非圆齿轮与机械压力机运动学优化外文文献翻译、中英文翻译、外文翻译

1 附录一 :英文文献原文  Optimized Kinematics of Mechanical Presses with Noncircular Gears E. Doege ( l ) , M. Hindersmann Received on January 8, 1997 Abstract： The quality of parts manufactured using metal forming operations depends to a large degree on the kinematics of the press ram. Non-circular gearsy to obtain those stroke-time behaviours we aim at as an optimum for the various metal forming ope with a rotational-angle-dependent speed ratio in the press drive mechanism offer a new wa rations in terms of manufacturing. The paper explains the principle using a prototype press which was built by the Institute for Metal Forming and Metal Forming Machine Tools at Hanover University. It will present the kinematics as well as the forces and torques that occur in the prototype. Furthermore, the paper demonstrates using one example of deep drawing and one of forging that the press drive mechanism with non-circular gears may be used advantageously for virtually all metal forming operations. Keywords: Press, Gear, Kinematics 1 lntroductior Increasing demands on quality in all areas of manufacturing engineering, in sheet metal forming as well as in forging, go hand in hand with the necessity to make production economical. Increasing market orientation requires that both technological and economic requirements be met. The improvement of quality, productivity and output by means of innovative solutions is one of the keys to maintaining and extending one's market position.In the production of parts by metal forming, we need to distinguish between the period required for the actual forming process and the times needed to handle the part. With some forming processes we have to add time for necessary additional work such as cooling or lubrication of the dies. This yields two methods of optimization, according to the two aspects of quality and output. In order to satisfy both aspects, the task is to design the kinematics taking into account the requirements of the process 湘潭大学兴湘学院毕业论文   during forming； also to be considered is the time required for changing the part as well as for auxiliary operations in line with the priority of a short cycle time. 2 Pressing Machine Requirements One manufacturing cycle, which corresponds to one stroke of the press goes through three stages: loading,forming and removing the part. Instead of the loading and removal stages we often find feeding the sheet, especially in sheer cutting. For this, the press ram must have a minimum height for a certain time. During the forming period the ram should have a particular velocity curve,which will be gone into below. The transitions between the periods should take place as quickly as possible to ensure short cycle time. The requirement of a short cycle time is for business reasons, to ensure low parts costs via high output. For this reason stroke numbers of about 24/min for the deep drawing of large automotive body sheets and 1200/min for automatic punching machines are standard practice.Increasing the number of strokes in order to reduce cycle times without design changes to the pressing machine results in increasing strain rates, however. This has a clear effect on the forming process, which makes it necessary to consider the parameters which determine the process and are effected by it. In deep drawing operations, the velocity of impact when striking the sheet should be as low as possible to avoid the impact. On the one hand, velocity during forming must be sufficient for lubrication. On the other hand, we have to consider the rise in the yield stress corresponding to an increase in the strain rate which creates greater forces and which may cause fractures at the transition from the punch radius to the side wall of the part. In forging, short pressure dwell time is desirable. As the pressure dwell time drops the die surface temperature goes down and as a result the thermal wear This is counteracted by the enhanced mechanical wear due to the greater forming force, but the increase due to the strain rate is compensated by lower yield stress because of the lower cooling of the part. The optimal short pressure dwell can nowadays be determined quantitatively using the finite element method 3. In addition to cost avoidance due to reduction in wear, short pressure dwell time is also an important technological requirement for the precision forging of near net shape parts, which has a promising future. The requirements of high part quality and high output will only be met by a machine technology which takes into account the demands of the metal forming 湘潭大学兴湘学院毕业论文   process in equal measure to the goal of decreasing work production costs. Previous press designs have not simultaneously met these technological and economical requirements to a sufficient extent, or they are very costly to design and manufacture, such as presses with link drives 6. This makes it necessary to look for innovative solutions for the design of the press. Its design should be largely standardized and modularized in order to reduce costs 6. Fig 1. Prototype press 3 Press Drive with Noncircular Gears 3.1 Principle The use of non-circular gears in the drive of mechanical crank presses offers a new way of meeting the technological and economic demands on the kinematics of the press ram. A pair of non-circular gears with a constant center distance is thus powered by the electric motor, or by the fly wheel, and drives the crank mechanism itself.The uniform drive speed is transmitted cyclically and 湘潭大学兴湘学院毕业论文   non-uniformly to the eccentric shaft by the pair of noncircular gears. If the non-circular gear wheels are suitably designed, the non-uniform drive of the driven gear leads to the desired stroke-time behaviour of the ram. Investigations at the Institute for Metal Forming and Metal Forming Machine Tools (IFUM) of Hanover University have shown that in this simple manner all the relevant uninterrupted motions of the ram can be achieved for various forming processes 2.     Apart from, the advantages of the new drive, which result from the kinematics and the shortened cycle time, the drive concept is distinguished by the following favourable propertties. Because it is a mechanical press, high reliability and low maintenance may be expected. In comparision to linkage presses the number of parts and bearings is clearly reduced. Above all, a basic press type can be varied without further design changes by installing different pairs of gears, designed according to the demands of the customer. Unlike link drives, bearing locations and installations do not change within one load class as a result of different kinematics. Thus the above mentioned requirement of modularization and standardization is taken into account Reductions in time and costs are possible for the design and press manufacture. 3.2 Prototype At the Institute for Metal Forming and Metal Forming Machine Tools (IFUM) a C-frame press has been remodeled and a pair of non-circular gears was installed. The previous backgears were replaced by a planetary gear set for this purpose. The work carried out shows that remodeling of existing presses for the new drive is possible. The state of the press at the end of the remodelling is shown in fiqure 1. The press is designed for a nominal ram force of 1,000 kN and 200 kN of the die cushion. The center distance of the non-circular gears is 600 mm. The pair of non-circular gears has an average transmission ratio of 1.Each gear wheel has 59 gear teeth, straight-toothed,module 10 mm (fiaure 2). The face width is 150 mm. The gears have involute gear teeth. We assume a non-circular base curve for the design of the flank geometry. As a result the tooth geometry of a non-circular gear varies along the circumference. In spite of this, it can be derived from the well-known trapezium rack, however 4, 51. An algorithm for the computation, which takes the addendum and dedendum into account exactly, has been developed. 湘潭大学兴湘学院毕业论文   Fig. 2 View of the gears from the rear The press is designed for deep drawing of flat parts in single stroke operation mode. The maximum ram stroke is 180 mm, the number of strokes 32/min. At a stroke of 140 mm the ram velocity almost remains constant 71 mmls from 60 mm before lower dead center until lower dead center, see fiqure 3. Thus the velocity corresponds to the working velocity of hydraulic presses. The velocity of incidence of a crank mechanism with the same number of strokes would be 220 mmls, in 湘潭大学兴湘学院毕业论文   comparison. In order to keep the same average velocity with a crank press, the number of strokes would have to be halved. The short cycle time of the remodelled machine results from the fast upward motion. Because the press is run in single stroke operation mode, no particular requirements were made concerning handling time during design. The drive mechanism of the prototype with non-circular gears has in addition a favourable effect on the ram forces and the driving torques (ficlure 4). For a crank press the nominal force is normally available at 30" rotation of the crank shaft before the lower dead center. This corresponds to a section under nominal force of only 7 5% relative to the stroke. To reach the nominal force of 1,000 kN, the drive has to supply a torque of 45 kNm at the crank shaft. The prototype only requires 30 kNm on account of the additional transmission of the non-circular gears. They are transmitted to a cyclic. non-uniform crank shaft torque, resulting in a nominal force range from 60" to the lower dead center. This corresponds to 27.5% of the stroke. We always find similar conditions if the pair of non-circular gears is stepped down in the operating range of the press. This will almost always be the case with sheet metal forming and stamping. It is thus possible to design some machine parts in a weaker form and to save costs this way. 4 Further Design Examples Using the examples of two stroke-time behaviours the design is illustrated in the following. A range of parts is assumed which are to be manufactured by the press. For this purpose the ram velocity requirements and the forming section of the assumed stroke need to be quantified.Furthermore, the time needed for the handling of the part needs to be determined, and also the minimum height which the ram has to assume during the handling. From this, we design the sequence of movements, and we describe it mathematically. At the IFUM, a software program developed by the institute is used. From this mathematical description of the stroke-time behaviour we can calculate the speed ratio of the non-circular gears needed.From this we obtain the rollcurves of the gears l, 2, 7. In a first example the ram velocity in deep drawing is supposed to be constant during the sheet metal forming at least over 100 mm before the lower dead center and it is supposed to be about 400mm/s. Let the number of strokes be fixed at 30/min. Above 450mm section of stroke, let the time for the handling of the part be the same 湘潭大学兴湘学院毕业论文   as for a comparable crank press with 25 strokes per minute. Fiqure 5 shows the stroke-time behaviour , which is attained by the sketched pair of gears. The gear wheels are represented by their rollcurves. The conventional cosine curve at 25/min is given for comparison. In addition to the reduction of cycle time by 20%, the ram velocity of impact onto the sheet is also considerably reduced.110 mm before the lower dead center, the velocity of impact is 700 mmls when using the crank mechanism and only 410 mm/s when operated with non-circular gears.     A second example shows a drive mechanism as is used for forging. In fioure 6, stroke-time behaviour of a conventional forging crank press is compared with the kinematics of the press with non-circular gears illustrated in the picture.The cycle time of the crank press is 0.7 s, the number of strokes is 85/min and the nominal force is 20 MN.Its pressure dwell time is 86 ms with a forming section of 50 mm. The pressure dwell of the press depicted with non-circular gears decreases by 67% to 28 ms. It thus reaches the magnitude familiar from hammers. By increasing the number of strokes by a factor of 1.5, the cycle time decreases by 33% to 46 ms. In spite of this,the handling time remains the same compared to conventional crank press on account of the kinematics of the non-circular gears. In order to achieve these kinematics in this case, a conventional circular gear may be used as driving gear, arranged eccentrically. This reduces the costs for gear manufacture.These examples show that different kinematics can be achieved by using non-circular gears in press drives At the same time the potential of this drive with respect to the realization of the desired kinematics becomes clear as does the reduction of cycle times in production. By varying the examples it is also possible to increase the velocity after inpact in deep drawing operations if :his sequence of motions is advantageous for the range of pans to be produced on the press, for reasons of lubrication, for example. 5 Conclusions The requirements of high productivity, reduced costs and the guarantee of high product quality to which all manufacturing companies are exposed, applies particularly to companies in the field of metal working. This situation leads us to reconsider the press drive mechanism in use up to now. The new drive for crank presses with non-circular gears described here allows us to optimize the kinematics of simple mechanical presses. This means that the cycle time is shortened to achieve high productivity and the kinematics follows the requirements of the forming process.The design effort needed is low. In contrast to 湘潭大学兴湘学院毕业论文   presses with link drives, other kinematics can be achieved during the construction of the press by using other gears without changing bearing locations This allows the modularization and standardization of presses. 6 Acknowledgement The authors would like to express their appreciation to the German Machine Tool Builders Association (VDW), located in FrankfurVGermany, for its financial assistance and to some members for their active support. 7 References I Bernard, J., 1992, Optimization of Mechanism Timing Using Noncircular Gearing, Mechanical Design and Synthesis, Vol. 46, p. 565-570. 2 Doege, E., Hindersmann, M., 1996, Fertigungsgerechte Kurbelpressenkinematik durch Unrundzahnrader. VDI-Z Special Antriebstechnik 1/96, p. 74-77. 31 Doege, E., Nagele, H., 1994, FE-Simulation of the Precision Forging Process of Bevel Gears, Annals of the CIRP, Vol. 43, p. 241-244. 4 Hindersmann, M., Betke, V., 1996, Unrunde Zahnrader- ein wiederentdecktes Maschinenelement, Konstruktion, Vol. 48, p. 256-262. 5 Litvin, F. L.: 1994, Gear qeometrv and applied theory,PTR Prentice Hall, Englewood Cliffs (NJ, U.S.A.). 6 Niemitz, D., 1992, Anforderungen an Grof3raumstufenpressen；Pflichtenheft fur die Auftragsvergabe. In:Blechbearbeitung '92, Int. Congress 27 -28.0ct.1992,VDI-Bericht, Vol. 946, p.231-253. 7 Ogawa. K., Yokoyama, Y., Koshiba, T., 1973, Studies on the Noncircular Planetary Gear Mechanisms with Nonuniform Motion, Bulletin of the JSME, Vol. 16. p. 1433-1442.   湘潭大学兴湘学院毕业论文                         附录二：英文文献翻译               非圆齿轮与机械压力机运动学优化                              1997 年 1 月 8 日研制  摘要：使用金属成形方法来加工生产零件的质量很大取决于压力杆。在机械压力传动时，有一种依赖于驱动旋转角度速度比的非圆齿轮，提供了一种获得这么动作时间的新途径，我们致力于为不同的优化金属成型运作的制造。本文阐述了由汉诺威的大学研究所建成的金属成形和金属成形加工机床的使用原型原则，它就是目前运动学以及在原型产生的 力和力矩。此外，本文展示了如何使用拉深和锻造的一个例子，几乎所有的金属成形操作可有利用于机械传动机构的非圆齿轮。  关键词：压力，齿轮，运动学。  1. 简介      提高质量的要求在生产工程制造，所有的金属成形以及在锻造，有必要去携手制定生产经济。日益增长的市场定位要求技术和经济条件都得到满足。提高质量、生产力、生产手段的创新解决方案 ,是一种用来维持和扩大的市场地位的关键所在。  所生产的金属部件 ,我们需要分清期间所需的形成过程和处理零件所需的时间。随着我们必须添加一些必要的额外工作，例如冷却或润滑的模具一次成 型过程。根据质量和产量两个方面，产生了两个最优化方法。为了满足这两个方面，我们的任务是设计运动学形成过程中考虑到该进程的要求，也考虑到的是改变部分以及与一个优先线辅助运作所需的时间短周期的时间。  2. 压力机的要求     一个生产周期 ,这相当于一个冲程来回压的过程 ,大致经历了三个阶段 :加载、成型和移除零件。相反 ,在加载和移除零件阶段，我们经常发现送料的薄板 ,尤其是在纯粹的切割时候。为此，压力泵必须要一个确定时间的最小高度。成型周期中杆应该有一个特别速度曲线 ,它将会降到最低。这个转变期之间应尽快来确保短周期时 间。  短周期的要求是事件的原因 ,以确保通过高产量低成本的部分。基于这个原因，关于对大型汽车车身冲压片机和自动湘潭大学兴湘学院毕业论文   1200/min、拉深 24/min 的冲程数是标准的做法。增加冲程数是为了减少设计的周期变化导致增加的压实机械应变率 , 然而，这对成形过程有很明显影响 ,使它必须考虑参数确定过程和被它所影响。  在拉深成形过程中 ,当敲打板块时的撞击速度应尽量避免产生了深远影响。一方面 ,速度成形时必须充分润滑。另一方面 ,我们必须要考虑提高产量的相应的压力来增加造成更大的应变速率力 ,这可能导致冲床半径一侧的一部分过渡疲劳而导致 断裂。在锻造时，停留时间短的压力是可取的。随着停留时间的压力下降了模具的表面温度将降低，其结果是热磨损。这是提高抵消了由于机械磨损形成更大的力量，但由于增加的应变率是较低的，因为较低的部分冷却屈服应力补偿。目前，最佳短住压力可以用有限元分析法莱分析。此外 ,避免由于成本降低磨损、短压住时间也是一个重要的技术要求的精密锻造，近净形部分有一个光明的未来。   高质量的要求和高产量将只能通过一个机技术 ,考虑到金属成形过程的考察要求等同于减少工作的目标成本。以前按设计已经不能同时满足这些技术要求和经济的充分程度，或他们 是非常昂贵的设计和制造，例如链接驱动压力机。这就需要寻找对泵创新设计的解决方案，它的设计应主要标准化，模块化，以降低成本。  3非圆齿轮的压力传动  3.1 原则   使用非圆齿轮传动机械曲柄压力机，它提供了一种新方式的技术和经济需求的压力杆运动。一对非圆齿轮有不变的中心距 , 因此采用了电动马达，或由飞轮、曲柄和驱动机制本身。制服驱动器的速度传送是通过一对非圆齿轮传递给非均匀的偏心轴。如果非圆齿轮的适当设计，从动齿轮的非均匀驱动器会导致泵所需的行程时间行为。调查中心的金属成形和金属成型机床 (IFUM)汉诺威的大 学已经表明 ,在这个简单的方式所有相关的压力杆的连续运动，可以达到各种成形过程。  此外从运动学和缩短生产周期，驱动概念导致新的驱动器的优点被以下的良好性能所区分。因为它是一个机械压力机，它具有高可靠性、低维护性和可预期性。对连杆压力机的数量和轴承零件显然是减少。首先，一个基本泵类型可以通过安装不同的齿轮而进一步改变设计，它根据客户的要求而设计。不同环节的驱动湘潭大学兴湘学院毕业论文   器，轴承的安装位置不会随着单一载荷方向的不同运动而改变。因此，上述要求的模块化和标准化是考虑到时间和成本，它降低了设计和冲压生产成本。  3.2 原型  在金 属成型和金属成型工具机（ IFUM） 1 架的 c 型泵，它已经进行了修整和安装了非圆齿轮副。为达到这种目的，先前的背轮背一个行星齿轮组做取代。这项工作表明了存在的新型传动印刷机是可能的，在最后对标准压力泵的改造在 Fig. 1 中进行说明。  图表 1 压力机设计是为了所受 1000KN 的柱塞力和 200KN 的冲压模具缓冲力。  这一对非圆齿轮传动比平均为 1，每个齿轮轮齿有 59，直齿，模数 10mm