(论文翻译 页数:12 字数:5387)摘要：普通车床作为最早的金属切削机车的一种，目前仍然有许多有用的和为人们所需要的特性。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，而不是进行大规模的生产。普通车床的加工偏差主要依赖于操作者的技术熟练程度。设计工程师应该认真地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。
关键词:机械；车床
用于车外圆、端面和镗孔等加工的机床称作车床。车削很少在其他种类的机床上进行，因为其他机床都不能像车床那样方便地进行车削加工。由于车床除了用于车外圆还能用于镗孔、车端面、钻孔和铰孔，车床的多功能性可以使工件在一次定位安装中完成多种加工。这就是在生产中普遍使用各种车床比其他种类机床都要多的原因。
两千多年前就已经有了机床。现代车床可以追溯到大约1797年，那时亨利.莫德斯利发明了一种具有丝杠的车床。这种车床可以控制工具的机械进给。这位聪明的英国人还发明了一种把主轴和丝杠相连接的变速装置，这样就可以切削螺纹。
车床的主要部件：床身、主轴箱组件、尾架组件、拖板组件、变速齿轮箱、丝杠和光杠。
床身是车床的基础件。它通常是由经过充分正火或时效处理的灰铸铁或者球墨铸铁制成，它是一个坚固的刚性框架，所有其他主要部件都安装在床身上。通常在床身上面有内外两组平行导轨。一些制造厂生产的四个导轨都采用倒“V”型，而另一些制造厂则将倒“V”型导轨和平面导轨相结合。由于其他的部件要安装在导轨上并在导轨上移动，导轨要经过精密加工，以保证其装配精度。同样地，在操作中应该小心以避免损伤导轨。导轨上的任何误差，常常会使整个机床的精度遭到破坏。大多数现代机床的导轨都要进行表面淬火处理，以减少磨损和擦伤，更大的耐磨性。
主轴箱安装在床身一端内导轨的固定位置上。它提供动力，使工件在各种速度下旋转。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。大多数车床有8～18种转速，一般按等级数排列。在现代车床上只需扳动2~4个手柄，就能得到全部挡位的转速。目前发展的趋势是通过电气的或者机械的装置进行无级变速。

Lathes
Abstract: The engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily 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 product on the engine lathe by a skilled operator. In redesigning an experimental part for production, economical tolerances should be used.
Key words: machine; lathe
The basic machines that are designed primarily to do turning, facing and boring are called lathes. Very litter turning is done on other types of machine tools, and none can do it with equal facility. Because lathe can do boring, facing, drilling, and reaming in addition to turning, their versatility permits several operations to be performed with a single setup of the workpiece. This accounts for the fact that lathes of various types are more widely used in manufacturing than any other machine tool.
Lathes in various forms have existed for more than two thousand years. Modern lathes date from about 1797, when Henry Maudsley developed one with a leadscrew. It provided controlled, mechanical feed of the tool. This ingenious Englishman also developed a change-gear system that could connect the motions of the spindle and leadscrew and thus enable threads to be cut.
Lathe construction. These are the bed , headstock assembly, tailstock assembly, carriage assembly, quick-change gear box, and the leadscrew and feed rod.
The bed is the backbone of a lathe. It usually is made of well-normalized 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 bed, 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. Because several other components are mounted and/or move on the ways they must be made with precision to assure accuracy of alignment. Similarly, proper 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 ways on most modern lathes are surface hardened to offer greater resistance to wear and abrasion.