第一单元 Types of Materials材料的类型 Materials may be grouped in several ways.Scientists often classify materials by their state: solid.liquid.or gas.They also separate them into organic (once living)and inorganic (never living) material 材料可以按多种方法分类。科学家常根据状态将材料分为：固体、液体或气体。他们也把材料分为有机材 料（曾经有生命的）和无机材料（从未有生命的）。 For industrial purposes,materials are divided into engineering materials or nonengineering materials.Engineering materials are those used in manufacture and becc 材料。 Nonengineering materials are the chemicals,fuels,lubricants,and other materials used in the 非工程材料则是化学品料 par 、润滑剂以及其它用于加 制造过程 不成为产品组成部分的材料 Engineering materials may be further subdivided into:DMetal 2Ceramics Composite Polymers, etc. 工程材料还能进一步细分为：①金属材料②陶瓷材料③复合材料④聚合材料，等等 Metals and Metal A1loys金属和金属合金 nte that ally have good electrical and thermal conductivity.Many metals have high strength,high stiffn nd ha ood ductility 金属就是通常具有良好导电性和导热性的元素。许多金属具有高强度、高硬度以及良好的延展性。 Some metals.such as iron cobalt and nickel,are magnetic.At low temperatures,some metals and onductors 某些金属能被磁化，例如铁、钻和镍。在极低的温度下，某些金属和金属化合物能转变成超导体。 What is the difference between an alloy and a pure metal?Pure metals are elements which come from a particular area of the periodic table.Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans. 合金与纯金属的区别是什么？纯金属是在元素周期表中占据特定位置的元素。例如电线中的铜和制造亨饪 箔及饮料罐的铝。 Alloys contain more than one metallic element.Their properties can be changed by changing the elements present in the alloy.Examples of metal alloys include stainless steel which is an alloy of iron,nickel,and chromium:and gold jewelry which usually contains an alloy of gold and nickel. 合金包含不止一种金属元素。合金的性质能通过改变其中存在的元素而改变。金属合金的例子有：不锈钢是一种铁， 镍、铬的合金，以及金饰品通常含有金镍合金。 Why are metals and alloys used?Many metals and alloys have high densities and are used in a nigh mas fuelch as those base 1 某些金全paC 。许多合金还具有高断裂韧性，这意味着它 erties of metals? Density is defin al mass divided by its volume.Most metals have relatively high densiti cially ed to polymers 金属有哪些重要特性？ 密度定义为材料的质量与其体积之比。大多数金属密度相对较高，尤其是和聚合物相比较而言。 Materials with high densities often contain atoms with high atomic numbers,such as gold or lead.However, some metals such as aluminum or magnesium have low densities,and are used in applications that require
1 第一单元 Types of Materials 材料的类型 Materials may be grouped in several ways. Scientists often classify materials by their state: solid, liquid, or gas. They also separate them into organic (once living) and inorganic (never living) materials. 材料可以按多种方法分类。科学家常根据状态将材料分为：固体、液体或气体。他们也把材料分为有机材 料(曾经有生命的)和无机材料(从未有生命的)。 For industrial purposes, materials are divided into engineering materials or nonengineering materials. Engineering materials are those used in manufacture and become parts of products. 就工业效用而言，材料被分为工程材料和非工程材料。那些用于加工制造并成为产品组成部分的就是工程 材料。 Nonengineering materials are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product. 非工程材料则是化学品、燃料、润滑剂以及其它用于加工制造过程但不成为产品组成部分的材料。 Engineering materials may be further subdivided into: ①Metal ②Ceramics ③Composite ④Polymers, etc. 工程材料还能进一步细分为：①金属材料②陶瓷材料③复合材料 ④聚合材料，等等。 Metals and Metal Alloys 金属和金属合金 Metals are elements that generally have good electrical and thermal conductivity. Many metals have high strength, high stiffness, and have good ductility. 金属就是通常具有良好导电性和导热性的元素。许多金属具有高强度、高硬度以及良好的延展性。 Some metals, such as iron, cobalt and nickel, are magnetic. At low temperatures, some metals and intermetallic compounds become superconductors. 某些金属能被磁化，例如铁、钴和镍。在极低的温度下，某些金属和金属化合物能转变成超导体。 What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table. Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans. 合金与纯金属的区别是什么？纯金属是在元素周期表中占据特定位置的元素。例如电线中的铜和制造烹饪 箔及饮料罐的铝。 Alloys contain more than one metallic element. Their properties can be changed by changing the elements present in the alloy. Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium; and gold jewelry which usually contains an alloy of gold and nickel. 合金包含不止一种金属元素。合金的性质能通过改变其中存在的元素而改变。金属合金的例子有：不锈钢是一种铁、 镍、铬的合金，以及金饰品通常含有金镍合金。 Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio. 为什么要使用金属和合金？许多金属和合金具有高密度，因此被用在需要较高质量体积比的场合。 Some metal alloys, such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy. Many alloys also have high fracture toughness, which means they can withstand impact and are durable. 某些金属合金，例如铝基合金，其密度低，可用于航空航天以节约燃料。许多合金还具有高断裂韧性，这意味着它 们能经得起冲击并且是耐用的。 What are some important properties of metals? Density is defined as a material’s mass divided by its volume. Most metals have relatively high densities, especially compared to polymers. 金属有哪些重要特性？ 密度定义为材料的质量与其体积之比。大多数金属密度相对较高，尤其是和聚合物相比较而言。 Materials with high densities often contain atoms with high atomic numbers, such as gold or lead. However, some metals such as aluminum or magnesium have low densities, and are used in applications that require
other metalli 常田 又 动原 于既需要 求重量轻的场合 a flaw is 11 kening 断袭韧性可以描述为材料防 特是出现缺陷时不断裂 般能在有缺口和凹痕的情况 不显著削弱，并且能抵抗冲击 棱球运动员据此相信他的面罩不会裂成碎片。 the abilit usuall r to lean to the oast aftor n stro woet wind 塑性变形就是在断裂前弯曲或变形的能力。作为工程师，设计时通常要使材料在正常条件下不变形。设有 人愿意一阵强烈的西风过后自己的汽车向东顿斜。 However,sometimes we can take advantage of plastic deformation.The crumple zones in a car absorb energy by undergoing plastic deformation hefore they break 然而，有时我们也能利用塑性变形。汽车上压皱的区域在它们断裂前通过经历塑性变形来吸收能量。 The atomic bonding of metals also affects their properties.In metals.the outer valence electrons are shared among all atoms,and are free to travel everywhere.Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires. 金属的原子连结对它们的特性也有影响。在金属内部，原子的外层阶电子由所有原子共享并能到处自由移 动。由于电子能导热和导电，所以用金属可以制造好的烹饪锅和电线。 It is impossible to see through metals.since these valence electrons absorb any photons of light which reach the metal.No photons pass through 因为这些阶电子吸收到达金属的光子，所以透过金属不可能看得见。没有光子能通过金属。 Alloys are compounds consisting of more than one metal.Adding other metals can affect the density, strength,fracture toughness,plastic deformation,electrical conductivity and environmental 以及环提 金是由一种以上金属组成的混合物。加一些其它金属能影响密度、强度、断裂韧性、塑性变形、导电性 stronger.Also,adding some chromium 性里加少量铁时使其更强。”样，在钢里加一格能它的生锈过。自也将使它更脆 第七单元 1.Rake angle.It is the angle between the face of the tool called the rake face and the normal to the machining direction.Higher the rake angle,better is the cutting and less are the cutting forces, increasing the rake angle reduces the metal backup available at the tool rake face. 1.前角：它是被称为前倾面的刀具面与垂直机加工方向的夹角。前角越大，则切削越好且切削力越小，增加 前角可以减少刀具前候面上产生的金属阻塞。 This reduces the strength o f the tool tip as well as the heat dissipation through the tool.Thus,there limit to the rake angle and this is generally of the order of 15 for high speed steel tools ，用高速钢刀具切削低碳钢通常为 15 the ncrea cuttin an angle of the angle reduces th ence norm
2 other metallic properties but also require low weight. 高密度材料通常由较大原子序数原子构成，例如金和铅。然而，诸如铝和镁之类的一些金属则具有低密度，并被用 于既需要金属特性又要求重量轻的场合。 Fracture toughness can be described as a material’s ability to avoid fracture, especially when a flaw is introduced. Metals can generally contain nicks and dents without weakening very much, and are impact resistant. A football player counts on this when he trusts that his facemask won’t shatter. 断裂韧性可以描述为材料防止断裂特别是出现缺陷时不断裂的能力。金属一般能在有缺口和凹痕的情况下 不显著削弱，并且能抵抗冲击。橄榄球运动员据此相信他的面罩不会裂成碎片。 Plastic deformation is the ability of bend or deform before breaking. As engineers, we usually design materials so that they don’t deform under normal conditions. You don’t want your car to lean to the east after a strong west wind. 塑性变形就是在断裂前弯曲或变形的能力。作为工程师，设计时通常要使材料在正常条件下不变形。没有 人愿意一阵强烈的西风过后自己的汽车向东倾斜。 However, sometimes we can take advantage of plastic deformation. The crumple zones in a car absorb energy by undergoing plastic deformation before they break. 然而，有时我们也能利用塑性变形。汽车上压皱的区域在它们断裂前通过经历塑性变形来吸收能量。 The atomic bonding of metals also affects their properties. In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere. Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires. 金属的原子连结对它们的特性也有影响。在金属内部，原子的外层阶电子由所有原子共享并能到处自由移 动。由于电子能导热和导电，所以用金属可以制造好的烹饪锅和电线。 It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal. No photons pass through. 因为这些阶电子吸收到达金属的光子，所以透过金属不可能看得见。没有光子能通过金属。 Alloys are compounds consisting of more than one metal. Adding other metals can affect the density, strength, fracture toughness, plastic deformation, electrical conductivity and environmental degradation. 合金是由一种以上金属组成的混合物。加一些其它金属能影响密度、强度、断裂韧性、塑性变形、导电性 以及环境侵蚀。 For example, adding a small amount of iron to aluminum will make it stronger. Also, adding some chromium to steel will slow the rusting process, but will make it more brittle. 例如，往铝里加少量铁可使其更强。同样，在钢里加一些铬能减缓它的生锈过程，但也将使它更脆。 第七单元 1. Rake angle. It is the angle between the face of the tool called the rake face and the normal to the machining direction. Higher the rake angle, better is the cutting and less are the cutting forces, increasing the rake angle reduces the metal backup available at the tool rake face. 1.前角：它是被称为前倾面的刀具面与垂直机加工方向的夹角。前角越大，则切削越好且切削力越小，增加 前角可以减少刀具前倾面上产生的金属阻塞。 This reduces the strength of the tool tip as well as the heat dissipation through the tool. Thus, there is a maximum limit to the rake angle and this is generally of the order of 15°for high speed steel tools cutting mild steel. It is possible to have rake angles at zero or negative. 但这会和减少通过刀具散发的热量一样减少刀尖强度。因此前角有一最大限制，用高速钢刀具切削低碳钢通常为 15°。前角取零度或负值也是可能的。 2. Clearance angle. This is the angle between the machined surface and the underside of the tool called the flank face. The clearance angle is provided such that the tool will not rub the machined surface thus spoiling the surface and increasing the cutting forces. A very large clearance angle reduces the strength of the tool tip, and hence normally an angle of the order of 5~6°is used
【切2.后角，这是机加工面与被称为后面。的分区其主云顶环机加上面的摩擦和增列 般采用5广6°的后角 (D)pi (1)间新切属 列连切 (③)带切屑瘤的连续切屑 rmented chip parates into short pieces,which may or may not adhere runs ahead of the tool. 间断切屑：分段的切屑分散成小碎片，既可能相互附若也可能不相互附若。在靠近切削面处发生金属的剧烈 变形，导致在运动刀具前方金屈层产生裂缝 Eventually,the shear stress across the chip becomes equal to the shear strength of the material,resulting in fracture and separation.With this type of chip,there is little relative movement of the chip along the tool face,Fig.7.3a. 最后，横过切屑的剪切应力与材料的剪切强度相等，造成断裂和分离。生成这类切屑时，切屑沿刀具面几乎没有相 对运动，见图7.3a。 Continuous chip.The continuous chip is characterized by a general flow of the separated metal along the tool face.There may be some cracking of the chip,but in this case it usually does not extend far enough to cause fracture 连续切屑： 续的切屑 般具有分离金属沿刀具面流动的特征。切屑可能有一些破裂，但在这种情况下切屑 通常不会延长到足以引起断裂 nere to tne too. ne con Ontinuous chip usually shows a good cutting ratio and tends tends 种切屑形成于用较 的物 速度机加 的向。连续切通常具有良好 率和趋 生最适宜的表面光洁 危险 1图 chip hows the existence of a localized,highly deformed zone of 带切屑瘤的连续切周：这种切屑显示了粘合或“焊接在刀具面上材料局部高度变形区的存在。 that this built is held in by the static until it be o large that the exterr on it se it to disl with some of it remaining on the machined surface and the rest passing off on the back side of the chip. 实际上，对显微照片的分析显示这种切屑受到静摩擦力抑制直至它变得大到作用在它上面的外力使其移动，一些 留在机加工表面上而另一些延伸到切屑的背面，见图7.3c。 Cutting Fluids切削液 The functions of cutting fluids (which are often erroneously called coolants)are: To cool the tool and workpiece To reduce the friction 切削液（经常误称为冷却液）的功能如下： 冷却刀具和工件 减少摩擦 To protect the work against rusting To improve the surface finish To prevent the formation of built-up edge To wash away t the chips from the cutting zone 保护工件不生 改善表面光洁度 刻
3 2. 后角：这是机加工面与被称为后侧面的刀具底面夹角。后角使刀具不产生会损坏机加工面的摩擦和增加 切削力。很大的后角会削弱刀尖的强度，因此一般采用 5~6°的后角。 (1) Discontinuous chip (2) Continuous chip (3) Continuous chip with BUE (Built up edge) (1)间断切屑 (2)连续切屑 (3)带切屑瘤的连续切屑 Discontinuous Chip. The segmented chip separates into short pieces, which may or may not adhere to each other. Severe distortion of the metal occurs adjacent to the face, resulting in a crack that runs ahead of the tool. 间断切屑：分段的切屑分散成小碎片，既可能相互附着也可能不相互附着。在靠近切削面处发生金属的剧烈 变形，导致在运动刀具前方金属层产生裂缝。 Eventually, the shear stress across the chip becomes equal to the shear strength of the material, resulting in fracture and separation. With this type of chip, there is little relative movement of the chip along the tool face, Fig.7.3a. 最后，横过切屑的剪切应力与材料的剪切强度相等，造成断裂和分离。生成这类切屑时，切屑沿刀具面几乎没有相 对运动，见图 7.3a。 Continuous chip. The continuous chip is characterized by a general flow of the separated metal along the tool face. There may be some cracking of the chip, but in this case it usually does not extend far enough to cause fracture. 连续切屑：连续的切屑一般具有分离金属沿刀具面流动的特征。切屑可能有一些破裂，但在这种情况下切屑 通常不会延长到足以引起断裂。 This chip is formed at the higher cutting speeds when machining ductile materials. There is little tendency for the material to adhere to the tool. The continuous chip usually shows a good cutting ratio and tends to produce the optimum surface finish, but it may become an operating hazard, Fig.7.3b. 这种切屑形成于用较高切削速度机加工有延展性的材料时。材料几乎没有粘附刀具的倾向。连续切屑通常具有良好 的切削率和趋向于产生最适宜的表面光洁度，但可能成为操作的危险之源，见图 7.3b。 Continuous with a built-up edge. This chip shows the existence of a localized, highly deformed zone of material attached or “welded” on the tool face. 带切屑瘤的连续切屑：这种切屑显示了粘合或“焊接”在刀具面上材料局部高度变形区的存在。 Actually, analysis of photomicrographs shows that this built-up edge is held in place by the static friction force until it becomes so large that the external forces acting on it cause it to dislodge, with some of it remaining on the machined surface and the rest passing off on the back side of the chip, Fig.7.3c. 实际上，对显微照片的分析显示这种切屑瘤受到静摩擦力抑制直至它变得大到作用在它上面的外力使其移动，一些 留在机加工表面上而另一些延伸到切屑的背面，见图 7.3c。 • Cutting Fluids 切削液 The functions of cutting fluids (which are often erroneously called coolants) are: • To cool the tool and workpiece • To reduce the friction 切削液(经常误称为冷却液)的功能如下： • 冷却刀具和工件 • 减少摩擦 • To protect the work against rusting • To improve the surface finish • To prevent the formation of built-up edge • To wash away the chips from the cutting zone • 保护工件不生锈 • 改善表面光洁度
防止切屑瘤的形 从切削区冲掉切屑 the prim total h This function of a cutt heat generate chani sms by whic 切制液实灵这些功能的 制热量 这可通 散发又减 生的热量来达到 和润滑作用 Cooling action. Originally oves the cutting performance by its 1: dthatcutingfuidipone。 1 冷却作用最设想切液仅仪是过冷却特性来改馨切作业这也是它被称为冷知液的原因。 e most of the tool wear mechanisms are thermally activated,cooling the chip tool interface 失数的报机都是热的却)健面有保的限有特性，从而延长其使用 tia of the tool an 寿命。 However a reduction in the temnerature of the workniece may under certain conditions increase the shear flow stress of the workpiece,thereby decreasing tool life.It has been shown through a number of investigations that cooling in fact is one of the major factors in improving the cutting performance 可是工件温度的降低在特定条件下会增加工件的剪切流动应力，从而降低刀具寿命。通过一些研究已经表明实际上 冷却只是改善切削作业的主要因素之一。 Lubricating action.The best improvement in cutting performance can be achieved by the lubricating action since this reduces the heat generated,thus reducing the energy input to the metal cutting operation 润滑作用：切削作业的最大改善可通过润滑作用来达到，由于它减少了热量的产生因而减少了金屈切削作 业的能量输入。 However,if the cutting fluid is to be effective,it must reach the chip tool interface.But it is not easy to visualize how it is accomplished in the case of a continuous turning with a single point chip-to 屑一刀具接触压力 切屑技能但如在用单尖羽具续车制的场合尤其是切 atpinle5speTiieexistedattechipolinterfaceandtheluid iti t认为：在切眉与 第十一单元 The Lathe and Its Construction车床及其结构 A lathe is a machine tool used primarily for producing surfaces of revolution and flat edges. 车床是主要用于生成旋转表面和平整边缘的机床。 Based on their purpose,construction,number of tools that can simultaneously be mounted,and degree lathes-or,more accurately,lathe-type machine tools can be classified as follows: 根据它们的使用目的、结构、能同时被安装刀具的数量和自动化的程度，车床一或更确切地说是车床类的机床，可 (2)Toolroom lathes ng and boring mills tic lath purpose lathes
4 • 防止切屑瘤的形成 • 从切削区冲掉切屑 However, the prime function of a cutting fluid in a metal cutting operation is to control the total heat. This can be done by dissipating the heat generated as well as reducing it. The mechanisms by which a cutting fluid performs these functions are: cooling action and lubricating action. 然而，在金属切削作业中切削液的主要功能是控制总热量。这可通过既散发又减少所产生的热量来达到。 切削液实现这些功能的机理是：冷却作用和润滑作用。 Cooling action. Originally it was assumed that cutting fluid improves the cutting performance by its cooling properties alone. That is why the name coolant was given to it. 冷却作用：最初设想切削液仅仅是通过冷却特性来改善切削作业。这也是它曾被称为冷却液的原因。 Since most of the tool wear mechanisms are thermally activated, cooling the chip tool interface helps in retaining the original properties of the tool and hence prolongs its life. 由于大多数刀具的磨损机理都是由热引起的，冷却切屑刀具接触界面有助于保持刀具的原有特性，从而延长其使用 寿命。 However, a reduction in the temperature of the workpiece may under certain conditions increase the shear flow stress of the workpiece, thereby decreasing tool life. It has been shown through a number of investigations that cooling in fact is one of the major factors in improving the cutting performance. 可是工件温度的降低在特定条件下会增加工件的剪切流动应力，从而降低刀具寿命。通过一些研究已经表明实际上 冷却只是改善切削作业的主要因素之一。 Lubricating action. The best improvement in cutting performance can be achieved by the lubricating action since this reduces the heat generated, thus reducing the energy input to the metal cutting operation. 润滑作用：切削作业的最大改善可通过润滑作用来达到，由于它减少了热量的产生因而减少了金属切削作 业的能量输入。 However, if the cutting fluid is to be effective, it must reach the chip tool interface. But it is not easy to visualize how it is accomplished in the case of a continuous turning with a single point turning tool, specially when the chip-tool contact pressure is as high as 70 MPa. 可是，如果要使切削液起作用就必须让它到达切屑刀具接触界面。但如何在采用单尖刀具连续车削的场合尤其是切 屑-刀具接触压力高达 70MPa 时实现并非易事。 Merchant thought that minute asperities existed at the chip-tool interface and the fluid was drawn into the interface by the capillary action of the interlocking network of these surface asperities. Merchant 认为：在切屑与刀具接触界面上存在微小的粗粒，切削液通过这些表面的微小粗粒组成连锁的网络的毛细 管被吸入到切屑与刀具的接触界面上。 第十一单元 The Lathe and Its Construction 车床及其结构 A lathe is a machine tool used primarily for producing surfaces of revolution and flat edges. 车床是主要用于生成旋转表面和平整边缘的机床。 Based on their purpose, construction, number of tools that can simultaneously be mounted, and degree of automation, lathes-or, more accurately, lathe-type machine tools can be classified as follows: 根据它们的使用目的、结构、能同时被安装刀具的数量和自动化的程度，车床—或更确切地说是车床类的机床，可 以被分成以下几类： (1)Engine lathes (2)Toolroom lathes (3)Turret lathes (4)Vertical turning and boring mills (5)Automatic lathes (6)Special-purpose lathes (1)普通车床
(②)万能车床 3) (④)立式车床 6)自动车床 (6)特殊车床 to constru g the mmonly used rer imciplo of opeteolth elements of a e.which is sho 11 虽然车床类的机床多种多样，但它们在结构和操作原理上具有共同特性。这些特性可以通过普通车床这 最常用的代表性类型来最好地说明。下面是关于图1山，1所示普通车床的主要部分的描述。 Lathe bed.The lathe bed is the main frame,involving a horizontal beam on two vertical supports. It is usually made of grey or nodular cast iron to damp vibrations and is made by casting. 车床床身：车床床身是包含了在两个垂直支柱上水平横梁的主骨架。为减振它一般由灰铸铁或球思铸铁钱 造而成。 It has guideways to allow the carriage to slide easily lengthwise.The height of the lathe bed should be appropriate to enable the technician to do his or her job easily and comfortably. 它上面有能让大拖板轻易纵向滑动的导轨。车床床身的高度应适当以让技师容易而舒适地工作。 Headstock.The headstock is fixed at the left hand side of the lathe bed and includes the spindle whose axis is parallel to the guideways (the slide surface of the bed).The spindle is driven through the gearbox, which is housed within the headstock 主轴箱：主轴箱固定在车床床身的左侧，它包括轴线平行于导轨的主轴。主轴通过装在主轴箱内的齿轮箱 驱动。 me modern lathes have ,电力或液压驱动的 is it has a th h hole extending lengthwise.Bar stocks can be fed th alays hollow,.e.. 主轴往往是中空的，即纵向有 通到 Also,that hole has 现连续生，棒料能通过此孔进给 pindle is threaded to allow tain la of a the lik The outer surface of the 同时，此孔为锥形表面可以安装普通车床顶尖。主轴外表面是螺纹可以安装卡盘、花盘或类似的装置。 Tailstock.The tailstock assembly consists basically of three parts,its lower base,an rts.its lower base intermediate par and the auill The lo asting that ca ng the guideways,and it has a clamping device to enable locking the entire tailstock at any desired location. depending upon the length of the workpiece. 尾架：尾架总成基本包括三部分，底座、尾架体和套筒轴。底座是能在车床床身上沿导轨滑动的铸件，它 有一定位装置能让整个尾架根据工件长度锁定在任何需要位置。 The intermediate part is a casting that can be moved transversely to enable alignment of the axis of the tailstock with that of the headstock.The third part,the quill,is a hardened steel tube,which can be moved longitudinally in and out of the intermediate part as required. 尾架体为一能横向运动的铸件，它可以调整尾架轴线与主轴箱轴线成一直线。第三部分，套筒轴是一淬硬钢管，它 能根据需要在尾架体中纵向进出移动。 This is achieved through the use of a handwheel and a screw,around which a nut fixed to the quill is engaged.The hole in the open side of the quill is tapered to enable mounting of lathe centers or other tools like twist drills or boring bars.The quill can be locked at any point along its travel path by means of a clamping device 这通过使用手轮和螺杆来 螺杆啮合的是 一固接在套筒轴上的螺母。套筒轴开口端的孔是锥形的，能安装 床顶尖或诸如麻花钻和镗杆之类的工具。套筒轴通过定位装置能沿着它的移动路径被锁定在任何点。 列
5 (2)万能车床 (3)转塔车床 (4)立式车床 (5)自动车床 (6)特殊车床 In spite of that diversity of lathe-type machine tools, they all have common features with respect to construction and principle of operation. These features can best be illustrated by considering the commonly used representative type, the engine lathe. Following is a description of each of the main elements of an engine lathe, which is shown in Fig.11.1. 虽然车床类的机床多种多样，但它们在结构和操作原理上具有共同特性。这些特性可以通过普通车床这一 最常用的代表性类型来最好地说明。下面是关于图 11.1 所示普通车床的主要部分的描述。 Lathe bed. The lathe bed is the main frame, involving a horizontal beam on two vertical supports. It is usually made of grey or nodular cast iron to damp vibrations and is made by casting. 车床床身：车床床身是包含了在两个垂直支柱上水平横梁的主骨架。为减振它一般由灰铸铁或球墨铸铁铸 造而成。 It has guideways to allow the carriage to slide easily lengthwise. The height of the lathe bed should be appropriate to enable the technician to do his or her job easily and comfortably. 它上面有能让大拖板轻易纵向滑动的导轨。车床床身的高度应适当以让技师容易而舒适地工作。 Headstock. The headstock is fixed at the left hand side of the lathe bed and includes the spindle whose axis is parallel to the guideways (the slide surface of the bed). The spindle is driven through the gearbox, which is housed within the headstock. 主轴箱：主轴箱固定在车床床身的左侧，它包括轴线平行于导轨的主轴。主轴通过装在主轴箱内的齿轮箱 驱动。 The function of the gearbox is to provide a number of different spindle speeds (usually 6 up to 18 speeds). Some modern lathes have headstocks with infinitely variable spindle speeds, which employ frictional ,electrical ,or hydraulic drives. 齿轮箱的功能是给主轴提供若干不同的速度(通常是 6 到 18 速)。有些现代车床具有采用摩擦、电力或液压驱动的 无级调速主轴箱。 The spindle is always hollow, i. e., it has a through hole extending lengthwise. Bar stocks can be fed through that hole if continuous production is adopted. 主轴往往是中空的，即纵向有一通孔。如果采取连续生产，棒料能通过此孔进给。 Also, that hole has a tapered surface to allow mounting a plain lathe center. The outer surface of the spindle is threaded to allow mounting of a chuck, a face plate, or the like. 同时，此孔为锥形表面可以安装普通车床顶尖。主轴外表面是螺纹可以安装卡盘、花盘或类似的装置。 Tailstock. The tailstock assembly consists basically of three parts, its lower base, an intermediate part, and the quill. The lower base is a casting that can slide on the lathe bed along the guideways, and it has a clamping device to enable locking the entire tailstock at any desired location, depending upon the length of the workpiece. 尾架：尾架总成基本包括三部分，底座、尾架体和套筒轴。底座是能在车床床身上沿导轨滑动的铸件，它 有一定位装置能让整个尾架根据工件长度锁定在任何需要位置。 The intermediate part is a casting that can be moved transversely to enable alignment of the axis of the tailstock with that of the headstock. The third part, the quill, is a hardened steel tube, which can be moved longitudinally in and out of the intermediate part as required. 尾架体为一能横向运动的铸件，它可以调整尾架轴线与主轴箱轴线成一直线。第三部分，套筒轴是一淬硬钢管，它 能根据需要在尾架体中纵向进出移动。 This is achieved through the use of a handwheel and a screw, around which a nut fixed to the quill is engaged. The hole in the open side of the quill is tapered to enable mounting of lathe centers or other tools like twist drills or boring bars. The quill can be locked at any point along its travel path by means of a clamping device. 这通过使用手轮和螺杆来达到，与螺杆啮合的是一固接在套筒轴上的螺母。套筒轴开口端的孔是锥形的，能安装车 床顶尖或诸如麻花钻和镗杆之类的工具。套筒轴通过定位装置能沿着它的移动路径被锁定在任何点