盤絲車床床頭箱部件設(shè)計

盤絲車床床頭箱部件設(shè)計,盤絲車床床頭箱部件設(shè)計,車床,床頭,部件,設(shè)計 本科畢業(yè)論文中英文翻譯 學生姓名： 所在院系： 機電學院 所學專業(yè)： 機械設(shè)計制造及其自動化 車 床 車床主要是為了進行車外圓、車端面和鏜孔等項工作而設(shè)計的機床。車削很少在其他種類的機床上進行，而且任何一種其他機床都不想車床那樣方便地進行車削加工。由于車床還可以用來鉆孔和鉸孔，車床的多功能性可以使工件在一次裝夾中進行幾種加工。因此，在生產(chǎn)中使用的各種車床比任何種類的機床都多。 普通車床：普通車床作為最早的金屬切削機床中的一種，目前仍然有許多有用的和人們所需要的特性?，F(xiàn)在，這些機床主要用在規(guī)模較小的工廠中，進行小批量的生產(chǎn)，而不是進行大批量的生產(chǎn)。 普通車床的加工偏差主要取決于操作者的技術(shù)熟練程度。設(shè)計工程師應(yīng)該認真的確定由熟練工人在普通車床上加工的試驗零件的公差。在把試驗零件重新設(shè)計為生產(chǎn)零件時，應(yīng)該選用經(jīng)濟的公差。 轉(zhuǎn)塔車床：對生產(chǎn)加工設(shè)備來說，目前比過去更著重評價是否具有精確的和快速的重復加工能力。應(yīng)用這個標準來評價具體的加工方法，轉(zhuǎn)塔車床可以獲得較高的質(zhì)量評定。 在為小批量的零件（100—200件）設(shè)計加工方法時，采用轉(zhuǎn)塔車床是經(jīng)濟的。為了在轉(zhuǎn)塔車床上獲得極可能小的公差值，設(shè)計人員應(yīng)該盡量將加工工序的數(shù)目減至最少。 自動螺絲車床：自動螺絲車床通常被分為以下幾種類型：單軸自動、多軸自動和自動夾緊車床。自動螺絲車床最初是用來對螺釘和類似的帶有螺紋的零件進行自動化和快速加工的。但是。這種車床的用途早就超過了這個狹窄的范圍?，F(xiàn)在，它在許多類型的精密零件的大批量生產(chǎn)中起著重要的作用。 車床的基本部件有：床身、主軸箱部件、尾架部件、溜板部件 絲杠和光杠。 床身是車床的基礎(chǔ)件。它通常是由于經(jīng)過充分正火或時效處理的灰鑄鐵或者球墨鑄鐵之城。它是一個兼顧的剛性框架，所有其他基本部件都安裝在車床身上。通常在床身上有內(nèi)外講足平行的導軌。有些制造廠對全部四條導軌都采用導軌尖頂朝上的三角形導軌（即山形導軌），而有的制造廠則在一組中或者兩組中都采用一個三角形導軌和一個矩形導軌。導軌要經(jīng)過精密加工，以保證其直線度精度。為了抵消磨損和擦傷，大多數(shù)現(xiàn)代機床的導軌式經(jīng)過表面淬硬的，但是在操作時還應(yīng)該小心，以避免損傷導軌。導軌上的任何誤差，常常意味著整個機床的精度遭到破壞。 主軸箱安裝在內(nèi)導軌的固定位置上，一般在床身的左端。它提供動力，并可是工件在各種速度下回轉(zhuǎn)。它基本上由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)。大多數(shù)車床由8—18種轉(zhuǎn)速，一般按等比級數(shù)排列。而且在現(xiàn)代機床上只需按動2---4個手柄，就能得到全部轉(zhuǎn)速。一種正在增長的趨勢是通過電氣的活著機械的裝置進行無極變速。 由于機床的精度在很大程度上取決于主軸，因此，主軸的結(jié)構(gòu)尺寸較大，通常安裝在預緊后的重型圓錐滾子軸承或球軸承中。主軸中有一個貫穿全長的通孔，長棒料可以通過該孔送料。主軸孔的大小是車床的一個重要尺寸，因為當工件必須通過主軸孔供料時，它確定了能夠加工的棒料毛坯的最大尺寸。 尾架部件主要有三部分組成。底板與床身的內(nèi)導軌配合，并可以在導軌上做縱向移動。底板上有一個可以使整個尾架部件夾緊在任意位置上的裝置。尾架體安裝在底板上，可以沿某種類型的鍵槽在底板上橫向移動，使尾架能與主軸箱中的主軸對正尾架的第三個組成部分是尾架套筒，它是一個直徑通常大約在51---76mm（2—3英寸）之間的鋼制空心圓柱體。通常手輪和螺桿，尾架套筒可以在尾架體中縱向移入和移出幾英寸。 車床的規(guī)格用兩個尺寸表示。第一個稱為車床床面上最大加工直徑。這是在車床上能夠旋轉(zhuǎn)地工件的最大直徑。它大約是兩頂尖連線與導軌上最近點之間距離的兩倍。第二個規(guī)格尺寸是兩頂尖之間的最大距離。車床床面上最大加工直徑表示在車床上能夠車削的最大工件直徑，而兩頂尖之間的最大距離則表示在車床上能夠車削的最大工件直徑，而兩頂尖之間的最大距離則表示在兩個頂尖之間能夠安裝的工件的最大長度。 普通車床是生產(chǎn)中最經(jīng)常使用的車床種類。它們是具有前面所敘述的所有那些部件的重載機床，并且除了小刀架之外，全部刀具的運動都有激動進給。它們的規(guī)格通常是：車床床面上最大加工直徑為305—610mm（12—24英寸）；兩頂尖之間距離為610—1219mm（24—48英寸）。但是，床面上最大加工直徑達到1270mm（50英寸）和兩頂尖之間距離達到3658mm（12英寸）的車床也并不少見。這些車床大部分都有切削盤和喲個安裝在內(nèi)部的冷卻系統(tǒng)。小型的普通車床—車床床面最大加工直徑一般不超過330mm（13英寸）--其中一些也可以被設(shè)計成臺式車床，即床身可安裝在工作臺或柜子上。 雖然普通車床很有很多用途，是很有用的車床，但是更換和調(diào)整刀具以及測量工件花費很多時間，所以它們不適合在大量生產(chǎn)中應(yīng)用。通常，它們的實際加工時間少于其加工時間的30%。此外，需要技術(shù)熟練地工人來操作普通車床，這種工人的工資高而且很難雇到。然而，操作工人的大部分時間卻花費在簡單的重要調(diào)整和觀察切削產(chǎn)生過程上因此為了減少或者完全不雇傭這類熟練工人，轉(zhuǎn)塔車床、螺紋加工車床和其他類型的半自動和自動車床已經(jīng)很好地研制出來，并已經(jīng)在生產(chǎn)中得到廣泛的應(yīng)用。 Lathes Lathes are machine tools designed primarily to do turning, facing, and boring. Very little turning is done on other types of maching tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the workpiece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. Engine Lathes:The engine lathe, one of the oldest metal remmoval machines, has a number of useful and highly desirable attributes. Today these lathes are used primarly in small shops where smaller quantities rather than large production runs are encountered. Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been poroduced on the engine lathe by a skilled operator. In redesigning an experimental part of production, economical tolerances should be used. Turret Lathes:Production machining equipmnt must be evaluated now, more than ever before, in terms of ability to repeat accurately now,more than ever before, in terms of ability to repeat accurateal and rapidly. Applying this criterion for establishing the production qualification of specific method, the turret lathe merits a high rating. In desingning for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turret lathe. The designer should strive for a minimum of operations. Automatic Serew Machines:Generally, automtic screw machines fall into several categories; single-spindle automatics,mulltiple-spindle automatics production of screws and similar threded part,the automatic screw machine has long since cxceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, carriage assembly, and the leadscrew and feed rod. The bed is the backbone of a lathe. It usually is made of well-noremalized or aged gray or nodular cast iron and provides a heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bad,usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets. Theyare precision machined to assure accuracy of alignment. On most modern lathes the ways are surface-hardened to resist wear and abrasion, 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. The headstock 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 a hollow spindle, mounted in accurate bearings, and a set of transmission gears—similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 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 incereasing trend is to provide a continuousiy variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construcition and mounted in heavy bearings,usually prealoaded tapered roller or ball types.The spindle has a hole extending through its length, through which long bar stock can be fed. The size of this hole is an important dimension of a lathe because it determines the maximum size of bar stock that can be machined when the material must be fed through spindle. The tailstork assembly consists, essentially, of three part. A lower casting fits on the inner ways of the bed and can slide longitudinlly thereon, with a means for clamping the entire assembly in any desired location. An upper casting fits on the lower one and can be moved transversely upon it,on some type of keyed ways, to permint alingning the tailstock and headstock spindles. The third major component of the assembly is the tailstock quill. The is a hollow steel cylinder, usually about 51 to 76mm in diameter, that can be means of a handwhell and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diamenions. The first is known as the swing. This the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways. The second size dimension is the maximum diameter between centers. The swing thus indicates the maximum workpiece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of workpiece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610mm swing and from 610 to 1219mm center distances, but swing up to 1270mm and center distances up to 3658mm are not uncommon. Most have chip pans abd a built-in coolant circulating system. Smaller engine lathes—with swings usually not over 330mm also are available in bench type, designed for the bed to be mounted on a bench or cabinet. Although engine lathes are versatile and very useful, because of the time required for changing and setting tools and for making measurements on the workpiece, they are not suitable for quantity production. Often the actual chipproduction time is less than 30% of the total cycle time. In addition, a skilled machinist is required for all the operations,and such persons are costly and often in short supply. However, much of the operator’s time is consumed by simple, repetitious adjustments and in watching chips being made. Consequently, to reduce or eliminate the amount of skilled labor that is required, turret lathes, screw machines, and other types of semiautomatic and automatic lathes have been highily developed and are widely used in manufacturing.