機械專業(yè)外文翻譯---車床及其結構

1、<p>　　The Lathe and Its Construction(原文)</p><p>　　From Mechanical Engineering English</p><p>　　A lathe is a machine tool used primarily for producing surfaces of revolution and flat edges.

2、Based on their purpose, construction, number of tools that can simultaneously be mounted, and degree of automation, lathes-or, more accurately, lathe-type machine tools can be classified as follows:</p><p>　

3、　(1)Engine lathes</p><p>　　(2)Toolroom lathes</p><p>　　(3)Turret lathes</p><p>　　(4)Vertical turning and boring mills</p><p>　　(5)Automatic lathes</p><p>　

4、　(6)Special-purposelathes In spite of that diversity of lathe-type machine tools, they all have common features with respect to construction and principle of operati

5、on. These features can best be illustrated by considering the commonly used representative type, the engine lathe. Following is a description of each of the main elements of an engine lathe, which is shown in Fig.11.1.&l

6、t;/p><p>　　Lathe bed. The lathe bed is the main frame, involving a horizontal beam on two vertical supports. It is usually made of grey or nodular cast iron to damp vibrations and is made by casting. </p>

7、<p>　　It has guideways to allow the carriage to slide easily lengthwise. The height of the lathe bed should be appropriate to enable the technician to do his or her job easily and comfortably.</p><p>

8、　　Headstock. The headstock is fixed at the left hand side of the lathe bed and includes the spindle whose axis is parallel to the guideways (the slide surface of the bed). The spindle is driven through the gearbox, which

9、 is housed within the headstock. The function of the gearbox is to provide a number of different spindle speeds (usually 6 up to 18 speeds). Some modern lathes have headstocks with infinitely variable spindle speeds, whi

10、ch employ frictional ,electrical ,or hydraulic drives.</p><p>　　The spindle is always hollow, i. e., it has a through hole extending lengthwise. Bar stocks can be fed through that hole if continuous producti

11、on is adopted. </p><p>　　Also, that hole has a tapered surface to allow mounting a plain lathe center. The outer surface of the spindle is threaded to allow mounting of a chuck, a face plate, or the like.<

12、;/p><p>　　Tailstock. The tailstock assembly consists basically of three parts, its lower base, an intermediate part, and the quill. The lower base is a casting that can slide on the lathe bed along the guideway

13、s, and it has a clamping device to enable locking the entire tailstock at any desired location, depending upon the length of the workpiece. </p><p>　　The intermediate part is a casting that can be moved tran

14、sversely to enable alignment of the axis of the tailstock with that of the headstock. The third part, the quill, is a hardened steel tube, which can be moved longitudinally in and out of the intermediate part as required

15、. This is achieved through the use of a handwheel and a screw, around which a nut fixed to the quill is engaged. The hole in the open side of the quill is tapered to enable mounting of lathe centers or other tools like t

16、wis</p><p>　　The carriage. The main function of the carriage is mounting of the cutting tools and generating longitudinal and/or cross feeds. It is actually an H-shaped block that slides on the lathe bed bet

17、ween the headstock and tailstock while being guided by the V-shaped guideways of the bed. The carriage can be moved either manually or mechanically by means of the apron and either the feed rod or the lead screw.When cut

18、ting screw threads, power is provided to the gearbox of the apron by the lead screw. I</p><p>　　Lathe Cutting Tools The shape and geometry of the lathe tools depend upon the purpose for which they are

19、employed.</p><p>　　Turning tools can be classified into two main groups, namely, external cutting tools and internal cutting tools. Each of these two groups include the following types of tools:</p>

20、<p>　　Turning tools. Turning tools can be either finishing or rough turning tools. Rough turning tools have small nose radii and are employed when deep cuts are made. </p><p>　　On the other hand, fini

21、shing tools have larger nose radii and are used for obtaining the final required dimensions with good surface finish by making slight depths of cut. Rough turning tools can be right-hand or left-hand types, depending upo

22、n the direction of feed. They can have straight, bent, or offset shanks.</p><p>　　Facing tools. Facing tools are employed in facing operations for machining plane side or end surfaces. There are tools for m

23、achining left-hand-side surfaces and tools for right-hand-side surfaces. Those side surfaces are generated through the use of the cross feed, contrary to turning operations, where the usual longitudinal feed is used. <

24、;/p><p>　　Cutoff tools. Cutoff tools, which are sometimes called parting tools, serve to separate the workpiece into parts and/or machine external annular grooves.</p><p>　　Thread-cutting tools. T

25、hread-cutting tools have either triangular, square, or trapezoidal cutting edges, depending upon the cross section of the desired thread. Also, the plane angles of these tools must always be identical to those of the thr

26、ead forms. </p><p>　　Thread-cutting tools have straight shanks for external thread cutting and are of the bent-shank type when cutting internal threads.</p><p>　　Form tools. Form tools have edge

27、s especially manufactured to take a certain form, which is opposite to the desired shape of the machined workpiece.</p><p>　　An HSS tool is usually made in the form of a single piece, contrary to cemented ca

28、rbides or ceramic, which are made in the form of tips. The latter are brazed or mechanically fastened to steel shanks．Fig.11.2 indicates an arrangement of this latter type, which includes the carbide tip, the chip breake

29、r, the pad, the clamping screw (with a washer and a nut), and the shank.As the name suggests, the function of the chip breaker is to break long chips every now and then, thus preventing the formatio</p><p>　

30、　車床及其結構（譯文）</p><p>　　學生：曾衡 江漢大學文理學院</p><p>　　指導教師：范超毅 江漢大學文理學院</p><p>　　車床是主要用于生成旋轉表面和平整邊緣的機床。</p><p>　　根據它們的使用目的、結構、能同時被安裝刀具的數(shù)量和自動化的程度，車床—或更確切地說是車床類的機床，可以被分成以下幾類： &l

31、t;/p><p><b>　　1.普通車床</b></p><p><b>　　2.萬能車床</b></p><p><b>　　3.轉塔車床</b></p><p><b>　　4.立式車床</b></p><p><b>

32、　　5.自動車床</b></p><p><b>　　6.特殊車床</b></p><p>　　雖然車床類的機床多種多樣，但它們在結構和操作原理上具有共同特性。這些特性可以通過普通車床這一最常用的代表性類型來最好地說明。下面是關于圖11.1所示普通車床的主要部分的描述。</p><p>　　車床床身：車床床身是包含了在兩個垂直支柱上

33、水平橫梁的主骨架。為減振它一般由灰鑄鐵或球墨鑄鐵鑄造而成。它上面有能讓大拖板輕易縱向滑動的導軌。車床床身的高度應適當以讓技師容易而舒適地工作。</p><p>　　主軸箱：主軸箱固定在車床床身的左側，它包括軸線平行于導軌的主軸。主軸通過裝在主軸箱內的齒輪箱驅動。齒輪箱的功能是給主軸提供若干不同的速度(通常是6到18速)。有些現(xiàn)代車床具有采用摩擦、電力或液壓驅動的無級調速主軸箱。</p><p&

34、gt;　　主軸往往是中空的，即縱向有一通孔。如果采取連續(xù)生產，棒料能通過此孔進給。同時，此孔為錐形表面可以安裝普通車床頂尖。主軸外表面是螺紋可以安裝卡盤、花盤或類似的裝置。</p><p>　　尾架：尾架總成基本包括三部分，底座、尾架體和套筒軸。底座是能在車床床身上沿導軌滑動的鑄件，它有一定位裝置能讓整個尾架根據工件長度鎖定在任何需要位置。尾架體為一能橫向運動的鑄件，它可以調整尾架軸線與主軸箱軸線成一直線。第三部

35、分，套筒軸是一淬硬鋼管，它能根據需要在尾架體中縱向進出移動。這通過使用手輪和螺桿來達到，與螺桿嚙合的是一固接在套筒軸上的螺母。套筒軸開口端的孔是錐形的，能安裝車床頂尖或諸如麻花鉆和鏜桿之類的工具。套筒軸通過定位裝置能沿著它的移動路徑被鎖定在任何點。</p><p>　　大拖板：大拖板的主要功能是安裝刀具和產生縱向和/或橫向進給。它實際上是一由車床床身V形導軌引導的、能在車床床身主軸箱和尾架之間滑動的H形滑塊。大拖

36、板能手動或者通過溜板箱和光桿(進給桿)或絲桿(引導螺桿)機動。</p><p>　　在切削螺旋時，動力通過絲桿提供給溜板箱上的齒輪箱。在其余車削作業(yè)中，都由光桿驅動大拖板。絲桿穿過一對固定在溜板箱后部的剖分螺母。</p><p>　　當開動特定操作桿時，剖分螺母夾在一起作為單個螺母與旋轉的絲桿嚙合，并帶動拖板沿著床身提供進給。當操作桿脫離時，剖分螺母釋放同時大拖板停止運動。另一方面，當使用

37、光桿時則通過蝸輪給溜板箱提供動力。 蝸輪用鍵連接在光桿上，并與溜板箱一起沿光桿運動，光桿全長范圍開有鍵槽?，F(xiàn)代車床一般在主軸箱下裝備快速變換齒輪箱，通過一系列齒輪由主軸驅動。它與光桿和絲桿連接，能容易并快速地通過簡單轉換適當?shù)牟僮鳁U選擇各種進給。快速變換齒輪箱可用于普通車削、端面切削和螺旋切削作業(yè)中。由于這種齒輪箱與主軸相連，主軸每轉一圈溜板箱(和切削刀具)運動的距離能被控制，這距離就可以被認為是進給。</p><p

38、><b>　　車床切削刀具</b></p><p>　　車床刀具的形狀和幾何參數(shù)取決于它們的使用目的。車削刀具可以分為兩個主要組別，即外部切削刀具和內部切削刀具。這兩組中的每一組都包括以下類型刀具：</p><p>　　車削刀具：車削刀具可以是精車刀具或粗車刀具。粗車刀具刀尖半徑較小，用于深切削。而精車刀具刀尖半徑較大，用于通過微量進刀深度來獲得具有較好表面光潔

39、度的最終所需尺寸。粗車刀具按其進給方向可以是右手型的或是左手型的。它們可以有直的、彎的或偏置的刀桿。</p><p>　　端面刀具：端面刀具用在端面作業(yè)中加工平板側面或端部表面，也有加工左右側表面之分。與一般采用縱向進給的車削作業(yè)相反，那些側表面通過采用橫向進給產生。</p><p>　　切斷刀具：切斷刀具，有時也稱為分割刀具，用于將工件分割成若干部分和/或加工外部環(huán)形槽。</p&g

40、t;<p>　　螺紋切削刀具：螺紋切削刀具根據所需螺紋的橫截面，有三角形的、矩形的或梯形的切削刃。同時，這些刀具的平面角必須始終與螺紋形狀的平面角保持一致。車外螺紋的螺紋切削刀具為直刀桿，而車內螺紋的螺紋切削刀具則是彎刀桿。</p><p>　　成形刀具：成形刀具有專門制成特定形狀的刀刃，這種刀刃形狀與被加工工件所需外形正好相反。</p><p>　　高速鋼刀具通常以單件形式

41、制造，而硬質合金或陶瓷刀具則以刀尖形式制造。后者用銅焊或機械方法固定于鋼質刀桿上。圖11.2所示為機械式固定布置方式，它包括了硬質合金刀尖、斷屑槽、襯墊、卡裝螺桿(帶有墊圈和螺母)及刀桿。顧名思義，斷屑槽的功能就是不時地折斷長切屑，以防形成很長的可能會在機加工操作中引起問題的纏繞切屑條。硬質合金刀尖(或陶瓷刀尖)根據采用它們的機加工操作，可以有不同的形狀。根據將刀尖裝配在刀桿上是通過用銅焊還是機械卡裝，刀尖可以是實心的或是帶有中心通孔的