带自动分度机构的法兰盘加工回转工作台的设计【含CAD图纸】
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徐州工程学院毕业设计(论文)任务书 徐州工程 学院 机械设计制造及其自动化 专业设计(论文)题目 带自动分度机构的法兰盘加工回转工作台设计 学 生 姓 名 陆爱军 班 级 04机本2班 起 止 日 期 2008.02.25到2008.06.02 指 导 教 师 陈跃 教研室主任 李志 发任务书日期 2008 年 2月 25 日1.毕业设计的背景:回转工作台是各种机床上必不可少的配件,目前应用在各种铣床和数控机床上,它配合步进电动机的自动分度加工在机械领域有更大的应用。它能准确的加工所需要的零件,而且加工方便简单。2.毕业设计(论文)的内容和要求: 设计内容: 1. 工作台机械机构设计2. 自动分度控制电路设计设计要求:设计一种专门加工法兰盘的钻床工作台,可以针对不同的法兰盘,进行自动分度加工,要求分度方便准确,工作台便于安装。1A0图纸三张,分别为系统装配图和各零件图,电路图;2毕业设计说明书一本(2万字);3相关外文资料翻译(5000字)。3.主要参考文献:1 实用机械设计手册上册,机械工业出版社,实用机械设计手册编写组 编,1992 年9月。2 机械精度设计基础,科学出版社,孙玉芹,孟兆新主编,2004年2月。3 电动机的单片机控制,北京航空航天大学出版社,2002年。4 金属切削原理,上海科学技术文献出版社,上海纺织工业专科学院,刘源灿主编,1984年4月。5 自动控制原理,机械工业出版社,陈玉宏主编,2003年。4.毕业设计(论文)进度计划(以周为单位):起 止 日 期工 作 内 容备 注第1周第2周第3,4周第5,6周第7,8周第9周第10周第11,12周第13,14周第15,16周2008.6.2了解设计的机本要求,查阅相关资料查阅相关资料,写开题报告外文资料翻译 设计方案比较选择工作台设计计算分度部分设计计算分度控制电路设计分度程序设计绘制机械和电路图撰写毕业设计说明书答辩准备教研室审查意见: 室主任 年 月 日学院审查意见: 教学院长 年 月 日附录附录1英文翻译Dimensional ControlIn the early days of engineer, the mating of parts was achieved by machining one part as nearly as possible to the required size, machining the mating part nearly to size, and then completing its machining, continually offering the other part to it, until thedesired relationship was obtained. If it was inconvenient to offer one part to the other part during machining, the final work was done at the bench by a fitter, who scraped the mating parts until the desired fit was obtained, the fitter therefore being a fitter in the literal sense. It is obvious that the two parts would have to be done all over again. In these days, we expect to be able to purchase a replacement for a broken part, and for it to function correctly without the need for scraping and other fitting operations. When one part can be used off the shelf to replace another of the same dimension and material specification, the parts are said to be to be interchangeable. A system of interchangeability usually lowers the production costs, as there is no need for an expensive fiddling operation, and it also benefits the customer in the event of the need to replace worn parts. It also, however, demands that the dimension of mating parts be specified, and that dimensional variations, due to machine and operator shortcomings, be taken into account. Some form of inspection must be introduced to ensure that the manufacture is controlled; this is particularly important, because dimensional errors may not be revealed until some time has elapsed, and often many miles from the place where the machining was done.1. Tolerance and Limits of sizeSince it is accepted that it is virtually impossible to manufacture a part without error, or in the rare event of a part being without error, to be able to proclaim it to be perfect (because the measuring instruments are subject to errors), it is necessary to indicate the maximum errors permitted. The draughtsman must indicate the largest and smallest sizes that the limits of size, and the difference between them is called the tolerance, the actual tolerance must be increased with size. The tolerance should be as large as possible, to keep the cost to a minimum.The method of indicating, on a drawing, the permitted tolerance depends mainly upon the type of operation involved, but local preference must also be taken into account. The following examples will illustrate some of the methods used,(1) Unilateral limits. These are usually used when the distance between two faces, or the diameter of a hole or shaft id specified. For example, when a diameter is being ground, the machinist would prefer to aim at the largest size permitted, so that, in the event of his reaching a diameter that is just a little larger than the maximum size permitted, he can take another cut, knowing that he can use up the whole of the tolerance before the job is rejected. A draughtsman might dimension a nominal 75-0.012 mm diameter shaft as D75. Similarly, a nominal 75mm hole might dimensioned as D75-0.012, the same reasoning applies as for shafts.(2) Bilateral limits. These are usually applied when, for example, the position of a hole is specified. The machine operator may position he hole nearer the datum or further from the datum than intended, he must aim between the limits of position, so that the maximum error can be made without causing the part to be rejected. The center distance between two holes would therefore be specified as, for example, 100+0.02mm.2. Fits are concerned with the relationship between two parts. Consider a shaft and a hole combination: if the shaft is larger than the hole, the condition is said to be of interference; and if smaller than the hole, the condition is said to be of clearance. The interference may be such that the two parts can be assembled only by shrinking, or it may be very slight, so that the parts can be assembled by hand-operated press. Similarly, the clearance can be slight, so that the shaft can rotate easily in the hole, or be large, so that there is ample clearance for bolts to pass through.In order that the precise condition is ensured, the limits of size of both the shaft and the hole must be stipulated.(1) Classes of fit. These are classified as follows.Clearance fit. When the limits of size of both the hole and the shaft are such that the shaft is always smaller than the hole, the fit id said to be a clearance fit.Interference fit. When the limits of size of both the hole and the shaft are such that the shaft is always larger than the hole, the fit id said to be a interference fit.Transition fit. When the limits of size of both the hole and the shaft are such that the condition may be clearance or interference, the fit id said to be a transition fit.(2) Hole-based system and Shaft-based system. In order to obtain a range of degrees of clearance, and degrees of interference, it is necessary to use a wide variation of hole sizes and shaft sizes. For example, a manufacturing company could be making a number of parts, all of a nominal 25-mm diameter, but which are all slightly different in actual limits of size, to suit the actual fit required of each pair of parts. This situation could mean that a large number of drills, reamers, gauges, etc. were required.It is logical that, to reduce this number, a standard hole could be used for each nominal size, and the variation of fit e obtained by making the mating shaft smaller or larger than the hole. This is known as a hole-based system. Alternatively, a standard shaft could be used for each nominal size, and the variation of fit is obtained by making the mating hole larger or smaller, as required. This is known as a shaft-based system. a hole-based system is usually preferred, because it standardizes “fixed size” equipment such as reamer and pluggauges; but a shaft-based system is usually also provided, because sometimes it is more convenient to employ a common shaft to which a number of components is assembled, each with a different fit, and sometimes it is convenient to use bar stock without further machining.3. Systems of limits and fits It is convenient to establish a standardized system of limits and fits, not only to eliminate the need for the draughtsman to determine the limits each time an assembly is detailed, but also to standardize the tools and gauges required. A system of limits and fits should cater for a wide range of nominal sizes. To satisfy the various needs of industry, and should cater for a wide range of quality of work. The system should, if possible, be tabulated, to save the user the trouble of having to calculate the limits of size to suit of the class of fit, the quality of the work, and the size of the part.4. British Standard 4500: 1969, ISO limits and fitsThis standard replace BS 4500 is essentially a revision of BS 1961 to bring the British Standard into line with the latest recommendations of the International Organization for Standardization (ISO). The system refers to holes and shafts, but these terms do not only apply to cylindrical parts but can equally well be applied to the space contained by. Or containing, two parallel faces or tangent planes. The system is tabulated,and covers sizes up to 3150mm.The Numerical Controls developmentThe first electronic computer in the world emerged in 1946, this indicates the mankind has created the tool that can strengthen and replace the mental labour partly . It, and mankind those that create to strengthen tool of manual labor compare among agriculture, industrial society, the qualitative leap has arisen , has established the foundation that the mankind enters the information-intensive society . 6 years later, namely in 1952, the technology of the computer was applied to the lathe , the first numerical control lathe has emerged in U.S.A. From then on, the traditional lathe had produced the change of the quality. In nearly half a century, the numerical control system went through two stages and six generations development The numerical control lathe is regarded as the integrated typical products of electromechanics, play an enormous role among mechanical manufacturing industry , solve structure complicated , accurate , batch little , changeable processing problem of part in the modern machine-building well, and can stabilize the processing quality of the products , improve production efficiency by a large margin . But seen from situation which enterprises face at present, because the numerical control lathe price is relatively expensive, ambassadors enterprises are unable to do what one wants very much to do to relatively make the investment once only. Our country can yet be regarded as a kind of better good plan to the numerical control transformation of the ordinary lathe as the lathe big country . This text proposes to the domestic enterprises current situation at present the economic numerical control of the simple and easy type transforms the thinking and design method for technical staff of numerical controls reference.Numerical control transformation mean to ordinary lathe some position make certain transformation generally, match the numerical control device, thus make the lathe have working ability of numerical control, its purpose is for improving machining accuracy of the old equipment and production efficiency, adapt to many variety and production , short run of part , can make industrial grade can process the high-quality part too than low worker at the same time, reduce investment of technological transformation of the equipment ,etc.Price performance on all these for improving been for lathe than,namely last mechanical performance and the working ability not higher with less money. So transform ordinary lathe as numerical control lathe whether one improve numerical control effective way of rate. Generally speaking, carry on the transformation concrete method of numerical control to the existing ordinary lathe, main transmission make change seldom, is it adopt high-accuracy ball guide screw is it is it give axle already existing ordinary guide screw to enter to replace to enter the transmission of giving. Machinery some transformation after finishing , mix M C S - 51 one-chip computer as numerical control system , with walk into electrical machinery urge the component, first class to moderate gear wheel urge X , sport , Z of axle. In our country in the numerical control lathe is transformed , the microcomputers mostly adopt M C S - type 51 one slice of microcomputers of systematic form, it is a result of very large scale integration development, widely used in the controlled field, develop very fast.According to the function level of the numerical control system , can divide the numerical control system into high , middle and low three to block , the low-grade numerical control system can be regarded as the economy numerical control system. The economy numerical control system is as to standard numerical control system, different periods, the meaning of different countries and regions is different. According to practising the instructions for use of the lathe, rational reduced system, lower costs , can be called economily. Different from the economy numerical control system , call the numerical control system with more complete function numerical control system of the whole function, or is called the standard numerical control system.As regards its function, economy numerical control system general resolution ratio is it give speed to be low moving axle count little , man-machine relatively simple excuse in succession to enter. If position /last control system sharply can last numerical control system not economy. As to its structure, make ring numerical control system general high performance, but of simple structure, the fabrication cost is cheap, can be the most economic numerical control system . So economy numerical control system mainly refer to turning on the numerical control system of the ring at the present stage at home.Have close standard numerical control system of ring, economy numerical control system is it change numerical control system right away there is no ample scope for abilities to turn on. In fact , make ring numerical control system use quite extensive even in our country. The high-performance standard numerical control system costs an arm and a leg, a lot of enterprises are difficult to bear . In addition recommend precise festival produce now, with what whom equipment process with low costs and quality can guarantee, process some equipment, if pursue the high precise equipment blindly, then the production cost increases, this is unnecessary.附录2中文译文尺寸控制在早期的工程(问题)中,配合零件获得的方法是,首先尽可能把一个零件加工到所需的尺寸,再将与它相配合的零件加工到接近所需尺寸,不断将这两个零件试配,再进一步加工直至获得所许的配合关系。如果加工中不便于将两个零件进行试配,则最后的工作是由钳工在钳工台完成,钳工刮削配合零件直至达到所许配合,因此“钳工”在英文中用fitter(适当的,适配的)这一词。显然,两个配合件应该总是在一起(工作)当其中任意一个需要替换时,所有的适配刮削工作又要从头开始。这时,我们期盼能购买到可以替换坏掉零件的替用品,而无须刮削或其它钳工操作就能正常工作。当一个零件一从架子上拿来就可以替换同样尺寸同样材料规格的另一个零件,就说这个零件是可互换的。具有可互换性的系统不必进行高成本的辅助刮削工作,因此降低了产品的成本。在要替换掉磨损的零件时,零件的可互换性对维护而言也是大有好处的。然而,可互换系统要求配合件的 尺寸必须规格化,还必须考虑由于加工操作的不足之处引入的尺寸变化。必须采用某种形式的检测方法以确保对加工的控制。这一点非常重要。因为尺寸误差有时可能要过一段时间才会发现,而此时却已远离加工的地方。1 公差与极限尺寸大家知道,事实上零件不可能毫无误差的加工出来,或者说没有误差的零件是不可能的,要说明尺寸的好坏(因为测量仪器必然有误差),就有必要指出最大允许误差。绘图人员必须标明零件正常工作时的最大允许尺寸和最小允许尺寸。这些尺寸的极限值就称作极限尺寸,它们之间的差值称为公差。公差的大小取决于所涉及的加工操作类型、机械工的技能、机床的精确度以及零件的尺寸。对于给定级别的公差,实际公差应随着尺寸的增大而增大。公差应尽可能取大以使加工成本最小。在图上标注公差时,许用公差主要取决于所用操作类型,但也必须考虑本国的优先级。以下用例子说明用到的一些标注方法:(1) 单边极限。单边极限通常用于当两个面之间的距离,或孔径、轴径被指定的情况下。例如,当直径要圆整时,机械工更愿意向最大允许尺寸圆整,这样,当他加工到所得直径尺寸略大于最大允许尺寸时,还可以在整个公差范围内再切一次而不产生废品。制图员可能将公称直径是75-0.012mm 的轴标注为D75mm。同样的,公称直径是75mm 的孔也可能标的尺寸是D75-0.012mm,这同样也适用于轴的标注。(2) 双边极限。双边极限通常用于:比如当孔的位置已确定的情况下。机床操作人员可能将孔的位置定得较接近或远离所需数据,而且,当孔的加工已经开始,操作人员不可能改变孔的位置,他必须在尺寸位置限度间加工,以便在最大误差时不会使零件变成废品。因此,应将两个孔的中心距规定出来,比如,为100+0.02mm。2. 配合配合是关于两个零件之间的关系。考虑孔和轴的装配;如果轴的尺寸大于孔的尺寸,这种情况称为过盈配合;如果轴的尺寸小于孔的尺寸,这种情况称为间隙配合。过盈配合的两个零件只有通过收缩才能装配,或者过盈量非常小可通过用手压力的操作装配零件。同样,间隙非常小,轴可以很容易的在孔中旋转,或者孔的尺寸大一些,以便于有足够的间隙供螺栓从中穿过。为了确保精确,孔和轴的极限尺寸都必须予以规定。(1)装配分类如下:间隙配合 当孔和轴的尺寸界限满足轴总是小于孔,则其配合为间隙配合。过盈配合 当孔和轴的尺寸界限满足轴总是大于孔,则其配合为过盈配合。过渡配合 当孔和轴的尺寸界限所处的情况可能是间隙也可能是过盈,则称为过渡配合。( 2 ) 基孔制和基轴制。为了得到不同程度的间隙和过盈,有必要使孔和轴的尺寸有变化范围。比如,制造公z_j_(躝_z_司可能生产许多零件,它们的基本直径都是25mm,但它们的实际尺寸都是在允许极限尺寸内稍有不同,以满足每对零件的实际装配要求。这就是说需要大量的钻头、绞刀和量具等。从逻辑上看,要减小钻头、绞刀和量具等的数量,应对每种基本的尺寸用一个标准的孔,通过把与它配合的轴的尺做得稍大或稍小以获得不同的配合关系,这就是基孔制。另一种方法,每种基本尺寸都 用一个标准的轴,用比它的尺寸稍大后稍小的孔与它配合以获得不同的配合关系,这就是基轴制。用基孔制更好些,因为它可使“固定尺寸”设备如绞刀、测量仪等标准化。但也可用基轴制,当要用同一个轴和许多零件装配实现不同配合关系时用基轴制更方便。有时,直接用棒料进行装配而无须进一步加工,也使用基轴制。3. 极限尺寸与配合系统建立一个标准化的极限尺寸及配合系统是很方便的,它不但省略了绘图员每次确定装配确定极限尺寸的需要,而且还可使刀具及量具标准化。一种极限尺寸及配合标准应适用于不同的质量范围的工件。如果可能,这个系统应做成表格形式以免除使用者根据配合种类工件质量及零件尺寸来计算尺寸的麻烦。4. 英制标准4500:1969,ISO极限尺寸及配合这个标准取代了bs1961,可以是英制的尺寸也可以是公制的尺寸 。除了完全采用公制外,基本上是的改进把英国标准和最近推荐的国际标准化组织结合起来。这个系统引用的是轴和孔,但这些术语不仅适用于圆柱型的工件,也同样适用于包含两个平行面或矩形面的地方。把这个系统列成表,其尺寸范围达到3150mm。数控车床的发展1946年诞生了世界上第一台电子计算机,这表明人类创造了可增强和部分代替脑力劳动的工具。它与人类在农业、工业社会中创造的那些只是增强体力劳动的工具相比,起了质的飞跃,为人类进入信息社会奠定了基础。6年后,即在1952年,计算机技术应用到了机床上,在美国诞生了第一台数控机床。从此,传统机床产生了质的变化。近半个世纪以来,数控系统经历了两个阶段和六代的发展。数控机床作为机电一体化的典型产品,在机械制造业中发挥着巨大的作用,很好地解决了现代机械制造中结构复杂、精密、批量小、多变零件的加工问题,且能稳定产品的加工质量,大幅度地提高生产效率。但从目前企业面临的情况看,因数控机床价格较贵,一次性投资较大使企业心有余而力不足。我国作为机床大国,对普通机床数控化改造不失为一种较好的良策。本文针对目前国内企业现状,提出简易型经济数控改造思路和设计方法供数控技术人员参考。数控改造一般是指对普通机床某些部位做一定的改造,配上数控装置,从而使机床具有数控加工能力,其目的是为了提高老设备的加工精度和生产效率,适应多品种和小批量零件的生产,同时可以使技术等级较低的工人也能加工出高质量的零件,减少设备技术改造的投资等。所有这些都是为了提高机床的价格性能比,即用较少的钱得到较高的机械性能和加工能力。因此,把普通机床改造为数控机床是一条提高数控化率的有效途径。一般来说,对现有普通车床进行数控改造的具体做法是,主传动系统一般不作变动,进给传动系统中采用高精度的滚珠丝杠替换进给轴原有的普通丝杠。机械部分改造完成后,配上-51单片机作为数控系统,用步进电机作驱动元件,经过一级减速齿轮驱动、轴的运动。在我国数控机床改造中,微型计算机大多采用51型系统单片微型计算机,它是超大规模集成电路发展的产物,在控制领域中得到广泛的应用,发展非常迅速。按数控系统的功能水平,可以把数控系统分为高、中、低三挡,低档数控系统即可认为是经济型数控系统。经济型数控系统是相对标准数控系统而言的,不同时期,不同国家和地区的含义是不一样的。根据实习机床的使用要求,合理简化系统,降低成本,即可称为经济型。区别于经济型数控系统,将功能比较齐全的数控系统称为全功能数控系统,或称为标准型数控系统。就其功能而言,经济型数控系统一般分辨率和进给速度较低、连动轴数少、人机借口较简单。如点位/直线切削控制系统都可以认为是经济型数控系统。对其结构而言,开环数控系统一般性能不高,但结构简单,造价低廉,可以说得上是最经济的数控系统。所以,经济型数控系统在国内现阶段主要是指开环数控系统。并不是有了闭环的标准型数控系统,经济型数控系统或开换数控系统就无用武之地了。事实上,开环数控系统在我国应用还相当广泛。高性能的标准型数控系统价格昂贵,许多企业难以承受。此外,现在都提倡精节生产,用什么设备加工的成本低并且质量能保证,就用什么设备加工,若盲目追求高精设备,则生产成本增加,这是不必要的。
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