真优化与集成计算材料工程]塑性加工摩擦定律的研究进展

塑性加工一般采用润滑油或固体润滑膜对工件进行润滑处理,干摩擦定律作为理解润滑条件下的摩擦行为的基础,可通过类金刚石镀膜镀层模具与板材进行侧拉摩擦试验和高面压摩擦试验来确定。对固体润滑膜下的摩擦定律进行了研究,最后基于干摩擦定律与侧拉摩擦试验,提出了油润滑条件下的摩擦定律。     

Experimental investigation of friction noise on lubricated contact

In order to remove friction noise, a lubricant is normally applied on the friction surface either after cleansing the contact surface or without any surface treatment. As the friction continues, the lubrication performance deteriorates and the friction noise can reoccur in the both cases, but the cause of friction noise may be different. This study originally investigates the mechanism of friction noise under a lubricant on either the clean or contaminated surface. During the friction noise test, the vibration and sound pressure, the changes in friction coefficient and the characteristics of the contact surfaces are measured for the two lubrication scenarios. Particularly, the surface image and chemical state on the contact area are measured by SEM/EDS analysis in sequence. The results show that friction noise under the lubrication on the clean surface is induced by the reduction of the lubricant causing the increase of friction coefficient. For the lubrication on the contaminated surface by wear debris, the lubricant is mixed and contaminated with wear debris, and then friction noise eventually occurs with the negative slope of the friction-velocity curve in the absence of the increase of friction coefficient.     

多组分纤维混杂增强树脂基摩擦材料研究

为提高摩擦材料高温下的摩擦磨损性能和摩擦因数的稳定性,利用正交试验法对多种纤维增强酚醛树脂基摩擦材料的配方进行优化设计,并通过极差分析,探讨多种纤维及含量对摩擦材料性能的影响及摩擦材料的磨损机制.研究表明:混杂纤维增强树脂基摩擦材料有着优异的耐磨性.陶瓷纤维硬度较高,开散混料后能够均匀分布在树脂基体内,对酚醛树脂基摩擦...     

Morphology and Toughness of Abrasive Particles and Their Effects on the Friction and Wear of Friction Materials: A Case Study with Zircon and Quartz

This study examined the friction and wear of brake friction materials containing two different abrasives: zircon and quartz. Commercial grade abrasives with two different sizes (fine and coarse) were compared in terms of the effects of the size, shape, and toughness of the abrasive particles on the friction and wear of the friction material and counter discs. The results showed that the morphology of the abrasives has a considerable effect on the friction effectiveness and wear of the friction couple. The level of friction was higher in the case of using quartz than zircon, and smaller particles were more effective in increasing the coefficient of friction. The toughness of the abrasives also played important roles in determining the friction effectiveness. Improved heat resistance at elevated temperatures was achieved when coarse zircon was used. The wear of the friction material was also dependent on the morphology and toughness of the abrasives and the large abrasive particles produced more wear on the gray iron disc.     

On friction layer formation in polymer matrix composite materials for brake applications

Due to the complexity of friction phenomena in polymer matrix composites, the friction mechanisms have not been fully understood. This paper concentrates on the characterization of friction layer formation and correlation of friction layer properties to the performance of a recently developed family of polymer matrix composites. It was demonstrated that character of the friction layer determines the friction performance of the investigated composite material. Structure and chemical composition of the friction layer generated on the friction surface significantly differs from the bulk. Mechano-chemical interaction occurring in the friction process is compared to a “non-friction” situation where an “equivalent” apparent temperature and compressive loading, respectively were applied to the same material. No simple relationship exists between composition of the friction layer and bulk material formulation. Phase stability and kinetics of interactions for “friction” and “equivalent non-friction” loading conditions significantly differ.     

基于销/盘试验机的摩擦噪声试验与仿真研究

为了研究摩擦噪声的产生机制和影响因素,利用销/盘试验机对以转子式压缩机曲轴-法兰材料制成的销/盘试样进行摩擦噪声试验研究;应用ABAQUS有限元软件,建立销/盘试验机有限元模型,利用复特征值分析方法预测该系统摩擦噪声的主频,并与试验结果进行对比;讨论相关参数对系统的稳定性和摩擦噪声的影响。结果表明：销与盘法向和横向振动的耦合是引起系统自激振动和摩擦噪声的重要因素;当系统摩擦界面处的摩擦因数大于系统临界摩擦因数时,系统开始出现不稳定振动,且摩擦因数越大,系统越不稳定,越易出现摩擦噪声;法向载荷对系统稳定性的影响不大;选择具有合适弹性模量的摩擦副材料可以抑制摩擦噪声的产生。     

Si_3N_4陶瓷旋转超声磨削加工的表面摩擦特性

为了探索结构陶瓷材料在摩擦过程中表面形貌的变化规律及其对摩擦特性影响,分析了摩擦过程中材料的接触过程及力学关系,并对旋转超声磨削加工的Si3N4陶瓷试样开展了摩擦表面形貌、摩擦因数等特性的试验研究。首先根据接触特点和材料特性,基于分形理论推导出接触面总载荷计算公式,基于该公式建立了结构陶瓷摩擦因数分形模型。分析结果表明:当初始表面轮廓分形维数分别为1.4,1.45,1.5和1.55时,摩擦因数与摩擦后表面轮廓分形维数呈类似正态分布曲线。然后通过旋转超声磨削加工的Si3N4陶瓷试样面面接触摩擦试验,研究了摩擦后陶瓷材料表面微观形貌和摩擦因数变化规律,分析了各因素对摩擦因数的影响。试验结果表明:产生微观裂纹是Si3N4陶瓷摩擦后表面微观形貌的显著特点;温度值等于160℃是Si3N4陶瓷摩擦因数由下降转为上升的拐点;当施加载荷为360N和往复频率为80Hz时,摩擦因数最大。得到的结果为通过表面形貌控制提高结构陶瓷耐磨性能提供了技术支撑。     

Effects of ZrSiO4 in non-metallic brake friction materials on friction performance

The effects of ZrSiO₄ (zirconium silicate or zircon) as an abrasive on brake friction performance and friction layers of non-metallic brake friction materials were evaluated. The experimental results indicated that ZrSiO₄ enhances friction coefficient, but depresses wear rate. However, ZrSiO₄ can improve the negative wear rate of the friction materials. The formation and development of friction layers are complex so that the friction layers formed during friction process were carefully characterized using scanning electron microscopy (SEM), light microscopy (LM), and X-ray diffraction (XRD) methods. Following characteristics of friction layers were identified—(1) dynamic behavior: the structure of friction layers changes at the different surfacial positions and across sample's thickness; (2) friction condition dependence: formation of friction layers depends upon temperatures, time, and thermal history such as fade and recovery; and (3) compositional dependence: the compositions of friction surface and bulk differ, nevertheless the bulk's composition determine the friction layers. The phenomena as baryte films, altered layers, iron patches, and zircon loose areas formed on the friction surfaces were observed. Baryte films were detected on the friction surfaces of Zr-0 (sample without zircon). Baryte films have positive effect on wear property, but the films disappear in the presence of ZrSiO₄. The amount of carbonaceous materials decreases with the increase in ZrSiO₄. Only negligible thickness of altered layers was found on the friction surfaces of Zr-0 sample, while samples containing zircon show out relatively thick altered layers. Both iron-patches and zircon loose areas increase with the ZrSiO₄ contents. The relationships among formulation, friction performance, and friction surfaces were summarized.