3281 气门摇杆轴支座加工工艺及关键工装设计

3281 气门摇杆轴支座加工工艺及关键工装设计,气门,摇杆,支座,加工,工艺,关键,症结,枢纽,工装,设计 南京理工大学泰州科技学院本科生毕业设计（论文）选题、审题表姓 名 王栓虎系部 机械工程系指导教师专业技术职 务 副教授课题名称 气门摇臂轴支座加工工艺及关键工序工装设计适用专业 机械工程及自动化A B C D E A B C D课题性质 课题来源 大 适中 小 难 适中 易课题预计工作量大小 课题预计难易程度 课题简介气门摇臂轴支座是某企业产品的主要零件之一。本课题要求根据企业生产需要和气门摇臂轴支座零件的加工要求，首先完成零件的加工工艺规程设计，在此基础之上，选择其关键工序之一进行专用夹具及加工用组合机床设计，并完成必要的设计计算。生产纲领 50000 件/年课题应完成的任务和对学生的要求论文工作要求：1气门摇臂轴支座加工工艺路线的设计与分析（至少有两种工艺方案的比较）2关键工序的专用夹具设计，包括装配图及主要零件图3关键工序加工用组合机床设计，包括“三图一卡”4详细的设计计算与分析条件要求：具有较好的结构设计能力，熟悉 CAD 设计软件，最好自己有计算机。所在专业审定意见：专业负责人(签名)： 年 月 日本课题由 冯 俊 同学选定，学号： 05010115 注：1该表由指导教师填写，经所在专业负责人签名后生效，作为该专业学生毕业设计（论文）选题使用；2有关内容的填写见背面的填表说明，并在表中相应栏内打“” ；3课题一旦被学生选定，此表须放在学生“毕业设计（论文）资料袋”中存档。南京理工大学泰州科技学院毕业设计(论文)前期工作材料学 生 姓 名 : 冯俊 学 号： 05010115系 部 : 机械工程系专 业 : 机械工程及自动化设计 (论 文 )题 目 : 气门摇臂轴支座加工工艺及关键工序工装设计指 导 教 师 : 王栓虎 副教授(姓 名) (专业技术职务)材 料 目 录序号 名 称 数量 备 注1 毕业设计(论文)选题、审题表 12 毕业设计(论文)任务书 13 毕业设计(论文)开题报告含文献综述 14 毕业设计(论文)外文资料翻译含原文 15 毕业设计（论文）中期检查表 12009 年 5 月 南京理工大学泰州科技学院毕业设计（论文）任务书系 部 ： 机械工程系专 业 ： 机械工程及自动化学 生 姓 名： 冯俊学 号：05010115设 计 (论 文 )题 目 ： 气门摇杆轴支座加工工艺及关键工序工装设计起 迄 日 期 : 2008 年 3月 09 日 6 月 14 日设计 (论文 )地点 : 南京理工大学泰州科技学院指 导 教 师 : 王栓虎专 业 负 责 人 : 龚光容发任务书日期: 2009 年 2 月 26 日任务书填写要求1毕业设计（论文）任务书由指导教师根据各课题的具体情况填写，经学生所在专业的负责人审查、系部领导签字后生效。此任务书应在第七学期结束前填好并发给学生；2任务书内容必须用黑墨水笔工整书写或按教务处统一设计的电子文档标准格式（可从教务处网页上下载）打印，不得随便涂改或潦草书写，禁止打印在其它纸上后剪贴；3任务书内填写的内容，必须和学生毕业设计（论文）完成的情况相一致，若有变更，应当经过所在专业及系部主管领导审批后方可重新填写；4任务书内有关“系部” 、 “专业”等名称的填写，应写中文全称，不能写数字代码。学生的“学号”要写全号；5任务书内“主要参考文献”的填写，应按照国标 GB 77142005文后参考文献著录规则的要求书写，不能有随意性；6有关年月日等日期的填写，应当按照国标 GB/T 74082005数据元和交换格式、信息交换、日期和时间表示法规定的要求，一律用阿拉伯数字书写。如“2008 年 3 月 15 日”或“2008-03-15”。毕 业 设 计（论 文）任 务 书1本毕业设计（论文）课题应达到的目的：气门摇杆轴支座是某企业产品中的关键零件之一，生产量比较大。为了保证产品质量，提高加工效率，需要对其加工工艺进行优化设计，并在关键工序使用组合机床或专用机床进行加工。本课题即以此为背景，要求学生根据企业生产需要和气门摇杆轴支座零件的加工要求，首先完成零件的加工工艺规程设计，在此基础之上，选择其关键工序之一进行专用夹具及加工用组合机床设计，并完成必要的设计计算。通过这样一个典型环节综合训练，达到综合训练学生运用所学知识，解决工程实际问题的能力。2本毕业设计（论文）课题任务的内容和要求（包括原始数据、技术要求、工作要求等）：本课题要求学生在对气门摇杆轴支座的加工要求、零件的结构工艺性进行认真分析的基础上，首先对零件的加工工艺规程做出优化设计，并对其关键工序之一进行专用夹具及加工用组合机床设计。具体任务及要求如下：（1）调查研究、查阅及翻译文献资料，撰写开题报告；（2）气门摇杆轴支座加工要求、零件的结构工艺性分析；（3）气门摇杆轴支座加工工艺规程设计；（4）气门摇杆轴支座关键工序的专用夹具设计；（5）气门摇杆轴支座关键工序的组合机床设计；（6）必要的设计计算与分析；（7）文档整理、撰写毕业设计说明书及使用说明书。设计技术要求包括：（1）生产纲领 50000 件/年（2）夹具采用液压驱动（3）组合机床采用液压滑台（4）每次加工一个零件毕 业 设 计（论 文）任 务 书3对本毕业设计（论文）课题成果的要求包括毕业设计论文、图表、实物样品等：（1）开题报告、文献综述、资料翻译；（2）气门摇杆轴支座加工工艺过程综合卡及各工序工序卡；（3）气门摇杆轴支座零件图及夹具装配图；（4）组合机床设计资料（三图一卡） ；（5）毕业设计说明书。 4主要参考文献：1 裘愉弢主编. 组合机床M. 第 1 版.北京：机械工业出版社，1995.2 金振华主编.组合机床及其调整与使用M. 第 1 版.北京：机械工业出版社，1990.3 沈延山.生产实习与组合机床设计D.第 1 版.大连：大连理工大学出版社，1989.4 上海市大专院校机械制造工艺学协作组编著.机械制造工艺学M （修订版）.福建科学技术出版社，1996.5 王华坤，范元勋编.机械设计基础M.北京：兵器工业出版社，2000.6 冯辛安等编.机械制造装备设计M. 北京：机械工业出版社,1998.7 陈日曜主编.金属切削原理M. 第 2 版.北京：机械工业出版社,1992.8 方子良等编.机械制造技术基础M.上海：上海交通大学出版社，2004.9 刘秋生，李忠文主编.液压传动与控制M.北京：宇航出版社，1994.10 陈于萍，周兆元等.互换性与测量技术基础M. 第 2 版.北京：机械工业出版社,2005.11 东北重型机械学院等合编.机床夹具设计手册M.上海：上海科学技术出版社，1979.12机械设计手册联合编写组. 机械设计手册M. 第 2 版.北京：机械工业出版社,1987.毕 业 设 计（论 文）任 务 书5本毕业设计（论文）课题工作进度计划：起 迄 日 期 工 作 内 容2009 年3 月 09 日 3 月 15 日3 月 16 日 3 月 29 日3 月 30 日 4 月 19 日4 月 20 日 5 月 03 日5 月 04 日 5 月 31 日6 月 01 日 6 月 07 日6 月 08 日 6 月 14 日熟悉毕业设计要求。查阅资料，完成外文资料翻译工作撰写开题报告及文献综述气门摇杆轴支座加工工艺规程设计（至少提出 2 个方案，进行分析比较，最后决定一个较优的方案）夹具设计（至少提出 2 个方案，进行分析比较，最后决定一个较优的方案）组合机床设计（完成三图一卡）文档整理、撰写毕业设计说明书。论文答辩所在专业审查意见：负责人： 2009 年 月 日系部意见：系部主任： 2009 年 月 日南京理工大学泰州科技学院学生毕业设计（论文）中期检查表学生姓名 冯俊 学 号 05010115 指导教师 王栓虎课题名称 支座体加工工艺及关键工艺设计难易程度 偏难 适中 偏易选题情况工作量 较大 合理 较小任务书 有 无开题报告 有 无符合规范化 的要求外文翻译质量 优 良 中 差学习态度、出勤情况 好 一般 差工作进度 快 按计划进行 慢中期工作汇报及解答问题情况优 良 中 差中期成绩评定：良所在专业意见：学习较主动、积极，态度认真，阶段成果较明显。负责人： 年 月 日 南京理工大学泰州科技学院毕业设计(论文)外文资料翻译系部： 机械工程系 专 业： 机械工程及自动化 姓 名： 冯俊 学 号： 05010115 外文出处： GEAR AND SHAFT INTRODUCTION 附 件： 1.外文资料翻译译文；2.外文原文指导教师评语：签名： 年 月 日附件 1：外文资料翻译译文齿轮和轴的介绍在直齿圆柱齿轮的受力分析中，是假定各力作用在单一平面的。我们将研究作用力具有三维坐标的齿轮。因此，在斜齿轮的情况下，其齿向是不平行于回转轴线的。而在锥齿轮的情况中各回转轴线互相不平行。斜齿轮用于传递平行轴之间的运动。倾斜角度每个齿轮都一样，但一个必须是右旋斜齿，而另一个必须是左旋斜齿。齿的形状是一渐开线螺旋面。如果一张被剪成平行四边形（矩形）的纸张包围在齿轮圆柱体上，纸上印出齿的角刃边就变成斜线。如果我展开这张纸，在角刃边上的每一个点就连接成一渐开线曲线。 直齿圆柱齿轮轮齿的初始接触处是跨过整个齿面而伸展开来的线。斜齿轮轮齿的初始接触是一点，当齿进行更多的啮合时，它就变成线。在直齿圆柱齿轮中，接触是平行于回转轴线的。在斜齿轮中，该线是跨过齿面的对角线。它使齿轮逐渐进行啮合并平稳的从一个齿到另一个齿传递运动，那样就使斜齿轮具有高速重载下平稳传递运动的能力。斜齿轮使轴的轴承承受径向和轴向力。当轴向推力变的大了或由于别的原因而产生某些影响时，那就可以使用人字齿轮。双斜齿轮（人字齿轮）与反向的并排地装在同一轴上的两个斜齿轮等效。它们产生相反的轴向推力作用，这样就消除了轴向推力。当两个或更多个单向双斜齿轮被安装在同一轴上时，齿轮的齿向应作选择，以便产生最小的轴向推力。交错轴斜齿轮或螺旋齿轮，它们是轴中心线既不相交也不平行的齿轮。交错轴斜齿轮的齿彼此之间发生点接触，它随着齿轮的啮合而变成线接触。因此它们只能传递小的载荷和主要用于仪器设备中，而且肯定不能在动力传动中使用。交错轴斜齿轮与螺旋齿轮在被安装后互相啮合之前是没有任何区别的。一对相啮合的交错轴斜齿轮通常具有同样的齿向，即左旋主动齿轮跟右旋从动齿轮相啮合。在交错轴斜齿设计中，当该齿的斜角相等时所产生滑移速度最小。然而当该齿的斜角不相等时，如果两个齿轮具有相同齿向的话，大斜角齿轮应用作主动齿轮。蜗轮与交错轴斜齿轮相似。小齿轮即蜗杆具有较小的齿数，通常是一到四个齿，由于它们完全缠绕在节圆柱上，因此它们被称为螺纹齿。与其相配的齿轮叫做蜗轮，蜗轮不是真正的斜齿轮。蜗杆和蜗轮通常是用于向垂直相交轴之间的传动提供大的角速度和减速比。蜗轮不是斜齿轮，因为其齿顶面通常做成中凹形状以适配蜗杆曲率，目的是要形成线接触而不是点接触。然而蜗杆蜗轮传动机构中存在齿间有较大滑移速度的缺点，正像交错轴斜齿轮那样。 蜗杆蜗轮机构有单包围和双包围机构。单包围机构就是蜗轮包裹着蜗杆的一种机构。当然，如果每个构件各自局部地包围着对方的蜗轮机构就是双包围蜗轮蜗杆机构。这两者之间的重要区别是，在双包围蜗轮组的轮齿间是面接触，而在单包围蜗轮组的轮齿间是线接触。一个装置中的蜗杆和蜗轮正像交错轴斜齿轮那样具有相同的齿向，但是其斜齿齿角的角度是极不相同的。蜗杆上的齿斜角度通常很大，而蜗轮上的则极小，因此习惯常规定蜗杆的倒角，那就是蜗杆齿斜角的余角；也规定了蜗轮上的齿斜角，该两角之和就等于 90 度的轴线交角。当齿轮要用来传递相交轴之间的运动时，就需要某种形式的锥齿轮。虽然锥齿轮通常制造成能构成 90 度轴的交角，但它们也可产生任何角度的轴交角。轮齿可以铸出 ，铣制或滚切加工。仅就滚齿而言就可达一级精度。在典型的锥齿轮安装中，其中一个锥齿轮常常安装于支承的外侧。这意味着轴的挠曲情况更加明显而使其在轮齿接触上具有更大的影响。 另外一个难题发生在难于预示锥齿轮轮齿上的应力，实际上是由于齿轮被加工成锥状而造成的。直齿锥齿轮易于设计且制造简单，如果它们安装的精密，在运转中会产生良好的效果。然而在直齿圆柱齿轮的情况下，在节线速度较高时，他们将发出噪音。在这些情况下，螺旋锥齿轮比直齿轮能产生平稳得多的啮合作用，因此碰到高速运转的场合那是很有用的。当在汽车的各种不同用途中，有一个带偏心轴的类似锥齿轮的机构。这样的齿轮机构叫做准双曲面齿轮机构，因为它们的节面是双曲回转面。这种齿轮之间的轮齿作用是沿着一根直线产生滚动与滑动相结合的运动并和蜗轮蜗杆的轮齿作用有着更多的共同之处。轴是一种转动或静止的杆件。通常有圆形横截面。在轴上安装像齿轮，皮带轮，飞轮，曲柄，链轮和其它动力传递零件。轴能够承受弯曲，拉伸，压缩或扭转载荷，这些力相结合时，人们期望找到静强度和疲劳强度作为设计的重要依据。因为单根轴可以承受静压力，变应力和交变应力，所有的应力作用都是同时发生的。“轴”这个词包含着多种含义，例如心轴和主轴。心轴也是轴，是既可以旋转也可以静止的轴，但不承受扭转载荷。短的转动轴常常被称为主轴。当轴的弯曲或扭转变形必需被限制于很小的范围内时，其尺寸应根据变形来确定，然后进行应力分析。因此，如若轴要做得有足够的刚度以致挠曲不太大，那么应力符合安全要求那是完全可能的。但决不意味着设计者要保证它们是绝对安全的，轴几乎总是要进行计算的，知道它们是处在可以接受的允许的极限以内。因此，设计者无论何时，设计动力传递零件，如齿轮或皮带轮都应该设置在靠近支承轴承附近。这就减低了弯矩，因而减小变形和弯曲应力。虽然来自 M.H.G 的方法在设计轴时难于应用，但它可以用来准确地预示实际失效。这样，它是一个检验已经设计好了的轴或者发现轴在运转中发生损坏原因的好方法。进而有着大量的关于设计的问题，其中由于别的考虑例如刚度考虑，尺寸已得到较好的限制。设计者去查找关于圆角尺寸、热处理、表面光洁度和是否要进行喷丸处理等资料，那真正的唯一的需要是实现所要求的寿命和可靠性。由于它们的功能相似，将离合器和制动器一起处理。简化摩擦离合器或制动器的动力学表达式中，各自以角速度 w1 和 w2 运动的两个转动惯量 I1 和 I2，在制动器情况下其中之一可能是零，由于接上离合器或制动器而最终要导致同样的速度。因为两个构件开始以不同速度运转而使打滑发生了，并且在作用过程中能量散失，结果导致温升。在分析这些装置的性能时，我们应注意到作用力，传递的扭矩，散失的能量和温升。所传递的扭矩关系到作用力，摩擦系数和离合器或制动器的几何状况。这是一个静力学问题。这个问题将必须对每个几何机构形状分别进行研究。然而温升与能量损失有关，研究温升可能与制动器或离合器的类型无关。因为几何形状的重要性是散热表面。各种各样的离合器和制动器可作如下分类： 1轮缘式内膨胀制动块；2轮缘式外接触制动块；3条带式；4盘型或轴向式；5圆锥型；6混合式。分析摩擦离合器和制动器的各种形式一般都应用同样的程序，下面的步骤是必需的：1假定或确定摩擦表面上的压力分布；2找出最大压力和任一点处压力之间的关系；3应用静平衡条件去找寻（a）作用力；（b）扭矩；(c)支反力。混合式离合器包括几个类型，例如强制接触离合器、超载释放保护离合器、超越离合器、磁液离合器等等。强制接触离合器由一个变位杆和两个夹爪组成。各种强制接触离合器之间最大的区别与夹爪的设计有关。为了在结合过程中给变换作用较长的时间周期，夹爪可以是棘轮式的，螺旋型或齿型的。有时使用许多齿或夹爪。它们可以在圆周面上加工齿，以便它们以圆柱周向配合来结合或者在配合元件的端面上加工齿来结合。虽然强制离合器不像摩擦接触离合器用的那么广泛，但它们确实有很重要的运用。离合器需要同步操作。有些装置例如线性驱动装置或电机操作螺杆驱动器必须运行到一定的限度然后停顿下来。为着这些用途就需要保护离合器。这些离合器通常用弹簧加载，以使得在达到预定的力矩时释放。当到达超载点时听到的“喀嚓”声就被认定为是所希望的信号声。超越离合器或连轴器允许机器的被动构件“空转”或“超越” ，因为主动驱动件停顿了或者因为另一个动力源使被动构件增加了速度。这种离合器通常装在外套筒和内轴件之间。该内轴件，在它的周边加工了数个平面。驱动作用是靠在套筒和平面之间契入的滚子来获得。因此该离合器与具有一定数量齿的棘轮棘爪机构等效。磁液离合器或制动器相对来说是一个新的发展项目，它们具有两平行的磁极板。这些磁极板之间有磁粉混合物润滑，电磁线圈被装入磁路中的某处。借助激励该线圈，磁液混合物的剪切强度可被精确的控制。这样从充分滑移到完全锁住的任何状态都可以获得。附件 2：外文原文GEAR AND SHAFT INTRODUCTIONIn the force analysis of spur gears, the forces are assumed to act in a single plane. We shall study gears in which the forces have three dimensions. The reason for this, in the case of helical gears, is that the teeth are not parallel to the axis of rotation. Helical gears are used to transmit motion between parallel shafts. The helix angle is the same on each gear, but one gear must have a right-hand helix and the other a left-hand helix. The shape of the tooth is an involute helicoid. If a piece of paper cut in the shape of a parallelogram is wrapped around a cylinder, the angular edge of the paper becomes a helix. If we unwind this paper, each point on the angular edge generates an involute curve. The surface obtained when every point on the edge generates an involute is called an involute helicoid.The initial contact of spur-gear teeth is a line extending all the way across the face of the tooth. The initial contact of helical gear teeth is a point, which changes into a line as the teeth come into more engagement. In spur gears the line of contact is parallel to the axis of the rotation; in helical gears, the line is diagonal across the face of the tooth. It is this gradual of the teeth and the smooth transfer of load from one tooth to another, which give helical gears the ability to transmit heavy loads at high speeds. Helical gears subject the shaft bearings to both radial and thrust loads. When the thrust loads become high or are objectionable for other reasons, it may be desirable to use double helical gears. A double helical gear (herringbone) is equivalent to two helical gears of opposite hand, mounted side by side on the same shaft. They develop opposite thrust reactions and thus cancel out the thrust load. When two or more single helical gears are mounted on the same shaft, the hand of the gears should be selected so as to produce the minimum thrust load.Crossed-helical, or spiral, gears are those in which the shaft centerlines are neither parallel nor intersecting. The teeth of crossed-helical fears have point contact with each other, which changes to line contact as the gears wear in. For this reason they will carry out very small loads and are mainly for instrumental applications, and are definitely not recommended for use in the transmission of power. There is on difference between a crossed helical gear and a helical gear until they are mounted in mesh with each other. They are manufactured in the same way. A pair of meshed crossed helical gears usually have the same hand; that is ,a right-hand driver goes with a right-hand driven. In the design of crossed-helical gears, the minimum sliding velocity is obtained when the helix angle are equal. However, when the helix angle are not equal, the gear with the larger helix angle should be used as the driver if both gears have the same hand. Worm gears are similar to crossed helical gears. The pinion or worm has a small number of teeth, usually one to four, and since they completely wrap around the pitch cylinder they are called threads. Its mating gear is called a worm gear, which is not a true helical gear. A worm and worm gear are used to provide a high angular-velocity reduction between nonintersecting shafts which are usually at right angle. The worm gear is not a helical gear because its face is made concave to fit the curvature of the worm in order to provide line contact instead of point contact. However, a disadvantage of worm gearing is the high sliding velocities across the teeth, the same as with crossed helical gears.Worm gearing are either single or double enveloping. A single-enveloping gearing is one in which the gear wraps around or partially encloses the worm. A gearing in which each element partially encloses the other is, of course, a double-enveloping worm gearing. The important difference between the two is that area contact exists between the teeth of double-enveloping gears while only line contact between those of single-enveloping gears. The worm and worm gear of a set have the same hand of helix as for crossed helical gears, but the helix angles are usually quite different. The helix angle on the worm is generally quite large, and that on the gear very small. Because of this, it is usual to specify the lead angle on the worm, which is the complement of the worm helix angle, and the helix angle on the gear; the two angles are equal for a 90-deg. Shaft angle.When gears are to be used to transmit motion between intersecting shaft, some of bevel gear is required. Although bevel gear are usually made for a shaft angle of 90 deg. They may be produced for almost any shaft angle. The teeth may be cast, milled, or generated. Only the generated teeth may be classed as accurate. In a typical bevel gear mounting, one of the gear is often mounted outboard of the bearing. This means that shaft deflection can be more pronounced and have a greater effect on the contact of teeth. Another difficulty, which occurs in predicting the stress in bevel-gear teeth, is the fact the teeth are tapered. Straight bevel gears are easy to design and simple to manufacture and give very good results in service if they are mounted accurately and positively. As in the case of squr gears, however, they become noisy at higher values of the pitch-line velocity. In these cases it is often good design practice to go to the spiral bevel gear, which is the bevel counterpart of the helical gear. As in the case of helical gears, spiral bevel gears give a much smoother tooth action than straight bevel gears, and hence are useful where high speed are encountered. It is frequently desirable, as in the case of automotive differential applications, to have gearing similar to bevel gears but with the shaft offset. Such gears are called hypoid gears because their pitch surfaces are hyperboloids of revolution. The tooth action between such gears is a combination of rolling and sliding along a straight line and has much in common with that of worm gears.A shaft is a rotating or stationary member, usually of circular cross section, having mounted upon it such elementsas gears, pulleys, flywheels, cranks, sprockets, and other power-transmission elements. Shaft may be subjected to bending, tension, compression, or torsional loads, acting singly or in combination with one another. When they are combined, one may expect to find both static and fatigue strength to be important design considerations, since a single shaft may be subjected to static stresses, completely reversed, and repeated stresses, all acting at the same time.The word “shaft” covers numerous variations, such as axles and spindles. Anaxle is a shaft, wither stationary or rotating, nor subjected to torsion load. A shirt rotating shaft is often called a spindle.When either the lateral or the torsional deflection of a shaft must be held to close limits, the shaft must be sized on the basis of deflection before analyzing the stresses. The reason for this is that, if the shaft is made stiff enough so that the deflection is not too large, it is probable that the resulting stresses will be safe. But by no means should the designer assume that they are safe; it is almost always necessary to calculate them so that he knows they are within acceptable limits. Whenever possible, the power-transmission elements, such as gears or pullets, should be located close to the supporting bearings, This reduces the bending moment, and hence the deflection and bending stress.Although the von Mises-Hencky-Goodman method is difficult to use in design of shaft, it probably comes closest to predicting actual failure. Thus it is a good way of checking a shaft that has already been designed or of discovering why a particular shaft has failed in service. Furthermore, there are a considerable number of shaft-design problems in which the dimension are pretty well limited by other considerations, such as rigidity, and it is only necessary for the designer to discover something about the fillet sizes, heat-treatment, and surface finish and whether or not shot peening is necessary in order to achieve the required life and reliability.Because of the similarity of their functions, clutches and brakes are treated together. In a simplified dynamic representation of a friction clutch, or brake, two in ertias I1 and I2 traveling at the respective angular velocities W1 and W2, one of which may be zero in the case of brake, are to be brought to the same speed by engaging the clutch or brake. Slippage occurs because the two elements are running at different speeds and energy is dissipated during actuation, resulting in a temperature rise. In analyzing the performance of these devices we shall be interested in the actuating force, the torque transmitted, the energy loss and the temperature rise. The torque transmitted is related to the actuating force, the coefficient of friction, and the geometry of the clutch or brake. This is problem in static, which will have to be studied separately for eath geometric configuration. However, temperature rise is related to energy loss and can be studied without regard to the type of brake or clutch because the geometry of interest is the heat-dissipating surfaces. The various types of clutches and brakes may be classified as fllows: 1. Rim type with internally expanding shoes2. Rim type with externally contracting shoes3. Band type4. Disk or axial type5. Cone type6. Miscellaneous typeThe analysis of all type of friction clutches and brakes use the same general procedure. The following step are necessary: 1. Assume or determine the distribution of pressure on the frictional surfaces.2. Find a relation between the maximum pressure and the pressure at any point3. Apply the condition of statical equilibrium to find (a) the actuating force, (b) the torque, and (c) the support reactions.Miscellaneous clutches include several types, such as the positive-contact clutches, overload-release clutches, overrunning clutches, magnetic fluid clutches, and others.A positive-contact clutch consists of a shift lever and two jaws. The greatest differences between the various types of positive clutches are concerned with the design of the jaws. To provide a longer period of time for shift action during engagement, the jaws may be ratchet-shaped, or gear-tooth-shaped. Sometimes a great many teeth or jaws are used, and they may be cut either circumferentially, so that they engage by cylindrical mating, or on the faces of the mating elements.Although positive clutches are not used to the extent of the frictional-contact type, they do have important applications where synchronous operation is required.Devices such as linear drives or motor-operated screw drivers must run to definite limit and then come to a stop. An overload-release type of clutch is required for these applications. These clutches are usually spring-loaded so as to release at a predetermined toque. The clicking sound which is heard when the overload point is reached is considered to be a desirable signal.An overrunning clutch or coupling permits the driven member of a machine to “freewheel” or “overrun” because the driver is stopped or because another source of power increase the speed of the driven. This type of clutch usually uses rollers or balls mounted between an outer sleeve and an inner member having flats machined around the periphery. Driving action is obtained by wedging the rollers between the sleeve and the flats. The clutch is therefore equivalent to a pawl and ratchet with an infinite number of teeth. Magnetic fluid clutch or brake is a relatively new development which has two parallel magnetic plates. Between these plates is a lubricated magnetic powder mixture. An electromagnetic coil is inserted somewhere in the magnetic circuit. By varying the excitation to this coil, the shearing strength of the magnetic fluid mixture may be accurately controlled. Thus any condition from a full slip to a frozen lockup may be obtained.