机械设计毕业论文中英文资料外文翻译文献

(11) Drawings．Are standardized parts used? Are the tolerances realistic? Is the surface finish over-specified? Must the design conform to any standards?

(12) Ergonomics．Has the operator of the equipment been considered? Are the controls conveniently located to avoid operator fatigue? Are knobs，grab bars，hand wheels，levers，and dial calibrations of proper size to fit the average operator? 1．4 A general procedure of machinery design

Whatever design tasks the designers are expected to complete，they

always，consciously or unconsciously，follow the similar process which goes as follows：

(1)Studies of feasibility

After understanding the product functions，operational conditions，manufacturing constraints and key technologies，go on to uncover existing solutions to some similar problems so as to clarify the design tasks，understand the needs，present the major functional parameters and evaluate design tasks，proposal of design aims，and feasibility analysis．

(2) Conceptual design of configuration

According to the design of tasks and functional parameter，designs need to extensively search for various feasible configurations and alternatives．For

convenience，usually，the system can be analyzed comprehensively by decomposing it

into power sources，transmission and work mechanisms．

A great effort needs to be devoted to the analysis and synthesis of these different parts．For example，the power source may be selected from motor，engine and turbine．Each power source may have a range of power and kinematical parameters ．Similarly, power trains may have numerous options available，e．g．belts，chains，gears，worm gears and many other drives．Obviously selecting an appropriate configuration would guarantee the Success of the whole design and the quality of the products．To make a best possible

decision，an iterative process is normally required to select，analyze，compare and evaluate different configurations．At this stage，the goals involve sketching of configuration，determination of kinematical mechanisms，and evaluation of functional parameter(power and kinematics)． (3)Detailed technical design

Based on the design of configuration and parameters，a number of

assembly and component drawings will be completed to reflect the detailed

design including kinematics，power，strength，stiffness，dynamics，stability， fatigue and SO on．Consideration should also be given to manufacturing factors by presenting structural details，materials，and both geometric and dimensional tolerances．This part of work will also be carried out in a repeated process in drawings，calculation，evaluation and modification until a best possible design is achieved．The goal at this stage is to

complete assembly and component drawings，structural details，design calculations and detailed technical documentations． (4)Modification of design

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After the design is completed，a prototype is usually made for a more realistic physical assessment of the design quality．This will help correct any drawback or fault that may be overlooked or neglected during the design process．At this stage，the goal is to correct the design imperfection，test the potential manufacturing or assembly flaws and refine /improve design． 1．5 Contents and tasks of the course

The course Machinery Design will cover the following contents： (1)Preliminaries．the fundamental principles of machinery and

Components design，design theory，selection of materials，structure，friction ，wear and lubrication．

(2)Connection．sand．joints．thread．fasteners，keys，rivets，welds，bonds ．and adhesive and interference joints．

(3)Transmission．screws，chains，belts，gears，worms，bevel．gears And helical gears．

(4)Shaft．system．rolling—contact．bearings，sliding

bearings，clutches，couplings，shafts，axles and spindles． (5)Other part s．springs，housings and frame s．

The course centers on engineering design of mechanical components and is in a category of fundamental methodology and procedure．It is not feasible or realistic for the students to become involved in the detailed

design considerations associated with all machine components．Instead，the textbook has its main focus on some typical components and parts．However， the methodologies and procedures to be developed in this course can be extended to more design cases．For this reason，an emphasis will be laid on the methods and procedure s over the course so that the student s will gain a certain competence in applying these skills and knowledge to designing more mechanical components．

As a professional fundamental course，it will help students to acquire

a sol id knowledge of mechanical design and engineering awareness．More specifically，the course will help to develop the students’ competence in the following facets：

Competence of creative design and solving practical problem； Competence of team work as well as professional presentation and communications：

Competence of apprehending the design principles and

regulations，synthesizing the knowledge to develop new designs： Competence of engineering research as well as using design code s，handbooks，standards and references：

Competence of doing experiments to solve problem in the design of typical components：

Competence of understanding newly introduced technological as well as economic codes to update the knowledge of machinery design． It is worth noticing that the course will also integrate a number of

preceding relevant subjects at the university—level ，including

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mathematics ，physics，electronics，chemistry，solid mechanics，fluid mechanics，heat transfer，thermodynamics，computin9，and so forth．It will combine the knowledge about science and professional skills to solve some practical engineering problems，which will significantly advance students’ competence and enlarge their vision to the professional engineers．It should be pointed out that skills and experience could be acquired only by a great deal of practice——hour after monotonous hour of it． It is acknowledged universally that nothing worthwhile in life can be achieved without hard work，often tedious，dull and monotonous，and engineering is no exception．

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机械设计的基本原则

这个导言章节是对机械设计的一个纵览。第一它给出定义并且指出机械设计的重要角色，以及机械与其组成部分之间的关系．然后它给出了机械设计的概述作为一基础的课程和列出所有工程师都应该遵循的机械设计的一般程序．最后，它列出课程的目录和主要要达成的目标。 1.1个机械设计的角色

机械设计用来规划述所有的机械示意图。工程学本质上是利用现有的资源河自然法则为人类谋利。作为工程学的一个主要部分，机械设计在材料、力学、热、流量、控制、电子学和生产方面有一系列的原则。虽然许多高技术都采用计算机化和自动化，并且迅速的融入我们的日常生活，机器是各种不同的特殊工作不可缺少的，那些特殊工作对人类来说是非常难执行的或者是不可执行的。此外，机器可以明显的改良改良生产的效率和品质，效率和品质在现在竞争强烈的国际市场上起着决定性作用。

在现代的工业化的世界中，一个国家的财富和生活水平是与他们的设计和制造机械产品紧密相连的。可以断言，机械产品的设计和制造的提高能明显的促进一个国家的工业化总体水平。这些在设计和制造领域发展不好的国家，在国际市场中竞争力差。明显的，一些国家曾经是设计和制造业中的领头羊，直到七八十年代，到了九十年代他们后退并且失去了他们的领导地位。相反的，自从八十年代以后，国家正在快速地发展占据她在制造业中的位置并且在国际市场中担任一个越来越重要的角色。为了加速我国的工业化进程，有广泛知识和专长的高技术设计工程师是不可或缺的。那就是机械设计课程对学习机械的学生的重要的原因。机械设计的课程与科学和数学中背景科学有相当多的不同。对许多学生来说，它或许是他们用来解决相关实际问题的基本的专业工程课程。可以明确的是，这些解决办法一定可以明确的描绘对基础科学的一种理解，通常这样的理解可能不够充分，经验得来的知识或工程判断同样也被牵涉在内。此外，由于这么学科的专业性，大多数的设计问题可能没有一个正确的解决方式。然而，从所有可行的解决办法中确定一个更好的设计是可取的。 1.2机械和组成部分

一个技术发展水平机器可能包含所有的或部分机械、电力有关，控制、感应器，监听和加油子系统。就这些部分的功能来说，机器也可以看作是由动力、传动、实行和控制／处理零配件组成的。不管其复杂性，然而，其主要功能部分可以依然是机械系统。为了方便分析，机械系统能够分成运行一些特定任务的机械装置。机械装置可以进一步分成机械构件。在这种情况下，机械构件是机械的基础元素。

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