顶置式四缸内燃机凸轮配气机构设计及运动仿真【带PROE三维】【4张CAD图纸+毕业论文+开题报告+任务书+外文翻译】【2011定做独家】
顶置式四缸内燃机凸轮配气机构设计及运动仿真48页 16000字数+论文说明书+任务书+4张CAD图纸【详情如下】PROE三维图及仿真视频rar任务书doc全部图纸dwg凸轮轴dwg外文翻译-运用材料汇编对立体空间构架装配结构的矢量层面解析doc弹簧压冒dwg气门dwg顶置式四缸内燃机凸轮配气机构装配图dwg顶置式四缸内燃机凸轮配气机构设计及运动仿真开题报告doc顶置式四缸内燃机凸轮配气机构设计及运动仿真说明书doc内容摘要 该设计是我在学校的最后一个设计,在设计过程运用到了很多的知识,PROE的使用,凸轮的设计,轴的应力计算,气门顶杆的设计,以及对整体装配的理解,尤其是运动仿真那一块,是我的薄弱环节,同时在设计过程中,由于很多的事情耽搁了,造成了后期时间紧,同时工作量巨大的结果,这是自己的一个不足。对于知识的利用与融会贯通,基础知识不扎实,在设计过程中体现了出来,不过通过同学,老师的帮助,终于是克服了种种困难,使图形得以完成。 工作大致内容:任务书,开题报告,翻译,模型设计,计算说明以及最后的运动仿真。 运用到的知识非常之多,PROE由于之前不怎么熟悉,所以刚接手的时候非常迷茫,后来通过同学,老师的指导,使自己熟悉了怎么运用,同时对于四冲程机构有了进一步的了解。 通过这次设计,发现了自己很多的不足,在不足中得以成长,同时也认识到应该合理分配时间,分清什么重要的事先做,做事得有调理。 关于配气机构在生活中的应用,非常广泛,在现代社会中越来越多的人开车,对于车子的安全性能进一步加强,因此配气机构的合理性以及科学性更是重中之重。 目录概述1配气机构的功用 3 2配气机构的设计要求 4 3配气机构计算参数的确定 51凸轮轴的设计:1凸轮轴的设计要求 62凸轮轴的选材 73凸轮轴的结构 84凸轮轴的支承轴颈轴承的材料 9 5凸轮轴的定位方式 106凸轮轴的最小尺寸定位方式 117凸轮轴的热处理 118凸轮轴的磨损形式 129凸轮轴的计算1310凸轮轴强度校核计算142气门组的设计 21气门的设计 18 211气门设计的基本要求 20 212气门的工作条件分析 22 213气门材料的选择 23 214气门头的设计 24 215气门杆的设计 2522气门旋转机构的设计 2623气门座圈的设计 2624气门导管的设计 2825气门的主要损坏形式和预防措 293气门弹簧的设计31气门弹簧的设计要求 3032气门弹簧的作用 3133气门弹簧的工作条件 3134气门弹簧的结构 3135气门弹簧的选材 3136气门弹簧特性曲线与气门惯性力曲线的配合 3237气门弹簧的有关计算 33 371弹簧的最大弹力 33 372弹簧最小的弹力 34 373弹簧的刚度 34 374弹簧变形 34 375内、外弹簧之间的负荷分配 35 376内外弹簧的刚度 35 377弹簧的尺寸 36 378提高气门弹簧疲劳强度的措施 374凸轮轴配气机构建模设计 3741工作装置零件建模 3842气门的建模 3843弹簧压帽的生成 4044箱体的生成 42 45装配部件的装配生成 435凸轮轴配气机构仿真设计 4451概述 4552凸轮配气结构的机械运动仿真 466参考文献 477致谢 48顶置式四缸凸轮配气机构的设计概述1、配气机构的作用:它是完成换气过程,根据发动机气缸的工作循环次序,定时地开启和关闭进、排气门,不断地用新鲜的气体来交换气缸内上一循环的的废气。气门的布置型式方式有顶置式和侧置式,如图1-1所示:2、配气机构的要求: 对于一个正常工作的配气机构具有如下的要求:振动、噪声较小,且工作可靠和耐磨。进、排气门的时间充足,泵气损失小,配气正时恰当,在排气过程中能较好的排出废气,进气过程中能吸入较多的新鲜空气,因而使发动机具有较高的充量系数和合适的扭矩特性。结构简单、紧凑。为了减轻惯性负荷,使配气机构运动零件的质量减到最小。 3、配气机构设计的计算参数确定: 从确定气门座处的通过截面 以及确定喉口流通截面 开始。气阀处的流通截面积根据气体不可压缩连续流动的条件确定,也即在额定转速I情况,气门最大升程时,按气门座截面处假设的平均速度来确定。已知:气缸直径D=95, 气道喉口的最大直径D,配气机构的结构方案以及燃烧是的形式都已给定的情况下,气门布置在气缸上可能性的限制。进气门 的数值应大于下列规定的范围: 采用气门顶置式: , 则可以得到: , 根据柴油机的195B的结构,选择 =36mm,排气门的气道喉口的直径,通常取得比进气门的气道喉口直径小10%20%,气阀升程h时,具有圆锥密封面之气门的流通截面为: 式中a气门头斜面角(现代发动机上,a=45度); 气门的升程,取值一般是气门头的25%左右,气门头的直径是40mm,则: =10mm 喉口的直径经校核取值正确。 1凸轮轴的设计凸轮轴的布置型式:1、下置:凸轮轴正时齿轮直接与曲轴正时齿轮啮合。 2、中置:推杆短,要加入中间传动装置。3、上置:凸轮轴通过摇臂或直接来驱动气门,要用惰轮、皮带、链条,及张紧装置。结构复杂,用于高速强化的轿车发动机。Step2系统弹出如图所示“测量结果”对话框,在该对话框中进行下列操作。(1)选取图形类型:单击“图形类型”区域中的 ,从弹出的下拉列表中选择“测量与时间”。(2)创建一个测量:单击创建测量图标 ,系统弹出如图5214所示的“测量定义”对话框,在该对话框中进行下列操作。a键入测量名字:在该对话框中的名字文本框中键入测量名字“举升臂连接轴速度与时间关系”。b选择测量类型:单击“类型”区域中的 ,从弹出的下拉列表中选择“速度”。c选取测量点:选取模型中的凸轮轴。d选取评估方法:单击“评估方法”区域中的 ,从弹出的下拉列表中选择“每一时间步距”。e单击“确定”按钮系统立即将新建测量添加到如图8213f所示的“测量结果”对话框中。仿真效果如图8214所示:6参 考 文 献专著:【1】付白学马彪藩旭峰现代汽车电子技术,20083【2】史绍熙柴油机设计手册北京:中国农业机械出版社,1984【3】UTOCAD 2004简明教程,科学出版社。2004【4】建新内燃机理论与设计北京:人民交通出版社,2009【5】 李澄,吴天生,闻百桥机械制图北京:高等教育出版社,2003【6】孝达金属工艺学 北京:高等教育出版社,1997【7】华大年,华志宏,吕静平连杆机构设计上海:上海科技技术出版社,1995【8】吴宗泽机械零件设计手册北京:机械工业出版社,2003【9】http:/wwwqutoedcation/com/carcare/intro/htm 7致 谢本论文的能够顺利的完成,灌注了齐导师诲人不倦的关怀、指导和教诲,他严谨的科学态度,严谨的治学精神。从课题的选择到项目的最终完成,齐从谦老师给我细心的指导和不懈的支持。在设计过程中,这个也是我在校期间最后的一个设计,感谢所有帮助过我,并且和我一起努力,克服一个个难题,相信在今后的道路中,我们也能一直像现在这样面对困难。同时也由于自身原因,在设计过程中,经常由于工作而耽误,导致了无法如期完成设计,但是在导师的帮助下,我也尽自己最大的努力将这个设计完成,这其中倾注了导师太多太多的精力。最后,由衷地向所有在校园曾经关心和帮助过我老师和同学表示最诚挚的谢意!
Decomposition-Based Assembly Synthesis ofSpace Frame Structures Using Joint LibraryThis paper presents a method for identifying the optimal designs of components and joints in the space frame body structures of passenger vehicles considering structural characteristics, manufacturability, and assembleability. Dissimilar to our previous work based on graph decomposition, the problem is posed as a simultaneous determination of the locations and types of joints in a structure and the cross sections of the joined structural frames, selected from a predefined joint library. The joint library is a set of joint designs containing the geometry of the feasible joints at each potential joint location and the cross sections of the joined frames, associated with their structural characteristics as equivalent torsional springs obtained from the finite element analyses of the detailed joint geometry. Structural characteristics of the entire structure are evaluated by finite element analyses of a beam-spring model constructed from the selected joints and joined frames. Manufacturability and assembleability are evaluated as the manufacturing and assembly costs estimated from the geometry of the components and joints, respectively. The optimization problem is solved by a multiobjective genetic algorithm using a direct crossover. A case study on an aluminum space frame of a midsize passenger vehicle is discussed. (DOI: 10.1115/1.1909203)Keywords: design for manufacturing, assembly synthesis, structural design, aluminumspace frame1 IntroductionAlthough often ideal from a structural viewpoint, monolithic designs are not a realistic solution for complex structures, such as automotive bodies, considering the cost-effectiveness of manufacturing processes. As a result, most structural products are designed as assemblies of components with simpler geometries. During the conceptual stage of such products, designers need to determine the set of components and the methods of joining the components, by decomposing the entire product geometry. In the automotive industry, for example, a handful of basic decomposition schemes considering geometry, functionality, and manufacturing issues have been used in this process. However, these decomposition schemes depend mainly on the designers experience, which may cause the following problems directly related to the component and joint configurations: Insufficient structural stiffness. Components and joining methods specified by designers cannot meet the desired stiffness of the final assembly because of the inappropriate allocation of joints, which are less stiff than components. Insufficient manufacturability. Components and joining methods specified by designers cannot be economically manufactured because of the inappropriate geometry in components and joints. Therefore, a cost-effective and systematic optimization method, which can be used in determining components set by considering overall structural characteristics, manufacturability, and assembleability, will be of significant impact on the industry. As such, this paper presents a method for identifying the optimal designs of components and joints in space frame body structures of passenger vehicles, considering structural characteristics, manufacturability, and assembleability. Dissimilar to our previous work based on graph decomposition (1,2), the problem is posed as a simultaneous determination of the locations and types of joints in a structure and the cross sections of the joined structural frames, selected from a predefined joint library (3). The joint library is a set of joint designs containing the geometry of the feasible joints at each potential joint location and the cross sections of the joined frames, associated with their structural characteristics as equivalent torsional springs obtained from the finite element analyses (FEA) of the detailed joint model made of solid and plate elements. To minimize the computational overhead during optimization, the artificial neural network (ANN) associated with the FEA analyses results (4,5) is built for each configuration type in the joint library by using sampled designs of feasible joints and joined frames (6) and utilized in the overall optimization problem.Structural characteristics of the entire structure are evaluated by the finite element analyses of a model made of beam elements (frames) and torsional spring elements (joints), constructed from the selected joints and joined frames. Manufacturability of components is evaluated based on the estimated manufacturing cost consisting of the costs of extrusion die, bending operation, and casting component for each joint. Assembleability is estimated by the cost of welding in the assembly process. The optimization problem is solved by a multiobjective genetic algorithm (7) using a direct crossover (8,9). A case study on an ASF of a mid-size passenger vehicle is discussed.2 Related Work2.1 DFA/DFM and Assembly Synthesis. Design for assembly (DFA) and design for manufacturing (DFM) refers to a collection of design methods that aim to identify and alleviate manufacturing and assembly problems at the product design stage. Boothroyd and Dewhurst (10), who are regarded as major estab-1Corresponding author. Contributed by the Design Engineering Division of ASME for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received June 13, 2004; final manuscript received November 25, 2004. Assoc. Editor: K.K. Choi. lishers of DFA/DFM concepts, suggest to reducing part count first, followed by part redesign to improve manufacturability and assembleability (11). The analyses of manufacturability and assembleability require a targeting product to be decomposed into elementary manufacturing and assembly features, such as surfaces, dimensions, tolerances, and their correlations (12). Therefore, the conventional DFA/DFM methods assume predetermined components with given geometries and suggests improvements by modifying the given geometries.Decomposition-based assembly synthesis 1,2,9,13,14 adopted in this paper, on the other hand, emphasizes the determination of components prior to the manufacturability and assembleability analyses. The method starts with no prescribed components and generates an optimal component set considering the properties, including structural characteristics of the assembled product, manufacturability, and assembleability.2.2 Automotive Body Structure Modeling. During the early design stage of automotive body-in-white (BIW), simple beam models are widely used. Although beam elements can reasonably model structural members, difficulties often arise in modeling the structural property of joints. Modeling joints as torsional springs (15) is a classic but popular method because of its simplicity, where equivalent torsional spring rates are identified from experiments or detailed FEA models made of shell elements. Lee and Nikolaidis (16) proposed a two-dimensional (2D) joint model in order to consider joint flexibility, the offset of rotation centers, and coupling effects between the movements of joint branches. Kim et al. (17) discussed the accuracy of FEA-based joint rate evaluations regarding transformation error from shell element model to spring rate and proposed their own model (18).Aiming at joint design, Long (6) presented two tools that link the performance targets for a joint in a BIW to its geometry. The first tool, called translator A, predicts the structural performance of a given joint geometry using an artificial neural network (ANN) and response surface method (RSM). The second tool, called translator B, solves the inverse problem of finding a joint geometry that meets the given performance targets, using the translator A and sequential quadratic programing (SQP). Nishigaki et al. (19) proposed a tool based on first-order analysis (FOA) to design basic layouts of automotive structures, considering models of beam and spring elements. The above works, however, are on the analyses of structural properties of joints, separately or as an integral of an overall structure, and do not addresses the automated synthesis of joint locations and designs within a BIW as addressed in this paper.2.3 Aluminum Space Frame (ASF) Design. During the last two decades aluminum has drawn significant attention from the automotive industry because of the increasing demands on highgas- mileage, lightweight, and environmentally friendly vehicles. Although aluminum has been successfully used in drivetrains and heat exchangers, its usage in the chassis and body is still under development. Since a body-in-white (BIW) accounts for approximately one third of the vehicle weight, much effort has been put on the adaptation of aluminum in BIW (2023), resulting in a number of commercial mass-produced vehicles with the ASF, such as Acuras NSX _24_, Audis A2 and A8 (25) (see Fig. 1), and BMWs Z8 (26). Ahmetoglu (27) discussed the design of extruded profiles, bending, friction and formability of aluminum components. Chung et al. (28) studied joint designs in the ASF by comparing FE models with experimental results. Powell and Wiemer (29) and Barnes and Pashby (30,31) summarized the joining technologies currently used in aluminum structure vehicles, including resistance spot welding (RSW), gas metal arc welding (GMAW), self-piercing joint, and laser welding. In the present paper, we are providing a way of finding optimized configurations of components in the ASF considering structural response, manufacturing, and assembly process.Fig. 1 (a) Audi A2 and (b) ASF 203 ApproachThe proposed method consists of the following two steps (Fig. 2):1. Geometry of a given structure is transformed into a structural topology graph that represents the liaisons between basic members, the smallest decomposable components of the given structure, identified by the potential joint locations specified by the user. For each potential joint location, a corresponding joint library is built.2. The structural topology graph defined in the first step is decomposed, through an optimization process, into subgraphs representing components by assigning to some of the potential joint locations the joint types and cross sections of the joined frames, selected from the joint library. During this optimization process, the components set represented as the subgraphs is evaluated by considering (i) stiffness of the assembled structure, (ii) manufacturability of components and cast “sleeves” for joints, and (iii) assembleability of the components with the selected joints. The rest of the section describes the details of the above steps with a sample space frame structure in Fig. 3. As illustrated in Fig. 3(b), it is assumed that frames are extruded tubes, bent or welded with cast “sleeves” at joints, following a typical construction method of AFS. Fig. 2 Approaches used in this paper3.1 Overview. Step 1: Construction of structural topology graph with joint libraries. Different from our previous approach (1,2) where the basic members are specified by the designer, the present method requires the designer to specify the potential joint locations. This is to guarantee that the final design contains only the joints feasible for the available frame manufacturing and joining methods.Figure 4 illustrates an example of six potential joint locations shown as gray boxes. At each potential joint location, the designer must also specify feasible joint types to be included in the joint library. The joint library is a set of joint designs containing the geometric configurations (types) of the feasible joints, the crosssectional dimensions of the joined frames, and the welding design at each potential joint location.The joint library Ji of potential joint location i is defined as a tripleJi = (Ti,Si,Wi) (1)where Ti , Si, and Wi are the set of the feasible geometric configuration types, the set of feasible cross sections of the intersecting frames, and the set of feasible welding designs, respectively, at potential joint location i. Since multiple frames intersect at a potential joint location, the elements si of Si is a vector where FSk is the set of valid beam cross section designs for frame k in the structure, FJi is the set of the intersecting frames at potential joint location i, and FJi= nfi. For example, the joint library J1 at the potential joint location 1 of Fig. 4 is T1 ,S1 ,W1 with T1=t1.0 , t1.1 , t1.2 , t1.3.The structural property of a joint is determined by a joint configuration type, a cross-section design of the joined frames, and a weld design. As described in Section 3.2, an ANN is constructed for each joint configuration type, in order to represent the mapping between the joint design variables (cross section and weld designs) and its structural property (torsional spring rates).With given potential joint locations, basic members in the structure can be identified as shown in Fig. 5(a). Then, the structural topology graph G=(V,E) is constructed from basic members such that the basic member mi is represented as node ni in V, and the liaison between two basic members mi and mj is represented as edge e=ni ,nj in E.Figure 5(b) illustrates the structural topology graph G with seven nodes corresponding to the seven basic members in Fig. 5(a) and ten edges connecting the adjacent nodes.Step 2: Creating optimal components set design using optimization procedure. Different from our previous approach 1,2 where structural topology graph G is decomposed by removing its edges, the present method decomposes G by selecting a joint configuration type in the library at each potential joint location. From the selected joint configuration types, the corresponding edges in G are removed.For example, by selecting joint configuration type t1.2 in T1 for the joint location 1 in Fig. 6, the corresponding edges e1=n1 ,n2 and e2=n1 ,n6 are removed. The motivation behind the new approach over the simple removal of edges (as in our previous work) is to establish one-to-one mapping between the topology of G and joint configuration designs. With the simple edge removal, multiple topologies of G can correspond to a joint configuration type. For example, all possible joint configuration types involving three frames (e.g., location 1 in Fig. 6) is 5, while number of possible graphs with three nodes is 2number of edges=23=8. This is because the case where all three frames are connectedcan be represented by four different topologies in the graph. The simple edge removal, therefore, often yields overly connected components, which can be prevented by using the new approach above.The selection of joint configuration types and the removal of the corresponding edges in G result in subgraphs of G, each of which corresponds to a component. The cross-sectional dimensions of a component are then set as the averages of the ones of the joining frames associated with the selected joint configuration types in the component, which are subsequently used for retrieving the precomputed structural properties of the joints from the joint library. Figure 6, for example, shows three subgraphs (Fig. 7(a), and the corresponding components (Fig. 7(b) resulted from the selection of the joint types in The optimal decomposed structures with component and joint designs are obtained using the decomposition procedures described above through an optimization loop for three objectives: (i) stiffness of the assembled structure, (ii) manufacturability of components and cast “sleeves” for joints, and (iii) assembleability of the components with the selected joint types.3.1.1 Structural Stiffness. The structural stiffness of the assembled structure is evaluated as a negative of the magnitude of total displacements at specific locations of the assembled structure under given loading conditions. The displacements are calculated with finite element analyses, where the components and joints are represented by beam elements and torsional spring elements, respectively.For example, a T-joint in Fig. 8(a) is modeled as three beam elements connected by torsional spring elements k0 , k1, and k2, each of which has torsional stiffness (rate) around three local orthogonal axes attached to the joint. Note that the relative translationsof these elements are constrained. The section properties of the beam elements are obtained from the cross-sectional dimensions of the components. The rate of the torsion spring elements are estimated by the finite element analyses of the detailed model of a joint, where frames are modeled with plate elements, a cast “sleeve” is modeled as solid elements, and welds joining the frames and the sleeve are modeled as plate elements, as illustrated in Fig. 9.Figure 10 illustrates the loading and boundary conditions for calculating torsional spring rates of in-plane rotation. To facilitate the load application and the measurement of distortion angles, a rigid beam element is added to the center of the frame, subject to rotation. In Fig. 10, distortion angles 0 , 1, and 2 account for the effects of k1 and k2 , k0, and k2, and k0 and k1, respectively, in Fig. 7. Assuming moment arm length L, which is measured as the distance from the rotational center to the point at which the loading P is applied, the following equations are used to estimate k0 , k1, and k2 for in-plane rotation:The other two components of torsional spring rates are calculated in a similar manner. The values of the torsional spring rates for typical joint types, cross-sectional dimensions of the joined frames, and amount of welds are precomputed to produce a set of training data for an artificial neural network (ANN) that implements the joint library. Similar to the translator As in (6), this approach allows the spring rates of a joint to simply be retrieved from the joint library without computational overheads during optimization.3.1.2 Component Manufacturability. The manufacturability of components is evaluated as a negative of the total cost of producing components. As stated earlier, it is assumed that frames are extruded tubes, bent or welded with cast “sleeves” at joints, following a typical construction method of AFS. For example, the design in Fig. 11(a) is composed of three frames (Fig. 11(b) and four cast sleeves (Fig. 11(c). The cost of producing components is estimated by the sum of the cost of extrusion die (assumed as proportional to the size and complexity of the frame cross sections) and the cost of bending operations (assumed as proportionalto the number of bending). The cost of producing cast sleeves is estimated by the cost of casting, which is assumed as simply proportional to its volume.3.1.3 Component Assembleability. The assembleability of components is calculated as a negative of the total cost of joining. In this paper, the method of joining is assumed to be the GMAW, which is widely used for the ASF (27). The welds are applied between the frames and the cast sleeves at joints. The cost is assumed to be proportional to the volume of total welds, which can be calculated from the total welding length multiplied by weld thickness.3.2 Mathematical Formulation.3.2.1 Definition of Design Variables. A design is uniquely specified by (i) the joint configuration types at all potential joint locations, (ii) the cross-sectional dimensions of all frames (basic members), and (iii) the welding designs at all joints, which are represented by the following three vectors x, y, and z, respectively:x T0 T1 Tn1y FS0 FS1 FSB1z W0 W1 Wn1 (4)where Ti is the set of feasible joint configuration types at potential joint location i (Eq. (1), n is the number of the potential joint locations, FSk is the set of valid beam cross-section a designs for frame k in the structure (Eq. (2), B is the number of frames in the structure, and Wi is the set
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