离合器摩擦片长期磨损规律研究

摩擦离合器是传动系统的重要构件,本文采用理论推导和计算机仿真相结合的方法,对摩擦片的宏观磨损规律进行了研究,得出了具有普遍意义的理论公式并提出了工程应用价值的计算方法。     

汽车制动摩擦片磨损可靠度估计

汽车制动摩擦片的台架磨损试验工况单一,通常被认为无法评估实车使用总寿命,而仅做磨损速率的要求.对实车数据进行了统计和分析,得出客户使用的离散性程度,同时结合台架恒定工况下的试验结果折算磨损量的里程期望,再用威布尔分布图估计得出摩擦片可靠度.通过对比一个车型,结果表明:该方法的台架估计与售后实车的估计误差仅为2.58％,...     

汽车制动器摩擦片早期磨损调查对策案例

介绍了一例汽车制动器摩擦片易磨损的调查对策过程。故障车辆为前盘后鼓式变比值制动力分配(带感载比例阀)的M1类车。过程涵盖系统分析、设计校核、三现调查及对策验证,为汽车制动器摩擦片早期磨损故障提供了较全面的调查思路。     

摩托车盘形制动器摩擦片材料磨损形貌分析

采用XDZ-A型摩擦材料制样机将有机石棉摩擦片材料制备成试验所需的标准试样,用X-DM型调压变速摩擦试验机模拟摩托车制动实际工况,对标准试样开展不同压力、滑动速度和温度下的组合试验.对扫描电子显微镜(SEM)观测到的有机石棉摩擦片材料与灰铸铁HT250摩擦盘对磨后的磨损形貌进行了分析.分析结果表明:无论是正压力、速度的增大还是温度的升高,都使得摩擦片磨损越来越严重,形貌越来越复杂.     

盘式制动摩擦片摩擦磨损特性的研究

进行了纤维增强合成摩擦片和现用合成摩擦片与QT450制动盘配副的制动摩擦试验,记录了制动过程中摩擦系数、磨损量与制动盘温度的变化情况,采用偏振光显微镜分析了磨损表面形貌.结果表明:纤维增强合成摩擦片的平均摩擦系数小于现用合成材料摩擦片,但摩擦系数稳定且耐磨性略高于现用合成材料摩擦片;在模拟制动工况下,纤维增强合成摩擦片比现用合成材料摩擦片所引起的制动盘温升略高;但都仍低于材料的热衰退温度。     

摩擦片直径与垂直度的自动检测装置

介绍了汽车鼓式制顺摩擦片直径与垂直度的自动检测装置,并重点分析了检测原理和微机系统的软硬件设计。该装置除上下料以外,全部实现了自动化,完成一只工件的检测公需４５ｓ,重复精度达到０．０２ｍｍ,满足了检测工艺的要求。     

A320飞机刹车组件碳刹车片磨损与预防

阐述A320飞机刹车组件碳刹车片磨损的机理及产生的原因，给出相应的排除方法，并从原理上对其可靠性进行说明。     

湿式换档离合器摩擦片摩擦磨损特性试验研究

介绍了综合传动湿式换档离合器工作原理,基于离合器摩擦片的结构与材料成分特征,分析了转速、裁荷和温度对摩擦片摩擦特性的影响;通过搭建的离合器摩擦片摩擦磨损试验台,验证了摩擦片摩擦因数随滑磨转速增大而减小,随结合油压升高而降低的规律;通过温度测试发现了结合过程中摩擦片中部温度较高,内外边缘处温度较低,多次结合试验后内齿摩擦片中部靠外部分磨损比较严重.     

某刹车装置刹车间隙不足故障的排除

采用弹簧套式组合活塞、碳/陶刹车盘的某型刹车装置某批次交付试验时,出现部分产品刹车间隙不足故障,经故障排查与分析,发现故障是由刹车装置轴向挠度导致活塞调隙后出现附加行程引起的。通过增加试验时工艺垫片厚度排除了刹车装置刹车间隙不足故障,而从产品结构计算上,将活塞组件的螺盖返退至与活塞端面齐平也可以起到同样效果。刹车装置的装配间隙一般大于验收间隙,对于刚性较差的刹车装置,使用超过产品工作压力进行功能性检查或试验时,应在活塞下放入不小于刹车装置轴向挠度的钢质工艺垫片,无法预知变形大小时,允许将刹车间隙塞实。     

Tribological Properties of Potassium Titanate in the Brake Friction Material; Morphological Effects

The tribological characteristics of brake friction materials containing different shapes of potassium titanate were investigated. They contain typical ingredients of a non-asbestos organic based friction material, including potassium titanate in the shapes of whiskers, platelets, and splinters. A Krauss type friction tester is used to obtain thermal stability and wear resistance of the friction materials at elevated temperatures. The results showed that the morphology of potassium titanate plays an important role in the formation of contact plateaus and transfer films on the rubbing surfaces, which are closely associated with tribological properties. The friction material with splinter shape potassium titanate shows better friction stability and improved wear resistance compared to those containing other types of potassium titanate due to larger contact plateaus and stable friction films at the sliding interface. On the other hand, the transfer films produced by the friction materials with platelet or whisker potassium titanate are not sustainable at elevated temperatures since they are easily detached during sliding, resulting in poor wear resistance.     

列车制动闸瓦磨损与制动材料分析

从列车制动闸瓦的工作条件和磨损失效的分析出发,详细讨论了铸铁、合成材料、粉末冶金材料、复合材料等4大类摩擦制动材料的基本特性和应用范围,指出列车运行速度和运行环境是选择闸瓦材料时应考虑的两大主要因素。     

Wear mechanisms of the C/SiC brake materials

The C/SiC brake materials were fabricated by chemical vapor infiltration combined with liquid melt infiltration. The wear mechanisms of C/SiC brake materials were investigated. The main wear mechanisms were grain-abrasion, oxidation-abrasion, fatigue wear, and adhesive wear. These wear mechanisms always occurred simultaneously , and showed mutual enhancing effects between them. Grain-abrasion mainly was the result of hard SiC grain action. Adhesive wear could cause high wear rates and a large unstable friction coefficient. Si was the significant factor on the adhesive wear, so Si in the C/SiC brake materials must be removed.     

Effects of Ceramic Fiber on the Friction Performance of Automotive Brake Lining Materials

Friction material containing aluminum-silicon fiber was prepared. The effects of the aluminum-silicon fiber content on fade, recovery, and wear properties of the friction material were studied using a friction tester with a constant speed. Morphologies of the wear surfaces were observed by scanning electron microscopy (SEM). It was found that the heat fading resistance property of friction material was clearly improved when the content of aluminum-silicon wool was more than 5 wt.%, but the property of recovery declined and the wear rate increased slightly at the same time. The wear mechanisms were adhesive and abrasive, caused by the zircon sand, for the semi-metal friction material, while the abrasive wear of hybrid fiber reinforced composites was caused by cracked ceramic fibers and zircon sand.     

基于分形理论的磨粒磨损模型

本文在M-B接触分形模型的基础上,根据塑变磨损理论导出了基于分形参数的磨粒磨损模型,建立了磨损率与分形维数之间的关系,综合反映了材料的磨损规律和表面特性。根据该模型可知,当分形维数在某一范围时,磨损率随分形维数的减小而迅速增大;而在另一范围时,磨损率随分形维数的增大而增大;当分形维数等于1.5时,磨损率达到最小值。当分形维数一定时,磨损率随尺度系数、磨损概率常数的增大而增大,随材料性能参数的增大而减小;当其余各影响参数保持一定值时,磨损率随接触面积的增大而增大。     

混合型轴承摩擦机理的研究

采用Timken摩擦试验机在空气中,水、润滑油及合成油脂润滑状态下对M50钢、热静等压氮化硅陶瓷轴承元件的摩擦机理进行了研究.对各种参数包括速度、滑动距离和润滑剂进行了比较.     

Comparison of Three Laboratory Tests to Quantify Mild Wear Rate

Because the viscosities of engine and transmission lubricants are lowered in order to reduce hydrodynamic friction and thus energy consumption, it is important to ensure that wear rates do not increase and thus machine durability is not impaired. In practical terms this means that we require reliable methods for measuring the mild wear rates present in most lubricated machine components.

This article compares three mild wear reciprocating laboratory tests, one based on the high-frequency reciprocating rig (HFRR) and two on the mini-traction machine (MTM), in order to explore the extent to which wear rate is determined by the test configuration. The results show that some additive-containing lubricants including blends of antiwear additive and dispersant give quite consistent wear rates, independent of whether the surface is in continuous or intermittent contact, whereas others such as two friction modifiers do not. Possible reasons for these differences are discussed. The importance of accounting for wear during running-in and the need to remove any thick tribofilms present before quantifying wear volume are also confirmed.     

WC—NiP合金密封材料的摩擦磨损特性

本文对研究开发的一种机械密封新型摩擦副材料ＷＣ－ＮｉＰ合金的摩擦磨损特性进行了研究。考察了在水润滑条件下ＷＣ－ＮｉＰ／石墨配对的摩擦性能,以及在３％ＮａＣＬ和１０％ＨＣｌ溶液中的腐蚀磨损性能。并与ＷＣ－Ｃｏ合金作了对比。结果表明：在水及３％ＮａＣｌ溶液中两种ＷＣ材料有相近的摩擦磨损特性,而在１０％ＨＣｌ溶液中ＷＣ－ＮｉＰ合金的腐蚀磨损性能则远优于ＷＣ－Ｃｏ。     

Advanced Friction–Wear Behavior of Organic Brake Pads Using a Newly Developed System

The objective of this study was to investigate the influence of an advanced performance system on the tribological behavior of brake pad material using a specially designed brake pad tester system following standard SAE J-661. The tribological behavior and friction and wear characteristics of the organic brake pad samples were evaluated. During braking tests, the samples, in contact with a cast iron disk, were studied at different disc speeds, temperatures, and braking cycles under a constant pressure. In order to understand the friction and wear behavior, the unworn surfaces, worn surfaces, and wear debris were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). Furthermore, the surface characteristics and differences in the wear modes of the brake pad samples were examined. Wear debris was permitted to deform the brake pad surfaces, leading to friction layers and enabling the estimation of the friction behavior of the brake pads. The results showed that the best friction–wear behavior was obtained with lower braking cycles at low speeds and temperature. Thus, the newly developed brake pad tester system proved very effective in evaluating the performance of the brake pad samples.     

液压制动管路整车布置设计

制动管路整车布置设计是汽车制动管路设计开发过程中关键环节.结合液压制动管路整车布置方案,介绍了液压制动管路(包括制动硬管和软管)的整车布置设计要求,并分析了制动管路布置设计对制动系统的影响,有利于指导制动管路的设计开发.