機械制造及其自動化專業(yè)英語匯總

1、Basic Concept in MechanicsThe branch of scientific analysis which deals with motions time and forces is called mechanics and is made up of two parts statics and dynamics.Statics deals with the analysis of Stationary ,i .e.,those in which time is not a factor,and dynamics deals with systems which cha

2、nge with time .對運動、時間和作用力進行科學分析的分支稱為力學 它由靜力學和動力學倆部分組 成。 靜力學對靜止系統(tǒng)進行分析 即在其中不考慮時間這個因素 動力學對隨時間而變化的 系統(tǒng)進行分析。Forces are transmitted into machine members through mating surfaces ,e.g.,form a gear to a shaft or form one gear through meshing teeth to another gear,from a V belt to a pulley,or from a cam to a f

3、ollower. It is necessary to know the magnitudes of these forces for a variety of Reasons. The distribution of the forces at the boundaries or mating surfaces must be reasonable and their intensities must be within the working limits of the materials composing thesurfaces. For example if the force op

4、erating on a journal bearing becomes too high it will squeeze out the oil film and cause metal-to-metal contact overheating and rapid failure of the bearing. If the forces betweens gear teeth are too large the oil film may be squeezed out from between them. This could result in flaking and spalling

5、of the metal noise rough motion and eventual failure. In the study of mechanics we are principally interested in determining the magnitude direction and location of the Forces.力通過接觸表面?zhèn)鞯綑C器中的各構(gòu)件上。 例如 從齒輪傳到軸或者從齒輪通過與其嚙合 的輪齒傳到另一個齒輪 從 V 帶傳到帶輪 , 或者從凸輪傳到從動件。由于很多原因 人們必 須知道這些力的大小。這些力在邊界或在接觸表面的分布必須合理 , 它們的大小必須

6、在構(gòu)成 配合表面的材料的工作極限以內(nèi)。 例如 如 果作用在一個滑動軸承上的力太大 , 它就會將油 膜擠出 , 造成金屬與金屬的直接接觸 , 產(chǎn)生過熱和使軸承快速失效。如果齒輪相嚙合的齒與齒 之間的力過大 就會將油膜從齒間擠壓出來。這會造成金屬表層的碎裂和剝落 , 噪音增大 , 運 動不精確直至報廢。在力學研究中 , 我們主要關(guān)心力的大小、方向和作用點。Some of the terms used in mechanics are defined below.在力學中要用到的一些術(shù)語定義如下。Force Our earliest ideas concerning forces arose bec

7、ause of our desire to push , lift , or pull various objects . So force is the action of one body on another . Our intuitive concept of force includes such ideas as place of application , direction ,and magnitude , and these are called the characteristics of a force .力 關(guān)于力的最早概念是由我們需要推、 舉或拉各種物體而產(chǎn)生的。 因

8、此, 力是物體之 間的相互作用。力的直接概念包括作用點、大小和方向,這些被稱為力的要素。Mass is a measure of the quantity of matter that a body or an object contains . The mass of the body is not dependent on gravity and therefore is different from but proportional to its weight . Thus , a moon rock has a certain constant amount of substance

9、, even though its moon weight is different from its earth weight . This constant amount of substance , or quantity of matter , is called the mass of the rock .質(zhì)量 是物體內(nèi)所包含的物質(zhì)的量。 物體質(zhì)量不受重力影響, 因此與物體重量不同, 但 是與其成比例。 盡管一塊月球巖石在月球上和地球上的重量不同, 但它的物質(zhì)含量是不變的。 這不變的物質(zhì)含量就稱為巖石的質(zhì)量。Inertia is the property of mass that c

10、auses it to resist any effort to change its motion .慣性 是質(zhì)量所具有的抵抗任何外力改變其本身運動狀態(tài)的性質(zhì)。Weight is the force with which a body is attracted to the earth or another celestial body , equal to the product of the object's mass and the acceleration of gravity .重量 是地球或其他天體對物體的吸引力,它等于物體的質(zhì)量與重力加速度的乘積。 Particle A

11、 particle is a body whose dimensions are so small that they may be neglected . 質(zhì)點 當一個物體尺寸特別小,可以忽略不計時,該物體可以被稱為質(zhì)點。Rigid Body A rigid body does not change size and or shape under the action of forces. Actually, all bodies are either elastic or plastic and will be deformed if acted upon by forces . When

12、 the deformation of such bodies is small , they are frequently assumed to be rigid , i.e. , incapable of deformation , in order to simplify the analysis . A rigid body is an idealization of a real body.剛體 剛體在受力后,其大小和形狀都不會發(fā)生變化。實際上,所有的物體, 不管是彈 性體還是塑性體,在外力作用下都會發(fā)生形變。當物體的變化非常小時,為了簡化計算,通 暢假設這個物體是剛體,也就是認為它

13、沒有發(fā)生形變。剛體是實際物體的理想化模型。 Deformable Body The rigid body assumption cannot be used when internal stresses and strains due to the applied forces are to be analyzed . Thus we consider the body to be capable of deforming . Such analysis is frequently called elastic body analysis , using the addit ional ass

14、umption that the body remains elastic within the range of the applied forces .變形體 在分析由于外力的作用所引起物體內(nèi)部的應力和應變時,不能采用剛體假設。 這時, 認為物體能夠變形。這樣的分析通常被稱為彈性體分析,這時所用的假設為,在作用 力范圍內(nèi),物體是彈性的。Newton's Laws Newton's three laws are :牛頓定律 牛頓三定律為:Law 1 If all the forces acting on a particle are balanced , the partic

15、le will either remain at rest or will continue to move in a straight line at a uniform velocity .第一定律 如果作用在一個質(zhì)點上的所有外力平衡, 那么, 這個質(zhì)點保持原來的靜止或 者勻速直線運動狀態(tài)不變。Law 2 If the forces acting on a particle are not balanced , the particle will experience an acceleration proportional to the resultant force and in th

16、e direction of the resultant force . 第二定律 如果作用在一個質(zhì)點上的所有外力都不平衡, 那么, 這個質(zhì)點將產(chǎn)生一個與 外力合力成正比的加速度,加速度的方向與合力方向相同。Law 3 When two particles react , a pair of interacting forces come into existence ; these forces have the same magnitudes and opposite senses , and they act along the straight line common to the t

17、wo particles .第三定律 兩個質(zhì)點相互作用時, 存在著一對作用力和反作用力。 作用力和反作用力大 小相等,方向相反,沿著同一條直線作用在兩個質(zhì)點上。Mechanics deals with two kinds of quantities : scalars and vectors . Scalar quant it ies in mechanics are time , volume ,density , speed , energy , and mass . Vector quantities , on the other hand , possess direction as

18、well as magnitude . Examples of vectors are displacement , velocity , acceleration , force , moment , and momentum .力學涉及兩種類型的量:標量和矢量。標量是那些只有大小的量。 在力學中,標量的例 子有時間、體積、密度、速率、能量和質(zhì)量。另一方面,矢量既有大小又有方向。矢量的例 子有位移、速度、加速度、力、力矩和動量。Shafts and CouplingsVirtually all machines contain shafts. The most common shape fo

19、r shafts is circular and the cross section can be either solid or hollow(hollow shafts can result in weight savings. Rectangular shafts are sometimes used, as in screwdriver blades, socket wrenches and control knob stems.實際上,幾乎所有的機器中都裝有軸。軸最常見的形狀是圓形,其截面可以是實心的, 也可以是空心的(空心軸可以減輕重量 。有時也可以采用矩形軸,例如,螺絲刀的頭、套

20、 筒扳手和控制旋鈕的桿。A shaft must have adequate torsional strength to transmit torque and not be overstressed. It must also be torsionally stiff enougth so that one mounted component does not deviate excessively from its original angular position relative to a second component mounted on the same shaft . Gen

21、erally speaking, the angle of twist should not exceed one degree in a shaft length equal to 20 diameters.為了在傳遞扭矩時不發(fā)生過載, 軸應該具有適當?shù)目古姸取?軸還應該具有足夠的抗扭 剛度, 以確保同一個軸上的兩個轉(zhuǎn)動零件之間的相對轉(zhuǎn)角不會過大。 一般來說, 當軸的長度 等于其直徑的 20倍時,扭轉(zhuǎn)角不應該超過 1度。Shafts are mouted in bearings and transmit power though such devices as gears,pulleys,

22、cams and clutches.these devices introduce forces which attempt to bend the shaft;hence,the shaft must be rigid enough to prevent overloading of the supporting bearings.Ingeneral,the bending deflection of a shaft should not exceed 0.5 mm per meter of length berween bearing supports.軸安裝在軸承中,通過齒輪、皮帶輪、凸

23、輪和離合器等零件傳遞動力。 通過這些零件傳 來的力可能會使軸產(chǎn)生彎曲變形。 因此, 軸應該有足夠的剛度以防止支承軸受力過大。 總而 言之,在兩個軸承支承之間,軸在每米長度上的彎曲變形不應該超過 0.5mm 。In addition,the shaft must be able to sustain a combination of bending and torsional loads.Thus an equivalent load must be considered which takes into account both torsion and bending.Also,the all

24、owable stress must contain a factor of safety which includes fatigue,since torsional and bending stress reversals occur.此外, 軸還必須能夠承受彎矩和扭矩的組合作用。 因此, 要考慮扭矩與彎矩的當量載荷。 因為扭矩和彎矩會產(chǎn)生交變應力,在許用應力中也應該有一個考慮疲勞現(xiàn)象的安全系數(shù)。 For diameters less than 75 mm,the usual shaft material is cold-rolled steel containing about 0.4

25、percent carbon.Shafts are either cold-rolled or forged in sizes from 75 mm to 125 mm.For sizes above 125 mm,shafts are forged and machined to the required size.Plastic shafts are widely used for light load applications.One adwantage of using plastic is safety in electrical applications,since plastic

26、 is a poor conductor of electricity.直徑小于 75mm 的軸可以采用含碳量大約為 0.4%的冷軋鋼,直徑在 75125mm之間的 軸可以采用冷軋鋼或鍛造毛坯。當直徑大于 125mm 時,則要采用鍛造毛坯,然后機械加工 到所要求的尺寸。輕載時,廣泛采用塑料軸。 由于塑料是電的不良導體,在電器中用他作軸 比較安全。Components such as gears and pulleys are mounted on shafts by means of key.The design of the key and the corresponding keyway

27、in the shaft must be properly evaluated.For example,stress concentrations occur in shafts due to keyways,and the material removed to from the keyway further weakens the shaft.齒輪和皮帶輪等零件通過鍵連接在軸上。 在對鍵及軸上與之相應的鍵槽進行設計時, 必 須進行認真的計算。 例如, 軸上的鍵槽會引起應力集中, 由于鍵槽的存在將使軸的橫截面積減小,會進一步減弱軸的強度。If shafts are run at critic

28、al speeds, severe vibrations can occur which can seriously damage a machine. It is important to know the magnitude of these critical speeds so that they can be avoided. As a general rule of thumb, the difference between the operating speed and the critical speed should be at least 20 percent.如果軸以臨界速

29、度轉(zhuǎn)動, 將會發(fā)生強烈地振動。 可能會毀壞整臺機器。 知道這些臨界速度的 大小是很重要的, 應這樣可以避開它。 根據(jù)一般經(jīng)驗來說, 工作速度與臨界速度之間至少應 該相差 20%。Another important aspect of shaft design is he method of directly connecting one shaft to another. This is accomplished by devices such as rigid and flexible couplings.軸的設計工作的另一個重要方面是軸與軸之間的直接連接方法。 這是有剛性或者彈性聯(lián)軸器 來

30、實現(xiàn)的。A coupling is a device for connecting the ends of adjacent shafts. In machine construction ,coupling 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,bu

31、t it can be broken and restored in an emergency or when worn parts are replaced.聯(lián)軸器是用來把兩個相鄰的軸端連接起來的裝置。 在機械結(jié)構(gòu)中, 聯(lián)軸器被用來實現(xiàn)相鄰的 兩根轉(zhuǎn)軸之間的半永久連接。 在機器的正常試用期間內(nèi), 這周連接一般不必拆開, 在這種意 義上, 可以說聯(lián)軸器的連接時永久性的。 但是在緊急情況下, 或者需要更換需要更換已磨損 的零件時,可以先把聯(lián)軸器拆開,然后再連接上。There are several types of shaft coupling,their characteristics dep

32、end on the purpose for which they are used.If an exceptional long shaft on a ship,it is made in sections that are coupled together with rigid coupling.A common type of rigid coupling consist of two mating radial flanges that are attached by key-driven hubs to the ends of adjacent shaft section and b

33、olted together through the flanges to form a rigid connection.Alignment of the connected shafts is usually effected by meant of a rabbet joint on the face of the flanges.聯(lián)軸器有幾種類型, 它們的特性隨其用途而定。 如果制造工廠中或者傳播的螺旋槳需要一根 特別長的軸, 可以采用分段的方式將其制造出來, 然后采用剛性聯(lián)軸器將各段連接。 一種常 用的聯(lián)軸器使用兩個配對的法蘭盤組成, 這兩個法蘭盤借助靠鍵傳動的軸套連接到相鄰兩節(jié) 軸

34、的兩端, 然后用螺栓穿過法蘭連接起來形成剛性接頭。 相互倆你就餓的兩根軸通常是靠法 蘭面上的槽口來進行找正的。In connecting shafts belongs to separate devices (such as an electric motor and a gearbox,precise aligning of the shafts is difficult and a flexible coupling is used ,this coupling connects the shafts in such a way as to minimize the harmful eff

35、ects of shaft misalignment. Flexible coupling also permit the shafts to deflect under their separate systems of loads and to move freely in the axial direction without interfering with one another, flexible coupling can also serve to reduce the intensity of shock loads and vibrations transmitted fro

36、m shaft to another. 在把屬于不同的設備 (例如一個電動機和一個變數(shù)箱 的軸連接起來的時候, 要把這些軸精 確的對準是比較困難的, 此時可以采用彈性聯(lián)軸器, 這種聯(lián)軸器連接軸的方式, 可以把由于 被連接的軸之間的軸線不重和所造成的有害影響減少到最小, 彈性聯(lián)軸器也允許被連接的在 他們各自的載荷系統(tǒng)作用下產(chǎn)生偏斜, 或在斜線方向自由移動而至于相互干擾, 彈性聯(lián)軸器 也可以用來減輕從一根軸傳到另一根軸上的沖擊載荷和震動的強度。Fasteners and SpringsFasteners are devices which permit one part to be joined

37、to a second part and, hence, they are involved in almost all designs, the acceptability of any product depends not only on the selected componects ,but also on the means by which they are fastensd together ,the principal purpose of fasteners are to provide the following design features:連接件是將一個零件與另一個

38、零件進行連接的零件。 因此, 幾乎在所有的設計中都要用 連接件。 人們對于任何產(chǎn)品的滿意程度不僅僅取決于其組成部件, 而且還取決于其連接方式。 連接件為產(chǎn)品設計提供了一下特性:(1 Disassembly for inspection and repair(2 Modular design where a product consistsof a number subassemblies. Modular design aids manufacturning as well as transportation.(1為檢查和維修提供拆卸的方便(2 為由許多部件組成的組合式設計提供方便。 采用組合

39、式設計可以便于生產(chǎn)制造和運輸。 There are three main classifications of fasteners, which are described as follows:(1 Removable. This type permits the parts to be readily disconnected without damaging the fastener . An example is the ordinary nut-and-bolt fastener.(2 Semipermanent. For this type,the parts can be dis

40、connected, but some damage usually occurs to the fastener . One such example is a cotter pin。(3 Permanent. 。 When this type of fastener is used, it is intended that the part will never be disassembled. Examples are riveted and welded joint.連接件可以分為以下三類:(1 可拆式。 采用這種方式連接的零件很容易被拆開,而且不會對連接件造成損傷。例 如普通的螺栓螺

41、母連接。(2半永久式。采用此類方式連接的零件雖然能被拆開,但通常會對所用的連接件造成損 傷,如開口銷。(3永久式。 采用這種連接件就表明所連接的零件不會被分開,例如鉚接和焊接。The following factors should be taken into account when selecting fasteners for a given application:對于一個特定的應用,在選擇連接件時應考慮以下幾個方面:(1 Primary function;基本功能(2 Appearance ;外觀(3 A large number of small size fasteners ve

42、rsus a small number of large size fasteners(an example is bolts;對于是采用大量的小型連接件還是采用少量的大型連接件的確定(螺栓可以作為一個例子 (4 Operating conditions such as vibration ,loads and temperature;諸如載荷、振動和溫度等工作條件(5 Frequency of disassembly;裝拆頻率(6 Adjustability in the location of parts;零件位置的可調(diào)性(7 Types of materials to be joined

43、;被連接零件的材料種類(8 Consequences of failure or loosening of the fastener;連接件失效或者松脫造成的后果The importance of fasteners can be realized when referring to any complex product. In the case of the automobile,there are literally thousands of parts which are fastened together to product the total product . The fail

44、ure or loosening of a single fastener could result in a simple nuisance such as a door rattle or in a serious situation such as a wheel coming off . Such possibilities must be taken into account in the selectiong of the type of fastener for the specific application.通過任何一個復雜的產(chǎn)品, 都能夠認識到連接件在其中的重要性。 以汽車

45、為例, 它是通 過數(shù)千個零件連接在一起而成為一輛整車的。 一個連接件的失效或者松脫可能會帶來像車門 嘎嘎響這類的小麻煩, 也可能造成像車輪脫落這種嚴重的后果。 因此, 在為一個特定的用途 選擇連接件時,應該考慮到上述各種可能性。Springs are mechanical members which are designed to give a relatively large amount of elastic deflection under the action of an externally applied load hooke s law,which states that def

46、ection is proportional to load,is the basis of behavior springs.however,some springs are designed to produce a nonlinear relationship between load and defection.the following is a list of the important purposes and applications of springs.彈簧是一種能夠在外載荷作用下, 產(chǎn)生相當大的彈性變形的機械零件。 描述變形與載荷 成正比的虎克定律表明了彈簧的基本性能。

47、然而, 也有一些彈簧在其設計時所確定的載荷與 變形之間的關(guān)系就是非線性的。彈簧的主要用途如下所述:(1Control of motion in machines.This category represents the majority of spring application s such as operating forces in clutches and brakes.also,spring are used to maintain contact betwee n two members such as a cam and its follower.控制機構(gòu)運動。 這類應用占彈簧用

48、途的主要部分, 如在離合器和制動器中起操縱力的作 用。彈簧也被用來保持凸輪與從動件接觸。(2Reduction of transmittes forces as a reuslt of impact or shock loading.Applications here in clude automotive suspension system springs and bumper spring.緩沖和減震。這類應用包括汽車懸架系統(tǒng)彈簧和緩沖彈簧。(3Storage of energy. Applications in this category are found in clocks, mov

49、ie cameras and lawn mowers.儲存能量。這類彈簧應用于鐘表、攝影機和割草機中。(4Measurement of force. Scales used to weigh people is very common application for this category.測量力的大小。用來稱體重的秤就是這類應用中最常見的一種。Compression and extension springs are the springs most often used.Deflection is linear in these types.Torsion springs are ch

50、aracterized by angular instead of linear deflection.Flat leaf springs are of the simple beam or cantilever type,their deflection is linear.壓縮彈簧和拉伸彈簧是最常用的彈簧 . 這些彈簧的變形是線性的 . 扭轉(zhuǎn)彈簧的變形是角度 而不是線性位移 . 平面板簧可以是簡支梁型 , 也可以是懸臂梁型 , 它們的變形是線性的 .Most springs are made of steel,although silicon bronze,brass and beryll

51、ium copper are also used.Springs are universally made by companies which specialize in the manufacture of springs.The helical coil spring is the most papular type of spring; torsion bars and leaf springs are also widely used.If the wire diameter (assuming a helical coil spring is less than 8mm. the

52、springwill normally be cold-wound from hard-drawn or oil-tempered wire. For larger diameters,springs are formed using hot-rolled bar.大部分的彈簧是用鋼制造的 , 但也有一些彈簧采用硅青銅 , 黃銅和銅鈹合金制造 . 彈簧通 常由專業(yè)生產(chǎn)彈簧的廠家制造 . 圓柱螺旋彈簧是最常用的彈簧 , 扭桿和板簧也有廣泛的應用 . 對于圓柱螺旋彈簧 , 如果彈簧絲直徑小于 8mm, 通常采用冷拔鋼絲或油回火鋼絲經(jīng)冷卷法制 成 . 如果彈簧絲直徑較大 , 采用熱軋鋼筋卷制彈簧It

53、 is good practice to consult with a spring manufacturing company when selecting a spring design, especially if high loads or temperatures are to be encountered, or if sress reverals occur or corrosion resistance is required. To properly select a spring, a complete study of the spring requirements, i

54、nclouding space linitations, must be undertaken. Many different types of special springs are available to safisfy unusual requirements or applications.選擇彈簧, 尤其是在遇到重載、 高溫、 需要承受交變應力或者需要具有抗腐蝕性的時候; 應該向彈簧制造廠家進行咨詢。 為了正確地選擇彈簧, 應該對彈簧的使用要求, 包括孔家限 制進行全面的研究。有許多不同種類的專用彈簧可以滿足一些特殊的要求或用途。Rolling BearingsRolling be

55、aring can carry radial,thrust or combination of the two loads.滾動軸承可以承受徑向載荷,軸向載荷或者同事承受這兩種載荷 .Accordingly,most rolling bearings are categorized in one of the three groips:因而,大部分滾動軸承可以被劃分為三種類型radial bearings for carrying loads that are primarily radial,thrust bearings for supporting loads that are prim

56、arily axial,and angular contact bearings or taper roller bearings for carrying combined radial and axial loads.向心軸承,主要承受徑向載荷,推力軸承,主要承受軸向載荷角接觸軸承或圓錐滾子軸承, 能同時承受徑向和軸向載荷Figure 11.1 shows a common single-row,deep groove ball bearing.一個普通的單列深溝球軸承的結(jié)構(gòu)如圖 11.1所示,the bearing consists of aninner ring,an outer ri

57、ng,the balls and the separator(also known as retainer.它由內(nèi)圈,外圈,球和保持架四部分組成 .To increase the contact area and hence permit larger loads to be carried ,the balls run in curvilinear grooves in the rings called raceway.為了增加接觸面積以承受更大的載荷,球在內(nèi)外圈上的被稱為滾道的弧形溝內(nèi)滾動 .the radius of the raceway is very little larger t

58、han the radius of the ball.滾道的圓弧半徑略大于滾動球的半徑。This type of bearing can stand a radial load as well as some thrust load.這種軸承能夠承受徑向載荷,也可以承受一定的軸向載荷 .The concern of a machine designer with ball and roller bearings is fivefold as follows:對于球軸承和滾子軸承,一個機器設計人員應該考慮下面 5個方面:(a life in relation to load;(bstiffnes

59、s,i.e. deflections under load;(c friction;(dweae;(enoise.(a壽命與載荷的關(guān)系; (b剛度,也就是在載荷作用下的變形; (c摩擦; (d磨損; (e噪聲。 For moderate loads and speeds the coeeect selection of a standard bearing on teh basis of load rating will usually secure satisfactory performance .對于中等載荷和轉(zhuǎn)速, 根據(jù)額定負荷選擇一個標準軸承, 通常都可以保證其具有令人滿意的 工作性能。The deflection of the bearing elements will become im