汽车转向器外文翻译.doc

湖北理工学院外文文献翻译汽车转向器结构轻量化设计克莱因一、简介汽车行业及其供应商在未来的关键任务在于迅速制定和实施是生态良好，经济上合理的流动系统系统。随着玻璃和碳纤维增强材料，陶瓷和复合材料的广泛应用，如铝、镁轻金属开辟了轻量化使具有发展潜力的“绿色”概念车得以投产。特别是铝可以为以后的新设计提供了动力。几十年前，铝在汽车结构中被认作是“概念”，如今它是减轻质量，从而降低油耗的一个重要因素。现在的的汽车一般都是包含60到70千克的铝，按照目前的发展趋势，在未来几年的这一数值将会增加一倍。汽车无论是现在还是将来必须满足的要求：更高的性能，更高的安全性，舒适性，低污染。轻型结构不只是降低重量，这是降低重量和结构效率之间的平衡的问题，它是一个很值得研究的课题。在汽车结构中中，这通常意味着充分利用有限空间可用于各个部件以使重量最小化，同时，还要求满足所有的刚度，强度，固有频率和声学要求。为了实现这一目标，必须强调强度在整个结构分布尽可能均匀。现代数值分析方法，如有限元分析允许一个非常详细的分析方法，能够提供具有成本效益、优化复杂过程的支持，从而为轻量化的进步做出了巨大贡献。在安装，安全，装配，成本等方面的考虑，在一定程度上可以实现轻量化。克虏伯股份公司提供范围广泛的专业知识，使该公司在分析转向系统，客户要求的规格上提供相应的解决办法。二、要求得到的满足的转向系统转向系统是车辆结构的一个重要的组成部分。转向系统使驾驶有良好的行驶过程，减轻来自路面的糟糕的振动，保证所需要的的转向手感。同样重要的是，无论在正常情况下还是在崩溃的情况下，高安全性的要求都可以得到满足。因此，影响转向系统的主要因素有：滚动摩擦、抗扭刚度/强度、阻尼温度、耐腐蚀性、抗疲劳性能、重量等。影响碰撞冲击力和能量吸收转向柱因素有：固有频率/刚度性能、应用广泛、阻尼作用、占用空间、强度、人体工程学设计、处理、声学、碰撞冲击力和能量吸收。其他基本条件：接口与相邻元件可靠、拆装方便、连接可靠、成本低。三、材料通过材料轻量化可以在实现保证强度的这一条件下，达到减轻重量的要求。当刚度或固有频率有相对严格的管径标准时，需要具有高弹性模量的低密度材料。选材一般选择常用材料，一方面要求材料利用率大，价格低廉，具有良好的耐用性。另一方面的要求是由制造业和连接过程来共同决定的。钢、铝、镁和复合材料是转向系统的首要选择的材料。低比重，高耐腐蚀性，制造成本低，高能量吸收和良性循环的能力，使铝倍受青睐。由于其热能含量高，可达90%用于汽车建设，铝可以很方便的回收（智能设计/没有与其他材料混合）。铝的回收利用率高，铝在环境方面比许多其他材料有很大的优势。所需的原料铝的初级能源的大量使用抵消了车辆的使用寿命，并且复合材料也将非常有发展前景，它有极大的刚性，低重量和能量吸收能力强，然而，目前，由于铝的复合材料造价成本高，只是被作为局部零件来减轻重量。四、减少零件的重量采用集成的方法来减轻组件的重量，需要一个轻量化的设计方法。设计方法（力分布、应力）、材料（材料的选择）、规格（可修改，现实的规格）。轻量化设计的关键因素包括：力流、材料特性、环境条件、安全要求、连接可靠、生产能力等。实践经验表明，汽车制造商的规格基础上需要修改的轻量化。有效需求为钢材转向轴，例如，可能会导致铝轴严重过度规划。降低组件的重量要求材料设计结合材料相容规格。五、轻量级组件作为其发展计划的克虏伯普雷斯塔正取代传统的钢转向部件，如转向杆转向部件，轴或轴叉相应的铝元件生产的新工艺。根据客户的提出的需求，可实现减轻20-30%的重量。转向柱已被用于铝和镁压铸件，并正在研究进一步的减轻重量的方法。轻巧的转向柱由克虏伯普雷斯塔生产的奥迪A6就是一个很好的例子。通过使用镁合金压铸件已经能够限制转向柱的重量达到5公斤，以此来减少15-20%常规（钢）设计。六、转向柱设计经验表明，这是有可能，或者仅靠其固有频率的基础上设计汽车转向柱。关键部件，可能需要额外的工作量设计，在崩溃或滥用（如被偷窃）的情况下，不能被打破。当转向柱在主要的工作流程时，达到尽可能大的固有频率，同时能够最大限度地减少重量。分析低刚度组件结构，实现结构的均匀加载。在解决这个任务，使用数值方法，如有限元分析。这是由特定的变动假设为特征的有限元结构所决定的。利用有限元分析检查的复杂结构，灵敏度分析以及互相之间存在的联系，分析如何作出改进和优化结构的数值。拓扑优化进行了分析低应力区的基本设计。CAD几何数据中能够处理FE预处理的基础。以下是正确的建立模型需要考虑的方面。单个零件，刚性，接触面，运动学质量。其次就是计算得到的数据和评估的模型。变应力的评估是广泛强调采取的措施。晶粒大小越细化，组织结构越均匀，则应变能力越好。振动会影响着转向柱的固有频率。通过评估应变力变化的状况，可以确定应力集中区。七、结论现有技术必须不断调整和完善以符合推动汽车行业的发展。减轻转向系统重量是一个重大的挑战，并需要汽车制造商和供应商之间的密切合作。材料，制造和连接技术，必须进一步改善。克虏伯公司持续成功的先决条件之一是不断创新完善以满足客户的愿望和需求。1 IntroductionThe key task for the automobile industry and its suppliers in future lies in speedily developing and implementing ecologically sound and economically justifiable mobility systems. Light metals such as aluminum and magnesium along with glass and carbon fiber reinforced materials, ceramics and composites have opened up the potential for considerable weight reduction and for green vehicle concepts which can be realized economically. Aluminum in particular can provide the impetus for new designs for the next millennium. Decades ago, the use of aluminum in auto construction was seen as an experiment; Today it is a vital factor in reducing weight and thus lowering fuel consumption.The average passenger car today contains 60 to 70 kg of aluminum, and current developments point to a doubling of this amount in the next few years. Motor vehicles both now and in future must meet requirements for: greater performance, greater safety, comfort, low pollution. Lightweight construction is not just about reducing weight; it is a question of -striking the right balance between reduced weight and structural efficiency. In vehicle construction this normally means making the best use of the generally very tight space available for individual components so as to allow weight to be minimized while still meeting all stiffness, strength, natural frequency or acoustical requirements. To achieve this, stresses must be distributed throughout the structure as evenly as possible. Modern numerical analysis methods such as FEA allow a very detailed analysis of system behavior, provide cost-efficient support for the complex process of optimization and thus make a huge contribution to advances in lightweight construction. Packaging, safety considerations, reproducibility and price place restrictions on the degree of weight reduction achievable.The broad range of expertise available to Krupp Presta AG allows the company to analyze customer specifications for steering systems and provide appropriate solutions.2 Requirements to be met by steering systemsThe steering is an important part of the feel of a car. The steering system should make driving an enjoyable experience with no unpleasant vibration from the road surface while guaranteeing the required hand- sing. It is also important that high safety requirements be met, both under normal conditions and in crash situations. The key criteria for the steering system are thus as follows:rolling friction, torsional stiffness /strength, Damping, temperature, corrosion, durability / fatigue, weight. Crash kinematics and energy absorption steering column requirements:natural frequency / stiffness, mass, damping, space, strength (crash, misuse), ergonomics, handling, acoustics, crash kinematics and energy absorption. Other basic conditions:interfaces with adjacent components, installation, joining techniques, price.3 Materialsmaterial light weighting can be achieved by using either stronger or lighter material. When stiffness or natural frequency are Important sizing criteria, low densitymaterials with a high modulus of elasticity by quired. Non-exotic materials must be selected which are readily recyclable, low in price and display good durability.Further requirements are set by the manufacturing and joining processes. Steel, aluminum, magnesium and a variety of plastics are the materials of choice for steering systems.Low specific gravity, high corrosion resistance, low fabricating costs, high energy absorption and good recycle ability make aluminum a favored light weighting material. Owing to its high energy content, up to 90% of the aluminum used in auto construction can be recycled (intelligent design / no mixing with other materials). The favorable energy balance of aluminum puts it at a great advantage over many other materials.In environmental terms aluminum scores highly. The large amounts of primary energy required to make raw aluminum are offset over the lifetime of the vehicle. Composites could also become a very attractive proposition on account of their extreme stiffness, low weight and energy absorption capabilities. At present, howler, price is a problem, as are joining and quality assurance.4 Reducing component weightA focused strategy to reduce component weight requires a lightweight approach to design (force distribution, stresses), material (material selection), specifications (modified, realistic specifications)Key factors in lightweight design include 1: force flows, material properties, ambient conditions ? safety requirements, reliability of joints, manufacture ability. Practical experience has shown that car makers specifications based on steel need to be revised for lightweighting. Requirements valid for a steel steering shaft, for example, can result in severe oversizing of an aluminum shaft. Reducing component weight requires material compatible designs combined with material- compatible specifications.5 Lightweight componentsAs part of its development program Krupp Presta is replacing conventional steel steering components such as steering rods , shafts or forks with corresponding aluminum components produced by new processes. Weight savings of 20-30% are achievable depending on the basic conditions stipulated by the customer. Aluminum and magnesium die castings are already being used in steering columns , and further opportunities for weight reduction are being investigated. The lightweight steering column (Fig. 1) produced by Krupp Presta for the Audi A6 is a good example. By using magnesium die castings it has been possible to limit the weight of the steering column to just 5kg, a reduction of 15-20% over conventional (steel) designs.6 Steering column designExperience has shown that it is possible to design steering columns for cars more or less on the basis of their natural frequency alone. Additional engineering work may be required to design critical parts which must not break in the case of a crash or misuse (e.g. theft). The main task when engineering a steering column is thus to achieve the highest possible natural frequencies while minimizing weight. Low-stiffness components are being analyzed and refined in an effort to achieve uniform loading of the structure. In solving this task, use is made of numerical methods such as FEA. The structure is divided into finite elements which are characterized by specific deformation assumptions. Using FE analysis it is possible to examine complex structures, analyze sensitivities and links, discuss variations or ways of making improvements and optimize the structure numerically. Topological optimization is carried out for the analysis of low-stress areas and for the basic design of ribs and beads. CAD geometrydata are processed in an FE pre-processor. Correct modeling of the following is essential, individual parts, stiffness, contact faces, kinematics