共查询到19条相似文献,搜索用时 109 毫秒
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树脂基体作为粘结剂,对NAO刹车片的各项性能有着很大的影响,酚醛树脂已经不能满足要求,必须对酚醛树脂进行物理或化学改性。通过分析酚醛树脂的分子结构特点,指出了酚醛树脂的改性途径和方向。全面介绍了近年来常用的几种化学和物理改性酚醛树脂方法,以及对刹车片摩擦材料性能的影响。 相似文献
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超深矿井提升机制动盘在紧急制动过程中由于受到摩擦循环热载荷的作用,内部产生较大的热应力,同时高温会导致制动盘和闸片摩擦制动性能下降甚至失效。针对制动盘制动热性能问题,根据热传导理论和有限元分析方法,建立了制动盘组件三维有限元模型,采取直接耦合方法对制动盘制动过程中的热应力场进行模拟研究,并通过实验验证了仿真参数设置的正确性。分析了闸片数量和排布方式对制动工况下制动盘温度和应力分布的影响。结果表明,在制动阶段,制动盘摩擦面温度先急剧上升,后缓慢下降,摩擦面温度呈现锯齿状波动性变化,制动过程中应力变化规律与温度变化规律相同。原制动盘在制动过程中的最高温度为134.8℃,最大应力为230.2 MPa,高温和大应力区域集中于摩擦面附近;增加闸片数量的制动盘最高温度为142.4℃,最大应力为251.1 MPa,高温和大应力区域同样集中于摩擦面附近;改变闸片排布方式的制动盘最高温度为86.5℃,最大应力为119.1 MPa,高温区域和大应力区域范围较小。由此可知,改变闸片排布方式更能显著降低制动盘温度和应力,并且温度场和应力场分布更均匀。研究结果可为制动盘热性能优化设计提供理论参考。 相似文献
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盘式制动器广泛应用于交通工具和工业装备,在制动过程中出现的摩擦振动噪声和制动盘与制动块之间的接触摩擦作用有密切关系。由于受到多种因素影响,建立准确的制动器关键零件接触关系仍是当前制动器振动噪声研究的难点。基于接触刚度能够影响系统刚度从而改变制动盘模态频率的动力学特性,针对乘用车浮钳盘式制动器,提出一种基于模态频率特征的制动器盘块间法向接触刚度辨识方法。应用锤击模态试验测得不同制动压力条件下制动盘各模态的频率特征;基于ABAQUS软件建立约束条件下制动盘与制动块装配体的有限元模型,在1~10 kHz范围内对该模型进行前7阶面外模态频率分析,辨识得到制动盘与制动块之间的法向接触刚度,并对接触刚度变化原因进行了分析。结果表明,随着制动压力的增加,由于制动块摩擦材料的孔隙度减小,接触刚度增大;随着制动盘模态阶次的提高,由于制动盘与制动块在谐振状态时其接触面积发生变化,接触刚度会先增大然后基本保持不变。该方法可用于建立准确的制动器盘块间接触关系,以开展制动器振动噪声仿真分析,能够提高计算精度,保证分析结果的可靠性。 相似文献
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G. P. Ostermeyer 《Forschung im Ingenieurwesen》2001,66(6):267-272
The contact area in brake systems shows characteristic structures. With respect to wear an equilibrium of flow of growing and destruction of hard patches is to be found on the contact surface. These patches modulate the friction coefficient of the brake system. The paper deals with this principal wear mechanism of brake pads which leads to a new type of differential equation of second order for the dynamic friction coefficient describing the stationary and transient friction behaviour of brake pads. Many known effects of friction in such systems are covered by the solutions of this new model. 相似文献
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This study improves brake noise by optimizing the manufacturing processes of brake discs and pads. Taguchi techniques and designed experiments were used for the optimization. The signal-to-noise ratios of the key output responses, such as runouts of brake discs and compressibility of brake pads, were maximized to optimize the mean and variation. Analysis of the variance was performed to obtain the influence percentage. Fine adjustment of the mean was performed using designed experiments and regression analysis. The improvement was verified by process capability analysis, control charts, and confidence intervals. 相似文献
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Successful brake caliper designs must be light and stiff, preventing excessive deformation and extended brake pedal travel. These conflicting requirements are difficult to optimize owing to complex caliper geometry, loading and interaction of individual brake components (pads, disc and caliper). The article studies a fixed, four-pot (piston) caliper, and describes in detail the computer-based topology optimization methodology applied to obtain two optimized designs. At first sight, relatively different designs (named ‘Z’ and ‘W’) were obtained by minor changes to the designable volume and boundary conditions. However, on closer inspection, the same main bridge design features could be recognized. Both designs offered considerable reduction of caliper mass, by 19% and 28%, respectively. Further finite element analyses conducted on one of the optimized designs (Z caliper) showed which individual bridge features and their combinations are the most important in maintaining caliper stiffness. 相似文献
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The aim is to study the effect of several distinct manufacturing processes, parameters and ingredients on the physical, mechanical and frictional characteristics of brake pad developed using hand lay method (sample 1), brake pad developed using hot compression method (sample 2) and commercial brake pad (sample 3). The non asbestos brake pad samples were compared with the selected commercial brake pad sample using pin on disc test set up. Results showed that friction performances of all three samples were insensitive to water and oil absorption test. Sample 2 had better mechanical properties and greater wear resistance than other two samples which are attributed to use of hot press method of manufacturing the composite and selecting the carbon-based ingredients. Sample 1 maintained high coefficient of friction even though manufactured with the help of hand lay method. Both fabricated brake pads are stable upto the temperature 220 °C without any weight loss and degradation. Brake pad surfaces showed different shape wear debris and plateaus significantly affecting the friction characteristics. Finally, the test results indicated that both fabricated brake pad samples have potential braking characteristics to be used as a brake pad material. 相似文献
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飞机刹车用长寿命高摩擦特性炭/炭复合材料制备技术(英文) 总被引:1,自引:0,他引:1
以针刺炭纤维准三向结构整体毡为预制体,经丙烯气体狭缝定向流的"外热内冷"、"内热外冷"径向热梯度CVI工艺致密技术,优化组合的热解炭/树脂炭双元炭基体技术,通过调控高温处理技术等三大关键技术制备了A320系列飞机炭刹车盘材料。与现用的A320系列飞机进口炭刹车盘进行了地面台架对比试验和装机应用。结果表明:自主开发的炭刹车盘其设计着陆能量和超载着陆能量的摩擦特性与国外相当,但在高能载(RTO)刹车时,其摩擦系数提高了21%~48%,静摩擦系数提高了28%;装机应用寿命平均达到2700次以上,比国外产品寿命提高了23%,凸现出长使用寿命和高摩擦特性的特色。 相似文献