Lesson 23 Lathes车床 机械专业专业英语教学用书.pptVIP

Lesson 23 Lathes车床 Lathes are machine tools designed primarily to do turning, facing, and boring（车外圆、车端面和钻孔）. Very little turning is done on other types of machine tools, and none can do it with equal facility（灵巧，设备）. Because lathes also can do drilling and reaming（铰孔）, their versatility permits several operations to be done with a single setup（一次安装）of the workpiece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. Lesson 23 Lathes车床 The essential components of a lathe are the bed (床身），headstock assembly（主轴箱组件）, tailstock assembly（尾架组件）, carriage assembly, and the leadscrew and feed rod（溜板组件、丝杠和光杠）. Lesson 23 Lathes车床 The bed is the backbone （基础件）of a lathe. It usually is made of well-normalized or aged （充分正火或时效处理）gray or nodular cast iron（灰铸铁或者球墨铸铁） and provides a heavy, rigid frame on which all the other basic components are mounted（安装）. Two sets of parallel, longitudinal ways（纵向导轨） , inner and outer, are contained on the bed, usually on the upper side. …... Lesson 23 Lathes车床 ……Some makers use an inverted V-shape（尖顶朝上的）for all four ways, whereas others utilize one inverted V and one flat way（一个三角形导轨和一个矩形导轨）in one or both sets. They are precision-machined to assure accuracy of alignment. On most modern lathes the ways are surface-hardened to resist wear and abrasion（磨损和擦伤）, 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. Lesson 23 Lathes车床 The headstock（主轴箱）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 hollow spindle, mounted in accurate bearings, and a set of transmission gears--similar to a truck transmission（卡车变速箱）—through which the spindle can be rotated at a number of speeds. …… Lesson 23 Lathes车床 ……Most lathes provide 8 to 18 speeds, usuall