完整版)機(jī)械_畢業(yè)設(shè)計(jì)外文翻譯_43164266

1、Gears are vital factors in machinery. One of the first mechanism invented using gears was the clocks. In fact, a clock is little more than a train of gears.Considerablestudy and research made on gears in recent years because of their wide use under exacting conditions. Theytt ever before. The engine

2、ers and the machinists all consider gearing the prime element in nearly all classes of machinery.齒輪在機(jī)械中占有極其重要的作用。第一個利用齒輪做成的機(jī)械裝置就是 鐘表，事實(shí)上，它只不過是用了一系列的齒輪。對于它可以在嚴(yán)格的條件 下的廣泛使用，在齒輪上做了大量的學(xué)習(xí)和研究。相比過去，它們現(xiàn)在必 須在更高的速度下傳遞更重的負(fù)荷。工程師和機(jī)器操縱工人都認(rèn)為齒輪在 幾乎所有的機(jī)器的零件中占有首要的因素。1. Spur gearsSpur gears are used to transmit power a

3、nd rotary motion between parallel shafts. Theteeth are cut parallel to the axis of the shaft on which the gears are mounted. The smaller of two gears in mesh is called the pinion and the larger is customarily Designated as the gear. In most applications, the pinion is the driving element whereas the

4、 gear is the driven element.1. 直齒圓柱齒輪直齒圓柱齒輪用于平行軸之間傳遞力和回轉(zhuǎn)運(yùn)動，輪齒被切制成與安裝齒 輪的軸之軸線相平行。兩嚙合齒輪中較小的叫小齒輪，大的習(xí)慣上叫齒輪， 在大多數(shù)情況下，小齒輪是主動輪，大齒輪叫從動輪。2. Helical gearsHelical gears advantages, for example, when connecting parallel shafts they spur gear with the same tooth numbers and cut with the same cutter.2. 斜齒圓柱齒輪斜齒圓柱

5、齒輪具有特定的優(yōu)點(diǎn)，比如，當(dāng)連接平行軸的用相同刀具切削出 來的并齒數(shù)相同的斜齒輪比直齒輪具有較高的承載能力。斜齒輪也能用于 連接相互成任意角度的非平行軸。Helical gears can also be used to connect nonparallel , non-intersecting shaftsat any angle to one another.斜齒輪也能用于連接相互成任意角度的非平行軸。The maximum gear ratio obtainable with a single pair of gears varies with the type of gear and

6、 the application. The following are approximate maxim a for the various type for average load conditions:spur, 8; parallel-shaft be exceeded.Rations as be obtained with gears that resemble tapered worms meshing with rations may be so .一對齒輪能獲得的最大傳動比隨齒輪類型和應(yīng)用的變化而變化，以下是各 種類型的齒輪的平均載荷條件的近似最大化，直齒是 8,平行軸斜齒輪

7、是 10,直齒錐齒是6,曲線齒錐齒輪8,準(zhǔn)雙曲面12,蝸輪蝸桿8，對于輕載 荷和定位齒輪這些傳動比被超出，類似于成錐形的蝸輪蝸桿，和準(zhǔn)雙曲面 齒輪能夠獲得的傳動比高達(dá) 400或更高，如此高以至于00的齒輪尺寸不 可能令人滿意。Since the ratio in a single pair of gears is the quotienbf the tooth number, and since there usually are limitations on both the minimum and maximum numbers of teeth on the available gear

8、s,it follows that the number of ratios obtainable in a single pair is limited. To enlarge the coverage it is necessary to use multiple pairs, or trains. The overalspeed ratio in a train is the product of the ratios in each pair. In certain casesan exact ratio cannot be obtained with gears, but by us

9、ing two or more parts, the desired ratio can be approximated to any degree of precision.一對齒輪的傳動比齒數(shù)的商，它們通常是限制在有效齒輪的最大和最小齒 數(shù)之間，因此，一對齒輪獲得的傳動比是受限制的，為了擴(kuò)大范圍，用多 級齒輪副或系列是必要的，在一個系列中，總速比是每對齒輪產(chǎn)生的傳動 比。As a convenience for machine builders and users, packaged speed reducers, following an industry-accepted patter

10、n , are manufactured in a wide variety of types,configurations , speed ratios, and capacities; these consist of a box or operating continuouslybecome in the teeth, in the lubricant, in the bearings, and in the oil seals. If theit can be dissipated to the atmosphere, the lubricant may deteriorate and

11、 the gear or bearing fail.所有的減速器當(dāng)被連續(xù)使用時，由于輪齒在潤滑劑軸承和油封件的摩擦?xí)?變熱，如果熱量的產(chǎn)生在空氣中散逸的速度還快的話，潤滑劑不能損壞， 并且軸承和齒輪失效。Worm gear sets are widely used because of the many advantages obtained by their tooth action and load carrying capacity. A large speed reduction or a be attained with the worm gear set. Compactnesso

12、f design is easy to obtain with such a combination, Worm gear drives are quiet and vibration free.蝸輪裝置由于嚙合作用和傳遞載荷能力獲得的許多優(yōu)點(diǎn)而被廣泛應(yīng)用，大 量轉(zhuǎn)矩的減速或增速裝置由蝸輪裝置完成，設(shè)計(jì)的緊湊，用這樣一個結(jié)合 體是容易得到的，蝸輪是平穩(wěn)且無振動的。A worm gear set consists of the worm, which is very similar to a screw, and the worm gear, which is a which the worm

13、and the gear are mounted are usually at right angels but not in the same plane. The usual practice is to be made with either right- be made with single, double, triple, or quadruple thread. A single-thread worm advances the worm gear a distance equal to pitch for each complete worm rotation. The dis

14、tance advanced is called the lead. Thus, the pitch equals the lead for a single thread. A double-threaded worm of the worm simulates a linearly advancing involute rack The geometry of worm gear(sometimescalled a worm wheel) is similar to that of a a machine which mechanically changes cylindrical mot

15、ion to straight-line motion. The cam, which is mounted on a shaft, is usually driven by a motor either applied directly to the cam shaft or connected by pulleys or gears. The purpose of a cam is to transmit various kinds of motions to other parts of a machine.一個轉(zhuǎn)動的凸輪是機(jī)械的一部分，也就是用機(jī)械的方式使回轉(zhuǎn)運(yùn)動變?yōu)橹?線運(yùn)動。凸輪被

16、安裝在軸上通常由直接用到凸輪軸或是由皮帶輪或齒輪聯(lián) 結(jié)成的任一原動力驅(qū)動。凸輪的目的是傳遞各種各樣的運(yùn)動到機(jī)械的其他 部分。Practically every cam must be designedand manufactured to fit special requirements. Though each cam appears to be quite different from the other, all the cams work in a similar ways. In each case, as thecam is rotated or turned, another p

17、art in contact with the cam, called a follower, is moved either left and right, up and down, or in and out. The follower is usually connected to other parts on the machine toaccomplish the desired action.The direction the follower move depends upon the position of the framework which attaches the ca

18、m and follower to the machine. If the follower loses contact with the cam, it will fail to work.幾乎每個凸輪必須被設(shè)計(jì)和制造以適合特殊的要求，雖然每個凸輪顯現(xiàn)的 十分不同于其他凸輪。但是所有的凸輪都以類似的方式工作。在任何情況 下，與凸輪轉(zhuǎn)動或旋轉(zhuǎn)時，與凸輪接觸的另一部分成為從動件，向左或向 右，向上或向下，向里或向外移動。從動件通常聯(lián)結(jié)機(jī)械的其他部分以完 成要求的運(yùn)動，從動件運(yùn)動的方向取決于結(jié)構(gòu)的位置也就是在機(jī)械中聯(lián)結(jié) 凸輪和從動輪。如果從動件與凸輪不接觸，它將不能工作。The faster th

19、e cam turns, the more rapid is the motion of the follower. The motion of the follower caused by rotating the cam is exactly the same for each complete turn of the cam.凸輪旋轉(zhuǎn)越快，從動輪的運(yùn)動越迅速，從動件的運(yùn)動是由凸輪轉(zhuǎn)動導(dǎo)致的 并且這種運(yùn)動與每個凸輪整個旋轉(zhuǎn)運(yùn)動是正好相反。Belt drives offer a maximum of versatility as power transmission elements.The

20、y allow the designerconsiderableflexibility in location of driver and driven machinery,and tolerancesare not critical as is the case with gear drives. Another advantage of belt drives is that they reduce vibration and shock transmission. Furthermore, belt drives are relatively quiet.皮帶傳動裝置作為傳遞動力的元件用

21、途極廣。這種裝置使設(shè)計(jì)人員在確定 主動機(jī)械與從動機(jī)械的位置時有相當(dāng)大的靈活性，而且公差要求也不像齒 輪傳動裝置那樣嚴(yán)格。皮帶傳動另一個優(yōu)點(diǎn)是可以減少振動及其傳播。不 僅如此，皮帶傳動噪聲也比較小。Large flat leather belts were in general use many years ago, when the usual practice was to use one large engine to driver several different pieces ofmachinery. Some leather belts are in use at this tim

22、e as well as flat steel, rubber, plastic, and fabric belts. Light, thin flat belts are practical on may be a problem用皮革制成的大的平皮帶在許多年前曾用得很普遍，那時，通常是用一臺 大功率的發(fā)動機(jī)驅(qū)動好幾臺不同的機(jī)器?，F(xiàn)在，除了平鋼帶、橡皮帶、塑 料帶和布帶外，一些皮革做的皮帶還在使用。輕質(zhì)薄型平皮帶在高速機(jī)械 上很實(shí)用，因?yàn)檫@里振動可能是一個問題。V belts are probably the most common means of transmitting power b

23、etween electric motor and driven machinery. Conventional V belts are made of rubber. Most often, both driver and driven pulleys lie in the same vertical plane, and the speed ration is constant.三角皮帶大概是在電動機(jī)與從動機(jī)械之間傳遞動力的最為普通的手段。普通的三角皮帶用橡皮制造。通常，主動輪與從動輪位于同一個垂直面上，速比是恒定的。Smooth flat belt and V belts depend

24、on friction on the pulleys and some slippage isInherent in their operation. Therefore, speed ratios are not precise. Most or formed steel.平皮帶和三角皮帶依靠在皮帶輪上的摩擦進(jìn)行傳動，所以在傳動中總是有 一些滑動，因此，速比就不精確。大多數(shù)大的皮帶輪是用鑄鐵和型鋼制造 的。Note that the capacity of the belt drive is determined by the angle of wrap on the smaller pul

25、ley, and that this is particularly critical for drives involving pullets of greatly differing size,special closely together.Screws used as fasteners for a long time . Asindicated in the section on single machine, a screw acts with a wedging action and consistsof a circular cylinder (or truncated con

26、e) with a it. When used for fastening, all screws are provided with means for applying a torque(twisting moment) to them; this may consistof a square of one end fitting a screwdriver or special wrench and no screwed into the proper sizeas cap screws . Screws with other types of as cap screws in the

27、larger sizes and as machine screws in the small sizes. All of these screws are used to clamp machine parts together when one of the parts internal thread. If neither part is threaded , a bolt must be used: this consist of screw with a internal thread), and usually a washer(flat扁 ring).帶有六角形頂端的螺釘通常稱為

28、有頭螺釘。這類螺釘用于當(dāng)零件之一有內(nèi) 螺紋時把機(jī)器的零件加緊在一起。如果零件上未切出螺紋，則必須使用螺 栓。螺栓由帶有六角形頂端的螺釘、螺母(是一個有內(nèi)螺紋的六角環(huán))、通常還有一個墊圈組成。In operation, shafts are subjected to a shearing stress, whose magnitude depends on the torque and the dimensions of the cross section. This stress is a measure of the resistancethat the shaft material off

29、ers to the applied torque. All shafts that transmit a torque are subjected to torsional shearing stress .軸在轉(zhuǎn)動時承受剪應(yīng)力，其大小取決于扭轉(zhuǎn)和斷面的尺寸。這個剪應(yīng)力是 軸的材料對作用扭矩所產(chǎn)生的抗力的一種量度。所有傳遞扭矩的軸都承受 扭轉(zhuǎn)剪應(yīng)力。In addition to the shearing stresses, twisted 曲 shafts are also subjected to shearingdistortions. The distorted state is us

30、ually defined by the angle of twisper unitlength, i.e., the rotation of one crosssection of a shaft relative to another cross section at a unit distance from it.軸的某一截面相對于間隔一個單位長度的另一截面的旋轉(zhuǎn)角度。除剪應(yīng)力 之外，傳遞扭轉(zhuǎn)的軸還會產(chǎn)生剪切變形。扭轉(zhuǎn)的狀態(tài)通常用每單位長度的 扭轉(zhuǎn)角來表示，即用軸的某一截面所轉(zhuǎn)過的角度來表示。A coupling is a device for connecting the ends o

31、f adjacent shafts. In machine construction, couplings are used to effect a semipermanent connection between adjacent rotating shafts. The connection is permanent in the sense that it is not meant to be broken during the useful life of the machine, but it can be broken and restored in an emergency or

32、 when worn parts are replaced.聯(lián)軸器是一種聯(lián)接兩根相鄰軸末端的裝置。機(jī)械構(gòu)件中，聯(lián)軸器可以用來 實(shí)現(xiàn)相鄰兩根旋轉(zhuǎn)軸的半永久性聯(lián)接。在機(jī)器的正常使用周期內(nèi)，聯(lián)軸器 通常不必拆開，在這個意義上可以說聯(lián)軸器的聯(lián)接是永久性的，而在緊急 情況下或者需要更換已磨損的零件時，可先把聯(lián)軸器拆開并重新聯(lián)接上。There are several types of shaft couplings; their characteristicdepend on the purposefor which they are used. If an exceptionally long shaf

33、t is required for a line shaft in a manufacturing plant or a propellershaft on a ship, it is made in sections that are coupled together with rigid couplings. A common type of rigid coupling consists of two matingradial flanges(disks) that are attached bykey-driven . Alignment of the connected shafts

34、 is usually effected by means of a rabbet joint on the face of the flanges, i.e., a short cylindrical projection on the face of one flange fits snugly in a circular recess on the face of the other flange聯(lián)軸器有幾種類型，其特性隨其用途而定。如果制造廠中或者船舶的螺旋 槳需要一根特別長的軸時，可以分段制造，然后采用剛性聯(lián)軸器將這些軸 聯(lián)接起來。常用的剛性聯(lián)軸器包括兩個匹配的徑向法蘭（盤），他們是

35、通過靠鍵傳動的輪轂來連接到相鄰兩軸的兩端，然后用螺栓穿過法蘭聯(lián)接起來 形成了剛性聯(lián)接。相互聯(lián)接的兩軸是靠法蘭面上的槽口來對準(zhǔn)的，也就是 說，在其中一個法蘭面上的短圓柱上的凸起部分與另一個法蘭面上的圓形 凹進(jìn)部分相互緊貼。In connecting shafts belonging to separate devices （such as an electric motor and a gear-box）, precise aligning of the shafts is difficult and a flexible coupling is used. This coupling conn

36、ectsthe shafts in such a way as to minimize the the axial direction without interfering with one another. Flexible couplings can also serve to reduce the intensity of shock loads and vibrations transmitted from one shaft to another.在把兩個屬于不同設(shè)備（如電機(jī)和變速箱）的軸聯(lián)接起來時，要把這些軸 精確對準(zhǔn)是很困難的，因此可以采用彈性聯(lián)軸器。采用這種聯(lián)軸器聯(lián)接兩 軸時

37、，可以把由于軸聯(lián)接中軸線不重合所造成的損害降到最小。彈性聯(lián)軸 器還可允許被聯(lián)接的軸在各自載荷系統(tǒng)中偏斜和在軸向上自由移動（浮 動），而不相互干擾。彈性聯(lián)軸器還能用來減小從一根軸傳到另一根軸的沖 擊載荷和振動強(qiáng)度。A clutch is a device for quickly and easily connectingor disconnectinga rotatable shaft and a rotating coaxial|kEu5AksEI shaft. Clutches areusually placed between the input shaft to a machine an

38、d the output shaft from the driving motor, and provide a convenient means for starting and stopping the machine and permitting the driver motor or engine to be started in an Unloaded state.離合器是一個用來使從動軸與位于同一軸線上的主動軸進(jìn)行快速和順利的 聯(lián)接或脫開的裝置。離合器通常位于機(jī)器的輸入軸和驅(qū)動電機(jī)的輸出軸之 間，以提供一個方便地啟動和停止機(jī)器的手段，并使得 驅(qū)動電機(jī)或發(fā)動機(jī)在無荷載的狀態(tài)下啟動。T

39、he rotor (rotating member) in an electric motor the motor is started. If the motor shaft is rigidly connected to a load with a large rotational inertia, and the motor is started suddenly by closing a switch, the motormay not motor are burned out by the excessivecurrent demands. A clutch between the

40、motor and the load shafts will restrict the starting torque on the motor to that required to accelerate the rotor and parts of the clutch only.電機(jī)中的轉(zhuǎn)子有轉(zhuǎn)動慣量，當(dāng)電機(jī)啟動時需要一個轉(zhuǎn)矩帶動其運(yùn)轉(zhuǎn)。如果 電動機(jī)的軸與具有很大轉(zhuǎn)動慣量的負(fù)載剛性地聯(lián)接在一起，當(dāng)合上開關(guān)使 電動機(jī)突然啟動時，有可能在電動機(jī)沒有來得及產(chǎn)生足夠的扭矩，使電動 機(jī)的軸達(dá)到應(yīng)有的轉(zhuǎn)速之前，電動機(jī)內(nèi)的線圈就會因?yàn)檫^大的電流而被燒 毀。電機(jī)和負(fù)載軸之間的離合器會限制電機(jī)的啟動轉(zhuǎn)矩只到所需要的加速 轉(zhuǎn)子和離合器部件的數(shù)值。On some machine tools, it is convenient to let the driving motor run continuously and to start and stop the machine by operating a clutch. Other machine too