工况条件对微型汽车离合器摩擦副摩擦因数的影响

分析了影响摩擦因数的因素,设计了一套试验方案,在高温摩擦磨损试验机上研究了工况条件对微型汽车离合器摩擦副摩擦因数的影响规律.结果表明:微型汽车离合器摩擦副的摩擦因数随工作载荷和滑动速度的增加先减小,然后逐渐趋于稳定;随着温度的上升,摩擦副的摩擦因数先下降,当温度上升到摩擦片的软化温度时,摩擦因数开始回升,当温度继续上升到摩擦片的分解温度时,摩擦因数又开始下降.     

经济型汽车干摩擦式离合器的磨损及影响因素

磨损是经济型汽车干摩擦离合器损坏的主要原因.通过分析经济型汽车干摩擦式离合器在滑动摩擦条件下磨损的基本类型及其影响因素,得出磨粒磨损、粘着磨损和疲劳磨损是其磨损的基本类型,摩擦材料、温度和滑动速度是磨损的主要影响因素;通过分析经济型汽车干摩擦离合器磨损过程三个阶段的磨损类型和磨损量,得出缩短磨合磨损阶段、延长稳定磨损阶段和推迟剧烈磨损阶段可以提高离合器的使用寿命;通过摩擦学性能试验和耐磨损性试验,得出提高离合器摩擦副的材料性能、降低离合器摩擦副的表面粗糙度和改善离合器工作条件(温度、滑动速度和工作载荷)等措施,有助于增强干摩擦式离合器的摩擦性能和耐磨性,从而降低经济型汽车干摩擦式离合器的磨损.     

销盘试验中影响超高分子量聚乙烯摩擦学性能的主要因素分析

分析了销盘试验中影响超高分子量聚乙烯(UHMWPE)摩擦学性能的主要因素。结果表明，选取适当的填料种类、尺寸和质量(体积)分数能有效地改善UHMWPE的摩擦磨损性能；相对滑动速度、载荷、磨损时间、温度、摩擦磨损环境和摩擦副等对样品的摩擦学性能有着不同程度的影响。     

滑动速度对缸套-活塞环摩擦副磨合性能的影响研究

为了研究滑动速度对缸套-活塞环摩擦副磨合性能的影响,在磨损试验机上进行了不同滑动速度下的缸套-活塞环摩擦副磨合磨损试验,通过摩擦因数和磨损表面分析了滑动速度对缸套-活塞环摩擦副磨合性能的影响。结果表明,随着滑动速度的增加,缸套-活塞环摩擦副达到磨合的时间越短,但磨合后的表面越粗糙。因此,为了缩短磨合时间,保证磨合质量,应选择合适的滑动速度。     

湿式摩擦副滑摩过程温度场分析及实验验证

湿式摩擦副滑摩过程温度场与应力场相互耦合作用,温度场分布受到多种因素影响,其中压力、旋转速度、润滑流量作为湿式摩擦副工作参数对其温度场的影响尤为显著。在理论分析基础上,采用有限元数值模拟分析与实验研究相结合的方法,对摩擦界面温度场时空分布特性进行研究,同时研究界面温度场在摩擦副工作压力、相对转速和润滑流量作用下的变化规律。研究表明:在对偶钢片和摩擦片近外径侧更易出现高温和应力集中区,且对偶钢片相对于摩擦片更易出现温度和应力分布不均匀情况;温度场中高温集中区与应力场中应力集中区相对应,最大温度随着压力增加、相对转速增大、润滑流量减少而显著上升,该结果得到试验结果的验证。     

碳化硼增强铝基复合材料的摩擦磨损性能

为了比较两种含量不同的碳化硼颗粒增强铝基复合材料的摩擦学性能,将其加工成销试样,在多功能摩擦磨损试验机上分别与钢盘试样进行对比摩擦磨损试验,重点研究了接触载荷和相对滑动速度对两种复合材料摩擦磨损性能的影响.结果表明:碳化硼增强铝基复合材料的磨损量随载荷与相对滑动速度的增大而增大,而摩擦因数随载荷与相对滑动速度的增大而减小,较高碳化硼含量的复合材料的耐磨性能比较低含量的复合材料好.     

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.     

航空舵机离合器摩擦片滑动性能的研究

本文介绍粉冶法制取飞机自动驾驶仪舵机离合用的Cu-77-1型摩擦片,探讨了材料组元的温度特性、制取工艺和粉末粒度对制品性能的影响,测试了各有关性能,进行了装舵机试验,证实该法制取的摩擦片滑动性能良好,综合性能能满足舵机使用要求。     

旋转滑动摩擦高频噪声产生机理的实验研究

为了深入研究金属旋转滑动摩擦高频噪声的产生机理,以多功能摩擦磨损试验机为平台,采用单因素实验法来研究相对滑动速度、接触压力、表面形貌等影响因素对摩擦高频噪声的影响规律。实验发现：金属旋转滑动高频摩擦噪声多发生在相对滑动速度低、接触压力较大以及摩擦因数-速度负斜率处;摩擦副间相对滑动速度、接触压力和表面粗糙度的变化几乎不会对高频噪声的频率产生影响,但高频噪声声压级随表面粗糙度的增大呈现明显减小趋势。对摩擦噪声声压信号和法向、切向振动加速度信号进行互相关分析,结果表明,法向振动加速度信号和摩擦噪声声压信号之间具有更高的相关性,从而为进一步理解摩擦高频噪声的产生机理和预测模型的建立提供了参考。     

聚酰亚胺材料自润滑性能研究进展

聚酰亚胺(PI)作为一类优异的自润滑材料近年受到广泛关注.PI的摩擦性能与诸多因素有关,其磨擦因数一摩擦时间(μ-t)曲线一般存在咬合和稳定阶段;不同温度下的摩擦性能与PI分子链的运动有关;不同滑动速度下,PI的摩擦性能取决于摩擦热与载荷;不同载荷下,PI摩擦性能与滑动速度和机械过载有关;纯PI在低湿度下具有更好的自润滑性能;摩擦副对摩擦性能的影响体现在界面粘结力和转移膜形成的难易;适当剂量的离子注入可以制备μ值很低的PI材料;运用材料复合能够有效进行材料增强和润滑改性.     

SiCp增强铝基复合材料与Kevlar增强摩擦材料摩擦副摩擦磨损机理研究

采用盘销式摩擦磨损试验机，对SiCp含量为20vol％的铝基复合材料和Kevlar增强摩擦材料组成的摩擦副在于摩擦条件下的摩擦磨损机理进行了实验研究。结果表明：摩擦副在跑合过程中，铝基复合材料中的SiCp颗粒对较软的有机复合材料产生犁削和微观切削效应，磨损机理为铝基复合材料的硬质颗粒对较软的有机复合材料的磨粒磨损；在跑合后的磨损试验中，摩擦材料磨损表面呈现出粘着磨损和塑性变形特征，随着转动速度的增加，塑性流动加剧；摩擦副接触表面发生材料的相互转移，并在铝基复合材料表面形成转移膜，且在较高速度下转移膜更易形成；在高速条件下，摩擦材料表面可见从铝基复合材料的铝合金基体中脱离的SiCp颗粒和熔融迹象；摩擦材料的磨损机理主要为磨粒磨损、粘着磨损和塑性变形。     

Geometrical Aspects of the Tribological Properties of Graphite Fiber Reinforced Polyimide Composites

A Latin-square statistical experimental test design was used to evaluate the effect of temperature, load, and sliding speed on the tribological properties of graphite fiber reinforced polyimide (GFRPI) composite specimens. Hemispherically tipped composite riders were slid against 440C HT stainless steel disks. Comparisons were made to previous studies in which hemispherically tipped 400C HT stainless steel riders were slid against GFRPI composite disks and to studies in which GFRPI was used as a liner in plain spherical bearings. The results indicate that sliding surface geometry is especially important, in that different geometrics can give completely different friction and wear results. Load, temperature, and sliding distance were found to influence the friction and wear results but sliding speed was found to have little effect. Experiments on GFRPI riders with 10 weight percent additions of graphite fluoride showed that this addition had no effect on friction and wear.     

PEEK450 FC30与SiC陶瓷在海水润滑下的摩擦磨损特性研究

碳纤维增强聚醚醚酮PEEK450 FC30与工程陶瓷SiC软硬组合作为海水柱塞泵关键摩擦副备选材料,利用MCF 10摩擦磨损试验机对其在海水润滑下的摩擦磨损特性进行试验研究,探讨接触压力、滑动转速对材料磨损率和摩擦系数的影响规律。试验结果表明：在一定范围内的滑动速度、接触压力下,该摩擦副呈现出较小的磨损率和摩擦系数。当滑动速度在0.5~1.5 m/s之间,接触压力为1.33 MPa时,磨损率最小。通过扫描电子显微镜观察摩擦副磨损表层发现,在海水润滑下,SiC磨损并不明显,而PEEK450 FC30的磨损主要是以塑性涂抹为特征的粘着和SiC表面粗糙峰引起的机械犁耕。研究结果对水液压元件的选材具有十分重要的指导作用。     

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...     

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.     

Friction and wear of highly stressed thermoplastic bearings under dry sliding conditions

The friction and wear behavior of sliding bearings made from high temperature thermoplastics was investigated to determine the possibility of dry sliding applications. A test apparatus for plain bearing testing was designed and built to enable load, speed, and temperature to be controlled and temperature, friction and wear to be continuously monitored.Bulk material bearings (polyaryletherketone-based composites and neat polybenzimidazole) and metal-thermoplastic compound bearings with a sliding layer of polyetheretherketone were investigated. Their suitability for dry sliding bearing applications was assessed using the values of friction coefficient, wear rate and friction induced temperature.In general, the operating performance is mainly influenced by the operating conditions and the precise construction of the bearing. A fiber reinforcement of the thermoplastic matrix is necessary at high loads, whereas it is unnecessary at low loads. A further increase of the operational limits is made possible by improving the heat conduction from the contact area, as comparison with results of pin-on-disk investigations indicates. The materials tested provide operation of dry sliding bearings to temperatures over 200°C.     

Tribological Behavior of Particles and Fiber-Reinforced Hybrid Nanocomposites

This article discusses the mechanical performance of alumina nanoparticles and randomly distributed short glass/carbon fiber-reinforced hybrid composites through microhardness and wear test. The open mold casting method was adapted to prepare the test coupons. The wear and friction behavior of composites sliding against hardened ground EN 32 steel in a pin-on-disc configuration is evaluated on a wear and friction tester. The microhardness properties of the neat epoxy, alumina nanoparticles, and alumina nanoparticle–embedded glass/carbon fiber–reinforced hybrid composites were determined. The morphology of the worn composites was analyzed with a scanning electron microscope. It was found that the particles as fillers contributed significantly to improve the mechanical properties and wear resistance of the polymer composites. This is because the fillers contributed to enhance the bonding strength between the fiber and the epoxy resin. Moreover, the wear and friction resistance of the glass/carbon fiber composites was increased by increasing the filler weight in the composite materials.     

Tribological Behaviors of Carbon Fiber–Reinforced PEEK Sliding on Ion-Nitrided 2Cr13 Steel Lubricated with Tap Water

Selecting the proper material and surface treatment methods for elements is one of the essential problems when designing water hydraulic components due to the corrosiveness and poor lubricity of water. Experimental investigation was performed to study the tribological properties of ion-nitrided 2Cr13, a kind of martensitic stainless steel, sliding on carbon fiber–reinforced polyetheretherketone (CFRPEEK). The influence of factors such as sliding velocity, load, and lubrication condition were studied through experiments mainly under tap water lubrication. It was found that the friction coefficients are influenced by both the pressure and the sliding velocity. In contrast, the friction coefficients between quenched 2Cr13 and CFRPEEK are much higher. Compared to water lubrication, both the wear rate and friction coefficients increase in the case of dry friction. Wear mainly occurred on the CFRPEEK. By examining the worn surfaces of the specimens, it was found that adhesion was the main form of wear of the PEEK composite.     

钢纤维和莫来石纤维增强陶瓷基摩擦材料的性能研究

采用热压烧结法制备出钢纤维和莫来石纤维增强陶瓷基摩擦材料,对比分析钢纤维、钢纤维和莫来石纤维的混杂纤维以及莫来石纤维增强陶瓷基摩擦材料的机械性能和摩擦磨损特性。利用扫描电子显微镜(SEM)观察不同温度下的磨损表面和磨屑形貌,并研究其磨损机制。研究结果表明,钢纤维和莫来石陶瓷混杂纤维增强的陶瓷基摩擦材料具有较高的机械强度以及良好的摩擦稳定性和耐磨性能,以莫来石纤维增强的陶瓷基摩擦材料,摩擦因数表现出严重的热衰退,且具有低的耐磨损性能。SEM分析表明,在从低温到高温的摩擦过程中,钢纤维和莫来石陶瓷混杂纤维增强的陶瓷基摩擦材料的磨损形式主要由黏着磨损转化为黏着磨损与磨粒磨损的复合磨损形式,而以莫来石纤维增强的陶瓷基摩擦材料,其磨损形式以磨粒磨损为主。     

Dry sliding friction and casing wear behavior of PCD reinforced WC matrix composites

The friction and casing wear properties of PCD reinforced WC matrix composites were investigated using a cylinder-on-ring wear-testing machine against N80 casing steel counterface under dry sliding conditions. The results indicate that the friction and casing wear rate of PCD reinforced WC matrix composites are the lowest among the materials. As the applied load and sliding speed steadily increase, the friction coefficients of PCD reinforced WC matrix composites decrease. In addition, the casing wear rates increase with increasing load, but decline with sliding velocity. The dominant wear mechanism of the PCD composite is the micro-cutting wear, accompanied by adhesive wear.