轻型冷藏车车厢总成设计说明书[带图纸].doc

毕业设计（论文）报告纸共33页第1页装订线目录第一章绪论··························································31.1冷藏保温汽车的特点···············································31.2冷藏保温汽车的经济意义···········································41.3国内外冷藏保温汽车的发展过程和现状·······························41.3.1冷藏保温汽车的发展过程·······································41.3.2国外冷藏保温汽车的发展现状···································51.3.3我国冷藏保温汽车的发展现状···································61.4我国冷藏保温汽车的发展趋势·······································7第二章隔热车厢结构···············································102.1制冷装置························································102.2隔热车厢分类····················································122.3隔热车厢结构····················································132.3.1隔热车厢的结构型式··········································132.3.2隔热层材料及其厚度··········································142.3.3断热桥结构··················································152.3.4车厢蒙皮····················································152.3.5密封条······················································162.3.6车厢门及其附件··············································162.3.7车厢内外附件················································182.4车厢制作技术现状················································20第三章隔热车厢设计···············································213.1车厢主要结构型式和技术参数的确定································213.2车厢设计主要技术参数分析和计算··································223.2.1车厢隔热壁传热系数的计算····································223.2.2隔热车厢平均传热系数的计算··································253.2.3制冷设备热负荷的计算········································253.3制冷机组的选择··················································283.4车厢换气倍数的确定··············································283.5车厢重量的计算··················································29总结··································································30毕业设计（论文）报告纸共33页第2页装订线致谢··································································31主要参考文献·························································32摘要通过对隔热车厢结构及尺寸的分析比较，完成冷藏车车厢总成设计，其中包括车厢设计、车厢对开门设计及性能计算与校核。本设计的隔热车厢各部分之间的连接多采用粘接剂而非螺栓和铆钉等金属件，不仅减少了热桥，而且增加了平整度和美观度。隔热材料选用应用最广泛的聚氨酯泡沫，其导热系数较小且具有一定的抗拉抗弯强度，与钢板和胶合板的粘接力较强且密度低，减少了隔热壁厚度，在车厢外尺寸确定的情况下增大了车厢装载容积。车厢门及其附件尽量采用简单可靠的零部件和装配固定方法，确保密封性。根据计算确定的热工参数选用合适的制冷机组并合理完成各部分的安装与固定。本设计的车厢总成结构简单，性能良好，成本不高，高性能材料和先进技术的应用有效降低了车厢的自重，各参数均符合设计要求。关键词：冷藏保温汽车，隔热材料，制冷机组，传热系数ABSTRACTThispapercompletedtheassembledesignofthecompartmentoftherefrigeratedtruckincludingthecarriagedesign,theopendoordesign,theperformancecalculationandverificationthroughanalysisandcomparisonthestructureandthesizeoftheinsulatedcompartment.Inthisdesign,theconnectionbetweenthepartsmostlyuseadhesiveratherthanrivets,boltsandothermetalpieces,whichnotonlyreducedthethermalbridge,butalsoincreasesthelevelanddegreeofbeauty.Themostextensiveapplicationofpolyurethanefoamisselectedforinsulationmaterialwhichnotonlyhassmallcoefficientofthermalconductivity,butalsohascertaintensilestrengthandbendstrength.Thepolyurethanefoamhasexcellentadhesiveforcewiththearmorplateandtheplywood.Andthedensityislowwhichreducesthethicknessoftheinsulatedwall.Sowhenthecompartmenthasfixedexternalsizethestowagevolumeofthecompartmentisincreased.Thedooranditsaccessoriesasmuchaspossiblyuseasimpleandreliablepartsandassemblymethodtoensuretheseal.Weshouldchooseaappropriaterefrigerationunitaccordingtocalculatingtheparameteroftheheatengineeringandcompletetheinstallationandfixedofvariouspartsreasonably.Thisdesignofthecompartmentassemblehassimplestructure,goodperformance,lowcostandtheusageofhigh-performancematerialsandadvancedtechnologywhichreducethecompartmentsweight.Allparametersinthisdesignareinlinewiththedesignrequirements.毕业设计（论文）报告纸共33页第3页装订线KEYWORDS:refrigeratedandinsulatedcar,insulationmaterial,refrigerationunit,heattransfercoefficient毕业设计（论文）报告纸共33页第4页装订线第一章绪论1.1冷藏保温汽车的特点冷藏保温汽车是冷藏运输用的专用汽车，用来运输易腐货物和对温度有特定要求的货物，主要为食品。冷藏保温汽车是重要的公路冷藏运输工具。一般将冷藏保温汽车分为冷藏汽车和保温汽车。装有隔热车厢而未装有任何制冷或加热装置的称为保温汽车，既装有隔热车厢又装有制冷装置的称为冷藏汽车。有些冷藏汽车还装有加热装置，或者其所采用的机械式制冷装置设有加热循环系统，用来对车厢内加热，以便在外界环境温度低于货物的运输适宜温度时，保持车厢温度于适宜状态。由此可见，保温汽车的专用装置仅为隔热车厢，冷藏汽车的专用装置除隔热车厢外，还有制冷装置和加热装置。见图1.1图1.1冷藏车对冷藏保温汽车的基本功能要求是在任何外界环境条件（主要是温度条件）下，均能保持货物在整个运输过程中不致腐败变质。可见，保温汽车只适宜于短距离的冷藏运输，以及运输适温范围较宽的易腐货物，冷藏汽车适于长距离冷藏运输以及环境温度变化范围大的场合。用保温汽车运输易腐货物时，车厢的隔热层起着阻滞厢内外热交换的作用，而车厢材料和厢内货物的热容量也起着维持厢内原有温度的作用。运输过程中，外界传入的热量和食物本身的呼吸热则会导致厢内温度身高。保温汽车只适宜于短距离的冷藏运输，以及运输适温范围较宽的易腐货物。冷藏汽车主要是靠制冷和加热装置来维持厢内温度，使其保持在所运货物的适温范围内，从而达到避免货物变质的目的。机械制冷汽车制冷机空气冷却器周围的低温是通过风机送风即强制通风来送到车厢内各处，这要求厢内货物的堆放不致切割厢内毕业设计（论文）报告纸共33页第5页装订线的空气循环。导风条、型材地板等附件也有利于形成正确的气流方向。1.2冷藏保温汽车的经济意义冷藏保温汽车的经济意义在于保证货物的运输质量，避免易腐货物在运输过程中腐烂变质而受到经济损失。食品的生产、加工、保管、贮藏、运输及销售分配与人民生活密切相关，食品冷藏链的各个环节都与人民生活休戚相关。据联合国粮农组织估计，目前世界各国农牧业每年生产食品三十多亿吨，其中易腐食品约占三分之一，这些食品在流通过程中腐烂变质不堪食用的有23亿吨。我国人民易腐食品的消费水品并不高，但损耗和浪费也十分惊人，肉类、水产、禽蛋、水果、蔬菜等每年都有大量腐烂损失，有的是在产地变质，有的在流通过程中遭受损失。外贸方面也有食品运到口岸后因质量不符要求而被退回内销造成大量经济损失的情况。建立和完善食品冷藏链就能大大减少和基本避免这类损失。冷藏保温汽车由于适用范围广、机动性强、中转环节和装卸次数少、可实行门对门运输等优越性而在冷藏运输中占有极为重要的地位，成为食品冷藏链中不可缺少的运输环节。与其它冷藏运输方式比较，公路冷藏运输的经济效益主要有“运距效益”、“时间效益”和“运输质量效益”。“运距效益”是指汽车运输其运距往往小于铁路运输或水路运输的运距；汽车运输速度比水路快，又不像铁路运输需要多次装卸转运、编组待运，其送达时间一般都比水路、铁路短，即具有较高的“时间效益”；汽车冷藏运输装卸次数和中转环节少，就减少了易腐货物因装卸和中转贮藏时碰伤及货温升高造成的损耗，具有十分明显的“运输质量效益”。以前人们常常只考虑运价和运输成本，其实这是远为不够的，还必须考虑货损、送达时间、能耗、投资经济效益等因素，即应综合考虑运方和货方的利益，更需考虑广泛的社会效益。我国以前常用敞车和篷车类普通货车来运输易腐食品，包括运输鲜冻鱼肉，不仅造成食品大量腐烂变质，而且使食品遭到污染，影响食用者的健康，也给国家造成大量经济损失。1982年我国颁布了食品卫生法，明文规定易腐食品的运输条件，这是从法律上肯定了冷藏运输的重要意义。1.3国内外冷藏保温汽车的发展过程和现状1.3.1冷藏保温汽车的发展过程在古代，人们就知道用冰降温可防止物品很快腐烂，当开始用厢式车辆来运输食品以保证食品的运输安全和免遭污染时，人们就用冰和易腐食品混装的办法，避免厢内温度上升太快而使货物变质。为提高车厢的保温性能，在制造车厢板壁时填嵌隔热材料，隔热材料要求使导热系数较小而比重较轻，这样就产生了保温车。早期的隔热材料有软木、米波拉、木料木屑等。现在多采用泡沫材料。用得最多的使聚苯乙烯泡