【正文】 金剛石用銅焊焊接在碳 鋼刀柄上。 陶瓷刀具是戰(zhàn)后出現(xiàn)的，還沒有在工廠里得到普遍應(yīng)用。 硬質(zhì)合金刀具在高溫時具有高硬度，故它們的切削速度比高速鋼高得多，切削低碳鋼時為 3～ 4m/s(600800ft/min),它們有幾種牌號專用于大多數(shù)加工場合。 ：為克服普通碳素鋼切削速度較低的特點，本世紀初，幾種稱為高速鋼的合金鋼開始用于金屬切削。 角度 8 為刀尖角，它是兩條切削刃之間的夾角。 角度 5 表示側(cè)后角，它是端切削刃下面的側(cè)后刀面與通過切削刃并垂直于刀具基面的直線之間的夾角。 角度 2 為側(cè)前角，它是刀具前刀面在垂直于刀具基面的橫向剖面內(nèi)的傾斜角。車刀、銑刀、鉆頭甚至是砂輪的設(shè)計，所要考慮的因素基本相同。齒輪箱的輸出端與光杠和絲杠連接。通過溜板箱前的換向手柄可使嚙合齒輪與其中的一個錐齒輪嚙合，為大拖板提供“向前”或“向后”的動力。橫拖板可以帶動刀具垂直于工件的旋轉(zhuǎn)軸 線切削。尾座組件的第三部分是尾座套筒，它是一個直 徑通常在 2～ 3 英寸之間的鋼制空心圓柱軸。而小型的車床常有螺紋截面供安裝卡盤之用。它基本上有一個安裝在精密軸承中的空心主軸和一系列變速齒輪 —— 類似于卡車變速箱所組成，通過變速齒輪，主軸可以在許多種轉(zhuǎn)速下旋轉(zhuǎn)。通常在床身上那個面有內(nèi)外另組平行的導(dǎo)軌。 兩千多年前就已經(jīng)有了車床。 畢業(yè)設(shè)計譯文 題 目 : 礦井提升及總體設(shè)計 學(xué)生姓名： 杜雨航 準考證號： 080112202073 指導(dǎo)老師： 張冬梅 2020 年 LATHES The basic machines that are designed primarily to do turning, facing and boring are called lathes. Very little turning is done on other types of machine tools, and nine 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. Modem 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 changegear system that could connect the motions of the spindle and leadscrew and thus enable threads to be cut. Lathe Construction. The essential ponents of a lathe are depicted in the block diagram of are the bed, headstock assembly, tailstock assembly, carriage assembly, quickchange gear box, and the leadscrew and feed rod. The bed is the backbone of a lathe. It is usually made of wellnormalized or aged gray or nodular cast iron and provides a heavy, rigid frame on which all the other basic ponents 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 Vshape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets. Because several other ponents 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. The headstock is mounted in a fixed position on the inner ways at one end of the lathe bed. It provides a powered means of rotating the work at various speeds. It consists, essentially, of a hollow spindle, mounted in accurate bearings, and a set of transmission gearssimilar to a truck transmissionthrough which the spindle can be rotated at a number of speeds. Most lathes provide from eight to eighteen 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 increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. A longitudinal hole extends through the spindle so that long bar stock can be fed through it. The size of this hole is an important size dimension of a lathe because it determines the maximum size of bar stock that can be machined when the material must be fed through the spindle. The inner end of the spindle protrudes from the gear box and contains a means for mounting various types of chucks, face plates, and dog plates on it. Whereas small lathes often employ a threaded section to which the chucks are screwed, most large lathes utilize either camlock or keydrive taper noses. These provide a largediameter taper that assures the accurate alignment of the chuck, and a mechanism that permits the chuck or face plate to be locked or unlocked in position without the necessity of having to rotate these heavy attachments. Power is supplied to the spindle by means of an electric motor through a Vbelt or silentchain drive. Most modern lathes h