车床机床改造毕业外文文献翻译、中英文翻译、外文翻译

本科毕业论文中英文翻译 学生姓名： 所在院系： 机电学院 所学专业： 机械设计制造及其自动化 车床 车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。车削很少在其他种类的机床上进行，而且任何一种其他机床都不想车床那样方便地进行车削加工。由于车床还可以用来钻孔和铰孔，车床的多功能性可以使工件在一次装夹中进行几种加工。因此，在生产中使用的各种车床比任何种类的机床都多。 普通车床：普通车床作为最早的金属切削机床中的一种，目前仍然有许多有用的和人们所需要 的特性。现在，这些机床主要用在规模较小的工厂中，进行小批量的生产，而不是进行大批量的生产。 普通车床的加工偏差主要取决于操作者的技术熟练程度。设计工程师应该认真的确定由熟练工人在普通车床上加工的试验零件的公差。在把试验零件重新设计为生产零件时，应该选用经济的公差。 转塔车床：对生产加工设备来说，目前比过去更着重评价是否具有精确的和快速的重复加工能力。应用这个标准来评价具体的加工方法，转塔车床可以获得较高的质量评定。 在为小批量的零件（ 100 200 件）设计加工方法时，采用转塔车床是经济的。为了在转塔车床上获 得极可能小的公差值，设计人员应该尽量将加工工序的数目减至最少。 自动螺丝车床：自动螺丝车床通常被分为以下几种类型：单轴自动、多轴自动和自动夹紧车床。自动螺丝车床最初是用来对螺钉和类似的带有螺纹的零件进行自动化和快速加工的。但是。这种车床的用途早就超过了这个狭窄的范围。现在，它在许多类型的精密零件的大批量生产中起着重要的作用。 车床的基本部件有：床身、主轴箱部件、尾架部件、溜板部件 丝杠和光杠。 床身是车床的基础件。它通常是由于经过充分正火或时效处理的灰铸铁或者球墨铸铁之城。它是一个兼顾的刚性框架，所 有其他基本部件都安装在车床身上。 通常在床身上有内外讲足平行的导轨。有些制造厂对全部四条导轨都采用导轨尖顶朝上的三角形导轨（即山形导轨），而有的制造厂则在一组中或者两组中都采用一个三角形导轨和一个矩形导轨。导轨要经过精密加工，以保证其直线度精度。为了抵消磨损和擦伤，大多数现代机床的导轨式经过表面淬硬的，但是在操作时还应该小心，以避免损伤导轨。导轨上的任何误差，常常意味着整个机床的精度遭到破坏。 主轴箱安装在内导轨的固定位置上，一般在床身的左端。它提供动力，并可是工件在各种速度下回转。它基本上由一个安装 在精密轴承中的空心主轴和一系列变速齿轮 -类似于卡车变速箱所组成。通过变速齿轮，主轴可以在许多种转速下旋转。大多数车床由 8 18 种转速，一般按等比级数排列。而且在现代机床上只需按动 2-4 个手柄，就能得到全部转速。一种正在增长的趋势是通过电气的活着机械的装置进行无极变速。 由于机床的精度在很大程度上取决于主轴，因此，主轴的结构尺寸较大，通常安装在预紧后的重型圆锥滚子轴承或球轴承中。主轴中有一个贯穿全长的通孔，长棒料可以通过该孔送料。主轴孔的大小是车床的一个重要尺寸，因为当工件必须通过主轴孔供料时，它确定 了能够加工的棒料毛坯的最大尺寸。 尾架部件主要有三部分组成。底板与床身的内导轨配合，并可以在导轨上做纵向移动。底板上有一个可以使整个尾架部件夹紧在任意位置上的装置。尾架体安装在底板上，可以沿某种类型的键槽在底板上横向移动，使尾架能与主轴箱中的主轴对正尾架的第三个组成部分是尾架套筒，它是一个直径通常大约在51-76mm（ 2 3 英寸）之间的钢制空心圆柱体。通常手轮和螺杆，尾架套筒可以在尾架体中纵向移入和移出几英寸。 车床的规格用两个尺寸表示。第一个称为车床床面上最大加工直径。这是在车床上能够旋转地工件的最大 直径。它大约是两顶尖连线与导轨上最近点之间距离的两倍。第二个规格尺寸是两顶尖之间的最大距离。车床床面上最大加工直径表示在车床上能够车削的最大工件直径，而两顶尖之间的最大距离则表示在车床上能够车削的最大工件直径，而两顶尖之间的最大距离则表示在两个顶尖之间能够安装的工件的最大长度。 普通车床是生产中最经常使用的车床种类。它们是具有前面所叙述的所有 那些部件的重载机床，并且除了小刀架之外，全部刀具的运动都有激动进给。它们的规格通常是：车床床面上最大加工直径为 305 610mm（ 12 24 英寸）；两顶尖之间距离为 610 1219mm（ 24 48 英寸）。但是，床面上最大加工直径达到1270mm（ 50 英寸）和两顶尖之间距离达到 3658mm（ 12 英寸）的车床也并不少见。这些车床大部分都有切削盘和哟个安装在内部的冷却系统。小型的普通车床 车床床面最大加工直径一般不超过 330mm（ 13 英寸） -其中一些也可以被设计成台式车床，即床身可安装在工作台或柜子上。 虽然普通车床很有很多用途，是很有用的车床，但是更换和调整刀具以及测量工件花费很多时间，所以它们不适合在大量生产中应用。通常，它们的实际加工时间少于其加工时间的 30%。此外，需 要技术熟练地工人来操作普通车床，这种工人的工资高而且很难雇到。然而，操作工人的大部分时间却花费在简单的重要调整和观察切削产生过程上因此为了减少或者完全不雇佣这类熟练工人，转塔车床、螺纹加工车床和其他类型的半自动和自动车床已经很好地研制出来，并已经在生产中得到广泛的应用。 Lathes Lathes are machine tools designed primarily to do turning, facing, and boring. Very little turning is done on other types of maching tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the workpiece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. Engine Lathes:The engine lathe, one of the oldest metal remmoval machines, has a number of useful and highly desirable attributes. Today these lathes are used primarly in small shops where smaller quantities rather than large production runs are encountered. Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been poroduced on the engine lathe by a skilled operator. In redesigning an experimental part of production, economical tolerances should be used. Turret Lathes:Production machining equipmnt must be evaluated now, more than ever before, in terms of ability to repeat accurately now,more than ever before, in terms of ability to repeat accurateal and rapidly. Applying this criterion for establishing the production qualification of specific method, the turret lathe merits a high rating. In desingning for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turret lathe. The designer should strive for a minimum of operations. Automatic Serew Machines:Generally, automtic screw machines fall into several categories； single-spindle automatics,mulltiple-spindle automatics production of screws and similar threded part,the automatic screw machine has long since cxceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, carriage assembly, and the leadscrew and feed rod. The bed is the backbone of a lathe. It usually is made of well-noremalized or aged gray or nodular cast iron and provides a heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bad,usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets. Theyare precision machined to assure accuracy of alignment. On most modern lathes the ways are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The headstock is mounted in a fixed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the work at various speeds. Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears similar to a truck transmission through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An incereasing trend is to provide a continuousiy variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construcition and mounted in heavy bearings,usually prealoaded tapered roller or ball types.The spindle has a hole extending through its length, through which long bar stock can be fed. The size of this hole is an important dimension of a lathe because it determines the maximum size of bar stock that can be machined when the material must be fed through spindle. The tailstork assembly consists, essentially, of three part. A lower casting fits on the inner ways of the bed and can slide longitudinlly thereon, with a means for clamping the entire assembly in any desired location. An upper casting fits on the lower one and can be moved transversely upon it,on some type of keyed ways, to permint alingning the tailstock and headstock spindles. The third major component of the assembly is the tailstock quill. The is a hollow steel cylinder, usually about 51 to 76mm in diameter, that can be means of a handwhell and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diamenions. The first is known as the swing. This the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways. The second size dimension is the maximum diameter between centers. The swing thus indicates the maximum workpiece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of workpiece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610mm swing and from 610 to 1219mm center distances, but swing up to 1270mm and center distances up to 3658mm are not uncommon. Most have chip pans abd a built-in coolant circulating system. Smaller engine lathes with swings usually not