468 柴油機齒輪室蓋鉆鏜專機總體及主軸箱設(shè)計

468 柴油機齒輪室蓋鉆鏜專機總體及主軸箱設(shè)計,柴油機,齒輪,室蓋鉆鏜,專機,總體,整體,主軸,設(shè)計 外 文 翻 譯專 業(yè) 機械設(shè)計制造及其自動化 學 生 姓 名 聞 志 祥 班 級 B 機 制 023 學 號 0210110316 指 導 教 師 劉 道 標 1鉆削與鏜削Addison-Wesley pub.Co.聞志祥 譯摘要：通過驅(qū)動刀具能在工件上鉆出通孔或盲孔，鉆刀是正對著工件繞著自己的軸線旋轉(zhuǎn)。當然，刀具從其軸線向外的切削距離應(yīng)和需加工的孔的半徑相等。在實際生產(chǎn)中，是采用關(guān)于同一軸線對稱的兩切削刀刃的刀具。鉆削既可被應(yīng)用于手工也可用于鉆床中。鉆床在尺寸和結(jié)構(gòu)上有所不同。然而，當工件被牢固地安裝好后，鉆刀總是繞著自己的軸線旋轉(zhuǎn)。這是和在車床上鉆孔是相反的。鏜孔是擴大以前鉆削或鏜削好了的孔。鏜孔能夠消除鉆空加工時孔所產(chǎn)生的偏心，使孔擴大到需鉸削的尺寸。下面是對鉆削、鉆床分類和鏜孔的簡要介紹。關(guān)鍵詞：鉆削、鏜削、鉆床、鉆削刀具、鏜刀、鉆床的分類鉆削刀具在鉆削操作中，采用的是一種柱形的螺旋式刀具，被稱之為鉆刀。鉆刀有一條或兩條切削刃和相應(yīng)的出屑槽，出屑槽呈直線或螺旋線形。出屑槽的作用是為在鉆削過程中產(chǎn)生的切屑提供一個通道，同時也是便于潤滑劑和冷卻劑到達鉆刀的切削刃和工件的被加工表面。以下是普通刀具的概括論述：圖 4.1麻花鉆。麻花鉆是最普通的一類鉆刀。麻花鉆有兩條切削刃和兩條螺旋線形的出屑槽，出屑槽連續(xù)地圍繞分布在整個鉆體上（如圖 4.1） 。鉆刀除了鉆體部分，還有鉆頸和鉆柄，鉆柄可以是圓柱形，也可以是錐行。在后者的情況下，鉆柄是通過柄舌的楔形作用安裝在主軸的錐形鉆套中，柄舌是安裝在主軸鉆套的狹槽中，這樣鉆刀和主軸形成一個整體來傳遞旋轉(zhuǎn)運動。在另一方面，圓柱形鉆柄是被安裝在鉆鉆體頂角楔邊死頂尖出屑槽 螺旋角頸部 柄部出屑槽 刀刃刃帶后刃面出屑槽刀刃刃帶柄舌2夾頭里，然后，以安裝錐形鉆柄的方法將其安裝進主軸的鉆套中。從圖 4.1 可以看出，兩條切削邊被稱為刀刃，兩條切削刃是通過楔子連接在一起。麻花鉆還有兩條刃帶，其能在鉆削操作中對刀具起正確的導向和定位的作用。兩條刀刃形成鉆刀的頂角，頂角大小的選擇是依據(jù)被加工材料的特性。工業(yè)生產(chǎn)中經(jīng)常使用的鉆刀的頂角是 118°，其適合鉆削低碳鋼和鑄鐵。對于硬度和剛度較高的金屬，譬如，硬剛，黃銅和青銅，宜選用稍大頂角（130°或 140°）的鉆刀。常用麻花鉆的出屑槽的螺旋角是范圍是在 24°-30°之間。當在鉆削銅或軟塑材料時，推薦使用螺旋角較大的刀具（35°-45°之間） 。圖 4.2空心鉆。 空心鉆是由倒棱，鉆體，鉆頸和鉆柄組成，如圖 4.2所示。此類的空心鉆有三條或四條出屑槽和相應(yīng)數(shù)量的刃帶保證良好的導向來獲得高的加工精度 。從圖 4.2還可以看出空心鉆有一平斷，倒棱可能有三條或四條切削邊，或稱為刀刃，頂角可在 90-120范圍內(nèi)變化?？招你@是用來擴大先前已有的孔，它不是用來鉆削新的孔的?？招你@有高的生產(chǎn)率，高的加工精度和能鉆削出高質(zhì)量的表面的特性。槍孔鉆。槍孔鉆是用來加工深孔的。所有的槍孔鉆的出屑槽都是直的，只有一單條切削刃。在槍鉆的鉆體上有一個孔，其起著導管的作用，冷卻劑在較的壓力下通過該孔流到槍鉆的頂尖部位?，F(xiàn)有兩種槍鉆，即，用來加工盲孔的中心鉆和套筒鉆。套筒鉆的中心有一個圓柱形孔，鉆孔時可在工件上形成一個芯子，當鉆頭連續(xù)進給進行鉆孔時，芯子對鉆起導向作用。平鉆。平鉆是用于鉆削大于 7/2英寸的孔（90mm）乃至更大的孔。該類的鉆易于磨削。鏜刀鏜孔是擴大以前鉆削或鏜削好了的孔。鏜孔能夠消除鉆空加工時孔所產(chǎn)生的偏心，使孔擴大到需鉸削的尺寸。平底擴孔是指擴大一個鉆孔的末端。這個擴大的孔的底部是平的，它與原來的頂角倒棱 鉆體鉆頸鉆柄3孔是同軸的。刀具與導向銷一起使用，導向銷裝進已鉆好的孔中，用于切削刃對中。平底擴孔主要用于在上面安裝螺栓下面安裝螺釘?shù)目椎募庸?。在一個已加工好的孔上加工一個小的平面，該面稱之為刮孔平面。在粗糙的表面上為螺栓提供平滑的沉頭座的操作是很普遍的。如果把一個已加工控切成斜邊以便適合一個平底螺栓的圓錐座，該操作稱為锪錐面。刀具用于臥式鏜床或是被安裝在一個大型桿上或是作一個鏜前頭，它們依次排布在 機床的主軸上。絕大多數(shù)鏜孔操作是使用具有一個單齒的鏜刀，如圖 4.3所示，因為他們易于安裝和維修。鏜桿的作用是將來機床自軸的動力傳遞到刀具上和保持在切削過程中的剛性，在加工過程中，工件通常不動，刀具在孔中作旋轉(zhuǎn)進給運動。如圖所示，通常需給鏜桿提供附加支撐。鏜桿必須足夠的長以達到末端支撐和為機床操作提供一定的縱向空間。圖 4.3在銑床、坐標鏜床、或鉆床上進行精密鏜削時，有必要使用一種帶有千分尺調(diào)整的工具。這種工具安裝在刀具頭上并作旋轉(zhuǎn)運動。因此任何孔徑的增加必須通過調(diào)整工具半徑來獲得。圖 4.3b所示的是最常見的組合式雙鏜刀布置形式,他包括兩個相對的刀具夾在溝槽中。螺柱是用來在指定位置鎖緊刀具和調(diào)整他們的位置。整體裝進一個矩形狹槽中,且鎖在固定位置。刀具固定在滑行刀架里,且與頂尖成一條直線。刀具的精度取決與刀具車間的全體人員而不是操作者.端部支承鏜桿工件 主軸床頭箱 鏜桿鏜刀鏜刀工作臺圖 4.44通常用于小型機床譬如車床的鏜刀是單齒鏜刀，他是被以其能進入孔內(nèi)的方式支承著。圖 4.4a所示刀具的末端事實鍛造的，然后通過磨削成型。它是安裝在一個單獨的支承桿上，該支承桿是安裝在車床的刀架上。對于轉(zhuǎn)塔車床所用的是類似于圖 4.4b所示的刀具，只是刀桿稍有不同。刀具的修改是鏜桿部分，如圖 4.4c所示，它被設(shè)計成在鏜桿的末端擁有一個小型高速鋼刀具。鏜桿的剛度強，其長度可根據(jù)孔的長度作相應(yīng)的調(diào)整。盡管這些刀具的間隙、斜度和切削角應(yīng)該接近那些在車床操作中推薦使用的相近，但如果孔較小的話，這些角度是不能使用的。在加工工件中，普遍使用多切削刃的鏜刀。如圖 4.4f，這些表面類似筒形絞刀的刀具，但具有鑲齒銑刀，它們被調(diào)整成補償磨損和直徑變化。這種類型的鏜刀比單刃刀具有較長的壽命，因此在加工中更經(jīng)濟。如圖 4.4e 所示的帶有導向銷的以保證同軸度的平底擴孔刀具是用來擴大孔的末端。鉆床的分類便攜式的小機床上可實現(xiàn)鉆削操作，一般的機床上也可以實現(xiàn)鉆削操作。一般的機床在形狀和尺寸上不同于便攜式小機床，但它們也有共同的特征。例如，它們都擁有一根或更多根的麻花鉆，當在加工以被固定裝好了的工件時，每根麻花鉆繞著自己的軸作旋轉(zhuǎn)運動。這和在車床上工件被夾緊并隨著卡盤作旋轉(zhuǎn)運動而進行的鉆削是相反的。下面是對一些普通式鉆床的概述。臺式鉆床。臺式鉆床通常是被放在工作臺上的普通加工用途的小型機床。這種鉆床包括一個動力來源的電動機，動力是通過滑輪和皮帶傳遞到裝有刀具的主軸上。進給運動是通過降低操縱桿，由操縱桿帶動主軸的下降（或上升）來實現(xiàn)的。臺鉆的主軸在套筒內(nèi)自由旋轉(zhuǎn)（套筒由操縱桿通過齒輪齒條系統(tǒng)驅(qū)動，但不隨主軸一起旋轉(zhuǎn)） 。加工工件時，工件是被放在機床的工作臺上，有時需要一個特殊的花鉗來固定。被加工工件的最大厚度是受機床主軸與工作臺之間的間隙限制。立式鉆床。立式鉆床可被用于輕度、中等、甚至相對重負荷強度的工作，這主要取決于立式鉆床的尺寸。立式鉆床與臺式鉆床基本相似，主要的不同點是里是立式鉆床的底座上裝有一較長的圓柱形支柱。在支柱上附加安裝了一個可以鎖定在任一想要高度的滑動工作臺。當立式鉆床用于中等強度的工作時，其所需的動力要比臺式鉆床的多。在立式鉆床里有比較的的鉆床。因此，這大的鉆床有一個箱柱和較高的動力，5以此滿足重負荷。此外，它是采用齒輪箱為主軸提供不同的旋轉(zhuǎn)速度和軸向進給量，通過齒輪箱可以預(yù)先設(shè)置任何想要的主軸轉(zhuǎn)速和進給速率。多軸鉆床。多軸鉆床的結(jié)構(gòu)堅固，其工作時需要很強的動力，每臺多軸鉆床能同時鉆削很多孔。為滿足加工要求，不同的刀具是可以調(diào)整的，同時根據(jù)需要，整個床頭箱部分（帶有主軸和刀具）是可以傾斜的。這類的鉆床主要用于批量生產(chǎn)且擁有很多孔的零件的加工。例如汽缸體。排式鉆床。當幾個獨立的鉆頭（每個都有一個單獨主軸）排列在一個單獨的普通的工作臺上，此時，該機床被稱之為排式鉆床。這種機床特別地適用于幾種需連續(xù)進行的操作。搖臂鉆床。搖臂鉆床，特別地適合那些不便于安裝在立式鉆床上的大型和重型工件進行鉆孔。在圖 4.5可以看出，搖臂鉆床有一安裝在底座上的立柱。搖臂鉆床的搖臂帶著鉆床的床頭箱主軸和刀具移動，該搖臂能夠沿立柱上升或下降，并可以鎖緊在任一所需的位置上。床頭箱沿著搖臂滑動并使主軸作旋轉(zhuǎn)運動和軸向進給運動。此外，搖臂能夠擺動，因此刀具可移動到圓柱坐標系統(tǒng)的任一位置。轉(zhuǎn)塔鉆床。歸屬于轉(zhuǎn)塔鉆床類的機床，或是半自動或是全自動控制的。轉(zhuǎn)塔機床的一個普遍的設(shè)計特征是用轉(zhuǎn)塔代替原來機床的主軸，轉(zhuǎn)塔上裝有幾把鉆削、鏜削和螺紋切削刀具。因此，幾種連續(xù)的操作只需要在一次初安裝下就可以完成，在兩種操作之間不需要再次裝夾工件。電動機立柱底座主軸搖臂鉆床的床頭箱絲桿圖 4.56如今，由數(shù)字或計算機控制系統(tǒng)控制的自動轉(zhuǎn)塔鉆床是相當?shù)钠毡榱?。在這種情況下，人的工作只是對工件進行初安裝和對其進行監(jiān)控。這類機床就空間要求（機床的物理尺寸）和工件裝夾次數(shù)而言比排式鉆床有優(yōu)越性。長孔鉆床。長孔鉆床是一類特殊的被用作鉆削長孔的機床，譬如，槍管的長孔就是用此類機床加工。通常長孔鉆在使用時對工件的進給速度是較慢的。這類機床在工作時，工件作旋轉(zhuǎn)運動，而刀具不作旋轉(zhuǎn)運動。長孔鉆床有立式結(jié)構(gòu)也有臥式結(jié)構(gòu)。然而，這兩種結(jié)構(gòu)的共同特征是在鉆削過程中工件的精確導向和剛性支承。坐標鏜床。這類機床是為獲得高的精確性和精密性而特別設(shè)計的。這類機床不但鉆孔而且能夠給孔定位，因為工作臺的運動由電子測量裝置監(jiān)控著。7DRILLING AND BORINGAddison-Wesley pub.Co.Abstract: Drilling involves producing through or blind holes in a workpiece by forcing a tool, which rotates around its axis, against the workpiece. Consequently, the range of cutting from that axis of rotation is equal to the radius of the required hole. In practice, two symmetrical cutting edges that rotate about the same axis are employ. Drilling operations can be carried out by using either hand drills or drilling machine. The latter differ in size and construction. Nevertheless, the tool always rotates around its axis while the workpiece is kept firmly fixed. This is contrary to drilling on a lathe. Boring is enlarging holes previously drilled or bored. Drilled holes are frequently bored to eliminate any possible eccentricity and to enlarge the hole to a reaming size. Following is a survey of drilling, drilling machine tool and boring. Keyword: drilling boring drilling machine tool classification of drilling machine cutting tool for drilling operations cutting tool for boring operations CUTTING TOOL FOR DRILLING OPERATIONSIn drilling operations, a cylindrical rotary-end cutting tool, called a drill, is employed. The drill can have either one or more cutting edges and corresponding flutes, which can be straight or helical. The function of the flutes is to provide outlet passages for the chips generated during the drilling operation and also to allow lubricants and coolants to reach the cutting edges and the surface being machined. Following is a survey of the commonly used drills.Twist drill. The twist drill is the most common type of drill. It has 8two cutting edges and two helical flutes that continue over the length of the drill body, as shown in Fig.4.1. The drill also consists of a neck and a shank that can be either straight or tapered. In the latter case, the shank is fitted by the wedge action into the tapered socket of the spindle and has a tang, which goes into a slot in the spindle socket, thus acting as a solid means for transmitting rotation. On the other hand, straight-shank drills are held in a drill chuck that is, in turn, fitted into the spindle socket in the same way as tapered shank drills.Fig.4.1 The twist drillAs can be seen in Fig.4.1, the two cutting edges are referred to as the lips, and are connected together by a wedge, which is a chisel-like edge. The twist drill also has two margins, which enable proper guidance and locating of the drill while it is in operation. The tool point angle (TPA) is formed by the two lips and is chosen based on the properties of the material to be cut. The usual TAP for commercial drills is 118, which is appropriate for drilling low-carbon steels and cast irons. For harder and tougher metals, such as hardened steel, brass and bronze, larger TAPs (130or 140) give better performance. The helix angle of the flutes of the commonly used twist drills ranges between 24 and 30 . When drilling copper or soft plastics, higher values for the helix angle are recommended (between35 and 45).9Fig.4.2 The core drillCore drills. A core drill consists of the chamfer, body, neck, and shank, as shown in Fig.4.2.This type of drill may have either three or four flutes and an equal number of margins, which ensure superior guidance, thus resulting in high machining accuracy. It can also be seen in Fig.4.2 that a core drill has flat end. The chamfer can have three or four cutting edges, or lips, and the lip angle may vary between 90° and 120° . Core drills are employed for enlarging previously made holes and not for originating holes. This types of drill is characterized by greater productivity, high machining accuracy, and superior quality of the drilled surfaces.Gun drills. Gun drills are used for drilling deep holes. All gun drills are straight-fluted, and each had a single cutting edge. A hole in the body acts as a conduit to transmit coolant under considerable pressure to the tip of the drill.There are two kinds of gun drills, namely, the center-cut dill used for drilling blind holes and the trepanning drill. The latter has a cylindrical groove at its center, thus generating a solid core, which guides the tool as it proceeds during the drilling operation.Spade drill. Spade drills are used for drilling large holes of 7/2in. (90mm) or more. Their which results in a marked saving in cost of the tool as well as a tangible reduction in its weight, which facilitates its handling. Moreover, this type of drill is easy to grind.BORING TOOLSBoring is enlarging holes previously drilled or bored. Drilled holes are frequently bored to eliminate any possible eccentricity and to enlarge 10the hole to a reaming size. Counterboring is enlarging one end of a dilled hole. The enlarged hole, which is concentric with the original one, is flat on the bottom. The tool is provided with a pilot pin that fits into the drilled hole to center the cutting edges. Counterboring is used principally to set bolt heads and nuts below the surface. To finish off a small surface around a drilled hole is known as spot facing. This is a customary practice on tough surface to provide smooth seats for bolt heads. If the top of a drilled hole is beveled to accommodate the conical seat pf a flat-head screw, the operation is called countersinking. Fig.4.3Tools used in horizontal boring machines are mounted in either a heavy bar or a boring head, which in turn is connected to the main spindle of the machine. Most boring operations use a single-point cutter as shown in Fig.4.3, because they are simple to set up and maintain. The bar serves to transmit power from the machine spindle to the cutter as well as to hold it rigidly during the cutting operation. The workpiece is normally stationary and the rotating cutter is fed through the hole. It is often necessary to provide additional support for the bar as shown in the figure. The bar must be long enough to reach the end support and also must provide the necessary longitudinal traverse for the machining operation.For precision boring work on milling machines, jig bore, or drill presses, it is necessary to use a tool having micrometer adjustment. Such 11tools are held in a cutter head and rotate. Hence, any increase in hole size must be obtained by adjusting the tool radially from its center.The most popular double-cutter arrangement is the block type shown in Fig.4.3b, which consists of two opposing cutters resting in grooves on the block. Screws are provided to lock the cutters in position as well as to adjust them. The entire assembly fits into a rectangular slot in the cutters in position as well as to adjust them. The entire assembly fits into a rectangular slot in the bar and is keyed in place. Cutters are ground while assembled in the block and are held in alignment by the center holes provided. The responsibility for tool accuracy and setup belongs to the toolroom personnel rather than the operator.Fig.4.4 Types of boring toolsThe boring tool commonly use in small machines such as lathes is a single -pointed tool, supported in a manner that permits its entry into a hole. This tool, shown in Fig.4.4a is forged at the end and then ground to shape. It is supported in a separate holder that fits into a lathe tool post. For turret lathes, slightly different holders and forged tools similar to the one shown in Fig.4.4b are used. A modification of this tool is the boring bar shown in Fig.4.4c, which is designed to hold a small high-speed steel tool bit at the end. The bar supporting the tool is rigid and may be adjusted according to the hole length. Although the clearance, rake, and cutting angles cannot be used if the tools should be similar to those recommended for lathe work, these angles cannot be used if the holes are small.12In production work, boring cutters with multiple cutting edges are widely used. These cutters, shown in Fig.4.4f resemble shell reamers in appearance but are usually provided with inserted-tooth cutters that may be adjusted radially to compensate for wear and variations of diameter. Boring tools of this type have longer life than single-pointed tools and hence are more economical for production jobs. The counterboring tool shown in Fig.4.4e provided with pilots to ensure concentric diameters. Is designed to recess or enlarge one end of a hole.CLASSIFICATION OF DRILLING MACHINES Drilling operations can be carried out by employing either portable small machines or appropriate machine tools. The latter differ in shape and size, although they have common features. For instance, they all involve one or more twist drills, each rotating around its own axis while the work piece is kept firmly fixed. This is contrary to the drilling operation on a lathe, where the work piece is held in and rotates with the chuck,. Following is a survey of the commonly used types of drilling machines.Beach-type drilling machines. Beach-type drilling machines are general-purpose, small machine tools that are usually placed on benches. This type of drilling machine includes an electric motor as the source of motion, which is transmitted via pulleys and belts to the spindle, where the tool is mounted. The feed is manually generated by lowering a lever handle, which is designed to lower (or raise) the spindle. The latter rotates freely inside a sleeve (which is actuated by the lever through a rackpinion system but does mot rotate with the spindle ).The workpiece is mounted on the machine table, although a special vise is sometimes used to hold, the workpiece. The maximum height of a workpiece to be machined is limited by the maximum gap between the spindle and the machine table.Upright drilling machines. Depending upon the size, upright drilling 13machine tools can be used for light, medium, and even relatively heavy jobs.It is basically similar to bench-type machines, the main difference being a longer cylindrical column fixed to the basic. Along that column is an additional, sliding table for fixing the workpiece which can be locked in position at any desired height. The power required for this type is more than that for bench-type drilling machines, since this type is employed in performing medium-duty job.There are also large drilling machines of the upright type. In this case the machine has a box column and a higher power to deal with large jobs. Moreover, gear boxes are employed to provide different rotational spindle speeds as well as the axial feed motion, which can be preset at any desired rate.Multispindle drilling machines. Multispindle drilling machines have sturdy construction and require high power; each is capable of drilling many holes simultaneously. The positions of the different tools (spindles)can be adjusted as desired. Also, the whole head (which carries the spindles and tools) can sometimes be titled, as required.This type of drilling machine is used mainly for mass production in jobs having many holes, such as cylinder blocks.Gang drilling machines. When several separate heads (each with a single spindle)are arranged on a single common table, the machine tool is then referred to as a gang drilling machine. This type of machine tool is particularly suitable where several operations are to be performed in succession.14Fig.4.5 A Sketch of radial drill.Radial drill. A radial drill is particularly suitable for drilling holes in large and heavy workpiece that are inconvenient to mount on the table of an upright drilling machine. As you can see in Fig.4.5, a radial drilling machine has a main column, which is fixed to base. The cantilever guide arm, which carries the drilling head spindle and tool, can be raised or lowered along the column and clamped at any desired position. The drill head slides along the arm and provides rotary motion and axial feed motion. Again, the cantilever guide arm can be swung, thus enabling the tool to be moved in all directions according to a cylindrical coordinate system.Turret drilling machines. Machines tools that belong to the turret drilling machines are either semi-or fully automatic. A common design feature is that the main spindle is replaced by a turret, which carries several drilling, boring, reaming, and threading tools. Consequently, several successive operations can be carried out with only a single initial setup and without the need for setting up the workpiece again between two operations.Nowadays, automatic turret drilling machines that are operated by NC or CNC systems are quite common. In this case, the human role is limited to the initial setup and monitoring. This type of machine tool therefore has advantages over the gang drilling machines with respect to space required 15(physical size of the machine tool) and the number of workpiece setup.Deep-hole drilling machines. Deep-hole drilling machines are special machines employed for drilling long holes like those of rifle barrels. Usually, gun-type drills are used; these are fed slowly against the workpiece. In this type of machine tool, it is the workpiece that is rotated, while the drill is kept from rotary motion. A deephole drilling machine may have either a vertical or horizontal construction. However, in both case, the common feature is the precise guidance and positive support of the workpiece during the drilling operation.Jig-boring machine. These machine tools are specially designed to posses high precision and accuracy. A machine of this type not only drills the holes but also locates them because the table movements are monitored by electronic measuring devices.References：[1] Valliere D.Computer Aided Designing Manufacturing. Prentic Hall, 1990[2] Goetsch D L.Midern Manufacturing Process. Delmar Publishers Inc, 1991[3] Goetsch D L.Advanced Manufacturing Technology. Delmar Publishers Inc, 1990[4] Amstead B H.Manufacturing Processes, 1987[5] Metalforming Digest. ASM international, 1993[6] Edwards Tr K S, McKee R B.Fundamentals of Mechanical Component Design. McGrawHill, 1991[7] Chemov N.Machine Tools. Mir Publishers, 1984[8] Wakil Sherif D E1. Processes and Design for Manufacturing. Prentice Hall, 198916[9] Wright R T. Processes of Manufacturing. The Coodheart-Willcox Company Inc, 1987