共查询到20条相似文献,搜索用时 15 毫秒
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铁路列车用制动梁架在疲劳试验过程中未能达到规定的疲劳寿命。为此,采用化学分析、力学性能检测、金相检验和热处理工艺试验等方法进行了分析。结果表明,制动梁架端部正火组织不良和疲劳试验时受到非正常外力的作用是导致其过早断裂的原因。 相似文献
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LIUJian-xiu GAOHong-xia WEIXiu-lan 《材料热处理学报》2004,25(5):126-129
The experiment is conducted on MM-1000 friction test machine, which tests friction wear property of copper-based brake materials by powder metallurgy at different brake speeds. It shows that the coefficient of friction and wear volume are greatly influenced by brake speed. When the brake speed is 4000 r/min, which is a bit higher, the material still has a higher coefficient of friction with 0.47. When the brake speed is over 4000r/min. the coefftcient of friction decreased rapidly. When the brake speed is 300Of/rain, the material‘s wear is in its minimum. That is to say no matter how higher or lower the brake speed is the wear volume is bigger relatively. With the brake speed of the lower one it mainly refers to fatigue wear; while of higher one it mainly refers to ahradant and oxidation wear. 相似文献
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为了完成飞机刹车组件弹簧日趋繁重的检测任务,满足对刹车弹簧的高性能要求,设计了自动式机轮刹车组件弹簧试验系统.介绍了该试验系统的组成、液压比例加载系统的工作原理及其PLC控制方式.通过最新研制成功的自动式机轮刹车组件弹簧试验系统的试验与现场试用表明,系统的自动化程度及检测精度较高. 相似文献
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根据汽车制动鼓失效的各种现象分析制动鼓失效的原因和机理。从制动鼓设计和生产工艺两方面提出相应的改进措施,并着重就高w(C)量铸铁在制动鼓生产中的应用进行了详细的介绍。 相似文献
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闸片材料参数不仅关系到摩擦副的摩擦磨损性能,也是影响制动盘温度分布的一个重要因素。采用ADINA软件,建立列车制动盘和闸片的三维热机耦合有限元模型,在制动速度100 km/h、压力0.538 MPa和惯量23 kg·m2条件下,研究闸片材料热膨胀系数、弹性模量、热传导系数对制动盘温度和接触压力的影响。结果表明:当闸片热膨胀系数从0.5×10-5 K-1增大到2.5×10-5 K-1时,制动盘峰值温度升高8.4%,最大接触压力增大47%,闸片热膨胀系数的增大加剧接触压力分布不均匀程度而使制动盘温度变化明显;弹性模量增大9倍,接触压力的分布对弹性模量不敏感,弹性模量对盘面温度影响不明显。闸片热传导系数增大7倍,制动盘峰值温度下降4.3%,热传导系数增大,加快热量的扩散速度使制动盘峰值温度降低,该研究结论可为高速列车闸片材料的开发提供参考。 相似文献
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为了提高电动汽车电液盘式制动器扭矩跟踪精度,降低车辆行驶中能量消耗,采用模型预测控制方法,并对控制输出结果进行仿真验证。创建电动汽车电液盘式制动器模型,根据离散一阶模型推导出电机转矩方程式,利用积分离散化对车轮打滑动力学方程进行离散化,从而推导出车辆滑移率空间表达式。设计模型预测控制系统,利用积分作用增强控制系统的抗干扰能力,通过李雅普诺夫函数对控制系统的稳定性进行证明。采用MATLAB软件对电动汽车电液盘式制动器控制效果进行仿真,与级联PI控制效果进行对比。结果显示:采用级联PI控制,电液盘式制动器控制系统反应速度较慢,车轮转矩和滑移率跟踪误差较大,电量消耗较多;采用模型预测控制,电液盘式制动器控制系统反应速度较快,车轮转矩和滑移率跟踪误差较小,电量消耗较少。电动汽车电液盘式制动器采用模型预测控制系统,可以提高控制系统的输出精度,回收能量较多。 相似文献
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分析了压力机离合器制动器在单次操作规范一个完整工作周期内的能量转化情况,明确指出这一动作过程存在明显的能量浪费,并论述了在该过程中采用的节能途径的原理及可行性。建立了节能途径的最低能量计算公式,并预测该节能途径在国内大面积推广可获得的巨大效益。 相似文献
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对小型材上冷床制动过程进行了分析 ,并给出了制动过程中各个阶段制动距离的计算方法 ,为小型型钢轧机设计时选择工艺参数和电气控制参数提供了参考。 相似文献
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It is very important to study the corrosion behavior of composite brake materials for their design, manufacture, and application. In the study, one kind of composite brake material used in engineering machinery, two kinds used in automobiles, and gray cast iron HT200 were selected as tested materials. Their corrosion behavior in typical acid solution, alkali solution, salt solution, running water, and air were investigated. The results showed that some components of composite brake materials, such as iron matrix, steel fiber, and iron powder, were easily subject to corrosion in acid solution. Corrosive pitting, net‐like cracking, and breakage appeared at their corrosion surfaces, and in the solution of 3.5% NaCl, corrosive pitting took place and corrosion holes of 2–8 µm diameter formed at the corrosion surface of these components. But when brake materials were exposed to the solution of 5% NaOH, the organic binder was corroded seriously, nearly parallel cracks formed at the corrosion surface and some samples even became loose powders because the corrosion makes the binder lose its adhering function. In running water and air, the tested samples have an excellent corrosion resistance, and the composite brake material containing organic binder has a better corrosion resistance compared with other tested materials. The investigation has also indicated that the interface between ingredients easily corrodes. 相似文献
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针对无级变速汽车下长坡的行驶问题,提出利用发动机制动来控制汽车行驶车速。通过试验得出不同发动机转速下的制动力矩。在不同道路坡度和速比条件下,对发动机制动能力进行分析。在此基础上,设计PID控制器来进行下长坡车速控制。试验结果表明:坡度较小时,设计的控制系统能够实现对车速的控制,而且有一定的响应速度;坡度较大时,也可以起到辅助制动的作用。 相似文献
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Peter J. Blau 《Journal of Materials Engineering and Performance》2003,12(1):56-60
Automotive and truck brake shoe materials are complex composites of metals, ceramics, and polymers. These are designed to
provide stable, reliable frictional performance over a range of vehicle operating conditions, exhibit acceptable wear life,
and offer freedom from noise and sensible vibrations. During their use, friction brakes tend to form thin, third-body layers
on their contact surfaces. Such tribo-layers play a part in frictional characteristics, and therefore it is of interest to
study their structure and properties. This article describes the structure of the friction-induced layers that formed on commercially
manufactured brake shoes on a trailer that was subjected to 4 years of highway driving. The layers consist of a thin, brittle
crust of nanoscale particulate material that easily delaminates from the substrate. Polished cross sections were studied with
both optical and scanning electron microscopy (SEM). Transmission electron microscopy (TEM) of extracted flakes revealed the
complex, fine structure of the friction-induced layer. Realistic brake friction models should not use bulk properties of the
starting materials, but rather should incorporate the properties of the fine-grained friction layers. 相似文献
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铁道车辆用制动盘早期失效原因分析及超声检测 总被引:1,自引:0,他引:1
制动盘是客车走行部分的关键零件,分析了制动盘早期失效的原因,认为制动盘盘面距表面较近距离处存在缩孔是制动盘早期失效的主要原因,提出运用超声检测的方法检测制动盘内部缺陷是切实可行的。而选择合适探头是超声检测成功的关键。 相似文献