外文翻译--机床的基本部件

Basic Machine Tool Elements Most machine tools are constructed by using two or more components. These components , although they may have different function in such as a lathe , mill or drill press , have common characteristics Because of the demand for metal removal machines such as lathes , machining centers ,milling machines ,grinders , and the many others shown throughout this book , there has been continuous development in flexible machining centers .the mass-produced and special machine tools are constructed of basic elements . this chapter describes those elements . Important requirements for machine tool structures include rigidity, shape , operator and part accessibility , ease of chip removal , and safety . In terms of machine tool performance , static and precision . Stability of the machine structure is necessary to appreciate the breadth of modern machining methods in the manufacture of products . Structures For Cutting Machines Castings , forgings , and hot-or cold-formed shapes usually require machining .The variety of sizes , shapes , and materials calls for diversity in machining. Machine tools differ not only in the number of cutting edges they employ , but also in the way the tool and workpiece are moved in relation to each other . In some machines (vertical machining centers , drill presses , boring machines , milling machines, shapers, and grinders) the workpiece remains virtually motionless and the tool moves . in others (planers , lathes , and boring mills ) the tool is virtually fixed and the workpiece moves. But it should be pointed out that seldom are these simple elements applied without modification . The dingle-piont tool-shaping machines are the easiest to visualize , the lathe and the boring machine are kinematic inversions employing the single-point tool . the work rotates in the lathe, but the cutting toll is stationary . In the boring machine the tool rotates while the work is stationary . Although the lathe tool and the boring machine worktable are not truly stationary , this is overlooked for the moment . To feed a tool carriage past rotating work is usually more acceptable than to feed rotating work with headstock and supports past a stationary tool post . The shaper and planer use single-point cutting tool . The smaller workpiece is more efficiently machined on the shaper than on the planer . The general appearance of the machine is changed by reversing the kinematic relationship of work and tool . However , the cutting action principle is identical . With the introduction of the milling cutter by Eli Whitney in the early 1800s , the rotating tool was used only as a boring tool . But Whitney gave it a new application . The milling cutter was no longer used for cutting keyways , slitting ,sawing , slab and face milling , gear cutting , and shaping irregularly-formed pieces . Use of the rotating tool combined with traversing work . The cylindrical grinder adopts motions of the lathe and boring machine except for the substituting of rotating tools (the grinding wheel ) for single-point tools . The characteristics of these basic cutting machines are listed in Tab . Tab Cutting and Feed Movement for Conventionnal Machines Machine Cutting Movement Feed Movement Types of Operation Lathe Workpiece rotates Tool and carriage Cylindrical surface, drilling, boring , reaming Boring machine Tool rotates Table Drilling , boring, reaming ,and facing planer Table traverses Tool Flat surfaces(planning) Shaper Tool traverses Table Flat surfaces(shaping) Horizontal Milling Tool rotates Table Flat surfaces, gears, cams, drilling, boring Horizontal boring machine Tool rotates Tool traverses Flat surfaces Cylindrical grinder Tool (grinding wheel) rotates Table and /or tool Cylindrical surface(grinding) Drill press Tool rotates Tool Drilling boring facing and threading Saw Tool Table and /or piece Cut off Broaching machine Tool Tool External and internal surfaces 机床的基本部件 大多数机床由两个或多个组件构成。这些组件，虽然他们可能有不同的功能如车床，铣或钻床，但他们有着共同的特点。 由于对如车床，加 工中心，铣床，磨床，整本书中显示的许多其他金属切削机床的需求，出现了柔性加工中心，在不断发展。大规模生产及专用机床的构造的基本要素。本章将介绍这些元素。 机床结构的重要的要求包括刚度，形状，操作员和部分附属物，易于排屑和安全性。在机床性能，静态和精度方面。 机器结构的稳定性是必要的，对产品制造的现代加工方法的广度的理解。 切割机的结构。 铸件，锻件，热或冷成形形状通常需要加工。不同的大小，形状和材料需要不同的加工。 机械加工设备不仅在拥有的切削刀的数量上不同，而且在工具和工件的相对运动方式上也有所不同。在一些 机床中（立式加工中心，钻床，镗床，铣床，牛头刨床，和磨床）工件依然保持静止而刀具运动。在另外一些机床中（刨床，车床，镗床）刀具是相对固定和工件移动。 但是，应该指出的是，很少有不加修改地应用了这些简单的元素。 单刃成型工具的机床是最容易想象的。 车床和掘进机是采用单点工具运动倒置。 在旋转的车床工作，但切割工具是固定的。 在掘进机中刀具旋转，而工作是固定的。虽然车刀和镗床工作台都没有真正固定的，但是这被忽略了。为了找到一个工具运输过去旋转的工作通常是比较可以接受，而不是找旋转启闭工作和过去的固定刀架支持。成型机和面 使用单刃刀具。小工件在插床上比刨床上更易加工。机器的整体外观通过扭转了工件和刀具运动的关系而被改变。然而，切割作用原理是相同的。 随着铣刀由礼惠特尼在 19 世纪初引进，旋转工具，只能作为一个没用的工具，但惠特尼给了它一个新的应用。铣刀不再是仅仅用于加工圆形的孔，而且还用来加工键槽、窄缝、锯削、铣平面、齿轮以及成型不规则的零件。 除了采用旋转工具（砂轮）代替单刃刀具外，外圆磨床和车床、镗床的运动方式是一样的。 这些