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为得到摩擦式制动器与非接触式轮边缓速器集成系统最佳的结构参数,采用优化设计方法,以提高汽车制动力矩为目标,分析摩擦式制动器与非接触式轮边缓速器的结构参数对制动力矩的影响规律.应用提出的集成系统结构参数分析方法,分析了不同结构参数方案,并且分别对安装集成系统的汽车和仅采用摩擦式制动器的汽车进行了仿真分析,结果表明:通过优化设计方法得到的结构方案使车辆制动时间缩短5.9 s,制动距离减小92.1 m. 相似文献
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介绍了转筒式车用电涡流缓速器的结构,提出了运用正交回归旋转设计来分析结构参数对制动力矩的影响程度,并且进行了试验验证。试验结果和分析为转筒式电涡流缓速器的优化设计打下了基础,为缓速器产品系列化设计提供了依据。 相似文献
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针对液力缓速器结构复杂、价格高,传统电涡流缓速器制动力矩热衰退严重等问题,提出一种液冷自励式电磁缓速器结构,建立其制动系统以及发电系统分析模型,分析了系统的磁路结构,利用有限元法分别对电磁场模型、制动特性以及温度场进行分析。设计了2 000 N·m样机并进行台架试验,对缓速器制动特性以及发电机特性进行测试,测试结果与有限元分析计算结果的误差在6%以内,在制动功率为180 k W时水道温度为85℃,持续制动时制动力矩热衰退仅为10.4%。在1 500 r/min时制动力矩达到最大值2 000 N·m,而汽车电源只需提供给发电机的励磁功率为720 W。 相似文献
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农用运输车、拖拉机的制动性能直接影响着车辆行驶的安全可靠性。而车辆制动性能的好坏 ,主要取决于制动器摩擦副产生的制动力矩和车轮对地面的附着条件。因此 ,车轮制动器的修理质量至关重要。下面以蹄式车轮制动器为例 ,分析影响车轮制动器修理质量的主要因素。一、摩擦衬片的摩擦系数摩擦系数是产生摩擦力的要素之一。影响它的因素主要有 :1.衬片材料 在更换摩擦片时 ,应选择厂家推荐使用的衬片 ,以保证原车的制动性能。同时应注意同一车辆各制动器必须使用同一厂牌的材料 ,它是保证各轮制动力均衡协调的重要因素。2 .摩擦衬片和制动鼓… 相似文献
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当今社会汽车已成为人们最主要的交通工具,为了保证驾车安全,现在汽车都普遍采用盘式制动器,而盘式制动器的工作性能是整个制动系中最复杂、最不稳定的因素。为提高制动系统的性能,采用优化设计建模、遗传学算法以制动减速度、制动力矩为优化目标进行优化设计。 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献