机械工程英语翻译.

1、? Drilli ng and Drills钻削和钻头Drilli ng invo Ives produci ng through or bli nd holes in a workpiece by forcing a tool, which rotates around its axis, aga inst the workpiece.钻削就是通过迫使绕自身轴线旋转的切削刀具进入工件而在其上生成通孔或盲孔。Consequently, the range of cutting from that axis of rotation is equal to the radius of the re

2、quired hole. In practice, two symmetrical cutt ing edges that rotate about the same axis are employed.因此，从旋转轴线开始的切削范围等于所需孔的半径。实际上，使用的是两条围绕相同轴线 旋转的对称切削刃。Drillingoperations can be carried out by using either hand drills or drillingmach in es. The latter differ in size and con struct ion.Nevertheless,

3、the tool alwaysrotates around its axis while the workpiece is kept firmly fixed. This is con trary to drilli ng on a lathe.钻削作业既能采用手钻也能采用钻床来实现。钻床在尺寸和结构上虽有差别，然而始 终都是切削刀具围绕自身轴线旋转、工件稳固定位的形式。这正好与在车床上钻孔相反。Cutti ng Tool for Drilli ng Operati onIn drilling operations,a cylindricalrotary-end cutting tool, c

4、alled a drill,is employed. The drill can have either one or more cutt ing edges and corresp onding flutes, which can be straight or helical.用于钻削作业的切削刀具在钻削作业中，要用到被称为钻头的圆柱形回转端切削刀具。钻头可以有一条或多条直的或是螺旋状的切削刃以及相应的出屑槽。The function of the flutes is to provide outlet passages for the chips gen erated duri ng th

5、e drilling operation and also to allow lubricants and coolants to reach the cutting edges and the surface being machi ned. Follow ing is a survey of the com monly used drills.出屑槽的功能是给钻削作业中产生的切屑提供排出通道，并允许润滑剂和冷却液到达切削刃 和正在被加工的表面。下面是常用钻头的概述。Twist drill. The twist drill is the most com mon type of drill.

6、 It has two cutting edges and two helical flutes that continue over the length of the drill body, as shown in Fig.12.1. The drill also consists of a neck and a shank that can be either straight or tapered.麻花钻：麻花钻是最常用的钻头类型。它有两条切削刃和两条沿钻头体全长连续的螺 旋状出屑槽，如图12.1所示。麻花钻还包括钻颈和钻柄，钻柄可以是直的也可以是锥形的。 In the latter

7、case, the sha nk is fitted by the wedge acti on into the tapered socket of the spin dle and has a tang, which goes into a slot in the spin dle socket, thus acti ng as a solid means for tran smitt ing rotati on.锥形钻柄通过楔入动作安装在主轴的锥形轴孔中，钻柄上还有柄舌插入主轴轴孔中的插槽， 从而作为传递转动的可靠方法。On the other hand, straight-sha nk

8、drills are held in a drill chuck that is, in tur n, fitted into the spin dle socket in the same way as tapered sha nk drills.另一方面，直柄钻头用钻头卡盘夹住，接下来钻头卡盘则象锥形钻柄钻头一样安装在主轴轴 孔内。As can be seen in Fig.12.1, the two cutting edges are referred to as the lips, and are conn ected together by a wedge, which is a c

9、hisel-like edge. The twist drill also has two margi ns, which en able proper guida nee and locati ng of the drill while it is in operati on.如图12.1所示，两条切削刃就是钻唇，通过凿子状边缘的楔形体连在一起。麻花钻 还有两条导向边，用于作业中钻头的正确导向和定位。The tool point an gle (TPA) is formed by the two lips and is chose n based on theproperties of th

10、e material to be cut. The usual TPA for commercial drills is 118° ,which is appropriate for drilli ng low-carb on steels and cast irons.两条钻唇形成钻顶角，并根据被钻削材料的性能来选取其大小。商品化钻头的钻顶角一般为 118°，这适用于钻削低碳钢和铸铁。For harder and tougher metals, such as hardened steel, brass and bronze, larger TPAs (130 °

11、; or 140° ) give better performanee. The helix angle of the flutes of the commonly used twist drillsranges between 24° and 30° . Whendrillingcopper or soft plastics,higher values for the helix angle are recommended (between 35° and 45 ° ).对于更硬更韧的金属，诸如淬火钢、黄铜和青铜，更大的钻顶角(130。或14

12、0° )才能有更好的效果。麻花钻常用的出屑槽螺旋角范围为24°到30。钻削紫铜或软塑料时，推荐采用更大的螺旋角(35。到45° )。Twist drills are usually made of high-speed steel, although carbide-tippeddrills are also available. The sizes of twist drills used in in dustrial practice range from 0.01 up to 3.25 in. (i. e., 0.25 up to 80 mm).虽然也有硬质

13、合金刀尖的钻头，麻花钻一般用高速钢制成。工业实际中使用的麻花钻 尺寸范围为0.01到3.25英寸(即0.25到80毫米)。Core drills. A core drill con sists of the chamfer, body, n eck, and sha nk, asshow n in Fig.12.2. This type of drill may have either three or four flutes and equal number of margins, which ensure superior guidanee, thus resulting in highm

14、achiningaccuracy.空心钻：空心钻包括斜面、钻头体、钻颈和钻柄，如图12.2所示。这类钻头可以有三条或四条出屑槽及相同数量的保证良好导向的导向边，这样使得加工有高精度。It can also be see n in Fig.12.2 that a core drill has flat end. The chamfer can havethree or four cutting edges or lips, and the lip angle mayvary between 90° and 120° . 在图12.2中同样能看到，空心钻具有平坦的端部。斜面可以

15、有三或四条切削刃或钻唇，并且 钻唇角可以在90°到120。之间变化。Core drills are employed for enlarging previously madeholes and not for originating holes. This type of drill is characterized by greater productivity, high mach ining accuracy, and superior quality of the drilled surfaces.空心钻用于扩大已有的孔而不是打孔。这类钻头具有较大生产率、高加工精度和优良钻

16、削表 面质量的特性。Gun drills. Gun drills are used for drilli ng deep holes. All gun drills are straight-fluted, and each has a sin gle cutt ing edge. A hole in the body acts as a con duit to tran smit coola nt un der con siderable pressure to the tip of the drill.深孔钻：深孔钻用于钻深孔。所有深孔钻都是直出屑槽的，并且均为单切削刃。钻头 体中有个孔作

17、为导管在相当大的压力下将冷却液传送到钻头顶端。There are two kinds of gun drills, n amely, the cen ter-cut gun drill used for drilli ng bli nd holes and the trepa nning drill. The latter has a cyli ndrical groove at its cen ter, thus gen erat ing a solid core, which guides the tool as it proceedsduri ng the drilli ng opera

18、ti on.深孔钻有两种类型，即用于钻盲孔的中心切削深孔钻和套孔钻。后者在其中心有一圆柱形沟槽，这样能生成整体芯在钻孔作业过程中引导钻头。Spade drills. Spade drills are used for drillinglarge holes of 3.5 in.(90mm)or more. Their desig n results in a marked sav ing in cost of the tool as well as a tan gible reduct ion in its weight, which facilitates its han dli ng. M

19、oreover, this type of drill is easy to grind.扁平钻：扁平钻用于钻削3.5英寸(90毫米)或更大的大孔。其设计使得钻头成本明 显节省、重量切实减轻，重量轻又使操作更方便。此外这种钻头容易磨利。? Milli ng and Milli ng Cutter铣削和铣刀Milli ng is a mach ining process that is carried out by means of a multiedge rotati ng tool known as a milli ng cutter.铣削是采用被称为铣刀的多刃旋转刀具完成的机加工作业。In

20、 this process, metal removal is achieved through combi ning the rotary moti on of the milli ng cutter and lin ear motio ns of the workpiece simulta neously. Milli ng operati ons are employed in produc ing flat, con toured and helical surfaces as well as for thread- and gear-cutt ing operati on.在此工艺中

21、，金属去除是通过铣刀的旋转运动和工件的直线运动的组合实现的。铣削作业既 可用于生成平面、轮廓面和螺旋面，也可用于切削螺纹和齿轮。Each of the cutt ing edges of a milli ng cutter acts as an in dividualsingle-pointcutter whenit engages with the workpiece metal. Therefore, each of thosecutt ing edges has appropriate rake and relief an gles.在铣刀切削工件金属时，铣刀的每条切削刃都象一单独的单刃

22、刀具一样作用。所以每条切削刃都适当的前后角。Since only a few of the cutting edges are engaged with the workpiece at a time, heavy cuts can be taken without adversely affecting the tool life. In fact, the permissible cutt ing speeds and feeds for milli ng are three to four times higher tha n those for turning or drilli ng

23、.由于同一时间只有部分切削刃切削工件，因此可以在对刀具寿命没有不利影响的情况下承担 重型切削。事实上，铣削允许的切削速度和进给比车削或钻削高三到四倍。Moreover, the quality of the surfaces mach ined by milli ng is gen erally superior to the quality of surfaces machi ned by tur ning, shap ing, or drilli ng.此外，由铣削加工的表面质量通常优于车削、刨削或钻削加工的表面质量。A wide variety of milli ng cutters i

24、s available in in dustry. This, together with the fact that a milli ng mach ine is a very versatile machi ne tool, makes the milli ng machi ne the backb one of a mach ining workshop.工业上可采用的铣刀类型众多。连同铣床是极通用机床的事实，使得铣床成为机加工 车间的支柱。As far as thedirecti on of cutter rotati on and workpiece feed are concern

25、 ed,milli ng is performed by either of the followi ng two methods.至于涉及到铣刀转动的方向和工件的进给，铣削可以通过下列两种方法之一进行。Up milling (conventionalmilling).In up milling the workpiece is fed againstthe direct ionof cutter rotati on, as show n in Fig.12.3a.As we can see in that figure,the depth of cut (and con seque ntly

26、 the load) gradually in creases on the successively en gaged cutt ing edges.逆铣（传统铣削）：在逆铣中，工件逆着铣刀转动的方向进给，如图12.3a所示。就像在此图中能看到的那样，切削深度（及作为结果的载荷）随着切削刃持续进入切削而逐渐增加。Therefore, the machining process invoIves no impact loading, thus ensuring smoother operati on of the machi ne tool and Ion ger tool life. The

27、 quality of the machi ned surface obta ined by up milli ng is not very high. Nevertheless, up milli ng is com monly used in in dustry, especially for rough cuts.所以，这种工艺没有冲击载荷，从而保证了机床的较平稳运行和较长寿命。通过逆铣所得机 加工表面质量不是很高。然而逆铣仍经常被用在工业上，尤其是粗切削时。Dow n milli ng （climb milli ng）. As can be see n in Fig.12.3b, in

28、 dow n milli ngthe cutter rotati oncoin cides with the directi on of feed at the con tact point betwee nthe tool and the workpiece. It can also be see n that the maximum depth of cut is achieved directly as the cutter en gages with the workpiece.顺铣（同向铣削）：如同在图12.3b中看到的那样，在顺铣时刀具与工件之间接触点上 铣刀旋转与进给方向一致。还

29、可以看到当刀具进入工件切削时直接达到最大切削深度。This results in a ki nd of impact, or sudde n load ing. Therefore, this method cannotbe used uni ess the milli ngmach ine is equipped with a backlash elim in ator on the feedscrew. The adva ntages of this method in clude higher quality of the mach ined surface and easier cla

30、mp ing of workpieces, since the cutt ing forces act dow nward.这会导致一种冲击，或突然加载。因此，这种方法只有当铣床在进给螺栓上配备间隙消除器 时才采用。这种方法的优点包括机加工表面质量较高和工件由于切削力向下作用而较容易夹 紧。Types of Milli ng CuttersThere is a wide variety of milli ng cutter shapes. Each of them is desig nedto perform effectively a specific milli ng operati on

31、.铣刀的类型铣刀的形状类型很多。其中每种都是为有效进行特定的铣削作业而设计的。Gen erally, a milli ng cutter can be described as a multiedge cutt ing tool hav ing theshape of a solid of revolution, with the cutting teeth arranged either on the periphery or on an end face or on both. Follow ing is a quick survey of the com monly used types

32、 of milli ng cutters.通常，铣刀可以被描述为具有旋转实体形状并将切削齿安装在周边或一到两个端面上的多刃 切削刀具。下面是常用铣刀类型的快速综览。Plain milli ng cutter. A plain milli ng cutter is a disk-shaped cutti ng toolthat may have either straight or helical teeth, as show n in Fig.12.4a. This type is always mounted on horizontalmilling machines and is used

33、 for machining flat surfaces.平面铣刀：平面铣刀是一种盘状切削刀具，它可以具有直齿或螺旋齿，如图12.4a所示。这类铣刀总是安装在卧式铣床上，用于机加工平面。Face milli ng cutter. A face milli ng cutter is also used for machi ning flat surfaces. It is bolted at the end of a short arbor, which is in turn moun ted on a vertical milli ng mach ine. Fig.12.4b in dicat

34、es a milli ng cutter of this type.端面铣刀：端面铣刀也可用于机加工平面。它用螺栓固定在短刀杆的端部，而短刀杆 则依次安装于立式铣床上。图12.4b显示了这类铣刀。Plain metal slitti ng saw cutter. Fig.12.4c in dicates a plain metal slitti ngsaw cutter. we can see that it actually invo Ives a very thin pla in milli ng cutter.可以看到它其平面金属开槽锯刃铣刀：图12.4c显示了一种平面金属开槽锯刃铣刀实

35、是一种很薄的平面铣刀。Sidemillingcutter. A side milling cutter is used for cutting slots, grooves,and splines. As shown in Fig.12.4d, it is quite similar to the plain millingcutter,the differe nee being that this type has teeth on the sides. As is the case with the pla in cutter, the cutt ing teeth can be stra

36、ight or helical.侧铣刀：侧铣刀用于切削狭槽、凹槽和花键槽。正如图12.4d所示，它与平面铣刀十分相似，差别在于此类铣刀齿在侧面。象平面铣刀的情况一样，切削齿既可以是直的也可以 是螺旋的。An glemilli ng cutter.An an gle milli ngcutter is employed in cutt ing dovetailgrooves, ratchet wheels, and the like. Fig.12.4e in dicates a milli ng cutter of this type.倾斜铣刀：倾斜铣刀用于切削燕尾槽、棘轮之类的。图12.4e

37、显示了这类铣刀。T-slot cutter. As shown in Fig.12.4f, a T-slot cutter invoIves a plain milling cutter with an in tegral shaft no rmal to it. As the n ame suggests, this type is used for milli ng T-slots.T型槽铣刀：如图12.4f所示，T型槽铣刀包括了一个平面铣刀和一根垂直于它的整体轴。正像其名字所表明的，这类铣刀用于铣削T型槽。End mill cutter.End mill cutters find com

38、 mon applicati onsin cutti ng slots,grooves, flutes, spli nes, pocketi ng work, and the like. Fig.12.4g in dicates an end mill cutter. The latter is always mounted on a verticalmillingmachine and can havetwo or four flutes, which may be either straight or helical.端面铣刀：端面铣刀在切削狭槽、凹槽、长凹槽、花键槽、凹状工件之类时均能发

39、现 其普遍应用。图12.4g为端面铣刀。它总是安装在立式铣床上，并具有两到四条既可是直的 也可是螺旋的长凹槽。Formmilling cutter. The teeth of a form millingcutter have a certain shape,which is ide ntical to the secti on of the metal to be removed duri ng the milli ng operati on. Examples of this type in clude gear cutters, gear hobs, con vex and con ca

40、ve cutters, and the like. From milli ng cutters are moun ted on horiz on tal milli ng mach in es.成形铣刀：成形铣刀的齿具有特定的形状，这个形状与铣削时要切削的那部分金属的 形状一致。这类铣刀的例子包括齿轮铣刀、齿轮滚刀、凸形和凹形铣刀等等。成形铣刀安装 在卧式铣床上。Materials of Milli ng CuttersThe com mon ly used milli ng cutters are made of high-speed steel, which is gen erally a

41、dequate for most jobs.铣刀的材料普通使用的铣刀用高速钢制造，这对一般大多数工作已足够。Milli ng cutters tipped with sin tered carbides or cast non ferrous alloys as cutt ing teeth are usually employed for massproduction, where heavier cuts and/or high cutting speeds are required.对大规模生产而言，因为其需要重型切削和/或高切削速度，铣刀顶端常装有烧结碳化物或有 色金属碳合金作为切削齿

42、。第十四单元? Dime nsio ning标注尺寸The desig n of a mach ine in eludes many factors other tha n those of determ iningthe loads and stresses and select ing the proper materials.机械设计除了计算载荷和应力、选择合适的材料外，还包括许多其它因素。Before con struct ion or manu facture can beg in, it is n ecessary to have complete assembly and det

43、ail draw ings to convey all n ecessary in formati on to the shop men.The desig ner freque ntly is called upon to check the draw ings before they are sentto the shop. Much experienee and familiarity with manufacturing processes are needed before one can become conv ersa nt with all phases of producti

44、 on draw in gs.在建造或制造开始前，完成装配图和零件图以把必要信息传达给车间工人是必须的。在送往 车间前设计者常常被召集来检查图纸。而在精通生产图纸的所有情况之前，需要有许多经验 并熟悉制造工艺。Draw ings should be carefully checked to see that the dime nsioning is done ina manner that will be most convenient and understandable to the production departments. It is obvious that a draw ing

45、 should be made in such a way that it has one and only one in terpretati on.图纸必须仔细检查其尺寸是否按生产部门最方便易懂的方式标注。很明显图纸应该只有唯一的解释。In particular, shop pers onnel should not be required to make trig ono metric or other invo Ived calculati ons before the product ion machi nes can be set up.Dime nsioning is an in

46、vo Ived subject and long experie nee is required for its mastery.尤其是不能要求车间工人在生产机械安排前进行三角或其它复杂的计算。尺寸标注是一项复杂的工作，要掌握它需要有丰富的经验。Tolera nces must be placed on the dime nsions of a draw ing to limit thepermissible variationsin size because it is impossible to manufacture a part exactlyto a give n dime nsio

47、n.由于要把零件加工到正好为给定尺寸是不可能的，因此图纸的尺寸必须加上公差以限制其可允许的变化。Although small tolerances give higher quality work and a better operating mechanism, the cost of manu facture in creases rapidly as the tolera nces are reduced, as in dicated by the typical curve of Fig14.1. It is therefore importa nt that the tolera n

48、ces be specified at the largest values that the operati ng or fun cti onal con siderati ons permit.虽然较小公差能得到较高加工质量和较好操作机构，但随着公差的减小制造成本会迅速增加，如图14.1的典型曲线所示。因此公差被定为从操作或功能考虑允许的最大值是重要的。Tolerances maybe either unilateral or bilateral. In unilateral dimensioning, one tolera nee is zero, and all the variati

49、o ns are give n by the other tolera nee. In bilateral dime nsioning, a mean dime nsion is used which exte nds to the midpo int of the toleranee zone with equal plus and minus variationsextending each way from thisdime nsion.公差既可以是单向的也可以是双向的。单向标注有一公差为零，所有变化都由另一公差给定。而双向标注则采用一平均尺寸，它将公差带中点从该尺寸双向扩展为相等的正负

50、变 化范围。The developme nt of product ion processes for large-volume manu facture at lowcost has been largely dependent upon interchangeability of component parts. Thus the desig ner must determ ine both the proper tolera nces for the in dividual parts, and the correct amount of clearanee or interferene

51、e to permit assembly with the mating parts.大规模低成本制造生产工艺的发展很大程度取决于组成零件的互换性。因此设计者必须确定单个零件的合适公差以及配合零件装配允许的正确间隙或过盈量。The manner of placing tolerances on drawings depends somewhat on the kind of product or type of manufacturing process. If the toleranee on a dimension is not specifically stated, the draw

52、ing should contain a bla nket note which gives the value of the tolera nee for such dime nsions.在图纸上标注公差的方法相当程度上依赖于产品的性质或制造工艺的类型。如果尺寸公差没 有特别注明，图纸应该包含一个给出这些尺寸公差值的普遍适用注释。However, some compa nies do not use bla nket no tes on the suppositi on that if each dimension is considered individually,wider tole

53、rances than those called for inthenote could probably be specified. In any eve nt it is very importa nt that a draw ing be free from ambiguities and be subject on ly to a si ngle in terpretati on.然而有些公司不采用普遍适用注释，假定每个尺寸是单独被考虑的，可能会规定出比注释中 要求的更宽的公差。在任何情况下图纸不模棱两可并只服从于单一的解释是十分重要的。? Dime nsion and Tolera

54、nee尺寸和公差In dimensioning a drawing, the numbers placed in the dimension lines represent dime nsion that are only approximate and do not represe nt any degree of accuracy uni ess so stated by the desig ner.在图纸标注尺寸时，除非设计者有意标明，注在尺寸线上的数字代表的尺寸仅仅是近 似的，并不代表任何精度等级。To specify a degree of accuracy, it is n ece

55、ssary to add tolera nee figures tothe dimension. Toleranee is the amount of variationpermitted in the part or the totalvariati on allowed in a give n dime nsion.为了详细标明精度等级，有必要在尺寸上增加公差数字。公差是零件允许的变动量或 给定尺寸允许的总变动。A shaft might have a nominal size of 2.5 in .(63.5mm), but for practical reas ons thisfigu

56、re could not be maintained in manufacturing without great cost. Hence, a certain toleranee would be added and, if a variation of土 0.003in.( 土 0.08mm) could bepermitted, the dimension would be stated 2.500± 0.003(63.5 ± 0.08mm).一根轴可能的名义尺寸为2.5i n.(63.5mm)，但由于实际原因不用大成本是不能在制造中保持 这个数字的，因此要增加确定的

57、公差。如果允许有土 0.003in.( ± 0.08mm)的变化，则此尺寸 可表达为 2.500 ± 0.003(63.5 ± 0.08mm),Dime nsions give n close tolera nces mean that the part must fit properly with someother part. Both must be given tolerances in keeping with the allowanee desired, the manu facturi ng processes available, and the

58、minimum cost of producti on and assembly that will maximize profit.具有紧密公差的尺寸表示该零件必须恰当地与某些其它零件配合。所采用的制造工艺和使利润最大化的最小生产及装配成本都要求给定公差以保持所需允差。Gen erally speak ing, the cost of a part goes up as the tolera nee is decreased. If apart has several or more surfaces to be machined, the cost can be excessive when little deviatio n is allowed from the nominal size.一般而言，零件的成本随着公差的减小而上升。如果一个零件有若干或较多表面要机加工， 且几乎不允许偏离名义尺寸，则成本会超过正常合理的界限。Allowa nee, which is sometimes con fused with tolera nee, has an altogetherdiffere nt meanin g. It is the minimum cleara nee space inten ded betwee n