人人文库网 > 图纸下载 > 毕业设计 > 牧草切根机传动装置的设计【7张CAD图纸和说明书】

评价表.docx

牧草切根机传动装置的设计【7张CAD图纸和说明书】

资源目录

牧草切根机传动装置的设计【7张CAD图纸和说明书】.rar

外文翻译--齿轮和轴的介绍.doc---(点击预览)

A0-总装图.dwg

A0-箱盖.dwg

A1-减速器装配图.dwg

A2-低速大齿轮.dwg

A3-轴.dwg

A3-齿轮轴1.dwg

A3-齿轮轴2.dwg

压缩包内文档预览：

编号：18012829 类型：共享资源大小：1002.58KB 格式：RAR 上传时间：2019-04-23 上传人：俊****计 IP属地：江苏

40
积分

版权申诉 word格式文档无特别注明外均可编辑修改；预览文档经过压缩，下载后原文更清晰！ 立即下载

关键词：: 7张CAD图纸和说明书张CAD图纸牧草切根机的设计传动装置说明书牧草切根机

资源描述：

1. 引言 1

1.1 我国草业的现状及研发前景 1

1.2 工作原理 3

1.3 牧草生长不良原因分析 3

2. 牧草复壮促生破土切根机的研究与设计 3

2.1 总体结构和工作原理分析 3

2.2 悬挂架 4

2.3 直切刀的选择 5

2.4 传动装置的选择与设计 9

2.4.1 传动装置的选择 9

2.4.2 齿轮变速箱的工作原理 10

2.4.3 齿轮变速箱的设计 10

2.5 切根机切根宽度和深度的设计 14

2.5.1 切根宽带的设计 14

2.5.2 切根深度的调节 14

2.6 滑块机构 15

2.7 凸轮机构 15

结论 16

参考文献 17

致谢 18

毕业设计说明书中文摘要

牧草切根机的设计——传动装置

摘要我国地域辽阔，畜牧业发达。很多地区种植着牧草，近年来由于土壤条件的变化，使得好多地区牧草生长状况出现了不良效果。分析了草场不同土壤条件对牧草生长和草场生态恢复的影响；研究了退化草场机械化破土切根技术和模式；探讨了高坚实度土壤条件的草场破土机理与根茎型或根茎疏丛型牧草横走根茎切根方式，针对典型草场板结严重且横走根茎错节致使自繁促生能力下降等问题。根据研发要求，应用力学和机械运动学等理论，设计了牧草复壮促生破土切根机具。该机采用齿轮变速箱传达改变动力，应用凸轮机构驱动直切刀对牧草进行垂直切根，减小了切根阻力和切缝宽度，通过简单操作可实现对不同间距、不同深度牧草进行切根作业，从而达到切断亚表层下的横走根茎、改良草地，扩繁促生的效果。经速度、加速度和受力分析证明，该机满足了设计要求，切割速度快，破土能力强，对土壤表皮损伤小，是比较理想的牧草切根机械。

关键词牧草切根机直切刀凸轮齿轮变速箱

毕业设计说明书外文摘要

Design of Rejuvenation and Acceleration Root-cutting

Machine—Gearing

Abstract

In order to counter the problem of reduced health promotion ability in typical grass with compacted roots, a root cutting machine was designed for pasture . The machine used came driven of direct cutter to cut root vertically, greatly reducing resistance and perturbations of soil surface while cutting the root,which reached easy work in varies of forage . The machine destroye- dsolid soil, improved grassland, and increased grass yield . Asproven by analyzing the velocity, acceleration and force of the machine was able

To meet the needs of designing . It is a more ideal agriculturalmachine for forage grass .

Keywords Forage grass Root cutting machine Direct cutter Design

牧草切根机的设计——传动装置

1.引言

牧草业是我国现代农业的重要组成部分。我国草地面积广阔，但近年来三化面积逐步扩大。牧草产量降低。针对这一情况设计研究牧草复壮促生机具。以改良牧草的生长情况。

破土切根技术是指在不破坏天然草地植被的情况下,对草原表皮进行破土切缝的一种草地培育措施。此技术大大改良了退化草场, 解决了草畜矛盾,为我国畜牧业的发展打下了良好的基础。我国对牧草切根这一破土切根复壮促生技术发展较晚,起步于20世纪80年代,通过对国外的先进经验和国内大量的试验数据积累, 黑龙江省穆棱林业局解全民等研制出自走式果岭梳草切根机, 中国农业大学草业机械工程技术研究中心主任王德成教授研制出9QD2430 型草地点线式破土切根机和9QP2830型草地盘齿式破土切根机,中国农业大学张淑敏等研制的多功能点、条式牧草切根机。虽然我国对牧草切根机进行了大量的试验和研究设计,但相对于欧美等发达国家来说,我国在草地畜牧业上的投入相对较少,在技术水平、制造手段和工艺设计等方面还存在很大差距, 我国牧草切根机的设计仍然不够成熟,仍需进一步改进和完善。

本设计针对我国天然草场严重退化现状,采用以机械化切根再不破坏土壤表皮的条件下达到牧草复壮促生，来改善我国的牧草生长。

1.1 我国草业的现状及研发前景

草业是现代农业的重要组成部分。它关系到种植业跟养殖业，也关系到我国的乡村生态发展，是农业的基础产业。但我国现在的牧草种植地土壤三化情况严重，大大影响了我国牧草业的产量和发展。据2006 年国家统计局统计资料，我国草原面积4亿公顷，占全国总土地面积的41.67%，占世界草地面积的12.5%，是耕地面积的3.7倍，林地面积的3.1倍。其中，可利用草地资源31333万公顷占国土面积的32.64%。我国的草地生产力条件得天独厚，生产潜力巨大，依靠丰富的草地资源发展畜牧业对建设小康社会、调整产业结构、保障粮食安全体系和促进经济发展与农民增收等诸多方面都具有重要意义。但由于不合理的利用制度和不当的放牧方法，我国草原出现大面积退化、沙化和盐碱化情况。国内外大量事实证明，对天然草场进行改良和建立人工草场是提高草场生产能力、解决草畜矛盾并使畜牧业生产稳定、高速、优质发展的一项关键措施。退耕还草、保护和建设生态环境都与草场改良和建立人工草场相关。运用机械化技术手段改良退化草场可以兼顾生态效益与经济效益，具有效率高、效果好的特点。天然草场经改良后与未经改良的草场相比产草量提高很多。因此对退化草场进行改良既是发展畜牧业的必然要求，也符合国家保护生态环境的要求。在我国的黑龙江、吉林、辽宁三省及内蒙古自治区东部的呼伦贝尔市、兴安盟、通辽市和赤峰市等地区，分布着以羊草在主要植被的温性草甸草原区，草场总面积约1224.4万公顷，是我国发展草原畜牧业十分宝贵的草场资源。该地区由于长期无养息超载放牧和家畜踩踏啃食，土壤板结严重，土壤板结层深达25～35cm，土壤坚实度达到2.87～4.87kg/cm。同时，羊草等多年生根茎型禾本牧草的根茎分布于50～200mm的土层或更深的地方，其地下横走茎每年延伸可达 1～1.5m，盘根错节的根系致使土壤透气性减弱，含水量和孔隙度下降，容重增大。研究表明在此地区更益采用在亚表层切根、深层松土的方法对退化草场进行改良。实施切根松土改良就是在不破坏原植被的前提下，通过机械手段切断横向须根，划开板结层，进行草场底层松土，改善土壤的透气、蓄水条件。切断后的草根能充分吸收养分，提高草产量。深入研究我国根茎型退化草场退化状况和机械化改良工艺，以驱动型土壤耕作机械设计理论为基础，研制开发适用于我国牧区普通牧民适用的驱动型退化草场破土切根改良专用机，即具有经济效益意义又具有生态效益意义。通过对这一问题的解决。为我国畜牧业的发展打下了一个良好的基础在整个机具的研发过程中，对草场破土切根机性能的研究是尤为重要的，而在整机性能当中刀具的破土性能更是重中之重。我国对牧草切根这一破土切根复壮促生技术发展较晚，起步于20世纪80年代，通过对国外的先进经验和国内大量的试验数据积累，黑龙江省穆棱林业局解全民等研制出自走式果岭梳草切根机，中国农业大学草业机械工程技术研究中心主任王德成教授研制出9QD2430型草地点线式破土切根机和9QP2830型草地盘齿式破土切根机，以及中国农业大学张淑敏等研制的多功能点、条式牧草切根机。虽然我国对牧草切根机进行了大量的试验和研究设计,但相对于欧美等发达国家来说，我国在草地畜牧业上的投入相对较少，在技术水平、制造手段和工艺设计等方面还存在很大差距，我国牧草切根机的设计仍然不够成熟，仍需进一步改进和完善。本文根据机具研发要求，设计出一套破土切根装置，和破土根刀具。工作性能优越。操作简单。

1.2 工作原理

本文针对我国天然草场严重退化现状，提出机械化切根复壮分蘖促生自我繁育工艺,研制开发适用于我国草场的切根机。该机具采用三点悬挂架连接于农业拖拉机尾部。通过链条连接拖拉机动力与齿轮变速箱，从而是动力传递到工作机具。通过齿轮变速箱改变调节工作动力。再经凸轮机构传达到直切刀。破土切根。采用直切方式，破土阻力小，切割快。满足初始的设计要求。该机具可调性高，可以试用于不同的牧草生长地。直切刀之间的间隔可以通过套筒装置调节，以适应于行宽不同的土地，进行多行同时切割。工作量适宜，减少了相应的工作时间。通过限深轮可以适应不同深度的切割。

全部文件.png

A0-总装图.gif

A0-箱盖.gif

A1-减速器装配图.png

A2-低速大齿轮.gif

A3-齿轮轴1.png

A3-齿轮轴2.png

A3-轴.png

字数统计.png

内容简介：: 齿轮和轴的介绍摘要:在传统机械和现代机械中齿轮和轴的重要地位是不可动摇的。齿轮和轴主要安装在主轴箱来传递力的方向。通过加工制造它们可以分为许多的型号，分别用于许多的场合。所以我们对齿轮和轴的了解和认识必须是多层次多方位的。关键词:齿轮；轴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。像我们要讨论的那样，尚有其他道理需要学习，掌握。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，但一个必须右旋斜齿，而另一个必须是左旋斜齿。齿的形状是一溅开线螺旋面。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，在血角刃边上的每一个点就发生一渐开线曲线。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，当齿进入更多的啮合时，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，该先是跨过齿面的对角线。它是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）是与反向的并排地装在同一轴上的两个斜齿轮等效。他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齿斜齿轮被在同一轴上时，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，他们是轴中心线既不相交也不平行。交错轴斜齿轮的齿彼此之间发生点接触，它随着齿轮的磨合而变成线接触。因此他们只能传递小的载荷和主要用于仪器设备中，而且肯定不能推荐在动力传动中使用。交错轴斜齿轮与斜齿轮之间在被安装后互相捏合之前是没有任何区别的。它们是以同样的方法进行制造。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减速比。蜗轮不是斜齿轮，因为其齿顶面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。着两者之间的重要区别是，在双包围蜗轮组的轮齿间有面接触，而在单包围的蜗轮组的轮齿间有线接触。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导角，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装于支承的外侧。这意味着轴的挠曲情况更加明显而使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造成的。直齿锥齿轮易于设计且制造简单，如果他们安装的精密而确定，在运转中会产生良好效果。然而在直齿圆柱齿轮情况下，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的多的啮合作用，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，那是常常所希望的。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上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，链轮和其他动力传递零件。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，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，那么合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。因之，设计者无论何时，动力传递零件，如齿轮或皮带轮都应该设置在靠近支持轴承附近。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方法在设计轴中难于应用，但它可能用来准确预示实际失效。这样，它是一个检验已经设计好了的轴的或者发现具体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。由于他们的功能相似，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 轮缘式内膨胀制冻块；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都应用一般的同样的程序，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予较长时间周期，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。他们可能在圆周面上加工齿，以便他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超载释放保护离合器。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。这种离合器通常使用装在外套筒和内轴件之间的滚子或滚珠。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，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。 GEAR AND SHAFT INTRODUCTIONAbstract: The important position of the wheel gear and shaft cant falter in traditional machine and modern machines.The wheel gear and shafts mainly install the direction that delivers the dint at the principal axis box.The passing to process to make them can is divided into many model numbers, useding for many situations respectively.So we must be the multilayers to the understanding of the wheel gear and shaft in many ways .Key words: Wheel gear;ShaftIn 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. And in the case of bevel gears, the rotational axes are not parallel to each other. There are also other reasons, as we shall learn.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 inertias 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

温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。