机械英文翻译

第一篇：机械英文翻译

Cutting tool design Physics of metal-cutting provide the theoretical framework by which we must examine all other elements of cutting tool design.We have workpiece materials from a very soft, buttery consistency to very hard and shear resistant.Each of the workpiece materials must be handled by itself;the amount of broad information that is applicable to each workpiece material is reduced as the distinctions between workpiece characteristics increase.Not only is there a vast diversity of workpiece materials, but there is also a variety of shapes of tools and tool compositions.The tool designer must match the many variables to provide the best possible cutting geometry.There was a day when trial and error was normal for this decision, but today, with the ever-increasing variety of tools, trial and error is far too expensive.The designer must develop expertise in applying date and making comparisons on the basis of the experience of others.For example: tool manufactures and material salesmen will have figures their companies have developed.The figures are meant to be guidelines;however, a careful examination of the literature available will provide an excellent place from which to start, and be must cheaper than trial and error.Material removal by machining involves interaction of five elements: the cutting tool, the toolholding and guiding device, the workholder, the workpiece, and the machine.The cutting tool may have a single cutting edge or may have many cutting edges.It may be designed for linear or rotary motion.The geometry of the cutting tool depends upon its intended function.The toolholding device may or may not be used for guiding or locating.Toolholder selection is governed by tool design and intended function.The physical composition of the workpiece greatly influences the selection of the machining method, the tool composition and geometry, the rate of material removal.The intended shape of the workpiece influences the selection of the machining method and the choice of linear or rotary tool travel.The composition and geometry of the workpiece to a great extent determines the workholder requirements.Workholder selection also depends upon forces produced by the tool on the workpiece.Tool guidance may be incorporated into the workholding function.Successful design of tools for the material removal processes requires, above all, a complete understanding of cutting tool function and geometry.This knowledge will enable the designer to specify the correct tool for a given task.The tool, in turn, will govern the selection of toolholding and guidance methods.Tool forces govern selection of the workholding device.Although the process involves interaction of the five elements, everything begins with and is based on what happens at the point of contact between the workpiece and cutting tool.The primary method of imparting form and dimension to a workpiece is the removal of material by the use of edged cutting tools.An oversize mass is literally carved to its intended shape.The removal of material from a workpiece is termed generation of form by machining, or simply machining.Form and dimension may also be achieved by a number of alternative processes such as hot or cold extrusion, sand casting, die casting, and precision casting.Sheet metal can be formed or drawn by the application of pressure.In addition to machining, metal removal can be accomplished by chemical or electrical methods.A great variety of workpiece may be produced without resorting to a machining operation.Economic considerations, however, usually dictate form generation by machining either as the complete process or in conjunction with another process.Cutting tools are designed with sharp edges to minimize rubbing contact between the tool and workpiece.Variations in the shapes of the cutting tool influence tool life, surface finish of the workpiece, and the amount of force required to shear a chip from the parent metal.The various angles on a tool compose what is often termed tool geometry.The tool signature or nomenclature is a sequence of alpha and numeric characters representing the various angles, signification dimensions, special features, and the size of the nose radius.This method of identification has been standardized by the American National Standards Institute for carbide and for high speed steel.

第二篇：机械专业课程英文翻译

机械制图Descriptive Geometry & Engineering Graphing85

机械工程材料Mechanical Engineering Material90

工程力学Engineering Mechanics89

机械原理Principle of Mechanics85

机械原理课程设计Course Exercise for Principle of Mechanicsgood良好 机械设计Mechanical Design80

机械设计课程设计Course Exercise for Mechanical Designgood良好 液压与气压传动Hydraulic & Pneumatic Technology89

机械制造技术基础Fundamentals of Manufacturing Technology77

机械制造装备设计Modern Manufacturing Equipment Design84

电工与电子技术Mechanical Electric Electronic Control Technique86

微型计算机原理Principle and Application of Microcomputer81

互换性与测量技术Fundamentals of Exchangeability and Measurement Technology 77

机械工程控制基础Introduction to Control Engineering85

计算机数控技术Technology and Application of Numerical Control Programming 77

PLCPrinciple and Application of PLC82

模具制造技术Mould Manufacture Technology76

传感器与测试技术Measurement and Testing Technology81

计算机辅助设计Computer-aided Design86

机械系统设计Mechanical System Design88

生产实习Production Practical Traininggood良好

机械制图、机械工程材料、工程力学、机械原理、机械原理课程设计、机械设计、机械设计课程设计、液压与气压传动、机械制造技术基础、机械制造装备设计、电工与电子技术、微型计算机原理、互换性与测量技术、机械工程控制基础、计算机数控技术、PLC、模具制造技术、传感器与测试技术、计算机辅助设计、机械系统设计、生产实习等

由于在大二第一学期就过了英语6级，所以，从那个时候起，一直都在通过选修口语课，加入英语角，看美剧，晨读等方式学英语口语，因此口语水平良好，可以和以英语为母语的人进行交流。

Descriptive Geometry & Engineering Graphing85

Mechanical Engineering Material90

Engineering Mechanics89

Principle of Mechanics85

Course Exercise for Principle of Mechanicsgood

Mechanical Design80

Course Exercise for Mechanical Designgood

Hydraulic & Pneumatic Technology89

Fundamentals of Manufacturing Technology77

Modern Manufacturing Equipment Design84

Mechanical Electric Electronic Control Technique86 Principle and Application of Microcomputer81

Fundamentals of Exchangeability and Measurement Technology 77 Introduction to Control Engineering85

计Technology and Application of Numerical Control Programming Principle and Application of PLC82

Mould Manufacture Technology76

Measurement and Testing Technology81

Computer-aided Design86

Mechanical System Design88

Production Practical Traininggood

Course Exercise for Fundamentals of Manufacturing Technology

Course Exercise for Modern Manufacturing Equipment Design77

第三篇：机械专业英文翻译

Design of machine and machine elements Machine design Machine design is the art of planning or devising new or improved machines to accomplish specific purposes.In general, a machine will consist of a combination of several different mechanical elements properly designed and arranged to work together, as a whole.During the initial planning of a machine, fundamental decisions must be made concerning loading, type of kinematic elements to be used, and correct utilization of the properties of engineering materials.Economic considerations are usually of prime importance when the design of new machinery is undertaken.In general, the lowest over-all costs are designed.Consideration should be given not only to the cost of design, manufacture the necessary safety features and be of pleasing external appearance.The objective is to produce a machine which is not only sufficiently rugged to function properly for a reasonable life, but is at the same time cheap enough to be economically feasible.The engineer in charge of the design of a machine should not only have adequate technical training, but must be a man of sound judgment and wide experience, qualities which are usually acquired only after considerable time has been spent in actual professional work.Design of machine elements

The principles of design are, of course, universal.The same theory or equations may be applied to a very small part, as in an instrument, or, to a larger but similar part used in a piece of heavy equipment.In no ease, however, should mathematical calculations be looked upon as absolute and final.They are all subject to the accuracy of the various assumptions, which must necessarily be made in engineering work.Sometimes only a portion of the total number of parts in a machine are designed on the basis of analytic calculations.The form and size of the remaining parts are designed on the basis of analytic calculations.On the other hand, if the machine is very expensive, or if weight is a factor, as in airplanes, design computations may then be made for almost all the parts.The purpose of the design calculations is, of course, to attempt to predict the stress or deformation in the part in order that it may sagely carry the loads, which will be imposed on it, and that it may last for the expected life of the machine.All calculations are, of course, dependent on the physical properties of the construction materials as determined by laboratory tests.A rational method of design attempts to take the results of relatively simple and fundamental tests such as tension, compression, torsion, and fatigue and apply them to all the complicated and involved situations encountered in present-day machinery.In addition, it has been amply proved that such details as surface condition, fillets, notches, manufacturing tolerances, and heat treatment have a market effect on the strength and useful life of a machine part.The design and drafting departments must specify completely all such particulars, must specify completely all such particulars, and thus exercise the necessary close control over the finished product.As mentioned above, machine design is a vast field of engineering technology.As such, it begins with the conception of an idea and follows through the various phases of design analysis, manufacturing, marketing and consumerism.The following is a list of the major areas of consideration in the general field of machine design: ① Initial design conception;

② Strength analysis;③ Materials selection;④ Appearance;⑤ Manufacturing;⑥ Safety;⑦ Environment effects;⑨ Reliability and life;

Strength is a measure of the ability to resist, without fails, forces which cause stresses and strains.The forces may be;① Gradually applied;② Suddenly applied;2

③ Applied under impact;④ Applied with continuous direction reversals;⑤ Applied at low or elevated temperatures.If a critical part of a machine fails, the whole machine must be shut down until a repair is made.Thus, when designing a new machine, it is extremely important that critical parts be made strong enough to prevent failure.The designer should determine as precisely as possible the nature, magnitude, direction and point of application of all forces.Machine design is mot, however, an exact science and it is, therefore, rarely possible to determine exactly all the applied forces.In addition, different samples of a specified material will exhibit somewhat different abilities to resist loads, temperatures and other environment conditions.In spite of this, design calculations based on appropriate assumptions are invaluable in the proper design of machine.Moreover, it is absolutely essential that a design engineer knows how and why parts fail so that reliable machines which require minimum maintenance can be designed.Sometimes, a failure can be serious, such as when a tire blows out on an automobile traveling at high speeds.On the other hand, a failure may be no more than a nuisance.An example is the loosening of the radiator hose in the automobile cooling system.The consequence of this latter failure is usually the loss of some radiator coolant, a condition which is readily detected and corrected.The type of load a part absorbs is just as significant as the magnitude.Generally speaking, dynamic loads with direction reversals cause greater difficulties than static loads and, therefore, fatigue strength must be considered.Another concern is whether the material is ductile or brittle.For example, brittle materials are considered to be unacceptable where fatigue is involved.In general, the design engineer must consider all possible modes of failure, which include the following: ① Stress;② Deformation;3

③ Wear;④ Corrosion;⑤ Vibration;⑥ Environmental damage;⑦ Loosening of fastening devices.The part sizes and shapes selected must also take into account many dimensional factors which produce external load effects such as geometric discontinuities, residual stresses due to forming of desired contours, and the application of interference fit joint.Selected from” design of machine elements”, 6th edition, m.f.sports, prentice-hall, inc., 1985 and “machine design”, Anthony Esposito, charles e., Merrill publishing company, 1975.Quality assurance and control

Product quality is of paramount importance in manufacturing.If quality is allowed deteriorate, then a manufacturer will soon find sales dropping off followed by a possible business failure.Customers expect quality in the products they buy, and if a manufacturer expects to establish and maintain a name in the business, quality control and assurance functions must be established and maintained before, throughout, and after the production process.Generally speaking, quality assurance encompasses all activities aimed at maintaining quality, including quality control.Quality assurance can be divided into three major areas.These include the following: ①Source and receiving inspection before manufacturing;②In-process quality control during manufacturing;③Quality assurance after manufacturing.Quality control after manufacture includes warranties and product service extended to the users of the product.Source and receiving inspection before manufacturing

Quality assurance often begins ling before any actual manufacturing takes place.This may be done through source inspections conducted at the plants that

supply materials, discrete parts, or subassemblies to manufacturer.The manufacturer’s source inspector travels to the supplier factory and inspects raw material or premanufactured parts and assemblies.Source inspections present an opportunity for the manufacturer to sort out and reject raw materials or parts before they are shipped to the manufacturer’s production facility.The responsibility of the source inspector is to check materials and parts against design specifications and to reject the item if specifications are not met.Source inspections may include many of the same inspections that will be used during production.Included in these are: ①Visual inspection;②Metallurgical testing;③Dimensional inspection;④Destructive and nondestructive inspection;⑤Performance inspection.Visual inspections

Visual inspections examine a product or material for such specifications as color, texture, surface finish, or overall appearance of an assembly to determine if there are any obvious deletions of major parts or hardware.Metallurgical testing

Metallurgical testing is often an important part of source inspection, especially if the primary raw material for manufacturing is stock metal such as bar stock or structural materials.Metals testing can involve all the major types of inspections including visual, chemical, spectrographic, and mechanical, which include hardness, tensile, shear, compression, and spectr5ographic analysis for alloy content.Metallurgical testing can be either destructive or nondestructive.Dimensional inspection

Few areas of quality control are as important in manufactured products as dimensional requirements.Dimensions are as important in source inspection as they are in the manufacturing process.This is especially critical if the source supplies parts for an assembly.Dimensions are inspected at the source factory

using standard measuring tools plus special fit, form, and function gages that may required.Meeting dimensional specifications is critical to interchangeability of manufactured parts and to the successful assembly of many parts into complex assemblies such as autos, ships, aircraft, and other multipart products.Destructive and nondestructive inspection

In some cases it may be necessary for the source inspections to call for destructive or nondestructive tests on raw materials or p0arts and assemblies.This is particularly true when large amounts of stock raw materials are involved.For example it may be necessary to inspect castings for flaws by radiographic, magnetic particle, or dye penetrant techniques before they are shipped to the manufacturer for final machining.Specifications calling for burn-in time for electronics or endurance run tests for mechanical components are further examples of nondestructive tests.It is sometimes necessary to test material and parts to destruction, but because of the costs and time involved destructive testing is avoided whenever possible.Examples include pressure tests to determine if safety factors are adequate in the design.Destructive tests are probably more frequent in the testing of prototype designs than in routine inspection of raw material or parts.Once design specifications are known to be met in regard to the strength of materials, it is often not necessary to test further parts to destruction unless they are genuinely suspect.Performance inspection

Performance inspections involve checking the function of assemblies, especially those of complex mechanical systems, prior to installation in other products.Examples include electronic equipment subcomponents, aircraft and auto engines, pumps, valves, and other mechanical systems requiring performance evaluation prior to their shipment and final installation.Selected form “modern materials and manufacturing process”

Electro-hydraulic drum brakes Application

The YWW series electro-hydraulic brake is a normally closed brake, suitable for horizontal mounting.It is mainly used in portal cranes, bucket stacker/reclaimers’slewing mechanism.The YKW series electro-hydraulic brake is a normally opened brake, suitable for horizontal mounting, employing a thruster as actuator.with the foot controlling switch the operator can release or close the brake.It is mainly used for deceleration braking of portal cranes’slewing mechanism.In a non-operating state the machinery can be braked by a manual close device.The RKW series brake is a normally opened brake, which is operated by foot driven hydraulic pump, suitable for horizontal mounting.Mainly used in the slewing mechanism of middle and small portal cranes.When needed, the brake is activated by a manual closed device.Main design features Interlocking shoes balancing devices(patented technology)constantly equalizes the clearance of brake shoes on both sides and made adjustment unnecessary, thus avoiding one side of the brake lining sticking to the brake wheel.The brake is equipped with a shoed autoaligning device.Main hinge points are equipped with self-lubricating bearing, making high efficiency of transmission, long service life.Lubricating is unnecessary during operation.Adjustable bracket ensure the brake works well.The brake spring is arranged inside a square tube and a surveyor’s rod is placed on one side.It is easy to read braking torque value and avoid measuring and computing.Brake lining is of card whole-piece shaping structure, easy to replace.Brake linings of various materials such as half-metal(non-asbestos)hard and half-hard, soft(including asbestos)substance are available for customers to choose.All adopt the company’s new types of thruster as corollary equipment which work accurately and have long life.Hydraulic Power Transmission The Two Types Of Power Transmission

In hydraulic power transmission the apparatus(pump)used for conversion of the mechanical(or electrical,thermal)energy to hydraulic energy is arranged on the input of the kinematic chain ,and the apparatus(motor)used for conversion of the hydraulic energy to mechanical energy is arranged on the output(fig.2-1)

The theoretical design of the energy converters depends on the component of the bernouilli equation to be used for hydraulic power transmission.In systerms where, mainly, hydrostatic pressure is utilized, displacement(hydrostatic)pumps and motors are used, while in those where the hydrodynamic pressure is utilized is utilized gor power transmission hydrodynamic energy converters(e.g.centrifugal pumps)are used.The specific characteristic of the energy converters is the weight required for transmission of unit power.It can be demonstrated that the use of hydrostatic energy converters for the low and medium powers, and of hydrodynamic energy converters of high power are more favorite(fig.2-2).This is the main reason why hydrostatic energy converters are used in industrial apparatus.transformation of the energy in hydraulic transmission.1.2.3.4.5.6.7.driving motor(electric, diesel engine);mechanical energy;pump;

hydraulic energy;

hydraulic motor;mechanical energy;

load variation of the mass per unit power in hydrostatic and hydrodynamic energy converters

1、hydrostatic;2.hydrodynamic Only displacement energy converters are dealt with in the following.The

elements performing converters provide one or several size.Expansion of the working chambers in a pump is produced by the external energy admitted, and in the motor by the hydraulic energy.Inflow of the fluid occurs during expansion of the working chamber, while the outflow(displacement)is realized during contraction.Such devices are usually called displacement energy converters.The Hydrostatic Power

In order to have a fluid of volume V1 flowing in a vessel at pressure work spent on compression W1 and transfer of the process, let us imagine a piston mechanism(fig.2-3(a))which may be connected with the aid of valves Z0 and Z1 to the external medium under pressure P0 and reservoir of pressure p1.in the upper position of the piston(x=x0)with Z0 open the cylinder chamber is filled with fluid of volume V0 and pressure P0.now shut the value Z0 and start the piston moving downwards.If Z1 is shut the fluid volume in position X=X1 of the piston decreases from V0 to V1, while the pressure rises to P1.the external work required for actuation of the piston(assuming isothermal change)is W1=-∫0x0(P-P0)Adx=-∫v1v0(P-P0)dv

Select from Hydraulic Power Transmission

机器和机器零件的设计

机器设计

机器设计为了特定的目的而发明或改进机器的一种艺术。一般来讲，机器时有多种不同的合理设计并有序装配在一起的部件构成的，在最初的机器设计阶段，必须基本明确负载、元件的运动情况、工程材料的合理使用性能。负责新机器的设计最初的最重要的是经济性考虑。一般来说，选择总成本最低的设计方案，不仅要考虑设计、制造、销售、安装的成本。还要考虑服务的费用，机械要保证必要的安全性能和美观的外形。

制造机器的目标不仅要追求保证只用功能的合理寿命，还要保证足够便宜以同时保证其经济的可行性。负责设计机器的工程师，不仅要经过专业的培训，而且必须是一个准确判断而又有丰富经验的人，具有一种有足够时间从事专门的实际工作的素质。

机器零件的设计

相同的理论或方程可应用在一个一起的非常小的零件上，也可用在一个复杂的设备的大型相似件上，既然如此，毫无疑问，数学计算是绝对的和最终的。他们都符合不同的设想，这必须由工程量决定。有时，一台机器的零件全部计算仅仅是设计的一部分。零件的结构和尺寸通常根据实际考虑。另一方面，如果机器和昂贵，或者质量很重要，例如飞机，那麽每一个零件都要设计计算。

当然，设计计算的目的是试图预测零件的应力和变形，以保证其安全的带动负载，这是必要的，并且其也许影响到机器的最终寿命。当然，所有的计算依赖于这些结构材料通过试验测定的物理性能。国际上的设计方法试图通过从一些相对简单的而基本的实验中得到一些结果，这些试验，例如结构复杂的及现代机械设计到的电压、转矩和疲劳强度。

另外，可以充分证明，一些细节，如表面粗糙度、圆角、开槽、制造公差和热处理都对机械零件的强度及使用寿命有影响。设计和构建布局要完全详细地说明每一个细节，并且对最终产品进行必要的测试。

综上所述，机械设计是一个非常宽的工程技术领域。例如，从设计理念到设计分析的每一个阶段，制造，市场，销售。以下是机械设计的一般领域应考虑的主要方面的清单：

①最初的设计理念

②受力分析

③材料的选择

④外形

⑤制造

⑥安全性

⑦环境影响

⑧可靠性及寿命

在没有破坏的情况下，强度是抵抗引起应力和应变的一种量度。这些力可能是：

①渐变力

②瞬时力

③冲击力

④不断变化的力

⑤温差

如果一个机器的关键件损坏，整个机器必须关闭，直到修理好为止。设计一台新机器时，关键件具有足够的抵抗破坏的能力是非常重要的。设计者应尽可能准确地确定所有的性质、大小、方向及作用点。机器设计不是这样，但精确的科学是这样，因此很难准确地确定所有力。另外，一种特殊材料的不同样本会显现出不同的性能，像抗负载、温度和其他外部条件。尽管如此，在机械设计中给予合理综合的设计计算是非常有用的。

此外，显而易见的是一个知道零件是如何和为什麽破坏的设计师可以设计出需要很少维修的可靠机器。有时，一次失败是严重的，例如高速行驶的汽车的轮胎爆裂。另一方面，失败未必是麻烦。例如，汽车的冷却系统的散热器皮带管松开。这种破坏的后果通常是损失一些散热片，可以探测并改正过来。零件负载类型是一个重要的标志。一般而言，变化的动负载比静负载会引起更大的差异。因此，疲劳强度必须符合。另一个关心的方面是这种材料是否直或易碎。例如有疲劳破坏的地方不易使用易碎的材料。一般的，设计师要靠考虑所有破坏情况，其包括以下方面：

①应力

②应变

③外形

④腐蚀

⑤震动

⑥外部环境破坏

⑦紧固件的松脱

零件的尺寸和外形的选择也有很多因素。外部负荷的影响，如几何间断，由于轮廓而产生的残余应力和组合件干涉。

质量保证与控制

产品质量是生产中最重要的。如果放任质量恶化下去，生产者会很快发现销售量锐减，可能从而会导致产业的失败。用户期望他们买的产品质量性能好，而且如果制造商想建立并维持其信誉，必须在产品制造前制造过程中及制造过程后进行质量控制和质量保证。一般来说，质量保证包括所有的活动，其包括质量建立和质量控制。质量保证可以被分为三个主要领域，他们如下所述： ①制造之前的原材料的检查 ②在制造加工过程中的质量控制 ③制造之后的质量保证

生产制造后的质量控制包括保证书和面对产品用户的服务。生产制造之前的原材料检验

质量保证常常在实际生产制造之前就开始了。这些都是生产者在供应原材料、散件或配件的车间里进行检验。生产制造公司的原材料检验员到供应厂并且检查原材料及于制造的另配件。原材料检验为生产者提供了一次机会，那就是在原料及散件被运到生产车间之前先进行挑选淘汰。原料检察员的责任是去检查原料和零件是否达到设计规格并且淘汰那些未达到特殊指标的原料。原料检验有很多于检查产品相同的检验。其如下所述： ①目测 ②冶金测试 ③尺寸测试

④损伤检验 ⑤性能检验 目测

目测检验一种产品或原料的某些特征，如颜色、纹理、表面光洁度或部件的总体外观，从而判断其是否具有明显的缺损。冶金测试

冶金测试常常是原料间严厉的一个很重要的部分，尤其是像棒料、建筑材料毛坯一些原材料。金属测试包含所有主要的检验类型，其中有目测，化学检验，光谱检验和机械性能检验，其包括硬度、伸缩性能、剪切性能、压缩性能和合成 12

成分的光谱分析。冶金测试既可用于成品件也可用于预制件。尺寸检验

质量控制的一些领域是重要的生产件的要求尺寸。尺寸在检验过程中，像其在生产过程中一样重要。如果这些零件是为总成供应的，那尺寸尤其严格。一些尺寸在生产车间用标准测量工具进行检验，像特种接头、造型和需求的功能标准度量。符合尺寸规格对所制造多部件的互换性和对多部件成功组装成复杂的装置，如汽车、轮船、飞机和其他多部件产品都地极其重要的。损伤检验

在一些情况下，对原材料或零部件采取损伤测试的原始测验是很必要的。特别是涉及到大批的原材料时。例如，在被运到生产车间作最终机器之前，对铸件进行X-射线、电磁离子、染色渗透剂技术的探伤是很必要的，又对机器总成的电子或持久运作测试而确定的规格，是无损测试的又一例证。有时，对材料及零件的测试是很必要的，但由于无损测试的花费和成本及时间不是任何时候都允许的。

例如，有压力测试决定在设计中其是否安全。损伤测试经常用于设计样机的测试，而不是原材料或零件的常规检验。一旦设计达到了所希望的材料强度，通常对零件做进一步的损伤测试是不必要的，除非他们确实存在疑点。

性能测试

性能测试在零部件被其他产品被安装之前，检查部件的功能，尤其是那些机械构造复杂的部件。例如电子设备零件，飞机和汽车发动机，泵、阀及其他需要在装运和最后安装前进行性能测验的机械系统。

选自《现代材料和制造工艺》

汽车起重机的不同类型

根据汽车吊的使用情况，像：工作的范围，工作的自然情况。他们的构造装备体现着不同的理念。

1、工作范围（不同的设计）

当起重机工作在一个小范围内（仓库，码头，戏台等）告诉是没有必要的。根据这种应用，我们的装置最高速为35km/h。

驱动装置布置在后面，集成了车辆和起重机的控制，这种类型称为：单驱起重机。当起重机在大场地内工作时，有几个较远的工作点，高速轴就是必要的了。随之而来的，布置在车辆后端的单驱动是不可能的。由于这个原因，提供两个驱动是必要的，相对的允许像传统卡车那样驱动车辆。这种类型的起重机，在构造上必须装备一个特殊的变速箱，对起重机允许像传统车辆那样的前进和后退。我们这种类型的起重机装备了一个特殊的变速箱，可以提供一个前进速度和一个后退速度，一般其最大运输速度为：55/60km/h，这种类型称为双驱起重机。

2、地面情况

当起重机操作困难时，在平整的路面上（体育场，码头，仓库等）起构造是传统概念的单驱动的运输工具。

如果起重机离开路面移动到恶劣路况下（脏且沙软的路面）不平的，其构造根据“全工况路面”的限定标准而建立，其要求实现：

双驱甚至是三驱；两种速度范围，有一个特别慢的值；不同驱动轴的转换系统；轴端的特殊轴承；特殊的制动；提供低压的大尺寸的轮胎，在软地面上运转；独立的大车轮；悬空的地面监视和清晰的构造是非常重要的；安装及驾驶服务

所有的主要点是绝对必要的对于在无路的情况下的各种类型的车辆，有一个良好的运行。

当然起重机不得不在各种路况下工作，为此其装备了双驱。

（附图见英文资料）

液力传动

动力传动的两种类型

在液力传动中，用来将机械能（电能、化学能）转化成液力能的装置（泵）被布置在传动链的输入端，而用来将液力能转化成机械能的装置（马达）被布置在输出端。（图2-1）

这种能量转化的理论上的设计依据是液力传动的各部分的伯努里方程。

在系统中，流体静压力主要用来替代泵和马达，而在某些方面，流体动力是作为液力能转化后的力传动而被利用的（如离心泵）这种能量转换的特征取决于单位力的传动。他能说明这种微小力的液体静压力能转换和高压力的液体动力能转换更受人们的欢迎。（图2-2）者是液力转换被应用于工业器械的主要原因。液力传动的能量转换

1、原动机（电机、内燃机）

2、机械能

3、泵

4、液力能

5、液压马达

6、机械能

7、负载 在流体静力能和流体动力能中单位里的质量变化

替代能量转换仅应用以下几方面，在液体静压力转换中相关的替代执行元件提供一个或数个工作室，他们恒定或尺寸可变。

泵的工作室在外部能量进入时伸长，马达是靠液力能，工作是伸长时液体流入，而收缩时实现流体流出。这些装置通常被称为能量转换装置。液体充满一个体积为V1的容器，在压力P1下所作的功W是压缩功W1和改变液体的功W2组成的。

为了分析这个过程，让我们假设一个活塞机构（图2-3（a）），它是有两个阀Z0、Z1和贮液器连接而成，表面压力为P0，贮

液器内部压力为 P1，活塞处于上部的X=X0处，Z0打开，液体充满体积为V0的汽缸，压力为 P0，现在关闭阀Z0，并且开始向下移动活塞，如果 Z1关闭，当活塞下降到 X=X1处时，液体体积由V0变为V1，此时压力升至P1，驱动活塞所作的外部功是（假设热量改变）

W1=-∫X1X0(P-P0)Adx=-∫V1V0(P-P0)dv

制动器的应用

YWW系列电力液压块式制动器是一种常闭、卧式安装的制动器，主要用于门座式起重机、斗轮堆取料机以及中大型塔式起重机回转机构的制动。

YKW系列电力液压块式制动器是一种常开、卧式安装的制动器，推动器为闭合（上闸）驱动装置，它通过脚踏开关控制，司机在司机室内可随意空。主要用于门座式起重机和塔式起重机等回转机构的减速制动。当需要在机构断电时（非工作状态）进行制动，可通过增设手动闭合（上闸）来实现。

RKW系列制动器为常开式、液压驱动、卧式安装的制动器。通过脚踏式液压泵进行控制，可实现随意制动。主要用于中小型门座式起重机和塔式起重机的回转机构。带有手动闭合（上闸）装置，在非工作状态下有需要时，可通过其进行维持制动。主要设计特点

联锁式退距均等装置，专利技术，在使用过程中可始终保持两侧瓦块制动衬浮贴制动轮的现象；设有瓦块自动随位装置。

主要摆动铰点均设有自动润滑轴承，传动效率高，寿命长，在使用过程中无需润滑。

设有可调式支撑装置，确保制动器工作灵活自如。

制动弹簧在方管内布置）（仅YWW产品）并在一侧设有标尺，用户可十分方便的读出制动力距值，免去测量和计算的麻烦。

制动衬垫为卡装式整体结构，更换十分方便，快捷，备有半金属（无石棉）硬质和半硬质，软质（含石棉）等不同材质的制动衬垫供用户选择。全部采用本公司新型推动器配套，动作灵敏，寿命长。

第四篇：有关机械的英文翻译

Robot is a type of mechantronics equipment which synthesizes the last research achievement of engine and precision engine, micro-electronics and computer, automation control and drive, sensor and message dispose and artificial intelligence and so on.With the development of economic and the demand for automation control, robot technology is developed quickly and all types of the robots products are come into being.The practicality use of robot products not only solves the problems which are difficult to operate for human being, but also advances the industrial automation program.Modern industrial robots are true marvels of engineering.A robot the size of a person can easily carry a load over one hundred pounds and move it very quickly with a repeatability of +/-0.006 inches.Furthermore these robots can do that 24 hours a day for years on end with no failures whatsoever.Through they are reprogrammable, in many applications(particularly those in the auto industry)they are programmed once and then repeat that ,exact same task for years.At present, the research and development of robot involves several kinds of technology and the robot system configuration is so complex that the cost at large is high which to a certain extent limit the robot abroad use.To development economic practicality and high reliability robot system will be value to robot social application and economy development.With the rapid progress with the control economy and expanding of the modern cities, the let of sewage is increasing quickly.With the development of modern technology and the enhancement of consciousness about environment reserve, more and more people realized the importance and urgent of sewage disposal.Active bacteria method is an effective technique for sewage diposal.The lacunaris plastic is an effective basement for active bacteria adhesion for sewage diposal.The abundance requirement for lacunaris plastic makes it is a consequent for the plastic producing with automation and high productivity.Therefore, it is very necessary to design a manipulator that can automatically fulfill the plastic holding.With the analysis of the problems in the design of the plastic holding manipulator and synthesizing the robot research and development condition in recent years, a economic scheme is concluded on the basis of the analysis of mechanical configuration, transform system, drive device and control system and guided by the idea of the characteristic and complex of mechanical configuration, electronic, software and hardware.In this article, the mechanical configuration combines the character of direction coordinate and the arthrosis coordinate which can improve the stability and operation flexibility of the system.The main function of the transmission mechanism is to transmit power to implement department and complete the necessary movement.In this transmission structure, the screw transmission mechanism transmits the rotary motion int linear motion.Worm gear can give vary transmission ratio.Both of the transmission mechanisms have a characteristic of compact structure.The design of drive system often is limited by the environment condition and the factor of cost and technical lever.＂The step motor can receive digital signal directly and has the ability to response outer environment immediately and has no accumulation error, which often is used in driving system.In this driving system, open-loop control system is composed of stepping motor, which can satisfy the demand not only for control precision but also for the target of economic and practicality.On this basis, the analysis of stepping motor in power calculating and style selecting is also given.The analysis of kinematics and dynamics for object holding manipulator is given in completing the design of mechanical structure and drive system.Kinematics analysis is the basis of path programming and track control.The positive and reverse analysis of manipulator gives the relationship between manipulator space and drive space in position and speed.The relationship between manipulator’s tip position and arthrosis angles is concluded by coordinate transform method.The geometry method is used in solving inverse kinematics problem and the result will provide theory evidence for control system.The function of dynamics is to get the relationship between the movement and force and the target is to satisfy the demand of real time control.In this chamfer, Newton-Euripides method is used in analysis dynamic problem of the cleaning robot and the arthrosis force and torque are given which provide the foundation for step motor selecting and structure dynamic optimal ting.Control system is the key and core part of the object holding manipulator system design which will direct effect the reliability and practicality of the robot system in the division of configuration and control function and also will effect or limit the development cost and cycle.With the demand of the PCL-839 card, the PC computer which has a tight structure and is easy to be extended is used as the principal computer cell and takes the function of system initialization, data operation and dispose, step motor drive and error diagnose and so on..At the same time, the configuration structure features, task principles and the position function with high precision of the control card PCL-839 are analyzed.Hardware is the matter foundation of the control.System and the software is the spirit of the control system.The target of the software is to combine all the parts in optimizing style and to improve the efficiency and reliability of the control system.The software design of the object holding manipulator control system is divided into several blocks such as system initialization block, data process block and error station detect and dispose model and so on.PCL-839 card can solve the communication between the main computer and the control cells and take the measure of reducing the influence of the outer signal to the control system.The start and stop frequency of the step motor is far lower than the maximum running frequency.In order to improve the efficiency of the step motor, the increase and decrease of the speed is must considered when the step motor running in high speed and start or stop with great acceleration.The increase and decrease of the motor’s speed can be controlled by the pulse frequency sent to the step motor drive with a rational method.This can be implemented either by hardware or by software.A step motor shift control method is proposed, which is simple to calculate, easy to realize and the theory means is straightforward.The motor’s acceleration can fit the torque-frequency curve properly with this method.And the amount of calculation load is less than the linear acceleration shift control method and the method which is based on the exponential rule to change speed.The method is tested by experiment.At last, the research content and the achievement are sum up and the problems and shortages in main the content are also listed.The development and application of robot in the future is expected.机器人是典型的机电一体化装置，它综合运用了机械与精密机械、微电子与计算机、自动控制与驱动、传感器与信息处理及人工智能等多学科的最新研究成果，随着经济的发展和各行各业对自动化程度要求的提高，机器人技术得到了迅速发展，出现了各种各样的机器人产品。现代工业机器人是人类真正的奇迹工程。一个像人那么大的机器人可以轻松地抬起超过一百磅并可以在误差+/-0.006英寸误差范围内重复的移动。更重要的是这些机器人可以每天24小时永不停止地工作。在许多应用中（特别是自动工业种）它们是通过编程控制的，但是它们一旦编程一次，便可以重复地做同一件工作多年。机器人产品的实用化，既解决了许多单靠人力难以解决的实际问题，又促进进了工业自动化的进程。

目前，由于机器人的研制和开发涉及多方面技术，系统结构复杂，开发和研制的成本普遍较高，在某种程度上限制了该项技术的广泛应用，因此，研制经济型、实用化、高可靠性机器人系统就有广泛的社会现实意义和经济价值。由于我国经济建设和城市化的快速发展，城市污水排放量增长很快，污水处理已经摆在人们的议事日程上来。随着科学技术的发展和人类知识水平的提高，人们越来越认识到污水处理的重要性和迫切性，科学家金额研究人员发现塑料制品在水中是用于污水处理的很有效的污泥菌群的附着体。塑料制品的大量需求，使得塑料制品生产的自动化和高效率要求成为经济发展的必然。本文结合塑料一次挤出成型机和塑料抓取机械手的研制过程种出现的问题，综述近几年机器人技术研究和发展的状况，在充分发挥机、电、软、硬件各自特点和优势互补的基础上，对物料抓取机械手整体机械结构、传动系统、驱动装置和控制系统进行了分析和设计，提出了一套经济型设计方案。采用直角坐标和关节坐标相结合的框架式机械结构形式，这种方式能够提高系统的稳定性和操作灵活性。传动装置的作用是将驱动原件的动力传递给机器人机械手相应的执行机构，以实现各种必要的运动，传动方式上采用结构紧凑、传都比大的涡轮蜗杆传动和将旋转运动转换为直线运动的螺旋传动。机械手驱动系统的设计往往受到作业环境条件的限制，同时也要考虑价格因素的影响以及能够达到的技术水平。由于步进电机能够直接接收数字量，响应速度快而且工作可靠并无累积误差，常用作数字控制系统驱动机构的动力元件，因此，在驱动装置中采用由步进电机构成的开环控制方式，这种方式既能满足控制精度的要求，又能达到经济性、实用化目的，在此基础上，对步进电机的功率计算及选型问题进行了分析。运动学分析是路径规划和轨迹控制的基础，对操作壁进行运动学正、逆问题的分析可以完成操作空间位置和速度向驱动空间的映射看，采用其次坐标变换法得到了操作臂末端位置和姿态随关节夹角之间的变换关系，采用几何法分析了操作臂的逆向运动学方程求解问题，对控制系统设计提供了理论依据。控制部分是整个物料抓取机械手系统设计关键和核心，它在结构和功能上的划分和实现直接关系到机器人系统的可靠性、实用性，也影响和制约机械手系统的研制成本和开发周期。在控制主机的选用上，采用结构紧凑、扩展功能强和可靠性高的PC工业控制计算机作为主机，配以PCL-839卡的结构特点、功能原理和其高定位功能等给予了分析。硬件是整个控制系统以及极限位置功能赖以存在的物质基础，软件则是计算机控制系统的神经中枢，软件设计的目的是以最优的方式将各部分功能有机结合起来，使系统具有较高的运行效率和较强的可靠性。在物料抓取机械手软件的设计上，采用的是模块化结构，分为系统初始化模块、数据处理模块和故障状态检测与处理等几部分。主控计算机和各控制单元之间全部由PCL-839卡联系，并且由该卡实现抗干扰等问题，减少外部信号对系统的影响。步进电机的启停频率远远小于其最高运行频率，为了提高工作效率发，需要步进电机高速运行并快速启停时，必须考虑它的升、降速控制问题。电机的升降速控制可以归结为以某种合理的力式控制发送到步进电机驱动器的脉冲频率，这可由硬件实现，也可由软件方法来实现。本文提出了一种算法简单、易于实现、理论意义明确的步进电机变速控制策略：定时器常量修改变速控制方案。该方法能使步进电机加速度与其力矩—频率曲线较好地拟合，从而提高变速效率。而且它的计算量比线性加速度变速和基于指数规律加速度的变速控制小得多。通过实验证明了该方法的有效性。最后，对论文主要研究内容和取得的技术成果进行了总结，提出了存在的问题和不足，同时对机器人技术的应用进行了展望。

第五篇：机械英文翻译

Shigley的机械工程设计

机械工程设计简介 基础知识部分

章节大纲

1-1设计 [4] 1-2机械工程设计 [5] 1-3阶段和设计过程的相互作用 1-4设计工具和资源

[8] 1-5设计工程师的职业责任 [10] 1-6标准和规范

[12] 1-7经济学

[12] 1-8安全和产品责任

[15] 1-9应力和强度

[15] 1-10不确定性

[16] 1-11设计因素和安全

[17] 1-12可靠性

[18] 1-13尺寸和公差

[19] 1-14单位

[21] 1-15计算和有效数字

[22] 1-16设计主题相互依赖

[23] 1-17输电案例研究规格

[24]

[5] 机械工程设计

机械设计是一个复杂的过程，需要很多技巧。广泛复杂的关系需要被细分为一系列简单的任务。复杂的设计过程在于要逐步按一定的规则去展现。

我们一般首先解决设计的本质，然后在机械工程设计中尤为如此。设计是有许多交互阶段的迭代过程。设计师需要许多资源的支持，包括许多来源丰富的信息和计算设计工具。设计师不仅要发展在自己领域的能力，他们也必须培养责任意识，并有专业的职业道德。

在设计过程中扮演比较重要角色规范和标准往往是经济性，安全性和产品责任的考虑。机械零件能否工作往往与应力和强度有关。无论是一个确定性的或者统计性的形式，不确定的因素在工程设计中无法排除，通常由设计因素和安全系数处理。后者，统计方法，能处理与设计的可靠性问题并且需要良好的统计数据。

在机械设计，其他考虑因素包括尺寸和公差，单元和计算。该书由四部分组成。第1部分，基础知识，首先解释一些差异和分析，并围绕引入一些基本概念来写的。它延续了3个章节，审查材料特性，应力分析，和刚度强度分析，对于这本书余下的部分这是必要的原理部分。

第2部分，预防失效，包括两章关于预防机械部件故障和为什么机器零件会发生故障，以及如何可以避免设计中失效的问题，所以我们用两章来回答这些问题，一是关于预防由于静载荷而发生的疲劳失效，而另一种预防由于载荷随时间变化和循环载荷的疲劳失效。

在第3部分，机械零件的设计，第1部分和第2部分的概念可用于分析，选择特定的机械元件，例如轴的设计，紧固件，焊接件，弹簧，滚动轴承，油膜轴承，齿轮，传动带，链，和钢丝绳。

第4部分，分析工具，介绍两个重要的方法来进行机械设计，有限元分析和统计分析。可以用这两种方法来选择和研究材料，实例1〜3说明了如何使用这些工具。

在书的最后有两个附录。附录A包含了许多有用的表遍布整本书的引用。附录B包括了怎样选尾章的问题。

1-1 设计

设计是为满足某一指定的需要或解决问题制定一个计划的具体问题。如果制定的计划具有现实意义，那么该产品必须是功能齐全，安全，可靠，有竞争力，可用，可制造，有市场性的。

设计是一个创新的，高度迭代的过程。

它也是一个决策的处理。有时决策只需要少量的信息，偶尔只有正确的信息数量，或用过量的部分矛盾信息。决定有时会做出试探性地用正确的预留调整随着越来越多的为人所知。有一点是，工程设计人员必须亲自参与决策，了解如何正确的解决问题。

设计是一个通信密集型活动，其中既有文字和图片的使用，又有书面和口头形式使用。工程师们进行有效的沟通并与许多学科的人工作。这些都是重要的技能，以及一个工程师的成功取决于它们。

一个设计师的个人资源包括创造力、交际能力，和解决问题技能与知识的技术和第一原则。工程工具（如数学，统计，计算机，图形和语言）被组合以产生一个计划，当进行时，会产生一种产品，是功能性的，安全，可靠，有竞争力，可用，可制造和销售，而不管是谁建造，或谁使用它。

1-2机械工程设计 机械工程师为能源生产和有关加工提供生产工具，使运输工具和技术自动化。技能和知识基础是广泛的。运用的基础形态是固体和液体，质量和动量运输，制造的力学过程，以及电气和信息论。机械工程设计涉及机械工程的所有学科。真正的问题抵制条块分割。一个简单的滑动轴承涉及流体流动，传热，摩擦，能源运输，材料选择，热处理，统计描述，等等。建筑物的环保控制。加热，通风和空调的考虑是足够的专门一些讲供暖，通风和空调的设计中，就好像它是独立的与机械工程设计截然不同。同样地，内燃机设计，涡轮机的设计，和喷气发动机的设计有时被认为是离散实体。在这里，字设计前述字句的领先字符串仅仅是一个产品描述符。同样，也有短语，如机械设计，机械元件设计，机器组件设计，系统设计和流体动力设计。所有的这些话是有点机械工程设计更有针对性的例子。他们都吸取知识的同一机构，类似组织，并要求类似的技能。

1-3阶段和设计过程的相互作用

什么是设计过程？它是如何开始的？请问工程师简单地坐到用一张白纸一张桌子，并记下一些想法？ 接下来发生什么？ 什么因素影响或控制了必须做出的决定？最后，请问该怎么让设计过程结束？

完整的设计过程中，从开始到结束，常被概述如图1-1。该过程开始于一个关于它的识别以及判定。许多次迭代之后，为满足需要该方法用这些计划的显现结束。根据设计任务的性质，一些设计阶段可以在整个产品生命周期中重复，从开始到结束。在接下来的几个小节中，我们将审查在设计这些步骤详细过程。

一般开始时需要一个鉴定的过程。认识需要和措辞需要往往构成一个具有高度创造性的行为，因为这种需要可能只有一个模糊的不满，一种不舒服的感觉，或者是感觉到了的东西是不正确的。通常情况下需要的是不明显的，识别可以由特定的恶劣环境或一组随机情况几乎同时出由噪音水平，通过在包装重量的变化，并通过轻微，但可察觉的变化现触法。例如，要做些什么食品包装机的需求可能会指示在包装或包裹的质量。图1-1

Identification of need

需要鉴定 Definition of problem

问题定义 Synthesis

合成 Analysis and optimization

分析与优化 Evaluation

评估 Presentation

介绍

还有就是需要的声明和定义之间有明显的区别的问题。的问题的定义是更具体的并且必须包括所有规格为对象，它是被设计。规格有输入和输出数量时，特征和对象必须占据的空间的尺寸，和所有这些量的限制。我们可以把被设计为对象在一个黑盒子。在这种情况下，我们必须指定框的输入和输出，他们的特点和局限性在一起。的规范定义了成本，在要制造号码，预期寿命，的范围内，操作温度，以及的可靠性。规定特性可以包括速度，饲料，温度限制最大范围，在该变量预期的变化，尺寸和重量限制等。

有迹象表明，导致无论是从设计师的特别是许多隐含的规格环境或从问题本身的性质。制造可用，具有某些植物的设施一起的过程，构成了上的设计师的自由的限制，并且因此是隐含的规格的一部分。它可以是一个小的植物，例如，不拥有冷作机械。知道了这一点，设计人员可能会选择其他金属加工的方法可以在植物中进行。可用的劳动技能和竞争态势也构成隐含的限制。凡是限制了设计师的自由选择的是一个制约因素。许多材料和尺寸都列在供应商的产品目录，例如，但这些都不是所有容易获得和短缺频频发生。此外，库存经济学要求制造商股票的最低的材料和尺寸数。一个规范的一个例子在二段中给出。1-17。这个例子是用于呈现整个动力传动的案例研究本文。

连接可能的系统元素的方案的合成所谓的概念或概念设计的发明。这是第一个也是最重要的步骤中合成的任务。各种计划必须提出，调查，并在建立metrics.1作为充实的计划进展来定量，分析必须被执行以评估系统的性能是否令人满意，如果满意，就如何它将执行。系统方案不这样做生存分析，修改，改进，或丢弃。这些潜在的优化以确定哪个的方案能够在最佳的性能。竞争机制进行比较，以便导致最具有竞争力的产品的路径可以被选择。图1-1显示了综合分析和优化是密切相关的。

我们已经注意到，我们强调，该设计是一个反复的过程，我们通过几个步骤进行，评估结果，然后返回到先前相的过程。因此，我们可以合成一个系统的几个组件，分析和对其进行优化，并返回到合成看到这这个系统其余部分有什么作用，例如，一个系统传输功率的设计需要注意个别组件（例如，齿轮，轴承，轴）的设计和选择。然而，这是常有的设计的情况，这些部件不是独立的。为了设计偏转轴的应力，有必要知道施加的力。如果力通过齿轮传递，有必要知道齿轮规格为了将确定的力传送到轴，但齿轮都具有一定的轴径，需要必要的轴径的知识。显然，粗略估计将需要了解实际的过程，炼油和迭代，直到最终的设计获得了对于每个令人满意单个组件以及用于整体设计规格。在整个文字，我们将详细阐述这一过程中产生的电力传输设计的案例研究。无论分析和优化要求我们建造或设计的抽象模型该系统会承认某种形式的数学分析的。我们把这些车型数学模型。在创建他们来说，这是我们的希望，我们可以找到一个会模拟真实物理系统非常好。如图8中所示。1-1，评价是总的设计过程的显著相。评估是一个成功的最终证明设计并通常涉及在实验室样机的测试。在这里，我们希望发现是否在设计确实满足了需求。它是可靠的？这将与同类产品争夺成功？是经济的制造和使用？是吗易于维护和调整？可获利从其销售或使用，制成？的可能性有多大它是导致产品责任诉讼？而且是保险容易和便宜获得？它是可能的召回将需要更换有缺陷的部件或系统？该项目的设计师或设计团队将需要解决工程无数和非工程的问题。

传达设计给他人是在设计的最后，是重要的介绍步骤处理。毫无疑问，许多伟大的设计，发明和创意作品已经失去了后人仅仅是因为创始人是无法或不愿好好解释一下自己的成就他人。演讲是一个销售的工作。工程师，呈现当新的解决方案的行政，管理或监督人员，正试图出售或向他们证明，他们的解决方案是一个更好的。除非能成功完成，花在获取解决方案的时间和精力已经在很大程度上浪费了。什么时候设计师卖一个新的想法，他们也卖自己。如果他们在多次中标销售理念，设计和新的解决方案来管理，就开始收到工资增加和促销活动;其实，这是任何人如何成功地在他或她的职业。

1这个主题一个很好的参考是由Stuart Pugh，总设计集成的方法介绍成功的产品工程，Addison-Wesley出版社，1991还提供了方Stuart Pugh法的说明在11.2节。8，大卫G.乌尔曼，机械设计流程，第三版，麦格劳2，说明了随着更精细的加工，制造成本的急剧增加，应该做公差减小处理。盈亏平衡点

有时会发生这样的情况，当2个或更多的设计方法相比，成本，两者之间的选择取决于一组条件，如生产数量，装配线的速度，或其他条件。然后发生了等于成本对应的点，称为盈亏平衡点。图1-2

成本与公差/加工过程。（摘自戴维·乌尔曼，该第三版，麦格劳-希尔，新纽约，2003年）图1-3

一个平衡点

作为一个例子，考虑一个特定的部分可以制造的情况每小时25个部件的速度在一个自动螺丝机或每小时10个零件上手动螺杆机。让我们假设，对于自动的设置时间是3小时和这两台机器的人工成本是每小时20美元，包括开销。图1-3是双方法成本与生产图。这个盈亏平衡点实例对应50个部分。如果所需的产量大于50部分，则自动机器使用。

成本测算

有很多方法获得相对成本的数字，使2个或更多的设计可以 大致比较。有些判断可能需要一定量的实例。例如，我们可以比较两个汽车的相对价值比较每磅重的美元成本。另一种比较成本的方法一种设计与另一个是简单地计算的数量的零件。设计有较小的零件数量可能会花费更少的成本。许多其他成本估计可以使用时，根据不同的应用，如面积，体积，马力，扭矩，容量，速度和各种性能比。

1-8安全及产品责任

严格责任概念及产品责任普遍在美国盛行。这一概念指出，一篇文章的制造企业对任何损害或损害承担责任这一结果是因为缺陷。而这并不重要，制造商是否知道关于这个缺陷，甚至可以知道它。例如，假设一篇文章制造，说，10年前。并且假设在那个时候这篇文章不能被认为有缺陷的基础上，所有的技术知识，然后可用。十年后，根据严格责任的概念，制造商仍然承担责任。因此，根据这一理念，原告只需证明该物品是缺陷和缺陷造成的损害或损害。制造商的疏忽 不需要证明。

预防产品责任的最佳途径是良好的工程分析设计，质量控制，综合测试程序。广告管理者经常会在保证产品的质量和销售方面做出承诺。这些陈述应该由工程人员认真审核，以消除过多的承诺，并插入适当的警告和使用说明。

1-9的压力和强度

许多产品的生存取决于设计师如何调整在关键位置的组件中的最大应力小于组件的强度。设计人员必须允许最大应力小于能保证安全的强度，使尽管有不确定性，失败是罕见的。应该侧重的是应力强度比较，在关键的（控制）的位置，我们经常寻找“在几何和使用条件的实际作用力。”强度是应力的幅度在该反应的东西，例如比例极限，0.2％偏置屈服，或断裂（见秒2-1）。在许多情况下，这样的事件表示在该功能丧失发生的应力水平。

强度是一种材料或一个机械部件的性能。一个元件的强度选择，处理，和材料的处理。例如，考虑一批弹簧。我们可以把一个强度与一个特定的弹簧当这个弹簧被引入到一台机器时，外部力被施加这导致在弹簧负载引起的应力，其大小依赖于它的几何形状和独立的材料及其加工。如果弹簧是 从机械地除去，由于外部势力的压力会回到零。但强度仍然是弹簧的特性之一。记住，然后，这种力量是一个部分的固有属性，一部分是因为有一个属性，因为使用一种特殊的材料和工艺。

各种金属加工和热处理过程，如锻造、轧制、和冷成形，导致强度的变化，从点到一个部分。这个上面提到的弹簧很有可能会有一种力量在外的线圈不同从内部的力量，因为春天已经形成了一个寒冷的绕组过程，双方可能不会被相同数量的变形。记住，因此，一个部分的强度值可能仅适用于一个特定的部分点或组点。

在这本书中，我们将使用大写字母S表示强度，拥有适当的标志来表示强度的类型。因此，SY是屈服强度，SU屈服极限，SSY剪切屈服强度和SE的持久强度。

按照公认的工程实践，我们将采用希腊字母σ（Sigma）和τ（TAU）指定的正应力和剪应力，分别。各种标会显示一些特殊的特性。例如，σ1是正应力，σY Y方向的正应力分量，和σR正常应径向方向分量。

应力是一个特定的点在一个物体上，这是一个函数的状态属性负载，几何，温度，加工工艺。在一个基本课程中材料力学，强调了荷载和几何关系，强调了一些热应力的讨论。然而，强调由于热处理，成型，组装等也很重要，有时被忽视。应力分析，回顾第3章的基本负荷状态和几何。

1-10不确定性

在机械设计中的不确定性比比皆是。关于压力和强度的不确定性的例子包括如下：

•材料的组成和变化对性能的影响。•在从一个地方到其它地方性质的变化。•加工的影响在本地，或附近，上属性。

•附近的组件，如焊件的影响和收缩应力状态下的配合。•对性能的形变热处理的影响。•强度和负荷分布。

•用来代表现实的数学模型的有效性。•应力集中的强度。

•时间对强度和几何形状的影响。•腐蚀的影响。•磨损的影响。•不确定因素的数量

工程师必须适应不确定性。不确定性总是伴随着变化。工程师必须关注材料特性，负载变化，制造保真度和数学的有效性。

用数学方法来解决不确定性。主要技术是确定性和随机性方法。确定性方法建立