3吨叉车的液压系统设计【cad高清图纸和说明书全套】
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Mechanical Engineering EnglishLesson 1 Modern Manufacturing EngineeringAWhat Is Manufacturing Maybe youve never thought about it before, but it is all around you. It affects every part of your life. What is it? In this case, “it” is manufacturing. Actually “manufacturing” is not all around you. But manufactured products are. Look around you right now. Name some things you see that were manufactured. Chairs, notebooks, blue jeans, books, floor tile, chalkboards, light bulbs, pencils, eyeglassesnearlyeverything around you was manufactured.The manufacturing industry is important to our society. Its essential to our economy. An economy is a system for producing and distributing products and services. Many people work in manufacturing. They help produce products. And they buy products with the money they earn. The more products people buy, the more products are manufactured. And this allows more people to work. Manufacturing is also important to the economy in another way. A piece of material is worth more after its been changed into a useful product. Thats added value. Value is increased by the manufacturing process.B. Modern Manufacturing A manufacturing industry needs three basic types of resources: Material resources, Human resources, Capital resources. The elements of industry are seven key steps for organizing production: Research and Development, Production Tooling, Production Planning and Control, Quality Control, Personnel Management, Manufacturing, Marketing. R&D is the planning of new products, processes, or materials and the improvement of old skill. R&D is such a large, important part of the industrial world and requires many people with different talents. Production Tooling is the element of industry concerned with these tools. The PT obtains the tools, machines, and equipment needed to make a product. The most important parts of Production Planning and Control are routing, scheduling, dispatching, and plan layout. The machinery and equipment must be arranged so that production can take place smoothly, without wasted time and effort. Quality Control can be defined as those activities which prevent defective articles. In this way management tries to insure that a product will be acceptable to the buyer. Marketing is the process of getting products from those who make them to those who use them and it helps to deliver the right kinds of goods to us, in the right form and amount, at the time and price.Lesson 2 Mechanical Engineering Design Mechanical engineering design is a major segment of engineering, it deals with the conception, design, development, refinement, and application of machines and mechanical apparatus of all kinds. For many students, mechanical engineering design is one of their first professional engineering courses. Professional engineering is concerned with obtaining solutions to practical problems, and the engineers are able to devise better solutions to practical problems. The most problems in mechanical engineering design do not have a single right answer. Hence, modern mechanical engineers are able to produce distinctly better solutions to meet todays needs. The engineer must use the best available scientific understanding together with empirical information, good judgment. When considering a complete machine, the engineer invariably finds that the requirements and constraints of the various components are interrelated. The modern engineer has become increasingly concerned with the broader considerations of safety, ecology, and overall “quality of life.”Good designs require trying new ideas and being willing to take a certain amount of risk, knowing that if the new idea does not work the existing method can be reinstated. Thus a designer must have patience, since there is no assurance of success for the time and effort expanded. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated.New designs generally have “bugs” or unforeseen problems which must be worked out before the superior characteristics of the new design can be enjoyed. Thus there is a chance for a superior product, but only at higher risk. It should be emphasized that, if a design does not warrant radical new methods, such methods should not be applied merely for the sake of change.During the beginning stages of design, creativity should be allowed to flourish without a great number of constraints. Even though many impractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which is ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise.Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to administrative, management, or supervisory persons, is attempting to sell or to prove to them that this solution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted. 英文文献翻译学 生 姓 名: 学 院: 专业及班级: 学 号: 指导教师: 2011年 4月 25 日湖 南 农 业 大 学全日制普通本科生毕业设计 3吨叉车液压系统设计3 TON FORKLIFT TRUCK HYDRAULIC SYSTEM DESIGN学生姓名: 学 号: 年级专业及班级: 指导老师及职称: 学 院: 工学院湖南长沙提交日期:2013年5月湖南农业大学全日制普通本科生毕业设计诚 信 声 明本人郑重声明:所呈交的本科毕业设计是本人在指导老师的指导下,进行研究工作所取得的成果,成果不存在知识产权争议。除文中已经注明引用的内容外,本论文不含任何其他个人或集体已经发表或撰写过的作品成果。对本文的研究做出重要贡献的个人和集体在文中均作了明确的说明并表示了谢意。本人完全意识到本声明的法律结果由本人承担。 毕业设计作者签名: 年 月 日目 录摘要.1关键词.11前言.21.1课题背景21.2叉车发展概况42 液压元件62.1液压阀块简介62.2集成块的设计步骤83.1液压系统设计概述93.2液压系统设计113.2.1原理图113.2.2起升油缸最大工作压力及流量123.2.3求液压系统最大压力133.2.4液压泵站及液压泵的规格及选用133.2.5油泵功率及电机选择143.2.6选择换向阀153.2.7管道设计与管件的选择193.2.8液压油选取213.2.9滤油器及油箱选取213.2.10压力损失的计算223.2.11节流阀的设计234 液压站结构设计254.1液压站的结构型式254.2液压泵的安装方式254.3液压油箱的设计274.3.1液压油箱有效容积的确定274.3.2液压油箱的结构设计274.4液压泵结构设计的注意事项285 倾斜机构设计计算285.1倾斜机构设计概述295.2倾斜机构设计295.2.1倾斜油缸受力分析及负荷计算305.2.2计算倾斜油缸缸径和活塞杆直径305.2.3计算油缸行程305.2.4计算油缸作用时间315.2.5稳定性校核31 5.2.6油缸壁厚的计算325.2.7活塞杆强度计算335.2.8缸体螺纹连接计算335.2.9 缸底厚度及缸底的焊缝强度计算33结论34参考文献35
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