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车辆与动力工程学院毕业设计说明书车辆与动力工程学院毕业设计说明书I3 3 吨柴油动力货车设计（后驱动桥与后悬架设计）吨柴油动力货车设计（后驱动桥与后悬架设计）摘要摘要驱动桥是将传动轴传来的扭矩进行减速增扭，并改变其扭矩的方向，再分配给左右车轮，并使左右车轮具有差速作用，以保证内外车轮以不同的转速转向。悬架是现代汽车上的重要总成之一,它用来感知不同地面给车架的不同程度的，方向上的力，并利用机构中的弹簧来减小路面的崎岖不平对乘客乘坐舒适感的影响。这次设计从驱动桥开始，首先是对驱动桥的总体认识，根据设计要求对驱动桥的形式进行选择。然后是对主减速器的设计计算，包括对主减速器的概述，形式的选择，主减速器齿轮参数的设计计算，主减速比及载荷的确定，差速器的选择，半轴和行星齿轮的参数计算，半轴的计算，选择以及对上述各个部分的强度校核计算。对悬架的设计参考了多种车型，选择钢板弹簧非独立悬架，内容包括悬架形式的选择，钢板和减震器的计算等。悬架的作用是传递车架（承载式车身）和车桥之间一切力和力矩。这次设计采用非独立悬架。设计的重点是对主减速器的齿轮进行设计和计算。悬架方面，钢板弹簧的选择和刚度校核是关键。对于各个轴和齿轮的接触和弯曲强度校核都符合要求。关键词：关键词：驱动桥，主减速器，半轴，钢板弹簧 车辆与动力工程学院毕业设计说明书车辆与动力工程学院毕业设计说明书II3T DIESEL FUEL POWER TRUCK DESIGN（REAR DRIVING AXLE AND REAR SUSPENSIONASSEMBLY)ABSTRACTDriving axle works that transmission shaft brought over torque proceed deceleration speed increased，combine transfer his tensional heading，reassign given about left and right wheel. combine gotten about possess differential acting ， withal guarantee wheel inside and outside and withal different rotation rate turn，The suspension system is the important part of the morden automotive, the suspension system feel much power of the frame from the road surface, sping in the system absorb the shocks of all kinds of the road surface, so that passengers have a comfortable ride.The design starts from the live axle ，first I know about type， It joins up handgrip carriage and axletree elastically. primary mission yes transfer action at wheel and carriage of compartment wholeness force and moment；relax pavement hand down to carriage shock load，attenuation resulting bearing systemic vibrate，guaranee garage gotten smoothness；guarantee wheel at pavement dissatisfaction and load fluctuation hour in the right would motility， The function of the suspension transfers all of force and moment between the frame ( bearing the weight of the body )and the axletree. This design adhibits the disindependencing suspension.The key of the design designs and calculate to gear wheel of the main reducing gear，The crux is the way of rear suspension,siderography selecting and rigidity.osculation intension Structure simplicity, usability best, adjust service easiness. KEY WORDS: driving axle，main reducing gear, semi axis, plate spring 车辆与动力工程学院毕业设计说明书车辆与动力工程学院毕业设计说明书III符号说明rr: 车轮的滚动半径np: 最大功率时发动机的转速vamax: 最高车速igH: 变速器最高档传动比Temax: 发动机最大转矩N: 驱动桥数目iTL: 由发动机至所计算的主减速器从动齿轮之间的传系最档传动比T：上述传动部分传动效率K0：离合器产生冲击载荷时超载系数G2: 满载时一个驱动轮上的静载荷系数: 轮胎与路面间的附着系数rr: 车轮的滚动半径 lB : 所计算的主减速器从动齿轮到驱动车轮之间的传动效率ilB : 所计算的主减速器从动齿轮到驱动车轮之间的传动比p：单位齿长上的圆周力 N/mm ig：变速器档传动比d1：主动齿轮节圆直径F：动齿轮的齿面宽: 半轴的扭转应力T ：半轴的计算转矩d：半轴杆部直径 K ：超载系数Ks：尺寸系数，反映材料性质的不均匀性，与齿轮尺寸及热处理等有关。Km：载荷分配系数Kv：质量系数，对于汽车驱动桥齿轮，当齿轮接触良好、周节及径向跳动精度高时车辆与动力工程学院毕业设计说明书车辆与动力工程学院毕业设计说明书IV目目 录录第一章第一章 前言前言.1第二章第二章 驱动桥结构方案分析驱动桥结构方案分析.22.1 驱动桥概述.22.2 驱动桥形式及选择.3第三章第三章 主减速器设计主减速器设计.43.1 主减速器结构方案分析.43.2 主减速比及计算载荷的确定.4 3.2.1 主减速比 的确定.40 3.2.2 齿轮计算载荷的确定. .43.3 主减速器齿轮主要参数计算.53.3.1 主、从动齿轮齿数的选择.63.3.2 从动齿轮节圆直径及端面模数的选择.63.3.3 齿面宽的选择 .73.3.4 双曲面齿轮的偏移距.73.3.5 螺旋角的选择.73.3.6 圆弧齿双曲面齿轮的几何尺寸设计.83.4 主减速器齿轮强度计算.18 3.4.1 单位齿上的圆周力.18 3.4.2 齿轮弯曲强度计算.19 3.4.3 齿轮接触强度计算.203.5 主减速器的材料和热处理.213.6 主减速器锥齿轮轴承的载荷计算.22 3.6.1 主减速器主动锥齿轮上的当量转矩的计算.221dT 3.6.2 主减速器主动锥齿轮齿面宽中点处圆周力计算.22 3.6.3 双曲面齿轮的轴向力与径向力的计算.22 3.6.4 悬臂式支承主动锥齿轮的轴承径向载荷的确定.233.6.5 主减速器从动锥齿轮的轴承计算.25第四章第四章 差速器设计差速器设计.274.1 差速器结构方案分析.27车辆与动力工程学院毕业设计说明书车辆与动力工程学院毕业设计说明书V4.2 差速器齿轮主要参数计算.284.3 差速器齿轮强度计算.31第五章第五章 半轴及桥壳设计半轴及桥壳设计.335.1 半轴的设计计算. .33 5.1.1 半轴的形式.33 5.1.2 半轴参数计算.33 5.1.3 半轴的强度计算.305.2 半轴的结构、材料与热处理.355.3 桥壳的设计计算.35 5.3.1 桥壳的设计.35 5.3.2 桥壳强度计算.36第六章第六章 后悬架设计后悬架设计.336.1 后悬架概述.336.2 后悬架的设计计算.35 6.2.1 悬架已知参数.39 6.2.2 悬架主要参数的确定.40 6.2.3 弹性元件的设计计算.40 6.2.4 后钢板弹簧的计算.43第七章第七章 结论结论.49参考文献参考文献.50致谢致谢.51外文资料译文燃料汽车电子设备随着油价的不断上涨，汽车制造商们正在重新设计发动机管理系统，以适应燃料中乙醇用量不断增加的趋势。世界原油产量预计将在20102020年之间达到顶峰，期间，原油的消耗量将比新探明储量更重要，原油价格也将会不停的上涨，交通业是耗油大户，随着油价的上涨，汽车必须提高燃油利用率。汽车同时也是最大的污染源，在法规的约束下，交通运输所带来的污染已经得到了有效地改善，特别是铅和一氧化碳的排放量明显降低了。然而，一些长期的污染问题仍待解决，特别是以二氧化碳为代表的温室气体排放。为了在竞争中生存，汽车制造商们正在研究能降低油耗或减少废气排放的新技术和代用燃料，作为一种代用燃料，乙醇凭借其灵活的使用方式，越来越多的受到青睐。驾驶员可以在标准的汽油和乙醇之间灵活的选择。“发动机管理系统对于这种柔性燃料系统来说是必不可少的。”法国供应商法雷奥称，“改系统可以控制扭矩、辅助系统、诊断故障、更重要的是，他能控制废气排放。”扭矩控制功能可根据驾驶员需要的操纵性和加速能力调控发动机的输出扭矩、发动机扭矩控制功能还可以和其他一些功能，如牵引力控制、巡航控制、变速器和制动器等相互配合。尾气排放主要分为3类：排气管排放、加油时产生的排放和蒸发性排放，要解决为期排放所带来的问题，关键是要符合尾气排放标准，同时尽量降低油耗。这两点可以通过专用后处理装置，如催化转换器、传感器和机电执行机构来实现。发动机管理系统控制扭矩和排放的方式很复杂，进入发动机的空气和再循环废气通过专用的传感器和执行机构实现精确的定量控制，首先喷入适量的燃油，以实现最能发挥催化剂效率的最佳空燃比，接着适时点燃混合气，三元催化会最终使废气排放保持在可接受的水平上。所有这些功能需要通过数据总线和导线的连接与其它电子装置相互配合。通过这些装置发回的反馈信息，发动机管理系统可以屏蔽无关的干扰和变化。提高燃油利用率和减少温室气体排放可通过采用发动机技术或使用不同的燃料来实现。至于哪种方法更好，这要取决于成本、市场接受度以及政治和财政上的刺激等因素。例如，使用E85燃料，即含85乙醇和15汽油的混合燃料的汽车，其排放量只有单纯使用汽油时的79，乙醇之所以成为广受欢迎的代用燃料，主要是因为它的含碳量比汽油少，所以燃烧时产生的废气也相对较少。与使用汽油的车相比，大部分使用酒精的车一氧化碳和二氧化碳排放量更低、烷烃或非烷烃碳氢排放量相等或更低，使用乙醇和汽油的汽车所产生的氮氧化物排放量大致相同，因为乙醇燃料的高挥发性成分含量比汽油低，所以蒸发性排放量也较低。此外，乙醇可以用农作物来生产，因此是一种可再生燃料，生物乙醇实际上不产生任何来自化石的二氧化碳，也就是说，二氧化碳的净增加值为零 。减少汽车排放量的潜力是巨大的，但如果完全依赖生物燃料，则需要大量的种植面积，因此在今后的一段时间里，乙醇的市场占有率与原油相比仍将十分有限，如果汽车能在两种燃料之间灵活选择，那么用乙醇做燃料仍不失为一种缓解石油危机的有效方法。与传统汽车发动机相比，装有柔性燃料发动机管理系统的发动机在不增加成本的情况下，可以在普通无铅汽油和含酒精0到100的混合燃料之间任意转换，正是因其几乎不需要增加额外成本，该技术在农业资源富庶的国家尤其受欢迎。然而，对原有发动机进行一些改装还是必要的。汽油发动机上使用的某些材料和酒精是完全不相容的。“燃料的腐蚀性和挥发性是对零部件影响最大的两个因素，”法雷奥公司称，“因此需要对油泵、燃油管路、油箱和喷油器的材料和设计进行更改。”但是并没有必要为乙醇特制热导传感器。乙醇的理论空/燃比与汽油相差很大，例如E100为9:1,E85为10:1,3而汽油则为14.7:1，因此，可以用汽油机上已有的标准氧化传感器来确定酒精和汽油的含量。尽管从加油泵中流出的混合燃料的酒精含量是一定的，但油箱里的酒精含量可能会不一样，因为加入的燃料可能会和油箱中原来剩余的燃料混合在一起，这就需要发动机管理系统根据汽车的实际情况进行调整，以保证最佳的运转效果。相同体积的乙醇所含的能量比汽油大约低30，燃料消耗也相应的比汽油机高30，为了解决效率降低的问题，汽车制造商们将油箱的容积相应增大，这样汽车的行驶里程就不会因此降低，喷油器的流量范围也必须相应的增大。由于乙醇中含有的高挥发性物质比汽油少，因此可能会因发冷起动问题，解决这一问题有两个方法：在美国和瑞典，混合燃料中至少含有一定量的汽油，冬季的汽油含量可高达30，在瑞典，冬天常常需要在10的低温下起动，为此，车辆都备有一种电热装置为汽车保温。 在巴西，人们用纯酒精作燃料，不过在车上要另加一个小型的备用汽油油箱，并且专门为冷起动增加一套燃油管。同时也可以通过改进启动器来增加起动时的转速。巴西产的柔性燃料汽车上，发动机管理系统必须控制来自冷起动油箱的输入信号，并且在该油箱油量过低时能够察觉；系统的输出信号必须能通过电控汽油泵继电器和冷起动喷油电磁阀，控制冷起动的供油量。这种车上还可以选装显示设备，包括显示所用燃料和冷启动油箱位过低的指示器。这些功能用标准汽油机ECU进行重新设计。在寒冷天气里，发动机管理系统在启动专用的电控泵和电磁阀的同时，用汽油进行“全组壁湿预喷”。一旦发动机达到足够快的转速，喷油器就会开始喷射乙醇。因此，汽油喷射在几秒钟之内就会停止。发动机管理系统是怎么知道燃油的混合比的？不是靠不断的测量混合气的浓度，而是通过标准的上游氧传感器来确定酒精和汽油的量。该传感器可测出实现最佳催化率所需的空然比和实际空燃比的差。“微小的误差可通过用于喷油正时的A反馈校正法直接消除，误差很大时，则说明燃料的性质发生了改变。”法雷奥公司称。“然后，发动机管理系统会重新对空然比进行估算，并根据实验所得的空/ 燃比和汽油/乙醇比之间的对应关系，将其换算为汽油和乙醇的混合比。”为了增强可靠性，一有迹象表明燃料很可能发生了改变，发动机管理系统就会对酒精浓度进行估算。估算的时候采用关于主油箱油位的信息，如果发动机管理系统能收到这样的信息的话。将发动机所需的扭矩换算为发动机管理系统所需的空气、燃料用量和点火时间时，需要考虑实际参数的变化，如理论空燃比、热值和燃烧效率等。“对于混和燃料，发动机管理系统的各个参数和各种行为是通过将估算的乙醇/汽油比作为插值参数而求出的，”法雷奥公司称，在计算喷油量和点火提前指时用的是同一参数。进气量也会发生变化，汽油和乙醇的蒸发潜热值相差很大，简单的说，乙醇会使吸入的空气因冷却而密度增加。进入气缸内的空气质量随之增大。为此，校准进气量时就必须按100%乙醇和100%汽油两种情况进行。“据我们估计，几年内大部分欧洲和美国汽车都会在燃油中加入乙醇。”法雷奥公司表示，“E85燃料是否会成为标准还很难说，不过我们以为此作好准备。”4 fuel electronicsAs oil gets more expensive, carmakers are looking at engine management systems that can cope with increasing levels of ethanol.Oil production could peak between 2010 and 2020.When it happens ,oil consumption will become more important than new discoveries ;and crude oil prices will rise and rise .Transport is the dominant sector in terms of oil use and motor vehicles will have to become more fuel-efficient.Vehicles are the largest source of pollution. Regulations have addressed the problem for transportation and real improvements have been achieved ,particularly in lead and carbon monoxide levels .But some long-term emissions have not been considered .This is particularly eve case for greenhouse gas emissions ;carbon dioxide in particular.To protect their livelihoods ,carmakers are investigating technologies and alternative fuels that either reduce oil consumption or cut emissions .Ethanol is starting to become more attractive as it can be used flexibly .The driver can run on standard gasoline or on The engine management system is an essential part of such systems success ,says French Tier One supplier Valeo :“They control Torque, ancillary systems ,diagnose servicing issues and ,most importantly ,emissions.”Torque control features deliver engine responses with levels of drivability and acceleration in agreement with users requests .Engine torque control also co-prorates functions such as traction control, cruise control, transmissions and brakes.Emissions break down into three main areas: those from the exhaust tailpipe; refueling losses and evaporative emissions .The issue is to comply with emission regulations and minimize fuel consumption .This is achieved through dedicated after-treatment components such as catalytic converters, sensors and electro-mechanical actuators.The way the engine management system controls torque and emission is complex .The quantities of air and recycled exhaust gases entering the engine are precisely managed with dedicated sensors and actuators .The right air/fuel mix for the catalyst to work properly .The mix has to ignite at the right time .The three-way catalyst then has to keep final pollutant emissions at acceptable levels.All these functions need to cooperate with other electronic units through data buses and eventually wired connections .Feedback from them allows the system to ignore any irrelevant disturbances and variations.Fuel efficient driving and reduction of greenhouse gas emissions can be achieved by using engine technologies or different fuels .Which prevails will depend on cost ,market acceptance ,and political and fiscal incentives.A vehicle fuelled with E85 fuel ,which contains 85 percent ethanol and 15 percent gasoline ,produces just 79percent of the emissions produced by pure gasoline .The interest in ethanol as an alternative fuel comes mainly from its clean burning qualities .Ethanol contains less carbon than gasoline.Compared with gasoline, most ethanol cars produce lower carbon monoxide and carbon dioxide emissions and the same or lower levels of hydrocarbon and non-methane hydrocarbon hydro carton emissions Oxides of nitrogen emissions are about the same for ethanol and gasoline vehicles.Ethanol fuel has fewer highly volatile components than gasoline and so has emissions.Moreover it can be produced from crops and so qualifies renewable fuel .Bio-ethanol produces no fossil carbon dioxide because the plants used to make ethanol take CO2 out of the air in order to grow . There is a net increase of zero.There is no need, however, to fit a specific ethanol conductivity sensor .The stoichometric air-fuel ratio of ethanol is very different to gasoline .For E100 it is 9:1, for E85 is it 10:1,for gasoline it is 14.7:1.Because of this ,it is possible to recognize the amount of ethanol and gasoline by using the standard oxygen sensor already found in gasoline architectures.Although the ethanol content of the blend at a refueling pump is specified ,the content of the vehicle tanks may be different because it may mix with any fuel already in the vehicle stank .It is the job of the engine management system to make the adjustments the vehicle needs to operate optimally.The energetic content of ethanol is around 30 percent less than the same volume of gasoline .Fuel consumption is potentially increased in the same proportion .To deal with the decline in fuel efficiency, carmakers install larger fuel tanks, so the vehicles range is not compromised .Injectors flow ranges have to be increased too.Ethanol has fewer highly volatile components than gasoline ,so Cole starting problems may occur .To solve this issue two kinds of solutions ate used ;In the US and Sweden ,a fuel with a minimal amount of gasoline is used ,the amount of gasoline can be as high as 30 percent in the winter .In Sweden ,where cold starts at -10 are common in the winter ,the vehicle is plugged in to an electric source to keep it warm.In Brazil, pure hydrated ethanol is used but with a small additional gasoline reserve tank and fuel line that is used only for cold starts .Starters can also be modified to increase the cranking speed.In Brazilian flex-fuel vehicle architectures, the engine management system must manage inputs from the cold start tank, recognizing when fuel is low .Its outputs must manage gasoline supply for cold start via an electric gasoline pump relay and a cold-start injection solenoid valve.Optional driver display information includes indicators to show the type of fuel in use and when the cold start tank is low .These features require hardware that is usually available as spares on standard gasoline ECUs .so no specific ECU has to be designed.In cold weather ,the engine management system orders a wall-wetting ,full-group pre-injection is performed using gasoline ,by simultaneously activating the dedicated electric pump and the solenoid valve .As soon as the engine speed is high enough the injectors inject the ethanol .Gasoline injection is then phased out within a few seconds.How does it know that the fuel blend is? Not by constantly measuring the mix .A standard upstream oxygen sensor recognizes the amount of ethanol and gasoline. This sensor measures the difference between the air/fuel ratio required for optimal catalyst efficiency and those effectively achieved.“Slight errors are directly cancelled with the lambda feedback correction performed on injection timing, while large ones are arreibuted to changes in fuel characteristic.” says Valeo .The new air