外文翻译--关于汽车喷油泵端面凸轮轨道冷锻的研究

附 录 附录 A： Research on orbital cold forging for the edge cam of automobile fuel injection pump ABSTRACT: The experimental investigation and theoretical analysis of an orbital cold forging of an edge cam was explored. The effects of blank shape and the process parameters on the edge cam forming are discussed. Photoplastic technology was successfully applied to the simulation of an orbital cold forging process applied to an edge cam. The China-made polycarbonate (PCBA) was used as a simulation material, and a 3-D strain distribution was obtained inside the model materials, which provided theoretical guidance for optimizing process parameters on the orbital cold forging of the edge cam. The factors that caused a crack were identified and the deformation laws in orbital cold forging of an edge cam were clarified. The metal flow line, hardness, microstructures and accuracy of the orbital cold forged edge cam were found to meet the required service properties of the product. Keywords: Orbital cold forging, edge cam, photoplasticity, simulation 1. INTRODUCTION The edge cam of the automobile fuel injection pump is a key part with complicated shape and high precision, encountered high contact stress and a high shearing stress. It is hard to be made by the conventional forming processes or machining processes, and it doesnt meet service properties of the product. The structural character and the forming property of materials of the edge cam were analyzed. Orbital cold forging is a forging process where a fixed bottom die and a moveable/orbiting top punch come together to form complex geometric workpieces with finished dimensional accuracy in a single forging operation. The orbiting upper die rolls over a metal blank while the bottom die is raised hydraulically. The billet is kneaded into the bottom die with relatively little force to produce a Near Net Shape or finished workpiece. This process features the orbiting upper die. Due to this orbiting motion over the workpiece, the resultant localized forces can achieve a high degree of deformation at a relatively low force level. As per the adjacent diagram, the forming force required, compared to conventional forming, is much lower due to a smaller contact area. 2. EXPERIMENT 2.1 Experimental equipment The orbital forging press Type PXWP-100C with capacity of 1600KN was employed for forming experiment. The orbital head completes 200 revolutions per minute. The inclined angle of the orbital head is adjustable 0 to 2 and there are four orbits selectable: circle, straight, spiral and daisy. 2.2 Selecting the blank shape The geometric shape of the blank influences greatly the filling performance and the die life of orbital cold forged parts. If the selection is incorrect, it would either damage the die or make the work piece formation unsuccessful. According to the characteristic of the geometric shape of the edge cam, three kinds of blank shape were adopted to test. Blank a) with the step and flange: The size of the protruding step of blank with the function of fixing position in the lower die is basically same as the size of the edge cam. The shape of the edge cam can be formed by the orbital forging with small deformation. Cylindrical blank b) with small step: The size of the protruding step of blank with the function of fixing position in the lower die is basically same as the size of the edge cam. The shape of the edge cam can be formed by the orbital forging with large deformation. Cylindrical blank c): By the outside diameter of the cylindrical blank to fix position in the lower die, the shape of whole edge cam can be formed by the orbital forging with large deformation. All three types of blanks can be successfully formed to the edge cam. Although the deformation of blank a) and blank b) are easier to form than the blank c), the blank a) and the blank b) require being preformed in mass production, thus it will incur high costs. In contrast, although the deformation of the blank c) is higher, its geometric shape is much simpler. Preforming is not a necessary process for blank c). It is suitable for mass production. The work hardening of material plays a very important part in orbital cold forging. So to avoid the surface cracking of the blank in orbital cold forging, the softening annealing and good lubricating for blank are very much required. The orbital cold forging process for the edge cam is as below: Blank Spheroidizing annealing Baiting Phosphating and soap treatment Orbital cold forging. 2.3 Selecting orbital cold forging Parameters If the orbit is a circle, the angle of oscillation can range from 0 to 2. Once the angle is decided, the movement of the rocker will be not changed. If the angle is larger, the area between the rocker and work piece surface is also decreased, so the required deformation force is rather less, the forming time shorter. While a larger angle can bring higher efficiency, the accuracy of the parts will also be affected. This type of orbit is suited for producing axisymmetrical parts. If the spiral orbit is selected, orbital forging will be helpful for the radial and axial flow of the metal, and also has a better centre deformation； this rocker will apply action cyclically to the central area of the blank. So it is easy to form a part with a much complicated end face. Selecting a linear orbit, it will be easier to form a longer part such as hammer and chisel. If a daisy orbit is selected, the part with tooth profile such as bevel gear and jaw clutch will be formed more easily. The angle of oscillation directly influences the deformation resistance and metal flow, the deformation resistance of theorbital cold forging is calculated as formula below: Where: S feed per revolution, mm/r； R maximum radius of the orbital cold forged part； angle of oscillation； s yield strength of materials； K influence coefficient of the friction, the inhomogeneous distribution of stress and the shape of forged part etc. For the edge cam, S=1.2 mm/r； = 2, s=700 N/mm2 (the average yield strength of material 20CrMo), K=1.8, R=32.5mm， So, P=1444KN. Thus, if the angle of oscillation is increased, the loading force is decreased, this is helpful for the radial flow of the metal. The maximum angle of oscillation 2 was applied for orbital cold forging of the edge cam. According to the characteristics of the edge cams geometric shape and the type of orbit, the circular motion of the orbital head is selected. The process trial proves the filling property of metal is better, and the clear top & bottom faces of the edge cam was obtained.The lower die of orbital cold forging is generally very highly stressed. The lower die of orbital cold forging is similar to extrusion die. The lower die of orbital cold forging for the edge cam is reinforced by two stress rings. The lower die of orbital cold forging with axially-split inset was employed so as to minimize dangerous stress concentrations. In order to prevent the curve surface and the protruding step of the edge cam from being worn down and a fracture failure, a mobile core is employed in the process, and then an ejector is used to push the forged part out after it is being formed. 3. PHOTOPLASTIC SIMULATION Orbital cold forging deformation for the edge cam was studied with a photoplastic method. The model blank of photoplastic simulation need not to be split before forming. So the defects which the approximate portion of other experimental simulation methods is too large in studying the large deformation are avoided for photoplastic method. The photoplastic method can directly give us a set of the difference lines of equal principal strain, and a set of the direction tracks of principal strain in the model. It has many advantages such as: the strain diagram was directly perceived through the senses, and its reality, high measuring precision and high sensitivity. It is convenient for data collection, and provides a good way to study the plastic deformation which reflects the real situation. The China made polycarbonate (PCBA) was used as a simulation material. The blank size of the model material (PCBA) was same as the blank size of the edge cam. The blank of the model material was directly orbital cold forged. The full-field strain distribution for orbital cold forging deformation was indirectly obtained by the similarity relationship.The full-field strain distribution which is on the section with height of 17mm along the Z axial direction of the edge cam for orbital cold forging. From the strain distribution diagram, it was observed in the deformation of the edge cam, that the Z of intermediate zone is compression strain, the radial strain r and the tangential strain of intermediate zone are tension strain where r10mm. This is identical with ordinary cylinder upsetting, and the fluctuation of strain value is low. But the fluctuation of strain value is higher where the intermediate zone r10mm. It indicates that the deforming zone is inhomogeneous deformation. The max.radial strain r was attained and the larger tangential strain was also attained where r=25mm. As a result, the cracks occur easily in this zone. This is consistent with the cracks occurrence of orbital cold forging of the edge cam. The strain distribution of each Z axis section and deformation rules can be seen from the strain distribution diagram in orbital cold forging of the edge cam, such as the cracks occur easily in the maximal tension strain zone. The deformation homogeneity and detailed deforming of each deformation zone can be explored by the fluctuation of each strain value. It provides experimental basis for keeping defects of deformation cracks from happening, and fixing quantify datum for process experimental analysis. Thereby correct metal deformation laws were obtained in orbital cold forging of the edge cam. 4. RESULT AND ANALYSIS Upon the completion of optimizing the process parameters, orbital forging of the edge cam analysis and experimental trials, the qualified orbital forged edge cam was obtained. The microstructure of blank (Spheroidizing annealed condition) is composed of ferrite and pearlite. After blank forging, the grain is elongated and distorted. It takes on the obvious fiber structure, and the crystal boundary and the slip line cant be identified. Thus the grains were fragmentized in orbital forging of the edge cam, the amount of recrystallizing nucleus were increased in the subsequent heat treatment. The interior zone of the edge cam is free from any defects. But the metal flow line of the machining made edge cam is cut off. The brinell hardness of blank (annealed condition) is 130-135HB on average, after deformation, as result of work hardening, the highest hardness of the edge cam reaches to 287HV, a 110% increase. The hardness distribution of the edge cam isnt uniform. The hardness of the edge cam is higher where the strain is higher. This is consistent with experimental simulation and physical measurement. It indicates that the mechanical property of the edge cam by orbital cold forging is better than the machining made edge cam. The work hardening of the material caused by orbital cold forming increases tensile strength and hardness of the edge cam. The wear resistant property of the edge cam was greatly improved. 5. CONCLUSIONS Upon the completion of the research on the orbital cold forging of the edge cam, the following conclusions are drawn: (1) The complicated 3D curved parts with finished dimensional accuracy such as the edge cam of automobile can be formed in a single forging operation. (2) The photoplastic technology can be applied to simulation of orbital cold forging process of the edge cam. (3) The photoplastic technology gives us a theoretical basis for further exploration on orbital cold forging process, as well as the selection of the optimization process parameters. (4) The metal flow line, hardness and metallographic structure of the orbital forged edge cam meet the service performance, which is better than machining made part. (5) In comparison with hot precision forging, the orbital cold forging of the edge cam can save 1/3 of the material consumption, and the productivity increases by over five times. In comparison with machining, the orbital cold forging of the edge cam can save 2/3 of the material consumption, and the productivity increases by over ten times. 附录 B： 关于汽车喷油泵端面凸轮轨道冷锻的研究 摘要 :对试验研究和理论分析的端面凸轮机构轨道冷锻进行了探讨。在零件毛坯形状的影响及工艺参数对成形的端面凸轮等方面进行了探讨。光范技术成功应用于模拟冷 锻工艺应用于端面凸轮。针聚碳酸酯 (PCBA)作为一个模拟的资料，并获得了三维塑性应变分布模型材料内提供了理论指导为优化工艺参数对轨道冷锻。这个因素所引起的裂缝识别和变形规律在端面凸轮轨道冷锻方面得到了澄清。发现了金属流线，硬度，组织和准确性端面凸轮轨道冷锻，满足所需的服务性质产品。 关键字 ： 轨道的冷锻造，凸轮，光塑力学，模拟 1. 引言 汽车燃油喷射泵的端面凸轮是一种形状复杂 ， 精度高 ， 遇到高接触应力、高剪切应力的关键部件。用传统的形成的过程或者机器加工过程做是很难的，并且它不是那些满足服务性质的产品。对其 形成的结构特点和材料性能的端面特征进行了分析。 轨道冷锻锻造工艺是一个固定的底模和活动的轨道顶端冲头一起完成具有一定几何尺寸精度的复杂工件的一个单一的锻造操作。 轨道上模滚过金属毛坯当底模被液压举升。揉进了钢坯底部和相对小的力模具生产近净形或完成的工件。该工艺是轨道上模。由于在工件上方的这种绕轨道运行的运动，因而发生的局限的力量在相对低的力量水平能实现高度的变形。按照邻近的图解，形成的力量需要，与传统的形成相比，由于一个更小的接触面积而低得多。 2. 试验 2.1 试验设备 重 1600KN 的 PXWP-100C锻 压机被用来做试验。轨道头完成 200 转 /分。轨道头的倾斜角度可调整 0到 2，有 4个轨道可选：圆形，直线形，螺线形和扁带形。 2.2 选择毛坯的形状 几何形状的毛坯很大的影响填充性能及模具寿命的轨道冷锻部分。如果选择是正确的 ， 它也不会破坏或使的工件形成以失败告终。根据特征的几何形状的端面凸轮 ， 对三种毛坯形状进行了测试。 毛坯 a： 用这种措施和凸缘： 突出的大小的毛坯功能定位在上下模基本上是一样大小的端面。这种形状的端面凸轮能形成轨道小变形。 圆柱体的毛坯 b：用简单的步骤 突出的大小毛坯的功能定位在上下模基本上 是一样大小的端面。端面凸轮的形状能形成轨道大变形。 圆柱体的毛坯 c: 通过外部的直径圆柱毛坯来定位在上下模形状的整体优势 ,可以形成凸轮和轨道大变形。 所有三种类型的毛坯可以成功地形成端面。虽然变形的毛坯 a)和毛坯 b)很容易形成需要被预先大批量生产 ， 因此它会承受高额的费用。相反 ,尽管变形毛坯 c)越高 ， 其几何形状是非常简单的，适用于大批量生产。 工作中起着非常重要的部分材料是轨道冷锻。所以 ,为了避免表面裂纹的毛坯在轨道冷锻、软化退火，良好的润滑是非常必需的。端面凸轮冷锻工艺如下 : 毛坯 球化退火 下料 磷 化、肥皂处理 轨道冷锻。 2.3选择轨道的冷锻造参数 如果轨道一圈、角振荡的范围可以从 0 2。一旦角确定了 ， 运动将没有改变。如果这个角度越大 ， 之间的区域 ,工件表面摇臂也下降 ， 导致变形力是需要较少的时间形成。而大角度可以带来更高的效率 ， 精确的部分也会受到影响。这种类型的轨道适合生产回转体零件。如果螺旋轨道被选中 ， 轨道锻造有利于径向、轴向流的金属 ， 也有较好的中心变形，这摇臂将适用于变形状况的毛坯的中心地区。所以很容易形成有一个更为复杂的顶面部分。选择一个线性轨道时 ， 它将会更容易形成一个较长的部分如铁鎚和凿 刀 ， 击碎它。如果一个扁带形轨道被选中 ，这个部分齿形锥齿轮和鄂式离合器将更容易形成。 这个角振荡会直接影响变形抗力和金属流动、耐候钢的变形抗力的 theorbital冷锻的公式如下 : S - -每转走刀量， mm/r； R - -轨道冷锻的最大半径； - -摆动角； s - -材料的屈服强度； K - -摩擦的影响系数，锻造部分的应力不均匀分布等。 对于端面凸轮， S = 1.2毫米 /转； = 2， s =