机械工程英语第二版叶邦彦_汉语翻译(全本书翻译

机械工程英语第二版叶邦彦_汉语翻译(全本书翻译
机械工程英语第二版叶邦彦_汉语翻译(全本书翻译

?Types of Materials 第一单元Unit1 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 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。

?Ceramics and Glasses 陶瓷和玻璃

A ceramic is often broadly defined as any inorganic nonmetallic material. By this definition, ceramic materials would also include glasses; however, many materials scientists add the stipulation that “ceramic”must also be crystalline.

陶瓷通常被概括地定义为无机的非金属材料。照此定义,陶瓷材料也应包括玻璃;然而许多材料科学家添加了“陶瓷”必须同时是晶体物组成的约定。

A glass is an inorganic nonmetallic material that does not have a crystalline structure. Such materials are said to be amorphous.

玻璃是没有晶体状结构的无机非金属材料。这种材料被称为非结晶质材料。

Properties of Ceramics and Glasses

Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.

陶瓷和玻璃的特性

高熔点、低密度、高强度、高刚度、高硬度、高耐磨性和抗腐蚀性是陶瓷和玻璃的一些有用特性。

Many ceramics are good electrical and thermal insulators. Some ceramics have special properties: some ceramics are magnetic materials; some are piezoelectric materials; and a few special ceramics are superconductors at very low temperatures. Ceramics and glasses have one major drawback: they are brittle.

许多陶瓷都是电和热的良绝缘体。某些陶瓷还具有一些特殊性能:有些是磁性材料,有些是压电材料,还有些特殊陶瓷在极低温度下是超导体。陶瓷和玻璃都有一个主要的缺点:它们容易破碎。

Ceramics are not typically formed from the melt. This is because most ceramics will crack extensively (i.e. form a powder) upon cooling from the liquid state.

陶瓷一般不是由熔化形成的。因为大多数陶瓷在从液态冷却时将会完全破碎(即形成粉末)。

Hence, all the simple and efficient manufacturing techniques used for glass production such as casting and

blowing, which involve the molten state, cannot be used for the production of crystalline ceramics. Instead, “sintering” or “firing” is the process typically used.

因此,所有用于玻璃生产的简单有效的—诸如浇铸和吹制这些涉及熔化的技术都不能用于由晶体物组成的陶瓷的生产。作为替代,一般采用“烧结”或“焙烧”工艺。

In sintering, ceramic powders are processed into compacted shapes and then heated to temperatures just below the melting point. At such temperatures, the powders react internally to remove porosity and fully dense articles can be obtained.

在烧结过程中,陶瓷粉末先挤压成型然后加热到略低于熔点温度。在这样的温度下,粉末内部起反应去除孔隙并得到十分致密的物品。

An optical fiber contains three layers: a core made of highly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage.

光导纤维有三层:核心由高折射指数高纯光传输玻璃制成,中间层为低折射指数玻璃,是保护核心玻璃表面不被擦伤和完整性不被破坏的所谓覆层,外层是聚合物护套,用于保护光导纤维不受损。

In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light.

为了使核心玻璃有比覆层大的折射指数,在其中掺入微小的、可控数量的能减缓光速而不会吸收光线的杂质或搀杂剂。Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle.

由于核心玻璃的折射指数比覆层大,只要在全内反射过程中光线照射核心/覆层分界面的角度比临界角大,在核心玻璃中传送的光线将仍保留在核心玻璃中。

The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of intensity.

全内反射现象与核心玻璃的高纯度一样,使光线几乎无强度损耗传递长距离成为可能。

?Composites 复合材料

Composites are formed from two or more types of materials. Examples include polymer/ceramic and metal/ceramic composites. Composites are used because overall properties of the composites are superior to those of the individual components.

复合材料由两种或更多材料构成。例子有聚合物/陶瓷和金属/陶瓷复合材料。之所以使用复合材料是因为其全面性能优于组成部分单独的性能。

For example: polymer/ceramic composites have a greater modulus than the polymer component, but aren’t as brittle as ceramics.

Two types of composites are: fiber-reinforced composites and particle-reinforced composites.

例如:聚合物/陶瓷复合材料具有比聚合物成分更大的模量,但又不像陶瓷那样易碎。

复合材料有两种:纤维加强型复合材料和微粒加强型复合材料。

Fiber-reinforced Composites

Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers. Fibers increase the modulus of the matrix material.

纤维加强型复合材料

加强纤维可以是金属、陶瓷、玻璃或是已变成石墨的被称为碳纤维的聚合物。纤维能加强基材的模量。

The strong covalent bonds along the fiber’s length give them a very high modulus in this direction because to break or extend the fiber the bonds must also be broken or moved.

沿着纤维长度有很强结合力的共价结合在这个方向上给予复合材料很高的模量,因为要损坏或拉伸纤维就必须破坏或移除这种结合。

Fibers are difficult to process into composites, making fiber-reinforced composites relatively expensive.

把纤维放入复合材料较困难,这使得制造纤维加强型复合材料相对昂贵。

Fiber-reinforced composites are used in some of the most advanced, and therefore most expensive sports equipment,

such as a time-trial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix.

纤维加强型复合材料用于某些最先进也是最昂贵的运动设备,例如计时赛竞赛用自行车骨架就是用含碳纤维的热固塑料基材制成的。

Body parts of race cars and some automobiles are composites made of glass fibers (or fiberglass) in a thermoset matrix.

竞赛用汽车和某些机动车的车体部件是由含玻璃纤维(或玻璃丝)的热固塑料基材制成的。

Fibers have a very high modulus along their axis, but have a low modulus perpendicular to their axis. Fiber composite manufacturers often rotate layers of fibers to avoid directional variations in the modulus.

纤维在沿着其轴向有很高的模量,但垂直于其轴向的模量却较低。纤维复合材料的制造者往往旋转纤维层以防模量产生方向变化。

Particle-reinforced composites

Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymers and carbon black.

微粒加强型复合材料

用于加强的微粒包含了陶瓷和玻璃之类的矿物微粒,铝之类的金属微粒以及包括聚合物和碳黑的非结晶质微粒。

Particles are used to increase the modulus of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix. An example of particle-reinforced composites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric polymer.

微粒用于增加基材的模量、减少基材的渗透性和延展性。微粒加强型复合材料的一个例子是机动车胎,它就是在聚异丁烯人造橡胶聚合物基材中加入了碳黑微粒。

?Polymers 聚合材料

A polymer has a repeating structure, usually based on a carbon backbone. The repeating structure results in large chainlike molecules. Polymers are useful because they are lightweight, corrosion resistant, easy to process at low temperatures and generally inexpensive.

聚合物具有一般是基于碳链的重复结构。这种重复结构产生链状大分子。由于重量轻、耐腐蚀、容易在较低温度下加工并且通常较便宜,聚合物是很有用的。

Some important characteristics of polymers include their size (or molecular weight), softening and melting points, crystallinity, and structure. The mechanical properties of polymers generally include low strength and high toughness. Their strength is often improved using reinforced composite structures.

聚合材料具有一些重要特性,包括尺寸(或分子量)、软化及熔化点、结晶度和结构。聚合材料的机械性能一般表现为低强度和高韧性。它们的强度通常可采用加强复合结构来改善。

Important Characteristics of Polymers

Size. Single polymer molecules typically have molecular weights between 10,000 and 1,000,000g/mol —that can be more than 2,000 repeating units depending on the polymer structure!

聚合材料的重要特性

尺寸:单个聚合物分子一般分子量为10,000到1,000,000g/mol之间,具体取决于聚合物的结构—这可以比2,000个重复单元还多。

The mechanical properties of a polymer are significantly affected by the molecular weight, with better engineering properties at higher molecular weights.

聚合物的分子量极大地影响其机械性能,分子量越大,工程性能也越好。

Thermal transitions. The softening point (glass transition temperature) and the melting point of a polymer will determine which it will be suitable for applications. These temperatures usually determine the upper limit for which a polymer can be used.

热转换性:聚合物的软化点(玻璃状转化温度)和熔化点决定了它是否适合应用。这些温度通常决定聚合物能否使用的上限。

For example, many industrially important polymers have glass transition temperatures near the boiling point of water (100℃, 212℉), and they are most useful for room temperature applications. Some specially engineered polymers can withstand temperatures as high as 300℃(572℉).

例如,许多工业上的重要聚合物其玻璃状转化温度接近水的沸点(100℃, 212℉),它们被广泛用于室温下。而某些特别制造的聚合物能经受住高达300℃(572℉)的温度。

Crystallinity. Polymers can be crystalline or amorphous, but they usually have a combination of

crystalline and amorphous structures (semi-crystalline).

结晶度:聚合物可以是晶体状的或非结晶质的,但它们通常是晶体状和非结晶质结构的结合物(半晶体)。

Interchain interactions. The polymer chains can be free to slide past one another (thermo-plastic) or they can be connected to each other with crosslinks (thermoset or elastomer). Thermo-plastics can be reformed and recycled, while thermosets and elastomers are not reworkable.

原子链间的相互作用:聚合物的原子链可以自由地彼此滑动(热可塑性)或通过交键互相连接(热固性或弹性)。热可塑性材料可以重新形成和循环使用,而热固性与弹性材料则是不能再使用的。

Intrachain structure.The chemical structure of the chains also has a tremendous effect on the properties. Depending on the structure the polymer may be hydrophilic or hydrophobic (likes or hates water), stiff or flexible, crystalline or amorphous, reactive or unreactive.

链内结构:原子链的化学结构对性能也有很大影响。根据各自的结构不同,聚合物可以是亲水的或憎水的(喜欢或讨厌水)、硬的或软的、晶体状的或非结晶质的、易起反应的或不易起反应的。

第七单元Unit7

The importance of machining processes can be emphasised by the fact that every product we use in our daily life has undergone this process either directly or indirectly.

(1) In USA, more than $100 billions are spent annually on machining and related operations.

机加工过程的重要性可通过日常生活使用的每件产品都直接或间接经历这一过程的事实来强调。

(1)在美国,每年花在机加工及其相关作业上的费用都多于千亿美元。

(2) A large majority (above 80%) of all the machine tools used in the manufacturing industry have undergone metal cutting.

(3) An estimate showed that about 10 to 15% of all the metal produced in USA was converted into chips.

(2) 用于制造业的全部机床中的大多数(多于80%)都经历过金属切削。

(3) 有估计显示美国生产的所有金属中约10到15%转变成了切屑。

These facts show the importance of metal cutting in general manufacturing. It is therefore important to understand the metal cutting process in order to make the best use of it.

这些事实说明了金属切削在常规制造中的重要性。因此了解金属切削过程以充分利用它是重要的。

A number of attempts have been made in understanding the metal cutting process and using this knowledge to help improve manufacturing operations which involved metal cutting.

在了解金属切削过程并运用这些知识帮助改善与金属切削有关的制造作业方面已经做了许多努力。

A typical cutting tool in simplified form is shown in Fig.7.1. The important features to be observed are follows.

典型切削刀具的简化形式如图7.1所示。要注意的重要特征如下。

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.

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。

The conditions which have an important influence on metal cutting are work material, cutting tool material, cutting tool geometry, cutting speed, feed rate, depth of cut and cutting fluid used.

对金属切削有重要影响的条件有工件材料、刀具材料、刀具几何形状、切削速度、进给率、切削深度和所用的切削液。

The cutting speed, v, is the speed with which the cutting tool moves through the work material. This is generally expressed in metres per second (ms-1).

切削速度v指切削刀具经过工件材料的移动速度。通常用米每秒 (ms-1)表示。

Feed rate, f, may be defined as the small relative movement per cycle (per revolution or per stroke) of the cutting tool in a direction usually normal to the cutting speed direction.

Depth of cut, d, is the normal distance between the unmachined surface and the machined surface.

进给率f可定义为每循环(每转或每行程)切削刀具在通常为垂直于切削速度方向的次要相对运动。

切削深度d是未加工面与已加工面之间的垂直距离。

?Chip Formation 切屑的形成

Metal cutting process is a very complex process. Fig.7.2 shows the basic material removal operation schematically.

金属切削过程是一个很复杂的过程。图7.2用图的形式显示了基本材料去除作业。

The metal in front of the tool rake face gets immediately compressed, first elastically and then plastically. This zone is traditionally called shear zone in view of fact that the material in the final form would be removed by shear from the parent metal.

在刀具前倾面前的金属直接受到压缩,首先弹性变形然后塑性变形。考虑到最终形状中的材料是通过剪切从母体金属去除的,此区域传统上称为剪切区。

The actual separation of the metal starts as a yielding or fracture, depending upon the cutting conditions, starting from the cutting tool tip. Then the deformed metal (called chip) flows over the tool (rake) face. 金属的实际分离始于屈服或断裂(视切削条件而定),从切削刀尖开始。然后变形金属(称为切屑)流过刀具(前倾)面。

If the friction between the tool rake face and the underside of the chip (deformed material) is considerable, then the chip gets further deformed, which is termed as secondary deformation. The chip after sliding over the tool rake face is lifted away from the tool, and the resultant curvature of the chip is termed as chip curl. 如果刀具前倾面与切屑(变形金属)底面之间的摩擦相当大,那么切屑进一步变形,这也叫做二次变形。滑过刀具前倾面的切屑被提升离开刀具,切屑弯曲的结果被称为切屑卷。

Plastic deformation can be caused by yielding, in which case strained layers of material would get displaced over other layers along the slip-planes which coincide with the direction of maximum shear stress.

屈服能导致塑性变形,在这种情况下材料变形层沿着与最大剪应力方向一致的滑移面被其它层所取代。

A chip is variable both in size and shape in actual manufacturing practice. Study of chips is one of the most important things in metal cutting. As would be seen later, the mechanics of metal cutting are greatly dependent on the shape and size of the chips produced.

在实际加工过程中切屑的尺寸和形状都是变化的。对切屑的研究是金属切削最重要的事情之一。如同后面将要看到的那样,金属切削力学极大地依赖于所产生切屑的形状和尺寸。

Chip formation in metal cutting could be broadly categorised into three types: (Fig.7.3)

(1) Discontinuous chip

(2) Continuous chip

(3) Continuous chip with BUE (Built up edge)

金属切削中的切屑形成可以宽泛地分成三个类型(图7.3):

(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。

?Shear Zone 剪切区

There are basically two schools of thought in the analysis of the metal removal process. One school of thought is that the deformation zone is very thin and planar as shown in Fig.7.4a. The other school thinks that the actual deformation zone is a thick one with a fan shape as shown in Fig.7.4b.

在对金属去除过程的分析中主要存在两种思想学派。一种思想学派认为变形区如图7.4a所示那样非常薄而平坦。另一学派则认为真实变形区象图7.4b所示那样为一厚的带有扇形的区域。

Though the first model (Fig.7.4a) is convenient from the point of analysis, physically it is impossible to exist. This is because for the transition from undeformed material to deform to take place along a thin plane, the acceleration across the plane has to be infinity.

虽然第一种模型(图7.4a)从分析的角度看是方便的,但实际上是不可能存在的。这是由于未变形的材料沿着剪切面发生变形,而且越过剪切面的加速度无穷大。

Similarly the stress gradient across the shear plane has to be very large to be practical.

同样在实际运用中越过剪切面的应力梯度必须很大才行。

In the second model (Fig.7.4b) by making the shear zone over a region, the transitions in velocities and shear stresses could be realistically accounted for.

在第二种模型(图7.4b)中让剪力区分布于一个范围,速度和剪应力的转变能说明得更符合实际。

The angle made by the shear plane with the cutting speed vector, Φ is a very important parameter in metal cutting. Higher the shear angle better is the cutting performance. From a view of the Fig.7.4a, it can be observed that a higher rake angles give rise to higher shear angles.

由剪切面和切削速度矢量形成的角度Φ在金属切削中是一个十分重要的参数。剪切角越大,切削作业越好。从图7.4a 观察,可以看到较大的前角能增大剪切角。

?Cutting Tool Materials 切削刀具材料

Various cutting tool materials have been used in the industry for different applications. A number of developments have occurred in the current century.

在工业中为了不同的应用可以使用各种各样的切削刀具材料。在最近的百年里产生了许多进展。

A large variety of cutting tool materials has been developed to cater to the variety of materials used in these programmes. Before we discuss the properties of these materials, let us look at the important characteristics expected of a cutting tool material.

多种切削刀具材料被开发出来以满足这些方案中使用材料的多样性。讨论这些材料性能之前,先看一下作为切削刀具材料应具备哪些重要特性。

1. Higher hardness than that of the workpiece material being machined, so that it can penetrate into the work material.

2. Hot hardness, which is the ability of the material to retain its hardness at elevated temperatures in view of the high temperatures existing in the cutting zone.

1. 硬度要比被切削工件材料高,这样它才能进入工件材料。

2. 热硬度,即材料由于存在于切削区的高温而升温时仍能保持其硬度的能力。

3. Wear resistance—The chip-tool and chip-work interfaces are exposed to such severe conditions that adhesive and abrasion wear is very common. The cutting tool material should therefore have high abrasion resistance to improve the effective life of the tool.

3. 耐磨性—切屑-刀具与切屑-工件的接触界面处于如此严酷的状态,粘附和磨损是很普遍的。因此切削刀具材料应具有高耐磨性以提高刀具的有效寿命。

4. Toughness—Even though the tool is hard, it should have enough toughness to withstand the impact loads that come in the beginning of cut or force fluctuations due to imperfections in the work material. This requirement is going to be more useful for the interrupted cutting, e.g. milling.

4. 韧性—虽然刀具是坚硬的,但也应有足够的韧性以经受住冲击载荷,这些载荷来自于切削的开始或由于工件材料的缺陷而产生的作用力波动。这个要求对如铣削之类的间断切削更有用。

5. Low friction—The coefficient of friction between the chip and tool should be low. This would allow for lower wear rates and better chip flow.

5. 低摩擦系数—切屑与刀具间的摩擦系数应当较低。这会使磨损率较小及切屑流动更好。

6. Thermal characteristics—Since a lot of heat is generated at the cutting zone, the tool material should have higher thermal conductivity to dissipate this heat in the shortest time, otherwise the tool temperature would become high, reducing its life.

6. 热特性—因为大量的热产生在切削区,刀具材料应当具有较高的热传导性以在最短的时间内散发热量,否则刀具温度会升高,寿命会减少。

All these characteristics may not be found in a single tool material. Improved tool materials have been giving a better cutting performance.

所有这些特性不可能存在于单一刀具材料中。改进的刀具材料已经被赋予较好的切削性能。

?Surface Finish 表面光洁度

Machining operations are utilized in view of the better surface finish that could be achieved by it compared to other manufacturing operations.

由于机加工能获得比其它制造作业更好的表面光洁度,所以机加工作业具有实用价值。

Thus it is important to know what would be the effective surface finish that can be achieved in a machining operation. The surface finish in a given machining operation is a result of two factors:

因而了解能在机加工作业中获得怎样的实际表面光洁度是重要的。给定机加工作业中的表面光洁度是两个因素共同作用的结果:

(1) the ideal surface finish, which is a result of the geometry of the manufacturing process which can be determined by considering the geometry of the machining operation, and

(2) the natural component, which is a result of a number of uncontrollable factors in machining, which is difficult to predict.

(1)理想的表面光洁度,是通过考虑机加工作业的几何体系所决定的制造工艺几何学的结果,和

(2)自然要素,即在机加工中一些难以预测的不可控因素作用的结果。

Ideal Surface Finish in Turning

The actual turning tool used would have a nose radius in place of the sharp tool point, which modifies the surface geometry as shown in Fig.7.5a. If the feed rate is very small, as is normal in finish turning, the surface is produced purely by the nose radius alone as shown in Fig.7.5.

车削中的理想表面光洁度

实际使用的车削刀具有一个刀尖半径取代锋利刀尖,它将表面几何形状加工为如图7.5a所示。如果进给率很小,象精车中很正常的那样,工件表面则完全是由刀尖半径单独产生的,如图7.5所示。

For the case in Fig.7.5, the surface roughness value is to be

R a=8f2/(18R√3)

Where: R a is the surface roughness value

R is the nose radius

f is the feed rate

对图7.5这种情况,表面粗糙度值为

R a=8f2/(18R√3)

式中:R a是表面粗糙度值

R是刀尖半径

f是进给率

The above are essentially geometric factors and the values represent an ideal situation. The actual surface finish obtained depends to a great extent upon a number of factors such as:

上述基本为几何要素,其值代表了理想情况。而实际获得的表面光洁度很大程度上还取决于下列一些因素:

(1) the cutting process parameter, speed, feed and depth of cut

(2) the geometry of the cutting tool

(3) application of cutting fluid

(4) work and tool material characteristics

(5) rigidity of the machine tool and the consequent vibrations.

(1)切削工艺参数、速度、进给和切削深度

(2)切削刀具的几何形状

(3)切削液的运用

(4)工件和刀具的材料特性

(5)机床的刚度及其伴随发生的振动

The major influence on surface finish is exerted by the feed rate and cutting speed. As the feed decreases, from the above equations, we can see that the roughness index decreases.

对表面光洁度产生主要影响的是进给率和切削速度。从上述公式可以看到,随着进给的减少,粗糙度指标会降低。Similarly as the cutting speed increases, we have better surface finish. Thus while making a choice of cutting process parameters for finish, it is desirable to have high cutting speed and small feed rates.

同样随着切削速度的增大,能得到较好表面光洁度。因此在为光洁度而选择切削工艺参数时,采用较高的切削速度和较小的进给率是适当的。

?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。

he 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。

第八单元Unit8

Grinding is a manufacturing process that involves the removal of metal by employing a rotating abrasive wheel. The latter simulates a milling cutter with an extremely large number of miniature cutting edges.

磨削是通过采用旋转磨轮去除金属的制造工艺。磨轮用非常大量的微型切削刃模仿铣刀进行切削。

Generally, grinding is considered to be a finishing process that is usually used for obtaining high-dimensional accuracy and better surface finish. Grinding can be performed on flat, cylindrical, or even internal surfaces by employing specialized machine tools, which are referred to as grinding machines.

一般而言,磨削被认为是一种通常用于获得高尺寸精度和较好表面光洁度的精加工作业。磨削通过采用被称为磨床的特殊机床能在平面、圆柱面甚至内表面上进行。

Obviously, grinding machines differ in construction as well as capabilities, and the type to be employed is determined mainly by the geometrical shape and nature of the surface to be ground, e.g., cylindrical surfaces are ground on cylindrical grinding machines.

显然,磨床根据结构和功能的不同有所区别,使用何种形式的磨床主要取决于被磨削表面的几何形状和物理性质。例如,圆柱面在外圆磨床上磨削。

?Type of Grinding Operations 磨削作业的类型

1. Surface grinding. As the name surface grinding suggests, this operation involves grinding of flat or plane surfaces. Fig.8.1 indicates the two possible variations, either a horizontal or vertical machine spindle. 1.表面磨削:就像其名称暗示的那样,表面磨削和平面磨削直接有关。图8.1表示了两种可能的变化:卧式磨床主轴或立式磨床主轴。

In the first case (horizontal spindle), the machine usually has a planer-type reciprocating table on which the workpiece is held. However, grinding machines with vertical spindles can have either a planer type table like that of the horizontal-spindle machine or a rotating worktable.

在第一种情况(卧式主轴),卧式磨床通常具有安装工件的刨床式往复工作台。而立式主轴磨床既可以像卧式主轴磨床那样具有刨床式工作台也可以具有旋转工作台。

Also, the grinding action in this case is achieved by the end face of the grinding wheel (Fig.8.1b), contrary to the case of horizontal-spindle machines, where the workpieces ground by the periphery of the grinding wheel. 而且在这种情况下,磨削动作是通过砂轮端面完成的(图8.1b),这与通过砂轮周边磨削工件的卧式主轴磨床正好相反。Fig.8.1a and b also indicate the equations to be used for estimating the different parameters of the grinding operation, such as the machining time and the rate of metal removal.

图8.1a和b同时简述了用于估计诸如加工时间和金属去除率之类的磨削作业不同参数的方程式。

During the surface-grinding operations, heavy workpieces are either held in fixtures or clamped on the machine table by strap clamps and the like, whereas smaller workpieces are usually held by magnetic chucks.

在平面磨削时,重的工件用夹具固定或用压板等夹紧在磨床工作台上,而小的工件则通常是用电磁卡盘固定的。

2. Cylindrical grinding. In cylindrical grinding, the workpiece is held between centers during the grinding operation, and the wheel rotation is the source and cause for the rotary cutting motion, as shown in Fig.8.2. In fact, cylindrical grinding can be carried out by employing any of the following methods:

2. 圆柱面磨削:在圆柱面磨削中,作业时工件支撑在两顶尖之间,砂轮转动是导致回转切削运动的动力源,如图8.2所示。实际上,圆柱面磨削能通过采用下列任意方法来实现:

(1) The transverse method, in which both the grinding wheel and the workpiece rotate and longitudinal linear feed is applied to enable grinding of the whole length. The depth of cut is adjusted by the cross feed of the grinding wheel into the workpiece.

(1) 横向方法:这种方法中砂轮与工件均旋转且采用线性纵向进给以保证能磨削整个长度。切削深度通过改变砂轮对工件的横向进给来进行调整。

(2) The plunge-cut method, in which grinding is achieved through the cross feed of the grinding wheel and no axial feed is applied. As you can see, this method can be applied only when the surface to be ground is shorter than the width of the grinding wheel used.

(2) 插入-切削方法:这种方法通过砂轮的横向进给完成磨削而不采用轴向进给。正如料想的那样,这种方法只在要磨削表面比所用砂轮宽度短时才使用。

(3) The full-depth method, which is similar to the transverse method except that the grinding allowance is removed in a single pass. This method is usually recommended when grinding short rigid shafts.

(3) 全深度方法:这种方法除了一次加工就能去除磨削余量外其它与横向方法相同。这种方法通常在磨削较短刚性轴时推荐

使用。

Internal grinding.Internal grinding is employed for grinding relatively short holes, as shown in Fig.8.3. The workpiece is held in a chuck or a special fixture. Both the grinding wheel and the workpiece rotate during the operation and feed is applied in the longitudinal direction.

内表面磨削:内表面磨削用于相对较短的孔,如图8.3所示。工件安装在卡盘或特殊夹具上。作业时砂轮和工件都回转并且采用纵向进给。

Any desired depth of cut can be obtained by the cross feed of the grinding wheel. A variation from this type is planetary internal grinding, which is recommended for heavy workpieces that cannot be held in chucks.

通过砂轮的横向进给能得到任意所需的切削深度。这种方法的一个变体是行星式内表面磨削,当工件较重不能用卡盘固定时推荐使用。

In that case, the grinding wheel not only spins around its own axis but also rotates around the centerline of the hole that is being ground.

在这种情况下,砂轮不但绕自身轴线回转,同时还绕被磨削孔的中心线旋转。

Centerless grinding.Centerless grinding involves passing a cylindrical workpiece, which is supported by a rest blade, between two wheels, i.e., the grinding wheel and the regulating or feed wheel.

无心磨削:无心磨削用于加工圆柱形工件,工件由托板支撑,在两轮即砂轮和调节或进给轮之间通过去。

The grinding wheel does the actual grinding, while the regulating wheel is responsible for rotating the workpiece as well as generating the longitudinal feed. This is possible because of the frictional characteristics of that wheel, which is usually made of rubber-bonded abrasive.

砂轮完成实际磨削,而调节轮负责旋转工件和产生纵向进给。由于调节轮通常用橡胶粘结的磨料制成,其摩擦特性使这成为可能。

As can be seen in Fig.8.4, the axis of the regulating wheel is tilted at a slight angle with the axis of the grinding wheel. Consequently, the peripheral velocity of the regulating wheel can be resolved into two components, namely, workpiece rotational speed and longitudinal feed.

正如在图8.4中所看到的那样,调节轮的轴与砂轮轴倾斜一个微小角度。因此调节轮的圆周速度可以分解为两个分量,即工件回转速度和纵向进给。

These can be given by the following equations:

V workpiece=V regulating wheel×cosα

Axial feed=V regulating wheel×c×sinα

Where c is a constant coefficient to account for the slip between the workpiece and the regulating wheel (c=0.94~0.98).

其值可由下列公式给出:

V工件=V调节轮×cosα

轴向进给=V调节轮×c×sinα

式中c是考虑工件和调节轮之间滑动的恒定系数(c=0.94~0.98)。

The velocity of the regulating wheel is controllable and is used to achieve any desired rotational speed of the workpiece. The angleαis usually taken from 1°to 5°and the larger the angle, the larger the longitudinal feed would be.

调节轮的速度是可控的并被用于实现工件任意所需的转动速度。α角通常取1到 5°,这角度越大则纵向进给也将越大。

Whenαis taken as 0°, i.e., the two axes of the grinding and regulating wheels are parallel, there is no longitudinal feed of the workpiece.

当α取0°时,即砂轮和调节轮轴线平行时,则工件没有纵向进给。

?Grinding Wheels 砂轮

Grinding wheels are composed of abrasive grains having similar size and a binder. The actual grinding process is performed by the abrasive grains. Pores between the grains within the binder enable the grains to act as separate single-point cutting tools.

砂轮由具有相近尺寸的磨料颗粒和粘合剂组成。实际磨削作业由磨粒完成。在粘合剂中磨粒之间的孔隙使磨粒能象独立的单刃切削刀具一样工作。

These pores also provide space for the generated chips, thus preventing the wheel from clogging. In addition, pores assist the easy flow of coolants to enable efficient and prompt removal of the heat generated during the

grinding process.

这些孔隙同时还为产生的切屑提供空间以防砂轮堵塞。另外孔隙帮助冷却液容易流动,从而使在磨削作业中产生的热量能有效而迅速地散发。

Grinding wheels are identified based on their shape and size, kind of abrasive, grain size, binder, grade (hardness), and structure.

砂轮根据它们的形状和尺寸、磨料的类型、磨粒的大小、粘合剂、等级(硬度)和结构组织来分类。

Shape and size of grinding wheels. Grinding wheels differ in shape and size, depending upon the purpose for which they are to be used. Various shapes are shown in Fig.8.5 and include the following types: 砂轮的形状和尺寸:根据砂轮的用途,它们的形状和尺寸是不同的。各种形状如图8.5所示,其中包括:

1)Straight wheels used for surface, cylindrical, internal, and centerless grinding.

2)Bevelled-face or tapered wheels used for grinding threads, gear teeth, and the like.

3)Straight recessed wheels for cylindrical grinding and facing.

1)用于表面、圆柱面、内部和无心磨削的直轮。

2)用于磨削螺纹、齿轮轮齿之类的斜面或锥形轮。

3)用于圆柱面和端面磨削的直凹轮。

4)Abrasive disks for cutoff and slotting operations. (thickness 0.02 up to 0.2in. (0.5 to 5mm)).

5)Cylinders, straight cups, and flaring cups are used for surface grinding with the end face of the wheel.

4)用于切断和开槽作业的砂轮片(其厚度从0.02到0.2英寸(0.5到5毫米))。

5)用其端面进行表面磨削的圆柱、直杯及外展杯状砂轮。

The main dimensions of a grinding wheel are the outside diameter D, the bore diameter d, and the height H. These dimensions vary widely, depending upon the grinding process for which the wheel is to be used.

砂轮的主要尺寸有外径D、孔径d和厚度H。根据采用砂轮的磨削工艺,这些尺寸变化很大。

Kind of abrasive. Grinding wheels can be made of natural abrasives such as quartz, emery, and corundum or of industrially prepared chemical compounds such as aluminum oxide or silicon carbide (known as carborundum).

磨料的类型:砂轮可以由象石英、金刚砂、刚玉之类的自然磨料制成,或者由象氧化铝或碳化硅(也称人造金刚砂)之类的工业制备的化学化合物制成。

Generally, silicon carbide grinding wheels are used when grinding low-tensile-strength materials like cast iron, whereas aluminum oxide wheels are employed for grinding high-strength metals such as alloy steel, hardened steel, and the like.

当磨削象铸铁类低拉伸强度材料时,一般采用碳化硅砂轮,而磨削合金钢、淬火钢等高强度金属则要用氧化铝砂轮。

Grain size of abrasive used. As you may expect, the grain size of the abrasive particles of the wheel plays a fundamental role in determining the quality of ground surface obtained.

所用磨粒的尺寸:正如料想的那样,砂轮磨粒的尺寸对决定所得磨削表面的质量起着根本的作用。

The finer the grains, the smoother the ground surface is. Therefore, coarse-grained grinding wheels are used for roughing operations, whereas fine-grained wheels are employed in final finishing operations.

磨粒越细,磨削表面越光滑。所以,粗粒砂轮用于粗加工,而细粒砂轮则用于最后精加工。

The grade of the bond. The grade of the bond is actually an indication of the resistance of the bond to pulling off the abrasive grains from the grinding wheel. Generally, wheels having hard grades are used for grinding soft materials and vice versa.

粘结体的等级:粘结体的等级实际上是其抵抗将磨粒从砂轮上拉脱的指标。一般而言,具有较硬等级的砂轮用于磨削较软材料,反之亦然。

If a hard-grade wheel were to be used for grinding a hard material, the dull grains would not be pulled off from the bond quickly enough, thus impeding the self-dressing process of the surface of the wheel and finally resulting in clogging of the wheel and burns on the ground surface.

如果较硬等级的砂轮用于磨削较硬材料,磨钝的磨粒将不能足够快地脱离粘结体,这会妨碍砂轮表面的自修复,最终导致砂轮的堵塞并在被磨表面留下灼斑。

In fact, the cutting properties of all grinding wheels must be restored periodically by dressing with a cemented carbide roller or a diamond tool to give the wheel the exact desired shape and remove all worn abrasive grains. 实际上,所有砂轮的磨削性能都必须定期地通过使用硬质合金滚轮或金刚石修整器修整而被恢复,以求很准确地把砂轮加工成要求的形状,并去除已磨钝的磨粒。

Structure.Structure refers to the amount of void space between the abrasive grains. When grinding softer

metals, larger void space are needed to facilitate the flow of the removed chips.

结构组织:结构组织与磨粒间的空隙量有关。当磨削较软金属时,需要较大的空隙以便去除切屑的流动。

The binder.Abrasive particles are bonded together in many different ways. These include bond, silicate, rubber, resinoid, shellac, and oxychloride. Nevertheless, the bond is the most commonly used one.

粘合剂:磨粒可用多种不同方法粘结在一起。其中包括粘合剂、硅酸盐、橡胶、树脂、虫胶和氯氧化物。然而,粘合剂是最常用的。

In fact, the standard marking system is employed for distinguishing grinding wheels, by providing all the preceding parameters in a specific sequence.

在实际生产中,为了区分砂轮采用标准标注系统,通过用一特定顺序将所有上述参数都表示出来。

第十一单元Unit11

?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)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。

The carriage.The main function of the carriage is mounting of the cutting tools and generating longitudinal and/or cross feeds. It is actually an H-shaped block that slides on the lathe bed between the headstock and tailstock while being guided by the V-shaped guideways of the bed.

大拖板:大拖板的主要功能是安装刀具和产生纵向和/或横向进给。它实际上是一由车床床身V形导轨引导的、能在车床床身主轴箱和尾架之间滑动的H形滑块。

The carriage can be moved either manually or mechanically by means of the apron and either the feed rod or the lead screw.

大拖板能手动或者通过溜板箱和光杆(进给杆)或丝杆(引导螺杆)机动。

When cutting screw threads, power is provided to the gearbox of the apron by the lead screw. In all other turning operations, it is the feed rod that drives the carriage. The lead screw goes through a pair of half nuts, which are fixed to the rear of the apron.

在切削螺旋时,动力通过丝杆提供给溜板箱上的齿轮箱。在其余车削作业中,都由光杆驱动大拖板。丝杆穿过一对固定在溜板箱后部的剖分螺母。

When actuating a certain lever, the half nuts are clamped together and engage with the rotating lead screw as a single nut, which is fed, together with the carriage, along the bed. When the lever is disengaged, the half nuts are released and the carriage stops.

当开动特定操作杆时,剖分螺母夹在一起作为单个螺母与旋转的丝杆啮合,并带动拖板沿着床身提供进给。当操作杆脱离时,剖分螺母释放同时大拖板停止运动。

On the other hand, when the feed rod is used, it supplies power to the apron through a worm gear. The latter is keyed to the feed rod and travels with the apron along the feed rod, which has a keyway extending to cover its whole length.

另一方面,当使用光杆时则通过蜗轮给溜板箱提供动力。蜗轮用键连接在光杆上,并与溜板箱一起沿光杆运动,光杆全长范围开有键槽。

A modern lathe usually has a quick-change gearbox located under the headstock and driven from the spindle through a train of gears. It is connected to both the feed rod and the lead screw and enables selecting a variety of feeds easily and rapidly by simply shifting the appropriate levers.

现代车床一般在主轴箱下装备快速变换齿轮箱,通过一系列齿轮由主轴驱动。它与光杆和丝杆连接,能容易并快速地通过简单转换适当的操作杆选择各种进给。

The quick-change gearbox is employed in plain turning, facing and thread cutting operations. Since that gearbox

is linked to the spindle, the distance that the apron (and the cuttingtool) travels for each revolution of the spindle can be controlled and is referred to as the feed.

快速变换齿轮箱可用于普通车削、端面切削和螺旋切削作业中。由于这种齿轮箱与主轴相连,主轴每转一圈溜板箱(和切削刀具)运动的距离能被控制,这距离就可以被认为是进给。

?Lathe Cutting Tools 车床切削刀具

The shape and geometry of the lathe tools depend upon the purpose for which they are employed.

车床刀具的形状和几何参数取决于它们的使用目的。

Turning tools can be classified into two main groups, namely, external cutting tools and internal cutting tools. Each of these two groups include the following types of tools:

车削刀具可以分为两个主要组别,即外部切削刀具和内部切削刀具。这两组中的每一组都包括以下类型刀具:Turning tools. Turning tools can be either finishing or rough turning tools. Rough turning tools have small nose radii and are employed when deep cuts are made.

车削刀具:车削刀具可以是精车刀具或粗车刀具。粗车刀具刀尖半径较小,用于深切削。

On the other hand, finishing tools have larger nose radii and are used for obtaining the final required dimensions with good surface finish by making slight depths of cut. Rough turning tools can be right-hand or left-hand types, depending upon the direction of feed. They can have straight, bent, or offset shanks.

而精车刀具刀尖半径较大,用于通过微量进刀深度来获得具有较好表面光洁度的最终所需尺寸。粗车刀具按其进给方向可以是右手型的或是左手型的。它们可以有直的、弯的或偏置的刀杆。

Facing tools. Facing tools are employed in facing operations for machining plane side or end surfaces. There are tools for machining left-hand-side surfaces and tools for right-hand-side surfaces. Those side surfaces are generated through the use of the cross feed, contrary to turning operations, where the usual longitudinal feed is used.

端面刀具:端面刀具用在端面作业中加工平板侧面或端部表面,也有加工左右侧表面之分。与一般采用纵向进给的车削作业相反,那些侧表面通过采用横向进给产生。

Cutoff tools. Cutoff tools, which are sometimes called parting tools, serve to separate the workpiece into parts and/or machine external annular grooves.

切断刀具:切断刀具,有时也称为分割刀具,用于将工件分割成若干部分和/或加工外部环形槽。

Thread-cutting tools.Thread-cutting tools have either triangular, square, or trapezoidal cutting edges, depending upon the cross section of the desired thread. Also, the plane angles of these tools must always be identical to those of the thread forms.

螺纹切削刀具:螺纹切削刀具根据所需螺纹的横截面,有三角形的、矩形的或梯形的切削刃。同时,这些刀具的平面角必须始终与螺纹形状的平面角保持一致。

Thread-cutting tools have straight shanks for external thread cutting and are of the bent-shank type when cutting internal threads.

车外螺纹的螺纹切削刀具为直刀杆,而车内螺纹的螺纹切削刀具则是弯刀杆。

Form tools. Form tools have edges especially manufactured to take a certain form, which is opposite to the desired shape of the machined workpiece.

成形刀具:成形刀具有专门制成特定形状的刀刃,这种刀刃形状与被加工工件所需外形正好相反。

An HSS tool is usually made in the form of a single piece, contrary to cemented carbides or ceramic, which are made in the form of tips. The latter are brazed or mechanically fastened to steel shanks.

高速钢刀具通常以单件形式制造,而硬质合金或陶瓷刀具则以刀尖形式制造。后者用铜焊或机械方法固定于钢质刀杆上。Fig.11.2 indicates an arrangement of this latter type, which includes the carbide tip, the chip breaker, the pad, the clamping screw (with a washer and a nut), and the shank.

图11.2所示为机械式固定布置方式,它包括了硬质合金刀尖、断屑槽、衬垫、卡装螺杆(带有垫圈和螺母)及刀杆。

As the name suggests, the function of the chip breaker is to break long chips every now and then, thus preventing the formation of very long twisted ribbons that may cause problems during the machining operation.

顾名思义,断屑槽的功能就是不时地折断长切屑,以防形成很长的可能会在机加工操作中引起问题的缠绕切屑条。

The carbide tips (or ceramic tips) can have different shapes, depending upon the machining operations for which they are to be employed. The tips can either be solid or with a central through hole, depending on whether brazing or mechanical clamping is employed for mounting the tip on the shank.

硬质合金刀尖(或陶瓷刀尖)根据采用它们的机加工操作,可以有不同的形状。根据将刀尖装配在刀杆上是通过用铜焊还是机械卡装,刀尖可以是实心的或是带有中心通孔的。

?Lathe Operations 车床操作

In the following section, we discuss the various machining operations that can be performed on a conventional engine lathe.

在下面这节中,要讨论的是能在传统普通车床上进行的各种机加工作业。

It must be borne in mind, however, that modern computerized numerically controlled lathes have more capabilities and can do other operations, such as contouring, for example. Following are conventional lathe operations. 然而,必须记住现代计算机数控车床具有更多的功能并且可以进行其它操作,例如仿型。下面是传统车床的操作。

Cylindrical turning. Cylindrical turning is the simplest and the most common of all lathe operations.

A single full turn of the workpiece generates a circle whose center falls on the lathe axis; this motion is then reproduced numerous times as a result of the axial feed motion of the tool.

圆柱面车削:圆柱面车削是所有车床操作中最简单也是最普通的。工件旋转一整圈产生一个圆心落在车床主轴上的圆;由于刀具的轴向进给运动这种动作重复许多次。

The resulting machining marks are, therefore, a helix having a very small pitch, which is equal to the feed. Consequently, the machined surface is always cylindrical.

所以,由此产生的机加工痕迹是一条具有很小节距的螺旋线,该节距等于进给。因此机加工表面始终是圆柱形的。

The axial feed is provided by the carriage or the compound rest, either manually or automatically, whereas the depth of cut is controlled by the cross slide.

轴向进给通过大拖板或复式刀架手动或自动提供,然而切削深度则由横向滑板控制。

In roughing cuts, it is recommended that large depths of cuts (up to 0.25in. or 6mm, depending upon the workpiece material) and smaller feeds would be used. On the other hand, very fine feeds, smaller depths of cut (less than 0.05in, or 0.4mm), and high cutting speeds are preferred for finishing cuts.

粗车中,推荐使用较大切削深度(根据工件材料可达0.25英寸或6毫米)和较小进给。另一方面,精车则最好采用很小的进给、较小的切削深度(小于0.05英寸或0.4毫米)和较高的切削速度。

Facing. The result of a facing operation is a flat surface that is either the whole end surface of the workpiece or an annular intermediate surface like a shoulder. During a facing operation, feed is provided by the cross slide, whereas the depth of cut is controlled by the carriage or compound rest.

端面车削:端面车削操作的结果是将工件整个端部表面或者像轴肩之类的中间环形表面加工平整。在端面车削操作中,进给由横向滑板提供,而切削深度则通过大拖板或复式刀架控制。

Facing can be carried out either from the periphery inward or from the center of the workpiece outward. It is obvious that the machining marks in both cases take the form of a spiral.

端面车削既可以从外表面向内切削也可以从工件中心往外切削。很明显在这两种情况下机加工痕迹都是螺线形式。Usually, it is preferred to clamp the carriage during a facing operation, since the cutting force tends to push the tool (and, of course, the whole carriage) away from the workpiece. In most facing operations, the workpiece is held in a chuck or on a face plate.

通常在端面车削作业时习惯于采用夹住大拖板,这是因为切削力倾向于将刀具(当然包括整个大拖板)推离工件。在大多数端面车削作业中,工件被支撑在卡盘或花盘上。

Groove cutting. In cut-off and groove-cutting operations, only cross feed of the tool is employed. The cut-off and grooving tools, which were previously discussed, are employed.

开槽:在切断和开槽操作中,刀具只有横向进给。要采用前面已经讨论过的切断和开槽刀具。

Boring and internal turning.Boring and internal turning are performed on the internal surfaces by a boring bar or suitable internal cutting tools. If the initial workpiece is solid, a drilling operation must be performed first. The drilling tool is held in the tailstock, and the latter is then fed against the workpiece.

镗孔和内部车削:镗孔和内部车削通过镗杆或合适的内部切削刀具在内表面进行。如果初始工件是实心的,则必须首先进行钻孔作业。钻孔刀具安装在尾架上,然后对着工件进给。

Taper turning. Taper turning is achieved by driving the tool in a direction that is not parallel to the lathe axis but inclined to it with an angle that is equal to the desired angle of the taper. Following are the different methods used in taper-turning practice:

锥面车削:锥面车削通过沿着与车床主轴不平行而倾斜成一个等于锥面所需角度的方向进刀来实现。下面是在实际

锥面车削中采用的不同方法:

(1) Rotating the disc of the compound rest with an angle equal to half the apex angle of the cone. Feed is manually provided by cranking the handle of the compound rest. This method is recommended for taper turning of external and internal surfaces when the taper angle is relatively large.

(1) 将复式刀架盘旋转一个等于圆锥体顶角一半的角度。通过摇动复式刀架操纵柄手动提供进给。当锥角相对较大时切削外锥面和内锥面推荐使用这种方法。

(2) Employing special form tools for external, very short, conical surfaces. The width of the workpiece must be slightly smaller than that of the tool, and the workpiece is usually held in a chuck or clamped on a face plate. In this case, only the cross feed is used during the machining process and the carriage is clamped to the machine bed.

(2) 对很短的外锥面采用特殊的成型刀具。工件的宽度必须略小于刀具的宽度,并且工件通常由卡盘支撑或夹紧在花盘上。在这种情况下,机加工作业时只有横向进给而大拖板则夹紧在床身上。

(3) Offsetting the tailstock center. This method is employed for external taper turning of long workpieces that are required to have small taper angles (less than 8°). The workpiece is mounted between the two centers; then the tailstock center is shifted a distance S in the direction normal to the lathe axis.

(3)偏移尾架顶尖。对需要较小锥角(小于8°) 的较长工件外锥面车削采用这种方法。工件安装于两顶尖之间;然后将尾架顶尖朝垂直于车床主轴方向移动一距离S。

(4) Using the taper-turning attachment. This method is used for turning very long workpieces, when the length is larger than the whole stroke of the compound rest. The procedure followed in such cases involves complete disengagement of the cross slide from the carriage, which is then guided by the taper-turning attachment. (4) 采用锥面车削附加装置。这种方法用于车削很长的工件,其长度大于复式刀架的整个行程。在这种场合下要遵循的步骤是将横向滑板完全脱离大拖板,然后通过锥面车削附加装置进行引导。

During this process, the automatic axial feed can be used as usual. This method is recommended for very long workpieces with a small cone angle, i.e., 8°through 10°.

在此作业中,能照常使用自动轴向进给。对具有较小锥角(即8°到10°)的很长工件推荐采用这种方法。

Thread cutting. When performing thread cutting, the axial feed must be kept at a constant rate, which is dependent upon the rotational speed (rpm) of the workpiece. The relationship between both is determined primarily by the desired pitch of the thread to be cut.

螺纹切削:在螺纹切削作业时,轴向进给必须保持恒定速率,这取决于工件的转速(rpm)。两者之间的关系基本上由被切削螺纹所需的节距决定。

As previously mentioned, the axial feed is automatically generated when cutting a thread by means of the lead screw, which drives the carriage. When the lead screw rotates a single revolution, the carriage travels a distance equal to the pitch of the lead screw.

如前所述,当依靠驱动大拖板的丝杆切削螺纹时轴向进给是自动产生的。丝杆旋转一圈,大拖板就行进等于丝杆节距的一段距离。

Consequently, if the rotational speed of the lead screw is equal to that of the spindle (i.e., that of the workpiece), the pitch of the resulting cut thread is exactly equal to that of the lead screw.

因此如果丝杆的旋转速度等于心轴的转速(即工件的转速),生成切削螺纹的节距就正好等于丝杆的节距。

The pitch of the resulting thread being cut therefore always depends upon the ratio of the rotational speeds of the lead screw and the spindle: Pitch of the lead screw/ Desired pitch of workpiece=rpm of the workpiece/rpm of lead screw=spindle-to-carriage gearing ratio.

所以被切削生成螺纹的节距总是取决于丝杆和心轴的转速比:丝杆的节距/工件所需节距=工件转速/丝杆转速=心轴到大拖板的传动比。

This equation is useful in determining the kinematic linkage between the lathe spindle and the lead screw and enables proper selection of the gear train between them.

这公式在决定车床心轴和丝杆之间的运动学关系时很有用,并且提供了正确挑选它们之间轮系的方法。

In thread cutting operations, the workpiece can either be held in the chuck or mounted between the two lathe centers for relatively long workpieces. The form of the tool used must exactly coincide with the profile of the thread to be cut, i.e., triangular tools must be used for triangular threads, and so on.

在螺纹切削作业中,工件既能支撑于卡盘中,对相对较长的工件也能安装在两个车床顶尖之间。使用的刀具外形必须正好与要切削螺纹的轮廓一致,即三角形刀具必须用于三角形螺纹等等。

Knurling. Knurling is mainly a forming operation in which no chips are produced. It involves pressing two hardened rolls with rough filelike surfaces against the rotating workpiece to cause plastic deformation of the workpiece metal.

滚花:滚花主要是一种不产生切屑的成型操作。它使用两个带有粗锉式表面的淬火滚轮压在旋转的工件上使工件金属产生塑性变形。

Knurling is carried out to produce rough, cylindrical (or conical) surfaces, which are usually used as handles. Sometimes, surfaces are knurled just for the sake of decoration; there are different types of patterns of knurls from which to choose.

滚花用于生成粗糙的圆柱(或圆锥)面,通常用来作手柄。有时表面滚花只为装饰之故;有不同的滚花图案类型可供选择。

?Cutting Speeds and Feed 切削速度和进给

The cutting speed, which is usually given in surface feet per minute (SFM), is the number of feet traveled in the circumferential direction by a given point on the surface (being cut) of the workpiece in 1 minute.

切削速度,通常用每分钟表面英尺给出,就是一分钟内工件(被切削)表面给定点在圆周方向上行进的英尺数。

The relationship between the surface speed and rpm can be given by the following equation: SFM=πDN Where

D=the diameter of the workpiece in feet

N=the rpm

表面速度与转速之间的关系可以用下式给出:

SFM=πDN

式中

D=用英尺表示的工件直径

N=转速

The surface cutting speed is dependant primarily upon the material being machined as well as the material of the cutting tool and can be obtained from handbooks, information provided by cutting tool manufacturers, and the like.

表面切削速度主要由被切削材料和切削刀具材料决定,可以从手册、切削刀具生产商提供的资料及类似的东西上查取。

Generally, the SFM is taken as 100 when machining cold-rolled or mild steel, as 50 when machining tougher metals, and as 200 when machining softer materials. For aluminum, the SFM is usually taken as 400 or above. There are also other variables that affect the optimal value of the surface cutting speed.

一般而言,SFM当机加工冷轧或低碳钢时取100,机加工较坚韧的金属时取50,而机加工较软材料时取200。对铝而言,SFM 通常可取400以上。也还存在其它一些变量影响表面切削速度的最佳值。

These include the tool geometry, the type of lubricant or coolant, the feed, and the depth of cut. As soon as the cutting speed is decided upon, the rotational speed (rpm) of the spindle can be obtained as follows:

N=SFM/(πD)

其中包括刀具形状、润滑剂或冷却液的类型、进给和切削深度。切削速度一旦确定,心轴转速(rpm)就能按下式得到:

N=SFM/(πD)

The selection of a suitable feed depends upon many factors, such as the required surface finish, the depth of cut, and the geometry of the tool used. Finer feeds produce better surface finish, whereas higher feeds reduce the machining time during which the tool is in direct contact with the workpiece.

合适进给的选择取决于许多因素,例如所需表面光洁度、切削深度和所用刀具的几何形状。进给越小生成的光洁度越好,而在刀具与工件直接接触时进给越大则可以减少机加工时间。

Therefore, it is generally recommended to use high feeds for roughing operations and finer feeds for finishing operations. Again, recommended values for feeds, which can be taken as guidelines, are found in handbooks and in information booklets provided by cutting tool manufacturers.

所以对粗车一般推荐使用较大进给,而精车则用较小进给。再者,作为指导方针的进给推荐值可以从手册和切削刀具生产商提供的资料小册子上找到。

第十二单元unit12

?Drilling and Drills 钻削和钻头

Drilling involves producing through or blind holes in a workpiece by forcing a tool, which rotates around its axis, against 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 required hole. In practice, two symmetrical cutting 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。

Drilling operations can be carried out by using either hand drills or drilling machines. The latter differ in size and construction. Nevertheless, the tool always rotates around its axis while the workpiece is kept firmly fixed. This is contrary to drilling 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。

Cutting Tool for Drilling Operation

In drilling operations, a cylindrical rotary-end cutting tool, called a drill, is employed. The drill can have either one or more cutting edges and corresponding 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 generated during the drilling operation and also to allow lubricants and coolants to reach the cutting edges and the surface being machined. Following is a survey of the commonly 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 common type of drill. 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 case, the shank is fitted by the wedge action into the tapered socket of the spindle and has a tang, which goes into a slot in the spindle socket, thus acting as a solid means for transmitting rotation. 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-shank drills are held in a drill chuck that is, in turn, fitted into the spindle socket in the same way as tapered shank 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 connected together by a wedge, which is a chisel-like edge. The twist drill also has two margins, which enable proper guidance and locating of the drill while it is in operation.

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 angle (TPA) is formed by the two lips and is chosen based on the properties of the material to be cut. The usual TPA for commercial drills is 118°, which is appropriate for drilling low-carbon 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°or 140°) give better performance. The helix angle of the flutes of the commonly used twist drills ranges between 24°and 30°. When drilling copper 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140°)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-tipped drills are also available.

《机械工程专业英语教程》课文翻译

Lesson 1 力学的基本概念 1、词汇: statics [st?tiks] 静力学;dynamics动力学;constraint约束;magnetic [m?ɡ'netik]有磁性的;external [eks't?:nl] 外面的, 外部的;meshing啮合;follower从动件;magnitude ['m?ɡnitju:d] 大小;intensity强度,应力;non-coincident [k?u'insid?nt]不重合;parallel ['p?r?lel]平行;intuitive 直观的;substance物质;proportional [pr?'p?:??n?l]比例的;resist抵抗,对抗;celestial [si'lestj?l]天空的;product乘积;particle质点;elastic [i'l?stik]弹性;deformed变形的;strain拉力;uniform全都相同的;velocity[vi'l?siti]速度;scalar['skeil?]标量;vector['vekt?]矢量;displacement代替;momentum [m?u'ment?m]动量; 2、词组 make up of由……组成;if not要不,不然;even through即使,纵然; Lesson 2 力和力的作用效果 1、词汇: machine 机器;mechanism机构;movable活动的;given 规定的,给定的,已知的;perform执行;application 施用;produce引起,导致;stress压力;applied施加的;individual单独的;muscular ['m?skjul?]]力臂;gravity[ɡr?vti]重力;stretch伸展,拉紧,延伸;tensile[tensail]拉力;tension张力,拉力;squeeze挤;compressive 有压力的,压缩的;torsional扭转的;torque转矩;twist扭,转动;molecule [m likju:l]分子的;slide滑动; 滑行;slip滑,溜;one another 互相;shear剪切;independently独立地,自立地;beam梁;compress压;revolve (使)旋转;exert [iɡ'z?:t]用力,尽力,运用,发挥,施加;principle原则, 原理,准则,规范;spin使…旋转;screw螺丝钉;thread螺纹; 2、词组 a number of 许多;deal with 涉及,处理;result from由什么引起;prevent from阻止,防止;tends to 朝某个方向;in combination结合;fly apart飞散; 3、译文: 任何机器或机构的研究表明每一种机构都是由许多可动的零件组成。这些零件从规定的运动转变到期望的运动。另一方面,这些机器完成工作。当由施力引起的运动时,机器就开始工作了。所以,力和机器的研究涉及在一个物体上的力和力的作用效果。 力是推力或者拉力。力的作用效果要么是改变物体的形状或者运动,要么阻止其他的力发生改变。每一种

机械工程英语翻译叶邦彦陈统坚第2版

? 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。

机械工程英语翻译

Unit1 1、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。 2、 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。 3、The atomic bonding of metals also affects their properties. In m etals, the outer valence electrons are shared among all atoms, and ar e free to travel everywhere. Since electrons conduct heat and electri city, 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. 4、Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance. 陶瓷和玻璃的特性高熔点、低密度、高强度、高刚度、高硬度、高耐磨性和

机械工程专业英语翻译 华中科技大学版 李光布

1.机械设计过程 机械设计的最终目标是生产一种满足客户需求的有用产品,而且这种产品安全,高效,可靠,经济,实用。当回答这个问题时,广泛地思考,我将要设计的产品或系统的客户是谁? 在产品设计之前,了解所有客户的期望和期望是至关重要的。营销专业人员经常被用来管理客户期望的定义,但是设计师可能会把他们作为产品开发团队的一部分。 许多方法被用来确定客户想要什么。一种被称为质量功能部署或QFD的流行方法寻求(1)识别客户期望的所有特征和性能因素,以及(2)评估这些因素的相对重要性。QFD过程的结果是产品的一组详细功能和设计要求。 考虑设计过程如何配合为客户提供令人满意的产品所必须发生的所有功能以及在产品的整个生命周期中为产品提供服务也很重要。事实上,重要的是考虑产品在使用寿命后如何处置。影响产品的所有这些功能的总和有时被称为产品实现过程或PRP。PRP中包含的一些因素如下: ?营销功能来评估客户的要求 ?研究确定可在产品中合理使用的可用技术 ?可以包含在产品中的材料和组件的可用性 ?产品设计和开发 ?性能测试 ?设计文件 ?供应商关系和采购职能 ?考虑全球材料采购和全球营销 参加工作的技能 ?物理工厂和设施可用

?制造系统的能力 生产计划和生产系统的控制 ?生产支持系统和人员 ?质量体系要求 ?销售操作和时间表 ?成本目标和其他竞争性问题 ?客户服务要求 ?产品在生产,操作和处置过程中的环境问题 ?法律要求 ?金融资本的可用性 你可以添加到这个列表吗?您应该能够看到,产品的设计只是综合过程的一部分。在本文中,我们将更加注意设计过程本身,但必须始终考虑设计的可生产性。产品设计和制造过程设计的同时考虑通常被称为并行工程。 2.机械设计所需的技能 产品工程师和机械设计师在日常工作中使用广泛的技能和知识。这些技能和知识包含在以下内容中: ?素描,技术制图和计算机辅助设计 ?材料的性质?材料加工*和制造过程 ?化学的应用,如腐蚀防护,电镀和喷漆 静力学动力学材料的强度,运动学和机制 流体力学,热力学和传热 ?流体动力,电气现象的基本原理和工业控制

机械工程专业英语翻译合集

1.我们可以把钢再次加热到临界温度以下的某一温度,然后在慢慢让其冷却。We can heat the steel again to a temperature below the critical temperature, then cool it slowly. 2.无论任何简单的机床,都是由单一元件即通称为机械零件或部件组成的。However simple, any machine is a combination of individual components generally referred to as machine elements or parts. 3.这些金属不都是好的导体。 All these metals are not good conductors. 4. 在做带电实验的时候,再怎么小心都不为过。 You can't be too careful in performing an experiment. 5.利用发电机可以把机械能转变成电能。 The mechanical energy can be changed back into electrical energy by means of a generator or dynamo. 6.假定电源输入的电压保持不变。 Assume that the voltage input of the power supply remains the same. 7.化石燃料是发电过程中最为频繁使用的能源。 Fossil fuels are most frequently used source daring the power generation process. 8单个机械零件的可靠性成为评估整台机器使用寿命的基本因素。 The individual reliability of machine elements becomes the basis for estimating the overall life 9.说我们生活在一个电子时代,这一点都不夸张。 It's no exaggeration to say that we live in an electronic age. 10.发动机的转速不应超过最大允许值。 Engine revolution should not exceed the maximum permissible. 11.如能从大型核电站获得成本极低的电力,电解氢的竞争能力就会增强。(Electrolytic hydrogen)。 If extremely low-cost power were ever to become available from large nuclear power plants, electrolytic hydrogen would become competitive. 12.电子技术提供了一种新的显示时间的方法。 A new way of displaying time has been given by electronics. 13.远距离输电需要高压,安全用电需要低压。 High voltage is necessary for long transmission line while low voltage for safe use. 14.铝的电阻大约是同等尺寸的铜的1.5倍。 The resistance of aluminum is approximately half again as great as that of copper for the same dimensions = size 15.In fact,it is impossible for no force to be exerted on a body,since in this world everything is subject to the for ce of gravity. 事实上,物体不受外力作用是不可能的,因为在这个世界上任何物体都要受到重力的作用。 16.In a thermal power plant,all the chemical energy is not

(完整版)机械工程专业英语词汇

陶瓷ceramics 合成纤维synthetic fibre 电化学腐蚀electrochemical corrosion 车架automotive chassis 悬架suspension 转向器redirector 变速器speed changer 板料冲压sheet metal parts 孔加工spot facing machining 车间workshop 工程技术人员engineer 气动夹紧pneuma lock 数学模型mathematical model 画法几何descriptive geometry 机械制图Mechanical drawing 投影projection 视图view 剖视图profile chart 标准件standard component 零件图part drawing 装配图assembly drawing 尺寸标注size marking 技术要求technical requirements 刚度rigidity 内力internal force 位移displacement 截面section 疲劳极限fatigue limit 断裂fracture 塑性变形plastic distortion 脆性材料brittleness material 刚度准则rigidity criterion 垫圈washer 垫片spacer 直齿圆柱齿轮straight toothed spur gear 斜齿圆柱齿轮helical-spur gear 直齿锥齿轮straight bevel gear 运动简图kinematic sketch 齿轮齿条pinion and rack 蜗杆蜗轮worm and worm gear 虚约束passive constraint 曲柄crank 摇杆racker 凸轮cams

机械工程英语第2版叶邦彦Unit 10

Unit 10 Surface Engineering Two major surface treatments Covering the surfaces Altering the surfaces

Surface Engineering Requirements (1) control friction and wear; (2) improve corrosion resistance; (3) change physical property, such as conductivity [导电率], resistivity, reflection; (4) alter dimension; (5) vary appearance, e.g., color and roughness; (6) reduce cost;

Covering the surfaces The treatments that cover the surfaces include: 1. organic coatings 2. inorganic coatings. Shown on the right.covering the surfaces organic coatings inorganic coatings Electroplating Thin-film coatings Furnace fusings Hot dippings Thermal sprayings Conversion coatings

Electroplating It is an electrochemical process by which metal is deposited on a substrate by passing a current through the bath. Anode [正极]: positively charged electrode. The source of the material to be deposited. electrochemistry: the medium through which metal ions are exchanged and transferred to the substrate to be coated. cathode: negatively charged electrode. the substrate to be coated.

机械工程专业英语 翻译

2、应力和应变 在任何工程结构中独立的部件或构件将承受来自于部件的使用状况或工作的外部环境的外力作用。如果组件就处于平衡状态,由此而来的各种外力将会为零,但尽管如此,它们共同作用部件的载荷易于使部件变形同时在材料里面产生相应的内力。 有很多不同负载可以应用于构件的方式。负荷根据相应时间的不同可分为: (a)静态负荷是一种在相对较短的时间内逐步达到平衡的应用载荷。 (b)持续负载是一种在很长一段时间为一个常数的载荷, 例如结构的重量。这种类型的载荷以相同的方式作为一个静态负荷; 然而,对一些材料与温度和压力的条件下,短时间的载荷和长时间的载荷抵抗失效的能力可能是不同的。 (c)冲击载荷是一种快速载荷(一种能量载荷)。振动通常导致一个冲击载荷, 一般平衡是不能建立的直到通过自然的阻尼力的作用使振动停止的时候。 (d)重复载荷是一种被应用和去除千万次的载荷。 (e)疲劳载荷或交变载荷是一种大小和设计随时间不断变化的载荷。 上面已经提到,作用于物体的外力与在材料里面产生的相应内力平衡。因此,如果一个杆受到一个均匀的拉伸和压缩,也就是说, 一个力,均匀分布于一截面,那么产生的内力也均匀分布并且可以说杆是受到一个均匀的正常应力,应力被定义为 应力==负载 P /压力 A, 因此根据载荷的性质应力是可以压缩或拉伸的,并被度量为牛顿每平方米或它的倍数。 如果一个杆受到轴向载荷,即是应力,那么杆的长度会改变。如果杆的初始长度L和改变量△L已知,产生的应力定义如下: 应力==改变长△L /初始长 L 因此应力是一个测量材料变形和无量纲的物理量 ,即它没有单位;它只是两个相同单位的物理量的比值。 一般来说,在实践中,在荷载作用下材料的延伸是非常小的, 测量的应力以*10-6的形式是方便的, 即微应变, 使用的符号也相应成为ue。 从某种意义上说,拉伸应力与应变被认为是正的。压缩应力与应变被认为是负的。因此负应力使长度减小。 当负载移除时,如果材料回复到初始的,无负载时的尺寸时,我们就说它是具有弹性的。一特定形式的适用于大范围的工程材料至少工程材料受载荷的大部分的弹性, 产生正比于负载的变形。由于载荷正比于载荷所产生的压力并且变形正比于应变, 这也说明,当材料是弹性的时候, 应力与应变成正比。因此胡克定律陈述, 应力正比于应变。 这定律服从于大部分铁合金在特定的范围内, 甚至以其合理的准确性可以假定适用于其他工程材料比如混凝土,木材,非铁合金。 当一个材料是弹性的时候,当载荷消除之后,任何负载所产生的变形可以完全恢复,没有永久的变形。

机械工程英语第二版叶邦彦_汉语翻译(机械工业出版社)--全本书翻译

?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 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.

机械工程英语翻译unit 1

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

机械工程专业英语单词

Lesson 1 Basic Concepts in Mechanics 机械学的基本概念 mechanics n.力学 modify v.修改,调解,变更manageable a.可控制【管理】的 incline v.(使)倾斜 ramp n.斜板,斜坡【道】 slope v.(使)倾斜 friction n.摩擦 roll v.滚动 multiplier n.放大器,乘法器 broom n.扫帚 convert v.转变【化】 handle n.手柄【把】 sweep v.扫荡【描】,掠过efficiency n.效率 gauge vt.测【计】量,校验bearing n.轴承 ideal mechanical advantage 理想的机械效益 neglect vt.忽略Lesson 2 Basic Assumption in Plasticity Theory 塑性理论的基本假设 assumption n.假定 plasticity n.塑性 investigate v.调查,研究deformation n.变形 metal forming process 金属成型工艺【过程】 strain (rate) n.应变【速率】 strength n.强度 stress n.应力 yield stress 屈服应力 flow stress 流动应力 tensile stress 拉【伸】应力compressive stress 压【缩】应力 shear stress 剪【切】应力 geometry n.几何形状 elastic a.弹性的 springback n.回弹 bending n.弯曲,折弯

机械工程专业英语第二版必考翻译(完整版)

1.With low-power machinery or vehicles the operator can usually apply sufficient force through a simple mechanical linkage from the pedle or handle to the stationary part of the brake. In many cases, however, this force must be multiplied by using an elaborate braking system.(P5)用低能机器或传力工具,操作者通过向踏板或把手的一个简单机械连接构件作用足够的力量到车闸固定的部分。大多数情况,然而,用一个详细(复杂)的车闸系统使这个力量成倍增加。 2. The fundamental principle involved is the use of compressed air acting through a piston in a cylinder to set block brakes on the wheels. The action is simultaneous o n the wheels of all the cars in the train. The compressed air is carried through a strong hose from car to car with couplings between cars; its release to all the separate block brake units, at the same time, is controlled by the engineer. (Braking Systems)(P5) 相关的基本原理是使用压缩气体,通过气缸内的活塞将闸块压在车轮起作用。列车的所有车厢上的车轮同时动作。压缩气体通过一个坚固的管道在由联轴器连接的车厢之间传输;工程师控制其在同一时间释放到所有独立的闸块单元。 3.When the brake pedal of an automobile is depressed, a force is applied to a piston in a master cylinder. The piston forces hydraulic fluid through metal tubing into a cylinder in each wheel where the fluid’s pressure moves two pistons that press the brake shoes against the drum. (Braking Systems)(P5) 当踩下汽车刹车的踏板,在主汽缸中的活塞上施加一个力。活塞驱动液压流体通过金属管道进入每个车轮气缸,在那里液压移动两个活塞将闸片压向轮圈。 4.Machinery ontology including mechanical rack, mechanical connections and mechanical transmission, which is the basis of mechanical-electrical integration, plays a role in supporting the other functional units of the system and transmitting motion and power. Compared to purely mechanical products, the performance and functionality of integration technology in electrical and mechanical systems have been improved a lot, which requires mechanical ontology to adapt its new status in mechanical structure, materials, processing technology, as well as the areas of geometry. Accordingly, the new ontology is with high efficient, multi-functional, reliable and energy-saving, small, light-weighted and aesthetically pleasing characteristics. (Mechatronics System) (P7) 机械体包括机架、机械联接和机械传动,它是机电一体化的基础,作用是支撑系统其他功能单元,传递运动和动力。和纯机械产品相比,一体化技术的性能和功能在机电系统中大幅提高,它要求机械本体适应在机械结构、材料、加工技术以及这些领域中的几何学下的新环境。相应的,新的一体化具有高效、多功能、可靠、节能、小轻和美学的令人赏心悦目的特征。 5. Detecting sensor detecting sensor part includes a variety of sensors and signal detection circuit, and its function is to detect the process of mechatronic systems in the work itself and the changes of relevant parameters in external environment and transmit the information to the electronic control unit. Electronic control unit check the information and sends the corresponding control issues to the actuator. (Mechatronics System) (P7) 检测传感器部分包括各类传感器、信号检测电路,它的功能是检测机电系统自身工作的工程,在外部环境下的相关参数的改变,将其信息传给电子控制单元。电子控制单元通过检查信息,送出相应的指令到执行机构。 6. Electronic control unit, also known as ECU, is the core of mechatronic systems, responsible for the external commands and the signals output by sensors. It centralizes stores, computes and analyzes the information. Based on the results of information processing,instruction are issued according to a certain extent and pace to control the destination for the entire system. (Mechatronics System) (P7) 电子控制单元,也被称为控制单元(ECU)控制,是机电系统的核心,负责外部命令和传感器的信号输出。它集中、存储、计算并分析信息。基于信息处理的结果,按照一定的范围和步调发出命令来实现控制整个系统的目标。 7. It is put into a fairly standard machine tool that has had position sensing and motors on the

机械专业术语英文翻译

机械专业英语词汇 陶瓷ceramics 合成纤维synthetic fibre 电化学腐蚀electrochemical corrosion 车架automotive chassis 悬架suspension 转向器redirector 变速器speed changer 板料冲压sheet metal parts 孔加工spot facing machining 车间workshop 工程技术人员engineer 气动夹紧pneuma lock 数学模型mathematical model 画法几何descriptive geometry 机械制图Mechanical drawing 投影projection 视图view 剖视图profile chart 标准件standard component 零件图part drawing 装配图assembly drawing 尺寸标注size marking 技术要求technical requirements 刚度rigidity 内力internal force 位移displacement 截面section 疲劳极限fatigue limit 断裂fracture 塑性变形plastic distortion 脆性材料brittleness material 刚度准则rigidity criterion 垫圈washer 垫片spacer 直齿圆柱齿轮straight toothed spur gear 斜齿圆柱齿轮helical-spur gear 直齿锥齿轮straight bevel gear 运动简图kinematic sketch 齿轮齿条pinion and rack 蜗杆蜗轮worm and worm gear 虚约束passive constraint 曲柄crank 摇杆racker

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