最终毕业设计

绪 论 第一章1.1 胎带机的构成及其工作原理胎带机的主体结构由底盘、伸缩皮带机、回转机构、变幅机构和活动配重等几大部分组成,伸缩皮带机是整机的核心工作部件.伸缩皮带机由两级伸缩臂架、伸缩驱动装置以及滚筒、托辊、输送带等组成,其中最关键的就是由伸缩臂架和伸缩驱动装置组成的伸缩机构. 两级伸缩臂架由套装在一起的三节臂架组成,最外层的基础节臂架尾部和底盘的回转机构、变幅机构分别铰接,固定于底盘上;内层的两节臂架可如拉杆天线一般自由伸出和缩回,改变输送机的输送距离,从而改变施工半径.1.2胎带机的优点胎带机的主体结构中伸缩皮带机是整机的。核心工作部件，借助伸缩机构其输送距离可在一定范围内连续改变。其机架后部与回转机构、变幅液压缸分别铰接，在回转机构、变幅机构的配合下，伸缩皮带机可在水平360。范围内回转，垂直方向上可在一1O。 +30。范围内连续改变输送倾角，动作灵活，作业范围大，适应性强1.3胎带机的结构特点1.结构简单。 胎带机仅有十多种部件，能够进行标准化生产，并可按照需要进行组合装配，结构十分简单。2.输送量大。运量可从每小时几公斤到几千吨，而且是连续不间断运送，这是火车、汽车运输望尘莫及的。3.运距长。单机长度可达十几公里一条，在国外已十分普及，中间无需任何转载点。德国单机60公里一条已经出现。越野的胎带机常使用中间摩擦驱动方式，使输送长度不受输送带强度的限制。4.除转载机与机尾有一搭接长度可供工作面快速推进外，通过收放胶带装置和储带装置也可使机身得到伸长和缩短，从而能有效地提高顺槽运输能力，加快回采和掘进速度。5.可靠性高。由于结构简单，运动部件自重轻，只要输送带不被撕破，寿命可长达十年之久，而金属结构部件，只要防锈好，几十年也不坏。6.营运费低廉。胎带机的磨损件仅为托辊和滚筒，输送带寿命长，自动化程度高，使用人员很少，消耗的机油和电力也很少。7.非固定部分的机身，采用无螺栓连接的快速可换支架，结构简单，拆卸方便，劳动强度低，操作时间短。设置在机身固定部分的胶带张紧1.4胎带机的其他系统组成上料系统主要由电动滚筒、输送带、上下托辊、张紧装置、清扫器（含空程清扫器）、防偏装置、金属结构以及电气控制系统等组成。上车系统主要由活动配重、转台、驾驶室、机棚和防护罩等组成。底盘选用徐工集团RT60越野轮胎起重机的底盘。额定起重量60t，底盘自重约30t。该底盘采用四轮驱动、全轮转向，采用原装进口康明斯电控发动机、自动变速箱、KESSLER车桥、德国力士乐专业配套开发的液压系统、CAN总线控制系统、故障诊断和安全报警装置，性能安全可靠。 1.5胎带机的研究目的及意义胎带机是使用最普通的一种输送机，其基本结构是在水平或倾斜的长机架两端装有输送带滚筒，在滚筒上的无接缝环形输送带连续地朝一个方向移动，货物放在带上输送。胎带机与其他类型的输送机相比，具有优良的性能14，在连续装载的情况下能连续运输，生产率高， 运行平稳可靠，输送连续均匀，工作过程中噪声小，结构简单，能量 消耗小，运行维护费用低，维修方便，易于实现自动控制及远程操作等优点。连续输送机是物料搬运机械的重要组成部分，带式输送机是连续输送机中效率高、使用最普遍的一种机型，带式输送机可以大大降低人力劳动强度，提高生产机械化水平，目前已经被广泛应用于采矿、冶金、电站建设工地、港口以及工业企业内部流水生产线上。在大型露天矿的作业中，带式输送机己成为不可缺少的输送设备。露天开采具有产能大、生产安全、复耕容易、绿色环保等诸多优点，因此国家大力提倡大型露天矿山建设。大型露天矿生产成本和效益主要取决于露天矿山成套装备的水平，而移置式带式输送机是成套设备设计研发中的关键设备之一，它可在不拆卸机械和电气部件的前提下，随着每次开采循环，在较短的时间内使整机移置到新的工作面。 带式输送机是散状物料实现远距离运输的高速度、自动化、连续性作业的理想设备,已广泛应用于电力、冶金、化工、煤炭、矿山、港口和粮食等许多部门。随着工业的需求,带式输送机向长距离、高速度、大运量、大功率等方向发展,带式输送机的动力学问题也越来越多。这就需要系统研究带式输送机的动态特性,实现在设计阶段预测和优化输送机的性能,从而使带式输送机在经济上更加合理、在技术上更加可靠。了结大型带式输送机的发展,对目前国内外的研究状况进行了分析,系统研究大型带输送机的动态特性是提高我国带式输送机设计水平及在国际市场的竞争能力的关键所在胎带机可用于水平和倾斜运输。沿倾斜使用的角度，依所运物料性质的不同和输送带表面形状不同而异。用普通光面输送带运原煤，向上运输的倾角可达18；向下运输的倾角可达151.6 胎带机的应用及发展胎带机是煤矿最理想的高效连续运输设备，与其他运输设备（如机车类）相比，具有输送距离长、运量大、连续输送等优点，而且运行可靠，易于实现自动化和集中化控制，尤其对高产高效矿井，带式输送机已成为煤矿开采机电一体化技术与装备的关键设备。带式输送机主要特点是机身可以很方便的伸缩，设有储带仓，机尾可随采煤工作面的推进伸长或缩短，结构紧凑，可不设基础，直接在巷道底板上铺设，机架轻巧，拆装十分方便。当输送能力和运距较大时，可配中间驱动装置来满足要求。根据输送工艺的要求，可以单机输送，也可多机组合成水平或倾斜的运输系统来输送物料。胎带机广泛地应用在冶金、煤炭、交通、水电、化工等部门，是因为它具有输送量大、结构简单、维修方便、成本低、通用性强等优点。胎带机还应用于建材、电力、轻工、粮食、港口、船舶等部门。近年来,国内外带式输送机又有了很大发展,大型化、大倾角和可弯曲成为其主要的发展方向,其运输物料的粒径也越来越大。运输土石料上坝是土石坝施工中的主要环节,从20世纪5060年代起,在国内外土石坝施工中,开始采用大型带式输送机代替汽车、铁路进行长距离运输和直接运输物料上坝技术优势首先是它运行可靠。在许多需要连续运行的重要的生产单位，如发电厂煤的输送，钢铁厂和水泥厂散状物料的输送，以及港口内船舶装卸等均采用胎带机。如在这些场合停机，其损失是巨大的。必要时，胎带机可以一班接一班地连续工作。胎带机消耗低。由于物料与输送带几乎无相对移动，不仅使运行阻力小（约为刮板输送机的1/3-1/5），而且对货载的磨损和破碎均小，生产高。这些均有利于降低生产成本。胎带机的输送线路适应性强又灵活。线路长度根据需要而定短则几米，长可达10km以上。可以安装在小型隧道内，也可以架设在地面交通混乱和危险地区的上空。根据工艺流程的要求，胎带机能非常灵活地从一点或多点受料也可以向多点或几个区段卸料。当同时在几个点向输送带上加料（如选煤厂煤仓下的输送机）或沿胎带机长度方向上的任一点通过均匀给料设备向输送带给料时，胎带机就成为一条主要输送干线。胎带机可以在贮煤场料堆下面的巷道里取料，需要时，还能把各堆不同的物料进行混合。物料可简单地从输送机头部卸出，也可通过犁式卸料器或移动卸料车在输送带长度方向的任一点卸料。 第二章布料臂架伸缩机构的设计计算 主要技术参数不同型号胎带机的设计技术参数有一定变化，主要技术参数范围如下：最大输送能力n13h 200250最大布料半径m 4061最小布料半径m 18226最大倾角 o) 2530最小倾角(。) 10输送带宽度mm 500600输送机带速(ms) 34输送机驱动功率kW 45 475一、 驱动功率计算在整个伸缩过程中，钢丝绳的张力主要用于克服各种运动的摩擦力以及臂架、托轨、胶带、漏斗、溜管等的自重下滑分力（倾斜运输时），而这些力又都随着倾角、伸缩行程的改变而变化，所以应该按最不利工况计算出最大驱动力和驱动功率，据此设计驱动装置，选取钢丝绳型号等。臂架伸缩驱动装置如图所示。臂架伸缩机构中，驱动功率最大的工况为：臂架全伸，且处于30仰角；此时下滑分力最大，因此驱动力和驱动功率应按此工况计算。用下式确定驱动滚筒处钢丝绳的驱动力：式中: 、绕入点和绕出点钢丝绳张力（N）；、分别是中间节臂架和前臂架移动部分质量（kg）；、分别是中间臂架和前臂架输送带上物料质量（kg）；前臂架前端漏斗、溜管等的质量；中间节臂架和基础节臂架之间的摩擦力（N）；前臂架与中间节臂架之间的摩擦力（N）；滑轮组机械效率。中支架驱动滚筒轴功率计算公式： 式中：驱动滚筒轴功率（kW）； 最大伸缩速度（m/s）；驱动滚筒机械效率。由已知条件及查阅相关参数，得到以下数据：中间臂装配体总重：；前臂装配体总重： ;聚四氟乙烯与钢材静摩擦系数 ；滑轮组机械效率：倍率m=8时，；驱动滚筒效率 ；设计最大伸缩速度 ；记漏斗及溜管等的质量；取输送带上物料的质量为50kg/m，根据输送带在中间臂架与前臂架上的长度分别约为14m和18m，可以得出中间臂架与前臂架托辊上输送带上物料的重量分别为：； 臂架行至最大行程，变幅角度为时臂架间的滑道支反力：中间臂架与基础臂架间的支反力 (kN)前臂架与中间臂架间的支反力 (kN)中间节臂架和基础臂间的滑道摩擦力：(kN)前臂架与中间臂间的滑道摩擦力：(kN)则按最不利工况计算驱动滚动处钢丝绳驱动力为： 二、 选择液压马达等驱动装置 由以上驱动滚筒的驱动力为来计算，驱动滚筒所需要的扭矩为：式中：驱动滚筒的底径，； 钢丝绳直径，。滚筒的转速为：式中，滑轮组的倍率，； 中间臂架的伸缩速度，；卷筒用液压马达和行星减速器组成的传动机构来驱动。一方面要满足卷筒的转速转矩要求，另一方面，也要满足液压马达的转速和转矩的要求。考虑到原来起升马达为A6V80（变量马达），现在的臂架伸缩没有调速要求，故选择定量马达。取马达的转速为, 则马达的排量为：所选马达的排量为56mL/r。实际的转速为：减速器的传动比为：所选取减速器的传动比为54。减速器型号为GFB17W2B54A2FE56WV，最大输出扭矩17000，重量为90kg。液压马达（A2FE56WV）的公称压力为40Mpa，尖峰压力45Mpa，公称扭矩为。液压马达的额定输出功率为：臂架伸缩液压马达的实际工作压力为：式中：滚筒的扭矩，;减速器的传动比，;液压马达的排量，;液压马达的机械效率，取;减速器的机械效率，取。所以, 臂架伸缩液压马达的实际工作压力为：液压马达的实际输出功率：滚筒实际的转速为：伸缩机构的平移速度为：选用行星齿轮减速机，型号为GFB17W2B54A2FE56WV。三、选择钢丝绳参照起重机械设计手册，可知起重机伸缩机构工作级别一般选取M4(最小安全系数4.5), 按高一级别选择，公称抗拉强度1550Mpa时，选择系数,钢丝绳直径为：S为钢丝绳工作的最大静拉力，由以上计算得S=F=19.7kN所以：选取钢丝绳直径由机械设计手册，选择钢丝绳规格为：16钢丝绳6W（19）型，抗拉强度 1550Mpa。安全计算：在钢丝绳工作最大静拉力下，破断拉力： 式中：钢丝绳折减系数，查得取为1；安全系数，按伸缩机构工作级别高一级别取为5。查得对应于公称抗拉强度为1570Mpa和1670Mpa的纤维芯钢丝绳的最小破断力分别为132kN和141kN，满足要求。四、驱动滚筒及被动滚筒组件设计计算滚筒是带式输送机的重要部件，按在输送机中所起的作用滚筒可分为传动滚筒和改向滚筒两大类。传动滚筒的作用是将驱动装置提供的转矩传到输送带上，改向滚筒包括用于输送带在输送机端部的改向、增加传动滚筒包角的导向滚筒、拉紧滚筒是用于拉紧装置的导向滚筒。改向滚筒不承担转矩，结构比较简单。传动滚筒和驱动装置相连，是带式输送机最重要的部件，驱动功率的大小往往取决于传动滚筒表面同输送带之间的摩擦系数和输送带在该滚筒上的包角18。按驱动方式分，传动滚筒有：1、人字形滚筒。用钢板卷圆焊接而成，中间部分筒径大于两边筒径约几毫米，目的是防止输送带跑偏。2、片式滚筒。滚筒由许多叶片组成，目的是便于清洁输送带，此类滚筒又称为自清扫滚筒。如果将叶片改为圆钢棒，称为棒式滚筒。自然也可以将圆柱形钢壳上开上横槽，也可以起到自清扫作用，此类滚筒称为格栅滚筒。3、槽胶面滚筒。滚筒的护面开上菱形、人字形、直线形、环形、梯形则分别称为菱形护面、人字形护面、直线形护面、环形护面、梯形护面等各种护面形状的滚筒，其目的是增大摩擦系数和便于排除黏着物料。传动滚筒护面常选用菱形和人字形。本设计选用菱形胶面滚筒。 （一）卷筒底径的计算按照卷筒计算卷绕直径，参考机械设计手册：卷筒名义直径为：式中：钢丝绳直径，；与机构工作级别和钢丝绳结构有关的系数，由系数表中查取，起重机伸缩机构工作级别一般取M4，取高一级别，对应查表h取值18。所以，卷筒底径为：取滚筒底径为315mm。驱动滚筒与被动滚筒的结构形式如下图所示，考虑到其在臂架上的安装要求，并满足驱动滚筒与减速机的连接以及驱动滚筒绳槽与被动滚筒绳槽在竖直方向上对齐，取驱动滚筒的设计长度为，被动滚筒的设计长度为。因为所选减速机为壳转减速机，减速器安装在驱动滚筒的内部，滚筒壁厚受到限制，最大滚筒壁厚为=12.5mm。驱动滚筒与被动滚筒的槽型依据钢丝绳的直径选取，如图 考虑结构紧凑的要求，取驱动滚筒与被动滚筒的中心距，此时钢丝绳在绳槽里的偏角为：式中，p绳槽节距，对应钢丝绳直径为16mm的卷筒，其加深槽形的节距；（二）滚筒强度校核：当L3D时，只计算压应力即可，滚筒的最大压应力出现在筒壁的内表面，压应力按下式计算为：式中：钢丝绳的最大静拉力（N）；滚筒的壁厚（mm）；绳槽节距（mm）；应力减少系数，一般取；多层卷绕系数，单层卷绕时。驱动滚筒与被动滚筒的铸造材料选为铸钢（ZG45）, ，满足强度要求。滚筒与轴之间采用键联接，一端用轴肩定位，另一端采用过盈配合，由于部件比较大，所以可以固定住。在主滚筒上覆盖胶用以增加滚筒与皮带之间的摩擦系数，无缝钢管与辐板之间采用焊接的方式。滚筒包胶的主要优点就是表面摩擦系数大，包胶是在光面钢制滚筒表面上用冷粘或硫化一层橡胶。本设计传动滚筒选用菱形（网纹）包胶滚筒。这种滚筒没有方向性，滚筒可正反转，对于可逆运输送机采用菱形滚筒比较适合短轴五、主动滑轮及被动滑轮组件设计计算（一）滑轮底径计算 滑轮的最小卷绕直径：式中：按钢丝绳中心计算的滑轮卷绕直径（mm）；钢丝绳直径，；与工作机构有关的系数，伸缩机构中，伸出用滑轮；缩回用滑轮。可得两种滑轮的最小卷绕直径：；为臂架伸缩机构中竖放滑轮及前臂架上横放滑轮的最小卷绕直径；为臂架伸缩机构中横放滑轮（除前臂架上外）的最小卷绕直径，该部分滑轮主要是在臂架缩回时起主要作用以及联接辅助钢丝绳，承受负载相对较小，可选系数的缩回用滑轮。两种滑轮分别记为滑轮1与滑轮2，则两种滑轮底径分别为：；圆整取：； 适用于16mm钢丝绳的滑轮底径对应的轴径：底径为190mm的滑轮对应轴径3045mm；底径为240mm的滑轮对应轴径3560。可选取最大值，则滑轮1与滑轮2的轴径分别取45mm与60mm。滑轮槽型具体尺寸，对应于钢丝绳的直径，在标准中选取。起重机械用铸造滑轮有六种型式，且都以标准化。计算滑动轴承的线速度：线速度，由于滑轮转速很低，实际转速,不必采用带滚动轴承的滑轮，选用F型的带滑动轴承的滑轮, 选用铸造滑轮，材料选用铸钢（ZG45）。根据标准汇编（起重机械卷）中相关设计规范，滑轮型号标记为滑轮F16190-45 JB/T9005.9-1999滑轮F16240-60 JB/T9005.9-1999（二）滑动轴承的校核滑动轴承选用的是锡合金，其许用值分别为，按承受载荷计算：式中：许用压强（Mpa）；许用值（Mpam/s）；许用圆周速度（m/s）；d、B轴的直径和工作宽度（mm）；n轴的转速（r/min）。 2.2 输送量可伸缩带式输送机的运输能力，决定于输送带上所装运的物料的断面积，输送带的运行速度及输送机的倾角，因为在倾斜的输送机上物料的堆积面积小。可伸缩带式输送机属于连续运行的运输机械，对于均匀、连续装载时，其运输能力为: 式中 -运输能力，； -单位长度上所装物料的质量，； -物料的运行速度，。由 得 式中 -在运行的输送带上，物料的最大横截面积，； -物料的堆积密度，。可伸缩带式输送机属连续运行式的运输机械，其运输能力按公式（2-3）计算。考虑到输送带在沿倾斜方向运行时，物料在输送带上的堆积面将减小。因此，计算带式输送机的最大运输能力时，应在工式（2-3）中乘一个倾斜系数，可知可伸缩带式输送机的最大运输能力用下式计算：=3.6 式中 -运输能力，； -在运行的输送带上，物料的最大堆积横截面积，； -物料的堆积密度，； -物料的运行速度，； -输送机的倾斜系数。六 键的强度校核1.滚筒轮毂处键的强度校核查机械设计手册表5-3-19选A型平键32120；由于是平键，所以工作面的挤压校核 式中 -键、轴、轮毂三者中最弱材料的许用压力，； -转矩，；-轴的直径，；-键与轮毂的接触高度，对于平键；-键的工作长度,；-键的宽度，；-键连接的许用挤压应力及许用挤压压强，；查机械设计手册表5-3-1得=所以 所以 由于，所以满足要求 参考文献1巩云鹏、田万禄等主编机械设计课程设计沈阳：东北大学出版社20002孙志礼，冷兴聚，魏严刚等主编机械设计.沈阳：东北大学出版社20003刘鸿文主编材料力学.北京：高等教育出版社19914哈尔滨工业大学理论力学教研组编理论力学.北京：高等教育出版社19975大连理工大学工程画教研室编机械制图.北京：高等教育出版社19936孙桓，陈作模主编机械原理.北京：高等教育出版社20007高泽远，王金主编机械设计基础课程设计.沈阳：东北工学院出版社19878喻子建，张磊、邵伟平、喻子建主编.机械设计习题与解题分析.沈阳：东北大学出版社20009张玉，刘平主编几何量公差与测量技术沈阳：东北大学出版社1999结 论胎带机凭借结构简单、便于维护、能耗较小、使用成本低的优点成为流水生产线作业中不可缺少的物流输送设备。皮带输送机是一种输送量大,运行费用低,使用范围广的输送设备,该机适用于输送散状物料或成件物体,根据输送工艺的要求可单机输送,也可多台或与其它输送设备组成水平或倾斜输送系统。本文设计了胎带机的伸缩机构。我们可以看出胎带机的优点为输送带是胎带机输送机重要部件之一，它既是承载件，又是传力件。在带式输送机运转过程中，输送带受各种大小和性质不同的载荷作用，处在极其复杂的应力状态下。正因为如此导致了胎带机的缺点变为的缺点胶带易受磨损，坡度不能太大，摩擦力大，设备费用较大。 随着计算机与各种经济的发展，未来在胎带机的领域有望实现短距离低成本的运输工程。致谢本论文是在韩林山老师的严格要求和精心指导下完成的，在完成论文的每一步中都凝聚着他的汗水和心血。韩老师学识渊博, 对待学生和蔼可亲，对我们的问题十分耐心的讲解，他的言行让人敬佩。为我们营造了一种良好的学习氛围，让我们在设计的过程中少走了很多的弯路。在设计过程中还得到了姚林晓老师的帮助，在此我向以上老师致以崇高的敬意和忠心的感谢！同时我也要感谢李金星，王吉涛等同学的帮助，感谢他们在论文工作过程中提出的建议和帮助，通过这次设计我接触到了很多课本上没有的知识，开阔了我的视野，再次感谢帮助我的老师和同学们。 附录 外文翻译Machine design theory machine design is through designs the new product or improves the old product to meet the human need the application technical science. It involves the project technology each domain, mainly studies the product the size, the shape and the detailed structure basic idea, but also must study the product the personnel which in aspect the and so on manufacture, sale and use question. Carries on each kind of machine design work to be usually called designs the personnel or machine design engineer. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, materials mechanics and machine manufacture technology has the deep elementary knowledge. If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of product Must regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly. A good design personnel should dare to propose the new idea,moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, because spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea. Newly designs itself can have the question occurrence which many flaws and has not been able to expect, only has after these flaws and the question are solved, can manifest new goods come into the market the product superiority. Therefore, a performance superior product is born at the same time, also is following a higher risk. Should emphasize, if designs itself does not request to use the brand-new method, is not unnecessary merely for the goal which transform to use the new method. In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts. Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on. In order to carry on the effective exchange, needs to solve the following problem: (1) designs whether this product truly does need for the people? Whether there is competitive ability (2) does this product compare with other companies existing similar products? (3) produces this kind of product is whether economical? (4) product service is whether convenient? (5) product whether there is sale? Whether may gain? Only has the time to be able to produce the correct answer to above question. But, the product design, the manufacture and the sale only can in carry on to the above question preliminary affirmation answer foundation in. Project engineer also should through the detail drawing and the assembly drawing, carries on the consultation together with the branch of manufacture to the finally design proposal. Possibly can request to some components size or the common difference makes some changes, causes the components the production to change easily. But, in the project change must have to pass through designs the personnel to authorize, guaranteed cannot damage the product the function. Sometimes, when in front of product assembly or in the packing foreign shipment experiment only then discovers in the design some kind of flaw. These instances exactly showed the design is a dynamic process. Always has a better method to complete the design work, designs the personnel to be supposed unceasingly diligently, seeks these better method Recent year, the engineerig material choice already appeared importantly. In addition, the choice process should be to the material continuously the unceasing again appraisal process. The new material unceasingly appears, but some original materials can obtain the quantity possibly can reduce. The environmental pollution, material recycling aspect and so on use, workers health and security frequently can attach the new limiting condition to the choice of material. In order to reduce the weight or saves the energy, possibly can request the use different material. Comes 3 from domestic and international competition, to product service maintenance convenience request enhancement and customers aspect the and so on feedback pressure, can urge the people to carry on to the material reappraises. Because the material does not select when created the product responsibility lawsuit, has already had the profound influence. In addition, the material and between the material processing interdependence is already known by the people clearly. Therefore, in order to can and guarantees the quality in the reasonable cost under the premise to obtain satisfaction the result, project engineer makes engineers all to have earnestly carefully to choose, the determination and the use material. Makes any product the first step of work all is designs. Designs usually may divide into several explicit stages: (a) preliminary design; (b) functional design; (c) production design. In the preliminary design stage, the designer emphatically considered the product should have function. Usually must conceive and consider several plans, then decided this kind of thought is whether feasible; If is feasible, then should makes the further improvement to or several plans. In this stage, the question which only must consider about the choice of material is: Whether has the performance to conform to the request material to be possible to supply the choice; If no, whether has a bigger assurance all permits in the cost and the time in the limit develops one kind of new material. In the functional design and the engineering design stage, needs to make a practical feasible design. Must draw up the quite complete blueprint in this stage, chooses and determines each kind of components the material. Usually must make the prototype or the working model, and carries on the experiment to it, the appraisal product function, the reliability, the outward appearance and the service maintenance and so on. Although this kind of experiment possibly can indicate, enters in the product to the production base in front of, should replace certain materials, but, absolutely cannot this point take not earnestly chooses the material the excuse. Should unify the product the function, earnestly carefully considers the product the outward appearance, the cost and the reliability. Has the achievement very much the company when manufacture all prototypes, selects the material should the material which uses with its production in be same, and uses the similar manufacture technology as far as possible. Like this has the advantage very much to the company. The function complete prototype if cannot act according to the anticipated sales volume economically to make, or is prototypical and the official production installment has in the quality and the reliable aspect is very greatly different, then this kind of prototype does not have the great value. Project engineer is best can completely complete the material in this stage the analysis, the choice and the determination work, but is not remains it to the production design stage does. Because, is carries on in the production design stage material replacement by other people, these people are inferior to project engineer to the product all functions understanding. In the production design stage, is should completely determine with the material related main question the material, causes them to adapt with the existing equipment, can use the existing equipment economically to carry on the processing, moreover the material quantity can quite be easy to guarantee the supply.1Research Status Development of mechanical design theory and methods and future trends1.1Development of mechanical design theory and method ofDesign is a complex human thought process , creative work, is one of the basic activities of human transformation of nature .In the long history of human understanding of the world and transform the world ,Has been engaged in the design activity .In a sense,PeopleOngoing class innovative design activities to promote the progress of human civilization.From the perspective of the development of design methods , design methods development has gone through four stages as follows .(1)Intuitive design phaseThe design is an intuition of ancient design,It is time to get inspiration from natural phenomena ,Or intuitive sense of their ownSense to design tools.Design exists in the minds of craftsmen ,The expression can not be recorded ,Product is relatively simpleThe . Intuitive design stage has experienced a long period of time in human history ,17Century ago,