螺旋输送机设计说明书

螺旋输送机设计说明书 目录 摘要„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„ 1 Abstract „„„„„„„„„„„„„„„„„„„„„„„„„„„„„ 2 第一章 引言„„„„„„„„„„„„„„„„„„„„„„„„„„„„3 1.1 关于本次毕业设计„„„„„„„„„„„„„„„„„„„„„„3 1.2 螺旋输送机产品概述„„„„„„„„„„„„„„„„„„„„„3 1.3 螺旋输送机的应用范围„„„„„„„„„„„„„„„„„„„„4 1.4 螺旋输送机主要热点„„„„„„„„„„„„„„„„„„„„„4 1.5 螺旋输送机工作原理„„„„„„„„„„„„„„„„„„„„„4 1.6 螺旋输送机整机布置形式„„„„„„„„„„„„„„„„„„„5 1.7 螺旋输送机的发展历史及趋势„„„„„„„„„„„„„„„„„5 第二章 螺旋输送机的设计„„„„„„„„„„„„„„„„„„„„„„8 2.1 总体 方案 气瓶 现场处置方案 .pdf气瓶 现场处置方案 .doc见习基地管理方案.doc关于群访事件的化解方案建筑工地扬尘治理专项方案下载 设计„„„„„„„„„„„„„„„„„„„„„„„„8 2.2 螺旋输送机总体结构设计„„„„„„„„„„„„„„„„„„„8 2.3 螺旋输送机机体的设计„„„„„„„„„„„„„„„„„„„„9 2.4 驱动端装置的设计„„„„„„„„„„„„„„„„„„„„„ 12 2.5 中间轴承装置„„„„„„„„„„„„„„„„„„„„„„„ 14 2.6 尾端装置的设计„„„„„„„„„„„„„„„„„„„„„„ 16 2.7 驱动装置和尾端装置轴的校核„„„„„„„„„„„„„„„„ 17 第三章 减速器的设计„„„„„„„„„„„„„„„„„„„„„„„ 19 3.1 蜗轮蜗杆减速器的运动和动力参数„„„„„„„„„„„„„„ 19 3.2 减速器的蜗杆设计„„„„„„„„„„„„„„„„„„„„„ 19 3.3 蜗轮轴的设计„„„„„„„„„„„„„„„„„„„„„„„ 23 3.4 蜗杆轴的设计„„„„„„„„„„„„„„„„„„„„„„„ 29 3.5 减速器箱体及附件的设计„„„„„„„„„„„„„„„„„„ 31 第四章 轴承的校核„„„„„„„„„„„„„„„„„„„„„„„„ 33 4.1 蜗杆轴滚动轴承计算„„„„„„„„„„„„„„„„„„„„ 33 第五章 键的校核„„„„„„„„„„„„„„„„„„„„„„„„„ 35 5.1 蜗杆轴端和联轴器的联结的键„„„„„„„„„„„„„„„„ 35 35 5.2 蜗轮与轴联结的键„„„„„„„„„„„„„„„„„„„„„ 5.3 蜗轮轴轴端和联轴器联结的键„„„„„„„„„„„„„„„„ 35 第6章 润滑和密封的设计„„„„„„„„„„„„„„„„„„„„„ 37 6.1 润滑„„„„„„„„„„„„„„„„„„„„„„„„„„„ 37 6.2 密封„„„„„„„„„„„„„„„„„„„„„„„„„„„ 37 6.3 附件的设计„„„„„„„„„„„„„„„„„„„„„„„„ 38 致谢„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„ 39 参考文献„„„„„„„„„„„„„„„„„„„„„„„„„„„„„ 40 附录1 英文文献翻译 „„„„„„„„„„„„„„„„„„„„„„„41 附录2 英文文献原文 „„„„„„„„„„„„„„„„„„„„„„„45 需要图纸请联系:xinanchong@163.com o螺旋输送机(倾斜10) 摘要:螺旋输送机是利用电机带动螺旋回转，推移物料以实现输送目的的机械，它能水平、倾斜或垂直输送，具有结构简单、横截面积小、密封性好、操作方便、维修容易、便于封闭运输等优点。本课 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 重点研究在与驱动装置的合理选择，对驱动装置的合理给螺旋输送机的效率，稳定，安全性的提高大的作用。 本次毕业设计是关于输送机的设计。首先对输送机作了简单的概述;接着分析了输送机的选型原则及计算 方法 快递客服问题件处理详细方法山木方法pdf计算方法pdf华与华方法下载八字理论方法下载 ;然后根据这些设计 准则 租赁准则应用指南下载租赁准则应用指南下载租赁准则应用指南下载租赁准则应用指南下载租赁准则应用指南下载 与计算选型方法按照给定参数要求进行选型设计;接着对所选择的输送机各主要零部件进行了校核。普通型输送机由六个主要部件组成:传动装置，机尾和导回装置，中部机架，拉紧装置以及胶带。最后简单的说明了输送机的安装与维护。 关键词:螺旋输送机 输送系统 选型设计 主要部件 oScrew conveyor(Tilt 10) Abstract:Screw conveyor is the use of motor driven rotary screw, the passage of materials in order to achieve the purpose of transportation machinery, it can level, tilt or vertical transmission, a simple structure, small cross sectional area, sealing, and easy to operate, easy maintenance, facilitate closure transportation and other advantages. Focus on the issue and drive in a reasonable choice. Drive screw conveyor to the reasonable efficiency, stability, security, the improvement of the role. The design is a graduation project about the conveyor. At first, it is introduction about the conveyor. Next, it is the principles about choose component parts of conveyor. After that the belt conveyor abase on the principle is designed. Then, it is checking computations about main component parts. The ordinary conveyor consists of six main parts: Drive Unit, Jib or Delivery End, Tail Ender Return End, Intermediate Structure, Loop Take-Up and Belt. At last, it is explanation about fix and safeguard of the belt conveyor. Key words:screw conveyor delivery system type design main parts 第一章 引言 1.1 关于本次毕业设计 1.1.1 毕业设计的目的 通过本次毕业设计，我们能够达到一些目的: 1) 培养我们综合运用和巩固扩展所学知识，提高理论联系实际的能力; 2) 培养我们搜集、阅读、分析和运用各种资料，手册等科技文献的能力; 3) 使我们更加熟练的运用AUTOCAD、Word等计算机办公软件，提高计算机辅 助设计的能力; 4) 训练和提高机械设计的基本理论和技能; 5) 培养独立思考，独立工作的能力 1.1.2 毕业设计的任务 1) 设计条件 3 运输物料为干燥煤粉，密度; ,,850Kg/m 运输量为; 12T/h 运输长度为。 12m 2) 设计内容 a) 设计方案的选择与计算 b) 总体结构的设计，成套图纸及说明书 3) 设计关键 a) 仔细分析联系输送机的工作原理 b) 根据输送要求选择合适类型的类型输送机 c) 保证设计的类型输送机能够满足工作要求 1.2 螺旋输送机产品概述 螺旋输送机俗称绞龙，GX型系列螺旋输送机是一种利用螺旋叶片的旋转，推动物料 沿着料槽运送的输送设备，在建筑工地，储粮仓库，制造车间等，并在倾角β, 20 ? 3 的情况下，输送粉状，颗粒状和小块物料，使螺旋输送机对提高生产工作效率得到了很大体现，本次设计旨在对螺旋输送机进行创新设计，进一步提高它的实用性。 GX型螺旋输送机是按照JB/T679-95《螺旋输送机》 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 设计制造，GX型螺旋输送机的螺旋直径有，共有7种规格。在物料温度小于200?，工作环境温150mm~600mm 度在-20?至+50?之间时，输送长度可达50,个别情况可达70。螺旋机驱动端轴承、mm 尾部轴承置于料槽壳体外部减少了灰尘对轴承的影响，提高了螺旋机关键件的适用寿命。中间吊挂轴承采用滑动轴承，并设防尘密封装置，密封件用尼龙或塑料，因而密封性能好，耐磨性强，阻力小，寿命长。滑动轴承的轴瓦有粉末冶金、尼龙和巴氏合金，可根据不同需要选用，进出料口的灵活布置使其适应性更强，得到用户认可。 1.3 螺旋输送机的应用范围 GX型螺旋输送机广泛应用在各种工业部门，如建材、冶金、化工、电力、煤炭、轻工、粮食及食品行业，适用于水平或者20 ?倾角的，如水泥、煤粉、粮食、化肥、灰渣、砂子、焦炭等。 GX型螺旋机对输送物料的要求，物料温度不得超过200?，螺旋机不宜输送易变质的、粘性大的、易结块的物料。因为这些物料在输送时会粘结在一起，并随之旋转而不向前移动，或者在吊轴承处物料积塞而使机器不能正常工作，因此对于输送距离短，输送量不大，五磨琢性或磨琢性小，五粘结性或粘接性小，不怕破碎而又要求密闭输送的粉状和小块状的物料，采用螺旋输送机是很适宜的。 1.4 螺旋输送机主要特点 1. 结构简单、造价便宜; 2. 维修容易、操作安全; 3. 外形尺寸矮小，布置紧凑，便于多点装料与卸料; 4. 槽体密闭，物料损耗少; 5. 可输送较高温度的物料。 1.5 螺旋输送机工作原理 物料从进料口加入，装螺旋轴转动时，物料受到螺旋叶片法向推力作用。该推力的径向分力和叶片对物料的摩擦力，有可能带着物料绕轴转动，但由于物料本身的重力 和料槽对物料的摩擦力的缘故，才不与螺旋叶片一起旋转，而在叶片法向推力的轴向分力的作用下，沿着料槽轴向前移动。 1.6 螺旋输送机整机布置形式 一台螺旋输送机通常由驱动装置、头节、若干标准中间节、选配中间节、尾节、进料口、出料口等组成，除头节和选配中间节外，各节螺旋机及机壳均有互换性。 螺旋机本体由头节、中间节、尾节三种组成。一般情况下，出厂总装时将中间节按长度长短依次排列，最长的中间节靠近头节，相同的中间节挨在一起。 在头节内装有止推轴承承受轴向力，在中间节装有中间吊挂轴承支承螺旋轴。螺旋面的形式有实体螺旋和带式螺旋两种。各螺旋轴之间采用法兰式联接，(S制法)(D制法) 保证了连接轴的互换性，便于维修。 进料口是方形进料口，出料口有方形卸料口、手推式卸料口及齿条式卸料口。布置进出料口应注意保证料口至端部的距离，同时避免料口与吊轴承加油杯，机壳联接法兰，底座等相碰。 驱动装置有由型电动机和型减速器组成，即双型。按其装配方式的不同，JQJZQJJ2 它分为右装和左装两种。 图1-1 螺旋输送机简图 1.7 螺旋输送机的发展历史及趋势 1.7.1 螺旋输送机的发展历史 螺旋输送机的发展，分为有轴螺旋输送机和无轴螺旋输送机两种型式的发展过程。 有轴螺旋输送机由螺杆，U型料槽，盖板，进，出料口和驱动装置组成，一般还有水平式，倾斜式和垂直式三种:而无轴旋输送机则采用螺杆改为无轴螺旋，并在U型槽内装置有可换衬体，结构简单，物料由进料口输入经螺旋推动后由出料口输出，整个传输过程可在一个密封的槽中进行。一般来讲，我们平常所指的螺旋输送机都指有轴型式的螺旋输送机。而对许多输送比较困难的物料，人们一直在寻求一种可靠的输送方法，而无轴螺旋输送机则是一种较好的解决方法。 GX型螺旋输送机是出现较早的一种螺旋输送机，也是我国最早定型生产的通用性生产设备。它以输送粉状、粒状、小块状物料为主，不适宜输送易变质的，粘性的易结块的物料和大块的物料，因为这些物料容易粘在螺旋上而随之旋转，或在吊轴承处产生堵料现象，给物料输送过程带来很大的不便。GX型螺旋输送机的优点主要是节能、降耗显著，其头部、尾部轴承移至壳体外，具有防尘密封性好，噪声低，适应性强，操作维修方便，进、出料口位置布置灵活等;缺点是动力消耗大，机件磨损快，物料在运输时粉碎严重。 1.7.2螺旋输送机的发展趋势 纵观螺旋输送机的发展历程，可以预见未来的发展方向主要有以下几方面: 1.大运量 、高速度、长使用寿命。高速度即意味着高生产率，减少单位时间生产成本.磨损是限制螺旋输送机寿命的主要原因，减少物料与螺旋之间的摩擦系数，增加螺旋轴的耐磨性，改善物料的性能，可以较大程度提高输送机的使用寿命。 2.低能源消耗及降低能量消耗.螺旋输送机的能源绝大部分都消耗在摩擦损失上。因此降低能源消耗是研究和设计螺旋输送机急待解决的难题和发展方向。 3.智能化发展。未来的螺旋输送机应与电脑密切联系，适合程序控制、智能操作。物料的装卸、机器安装与维护都应能实现智能化管理。 4.空间可弯曲输送。为了克服水平和垂直螺旋输送机由于构造上的限制而只能直线输送物料的不足，近年来出现了可弯曲螺旋输送机，弹簧输送机等。另外其他各种输送机也应为了实现空间、可弯曲输送研制新的机型。 5.组合复合化输送，向着大型化发展。使用螺旋输送机，结合各种连续输送机械，来完成复杂的物料输送。大型化包括大输送能力、单机长度和大输送倾角等几个方面。 6.扩大使用范围。目前，螺旋输送机的使用范围受到限制，要扩大其使用范围，研究能在高温、低温条件下有腐蚀性、放射性、易燃性物质的环境中工作的，以及能输送炽热、易爆、易结团、粘性物料的螺旋输送机。 7.环保意识设计，减少污染，实现绿色设计的目标。传统的连续运输机械是敞开状态下输送物料的，在输送粉状、颗粒状物料时，物料散落飞扬，严重影响周围的环境，特别是在输送水泥、化肥、矿石、煤炭、谷物等粉末易飞扬物料时尤显严重。为了解决 这个问题，人们应当提前研制多种形式的环保型输送机，而螺旋输送机对于解决这个难 题，无疑具有很大的优势和发展空间。 第二章 螺旋输送机的设计 2.1总体方案设计 2.1.1传动布置方案 电动机?联轴器?减速器?联轴器?螺旋输送机机 2.1.2设备的工作要求 载荷平稳，单向运转，每日工作一班，工作四年，允许螺旋输送机机主轴转速 误差小于5%，车间有三相交流电源。 2.2螺旋输送机总体结构设计 常见的倾斜固定式螺旋输送机，其结构比较简单。主要由驱动装置，料槽，螺旋轴，驱动端轴承，中间吊挂轴承，尾部端轴承，进料口，卸料口等部分组成，如下图所示: o图2-1 螺旋输送机(倾斜10)总体布置方式 1.电动机 2.联轴器 3.蜗轮蜗杆减速器 4 .联轴器 5.驱动端轴承 6.中间吊挂轴承 7.尾部端轴承 8.螺旋轴 9.进料口 10.卸料口 由于设计的螺旋输送机的长度为12米。为了制造,安装以及运输的方便,其槽体和 8 螺旋轴均采取分节制造,头节长2.5米,接着是2.5米、2米、2.5米长的中间节，尾节长2.5米，靠螺栓联接,并用中间轴承支承。同时,为了保证分节装配后输送机的整体刚度,槽体的连接处和螺旋轴的连接处需分开一段距离。由于物料在螺旋输送机中的运送完全是一种滑移运动,为了使螺旋轴处于较为有利的受拉状态，设计时将驱动装置和出料口安装在输送机的同一端,把进料口放在尾部附近。 2.3 螺旋输送机机体的设计 2.3.1输送机的螺旋直径和螺旋轴的转速 1) 螺旋直径的确定 Q2.5按公式，得螺旋直径 DK,,,C 式中 D——螺旋叶片直径(米); ——物料的输送量(吨/时); Q 3——物料的堆积比重(吨/米); , ——水平输送时物料在输送机内的填充系数; , K——表示物料综合特性的经验系数; ——倾斜向上输送时输送量的校正系数;(见表2-2) C 由表2-1，可以查得输送煤粉时:K=0.0415;=0.4;=0.6; A=75; ,, 由表2-2，=0.8;将原始数据, Q,12T/hC 12Q2.52.5，=0.0415=0.2170 mDK,0.4，0.6，0.8,,C D按表2-3将螺旋直径圆整为标准螺旋直径，=0.25m。 2) 螺旋轴转速的确定 Aa) 按公式n,带入螺旋直径，得螺旋轴转数: D A75 = =150 n,r/min 0.25D Q,把带入公式 ，校核填充系数:,D，n247DCs,n 12Q,==0.2837 ,2247，0.25，0.8，0.25，0.8，0.6，15047DCs,n 此时=0.2837<0.35,0.45，所以降低螺旋机的转数为n=120r/min ; , 12Q,再次校核填充系数==0.3546?,2247，0.25，0.8，0.25，0.8，0.6，12047DCs,n (0.35,0.45),所以螺旋机的转数确定为n=120r/min b) 螺旋叶片螺距:S=0.8D=0.8×250=200mm. 223.140.25，πD 20.35460.8输送机载荷的横断面面积:F===0.01391805,mC，，44 120，0.2ns物料在输送时的运移速度:===0.4m/s v6060 故:所选螺旋轴叶片直径D=250mm,螺旋轴转速n=120r/min 2.3.2 螺旋输送机的功率计算和驱动装置的型号选择 1) 螺旋输送机的功率计算 Q()螺旋轴克服阻力所需功率:N= kwL?H00367 在公式中 N——螺旋轴所需之功率(千瓦); 0 ——功率备用系数; k ——生产率(吨/时); Q ,——物料总阻力系数; 0 L---输送机水平投影长度(米) H---输送机垂直投影长度(米) 功率备用系数，考虑在低生产率时螺旋自重对功率的影响较大，以及为了计入空k 转时的损失，一般取=1.2,1.4; k 此时螺旋输送机倾斜向上输送，取“+”; 式中=1.2，取=1.3。 ,k0 12oo= =0.6914KW 带入公式计算得:N，，1.3，，1.2，12，cos10，12sin100367 N0.69140按公式得驱动装置功率:===0.7355KW N,0.94 由于采用浮动联轴器将驱动装置与螺旋轴直接连接，在其轴上不存在有悬臂负荷，故只需校验转速比: N0.69140 ==0.0058 n120 N，，由表2-6可知当=250时，=0.060。由于0.0058<0.060，故是安全的。 Dmm,,n，， 2) 驱动装置的型号选择 由,,查<<螺旋输送机手册>>表1-13,得驱动装置为:右N,0.7355KWn,120r/min 装的，功率为的型电动机和型的减速器构成. JOJZQJJ2125,11.10KW2 由，和选得的型号，从表2-6中便可查得，驱动装置的电动n,120r/minJJ2125,1 机为,,和减速器为,总传动比 JZQ250?,1ZJO21,4n,1500r/mini,12.642 2.3.3 螺旋叶片的表面展开尺寸 由计算得知螺旋叶片的大圆直径，螺旋螺距, D,250mmS,0.8D,0.8，250,200mm螺旋叶片内径为d=70mm,叶片宽度b=(D-d)/2=(250-70)/2=90mm 查相关参考书得出: ,D1=275mm,S=200mm,L=54mm,L`=19mm, δD,250mm =4mm,d=70mm. 所以叶片宽度b=(D-d)/2=(250-70)/2=90mm 图2-2 实体螺旋叶片展开图 222,bd，S螺旋叶片计算公式r, ，代入相关数据得 222222,D，S,,d，S 22290，3.14，70，200r,=52.14mm 2222223.14，250，200,3.14，70，200 按公式 R=b+r=90+52.14=142.14mm ooo222,180L180DS180810.08，，o,326.7按公式 ,,,,,R,R3.14142.14， 2.3.4 螺旋输送机的长度和标准螺旋节的长度 原始数据要求螺旋机全长为12米，根据《化工起重运输手册;螺旋输送机与斗式提升机》表1-10，头节长2.5米,接着是2.5米、2米、2.5米长的中间节，尾节长2.5米，GX型螺旋输送机的进料口是方形进料口，进料口下端直接焊牢在开孔的平盖板上，上端的为带孔法兰，可与各种给料设备连接使用。 2.4 驱动端装置的设计 2.4.1 驱动端轴的最小直径的确定 1) 求出轴上功率P.转速n和转矩T，有之前计算得:p=0.7355kw.n=120r/min p663 ，，， T=9.5510=9.55×100.7355/120=58.5310N,mmn 2) 初步确定轴的最小直径. 选取轴的材料为45钢,调质处理.根据表15-3(机械设计),取A=112于是得 30.7355P3， ==112=20.50mm. dAmin0120n 驱动端轴的最小直径，显然是安装联轴器处轴的直径，为了使所选联轴器的孔径与之相适应，故需同时选取联轴器型号联轴器的计算转矩T=KT,caA查《机械设计》表14-1.考虑到转矩变化不大，故取K=1.5,则: A ，T=KT=1.558.530=87.8N ,mcaA 按照计算转矩T应小于联轴器公称转矩的条件 ca 选用十字轴式万向联轴器。 2.4.2 驱动轴的结构设计 (1) 驱动轴如下图所示: 图2-3 驱动轴示意图 (2) 根据要求确定轴的各段直径和长度。 查螺旋输送机资料表6-3-13得知=40mm。半联轴器与轴配合的毂孔长da 度L=85mm. (3) 为了满足半联轴器的轴向定位要求，1段右端需制出一轴肩，故取 2段的直径=50mm。半联轴器与轴配合的毂孔长度L=70mm,现取da2 =68mm。由装备图可以知道，2段是来安放挡圈，根据端盖挡圈尺寸L1 及留余，取=73mm. L2 轴的3段和5段都是安放轴承的，初步确定滚动轴承。因为轴承承受径向力和轴向力的作用，故选用圆锥滚子轴。参照工作要求并根据=50mm。由于d2驱动轴主要承受轴向力和不大的径向力，故选择对开的圆锥滚子轴承。查手册选取0基本游隙组，标准精度级的单列圆锥滚子轴承30212，其尺寸为 ,故d,d,60mm,而L,L,23mm，d，D，T,60mm，110mm，23.75mm3535 右段滚动轴承采用轴肩定位。由手册查得30212型轴承的定位轴肩高度 ，取，。 d,69mmL,70mmh,4.5mm44 轴的6段为安装端盖处，，根据设计的端盖宽度，取d,d,50mm62 =87mm。轴的7段没有轴肩定位问题，考虑到与螺旋轴内孔配合，内孔还需L6 要焊接一个套筒加强强度，故取.长度. d,45mmL,100mm77 (4) 轴上键槽和销孔的位置设计 驱动轴、半联轴器与螺旋轴的周向定位均采用了平键连接，按,d,40mm1 查机械设计手则得平键截面,驱动轴右端与螺旋b，h，L,12mm，8mm，56mm 轴采用方向相互垂直的销轴联接，销孔直径为。 ,12 2.5 中间轴承装置 中间轴承又称为吊挂轴承，因为它脱空悬置在槽顶的内壁板条或角钢上。由于它处于输送物料之中，一般都做称对开式滑动轴承，其轴承采用粉末冶金，巴氏合金，青铜，铸铁及其他的减磨材料，在个别情况下为了减少摩擦阻力。视需要也可以安装上滚动轴承，不过必须保证有可靠的密封，以防止微尘物料进入轴承。所有的中间轴承都是用固定在平盖板上方的油杯注油润滑，在紧靠轴承附近的平盖板上，开设有观察孔，以便于观察轴承和消除轴承处因物料的堆积所引起的阻塞。GX型螺旋输送机的中间轴承装置，如图所示，它是用粉末冶金材料作轴衬的一种对开式滑动轴承，且轴衬呈球面型，以利于自动调心。 如下图所示为中间轴承装置。 图2-4 中间轴承示意图 而中间轴由《化工起重运输手册;螺旋输送机与斗式提升机》表1-37，查得 。其他尺寸见装配图。 d,50mm 螺旋轴呈螺旋输送机的回转部分，设计时可以采用实体螺旋，螺旋输送机的转轴一般采用钢管制成，在其两端头，焊偶连接法兰，结构如下图。 图2-5 螺旋轴示意图 由前面的计算得D=250mm.S=200mm。查考资料得,螺旋轴之间用对开式d,50mm 中间滑动轴承连接 2.6 尾端装置的设计 2.6.1计算轴的最小直径 ,由前知功率 P=0.7355=0.70kw,转速，扭矩T=58.53Nm ，0.95n,120r/min 初步确定轴的最小直径选取轴的材料为45钢，调质处理，根据《机械设计》表15—3，取,于是得 A,1120 33p0.703d,A,112，,20.16mm minn1203 轴的最小直径显然是安装在法兰轴套处，取此处d=45mm 2.6.2 尾端轴的结构设计 1)装备方案如装备图所示: 图2-6 尾端轴示意图 2) 根据要求确定轴的各段直径和长度:轴的左端与螺旋轴钢管内孔相接，由 于螺旋轴钢管外径为70mm，钢管不能太厚，本次设计的钢管内径为60mm，中间 还要焊接一个加强套筒，因此取=45mm确定=70mm，根据轴肩设计尺寸，参dL11 考驱动端端盖尺寸，选择=50mm，再由设计的端盖宽度确定=70mm，轴3段dL22 是轴承挡肩，取=62mm，=10mm,4段轴安放轴承段，取=56mm,由此选取dLd334 调心球轴承1212.其尺寸,故取=18mm，轴Ld，D，T,60mm，110mm，23.75mm4 最右端6段安装螺母挡圈，采用螺母M48×10,因为有螺纹，需要车退刀槽2×1， 即L=2mm，故d=44mm，d=48mm。 556 3)轴上零件的周向定位 螺旋轴钢管与轴的周向定位采用两个方向相互垂直的螺尾锥销固定，其尺 寸为M12 4)确定轴上的圆角和倒角尺寸 o 取轴端倒角为2，各轴肩圆角统一取为R2 ，45 2.7 驱动装置和尾端装置轴的校核 2.7.1 驱动装置的受力分析 根据设计任务，螺旋输送机长度为12m,为了制造,安装以及运输的方便,其槽 体和螺旋轴均采取分节制造,查资料应分5节，头节长=2.5米,接着是=2.5米、LL21 =2米、2.5米长的中间节，尾节长=2.5米头节，中间节及尾节，查表得LL,L435每段重力大小为，G,1911.98N1 ,,,,G,1521.94NG,1241.66NG,1521.94NG,1841.42N2345 ,,分解为垂直于螺M,195.1，155.3，2，126.7，187.9,820.3KgG,8038.94N总总旋轴的力,平行于螺旋轴的力 G,7916.75NF,1395.56N垂直 Q12为单位线载荷，物料阻力 qq,,,83.3N/mF,qL,999.6N物0.36v0.36，0.4 受力图如下: 图2-7 螺旋轴受力分析图 由力平衡 F1，F2，F3，F4，F5，F6,G G1 F1,,995.99N2 G1G2 F2,，,1716.96N22 G2G3 F3,，,1381.8N22 G3G4 F4,，,1381.8N22 G4G5 F5,，,1681.68N22 G5 F6,,920.71N2 , 尾部轴承只受径向力，不受轴向力，F1,F，F,2395.16N物 图2-8 尾部轴承受力分析 2.7.2 前端轴的校核 F1两轴承受径向力分别为 ,497.995N2 F1弯矩为 M,L,14679N,mm12 22M，(,T)13按弯扭强度进行校核 ,,,2.14MPacaW ,,<< []=275Mpa ,,,[,],275MPaca1ca,1 前端轴段径校核符合设计要求 2.7.3 尾端轴的校核 由于尾端轴承只承受径向力和扭矩作用，因此只对它进行扭转强度校核 T,, 《 ,,,2.34MPa,,[,]tt,tWT即满足要求 第三章 减速器的设计 3.1 蜗轮蜗杆减速器的运动和动力参数 转速 转矩 功率，，，，PKWTN,M传动 效率,轴名 ，，nr/min比 i输入 输出 输入 输出 电动机轴0 1(1 46.83 1500 1 0.99 蜗杆轴1 0.9475 0.938 47.3 46.83 1500 12(64 0.8 涡轮轴2 0(7504 0(7429 59.719 59.12 120 1 0.99 螺旋轴3 0(7355 58(53 120 表3-1 运动和动力参数计算结果 3.2 减速器的蜗杆设计 中间删了需要详细的请联系:xinanchong@163.com (1) 计算中心距 2160，2.93 取中心a,1.21，59789.458，mm,77.30mm 210.76 距。因,故从文献[2]的表11-2中取模数,蜗杆分度a,125mmi,12.64m,4 d,1圆直径。这时，从图11-18中可查得接触系数Z,2.7，d,40mm,0.4,1a ,因为，因此以上计算结果可用。 Z，Z,, 3.2.4 蜗杆与蜗轮的主要参数和几何尺寸 (1)蜗杆 19 蜗杆头数 ;轴向齿距;直径系数 z,4p,,m,3.14，4,12.561a d40*1;齿顶圆直径; d,d，2hm,40，2，1，4,48mmq,,,10aa11m4 *，，齿根圆直径 ，， d,d,2hm，c,40-2，1，4，1,30mmfa11 o,,,分度圆导程角 ,,214805 11蜗杆轴向齿厚 s,,m,，3.14，4,6.28mma22 (2)蜗轮 蜗轮齿数 ;变位系数 z,51x,，0.75022 z512验算传动比 ，这时传动比误差为i,,,12.75z41 12.75,12.64，是允许的。 ,0.0087,0.87%,5%12.64 蜗轮分度圆直径 d,mz,4，51,204mm22蜗轮喉圆直径 d,d，2h,204，2，7,218mma22a2蜗轮齿根圆直径 d,d,2h,204,2，2,200mmf22f2 11蜗轮咽喉圆半径 r,a,d,125,，218,16mmg2a222 3.2.5 校核齿根弯曲疲劳强度 KT1.532 ,,YY,,,,FFa2,Fddm12 z512当量齿数 z===54.93 v23o3,,,cos,(cos214805) 根据，，从文献[2]中的图11-19可查得齿形系数 z,54.93Y,2.028x,，0.750v2Fa22 o21.8,螺旋角系数 Y,1,,1,,0.84,oo140140 , 许用弯曲应力 ,,,,,,,,K FFFN ,从表11-18中查得由ZCuSn10P1制造的蜗轮的基本许用应力。 ,,,,56MPaF 中间删了需要详细的请联系:xinanchong@163.com 图3-1 蜗轮轴示意图 选用45号钢，调质处理 。 (1) 按扭转强度，初步估计轴的最小直径 33p0.75042d,A,112，,20.63mm minn1202 联轴器的计算转矩,查表14-1，考虑到转矩变化很小，故取T,KTcaA1 ，则 K,1.5A =1.5×59.719=89.58 TKT,N,mcaA2 按照计算转矩小于联轴器转矩的条件，查手册，选用十字轴式万向联轴器，其许用转矩为280。半联轴器的孔径=24mm， dN,m1 (2)根据轴向定位的要求确定轴的各段直径和长度 1)为了满足联轴器的轴向定位要求，，1段h,(0.07~0.1)dh,(1.68~2.4mm) d右端需制出一轴肩，故取2段的直接=28mm;左端用挡圈定位，按轴端直2 接取挡圈直径D=31mm。联轴器与轴配合的毂孔长度=82mm，为了保证轴端L1 挡圈只压在半联轴器上而不压在轴的断面上，故1段的长度应比略短一L1 些，现取=80mm。 l1 2)初步选择滚动轴承。因轴承同时受有径向力和轴向力的作用，故选用单列圆 锥滚子轴承。又d=28mm，选取0基本游隙组、标准精度级的30207，其尺2 寸，故=35mm，取l=20m。 d,dd，D，T,35mm，72mm，18.25mm737 右端滚动轴承采用轴肩经行轴向定位。由手册查得30207型轴承定位轴肩高 =42mm。 d6 3)取安装蜗轮处的轴段的直径=40mm，查手册并由前面所得数据计算蜗轮轮d4 毂的宽度为54mm，为了使套筒端面可靠地压紧齿轮，此轴段应略短于轮毂宽 度，故取=50mm，齿轮的右端采用轴肩定位，故取=3mm，则轴环处的直径lh4 =56mm。轴环宽度，故取=10mm。 ldb,1.4h55 4)轴承端盖的总宽度为20mm(装配图)，取端盖的外端面与半联轴器右端面的 距离=30mm,故取=50mm。 ll2 5)取蜗轮距箱体之距离a=16mm，滚动轴承距箱体内壁一段距离s=8mm,已知滚 动轴承T=18.25mm，蜗轮轮毂长为L=80mm，则: =T+s+a+(54-50)=20+8+16+4=48mm l3 =L+c+a+s+=12mm ll65 (4)轴上零件的轴向定位 蜗轮、半联轴器与轴的周向定位均采用平键连接。按表6-1查得 ;键槽用键槽铣刀加工，长为40mm，同时为了保证蜗轮与轴配b，h,12mm，8mm H7合有良好的中性，故选择蜗轮轮毂与轴的配合为;同样，半联轴器与轴的连r6 H7接，选用平键为，半联轴器与轴的配合为。 12mm，8mm，7mmf8 滚动轴承与轴的周向定位是过渡配合来保证的，此处选轴的直径尺寸公差为 。 H7 (2)确定轴上圆角和倒角尺寸 o参考表15-2，取轴端倒角为，各轴肩处的圆角半径见零件图。 1，45 3.3.2 求蜗轮轴上的载荷 首先根据轴的结构示意图(图3-1)做出轴的计算简图，从手册中查取a值(文献[2]图15-23)。对于30207型圆锥滚子轴承，从手册中查得a=16mm。因此，作为简支梁的轴的支承跨距。 L，L,39mm，49mm,88mm23 从轴的结构简图以及弯矩和扭矩图中可以看出截面C是轴的危险截面。现将计算出的M及的值列于下表M、MHV 载荷 水平面 垂直面 HV支反力 F,326.01N，F,259.28NF,,112.75N，F,338.15NNH1NH2NV1NV2 F M,,5524.75N,mm，M,26087.95N,mm M,12714.39N,mmV1V2H弯矩 M 22 M,12714.39，5524.75,13862.85N,mm1 总弯矩 22 M,12714.39，26087.95,29021.32N,mm2 T,59720N,mm2扭矩 T 图3-2 轴的载荷分析图 25 1)轴上受力分析 轴传递的转矩 T,59.72N,m2 2T2蜗轮的圆周力 F,,585.49N,mtd2 tan,蜗轮的径向力 F,F,225.4N,mrt,cos 蜗轮的轴向力 F,F,tan,,201.6N,mat 2)求支反力 d2F,L,F,ra32在垂直平面内的支反力 F,,,112.75NNV188 F,Fr,F,338.15NNV2NV1 F,Lt3在水平平面内的支反力 F,,326.01NNH188 F,F,F,259.28NNH2tNH1 3) 求弯矩和做弯矩图 在垂直平面内的弯矩 M,F,L,,5524.75N,mmV1NV23 d2 M,M,F,,26087.95N,mmVVa212 在水平平面内的弯矩 M,F,L,12714.39N,mmHNH12 2222 总弯矩 M,M，M,12714.39，5524.75,13862.85N,mm HNV11 2222 M,M，M,12714.39，26087.95,29021.32N,mmHNV22 扭矩 T,59.72N,m2 3.3.3 按弯扭合成应力校核轴的强度 进行校核时，只校核轴上承受最大弯矩和扭矩的截面的强度。根据式15-5及上表 中的数据，以及单向旋转，扭转切应力为脉动循环变应力，取，轴的计算力 ,,0.6 2222M，(,T)13862.85，(0.6，59720)13 ,,,MPa,7.55MPaca3W0.1，40 前已选定轴的材料为45钢，调质处理，由表15-1查得。因此[,],60MPa,1 ，故安全。 ,,[,]ca,1 3.3.4 精确校核轴的疲劳强度 a)截面A,B,C,D只受扭矩的作用，虽然键槽、轴肩及过渡配合所引起的应力集中均将削弱轴的疲劳强度，但由于轴的最小直径是按扭转强度较为宽裕来确定的，所以截面A,B,C,D无需校核。由于界面4,5是过盈配合，所引起的应力集中最严重;从受载的情况来看 ，截面E上的应力最大。截面F的情况和截面4相近，但截面E不受扭矩作用，同时轴径较大，不比校核，截面E上虽然应力最大， ，7更不必校核。由第三章附录可知，但应力集中不大，故也不必校核，截面6 键槽的应力集中系数比过盈配合的小，因而该轴只需校核截面4的左右两侧即可。 b)截面4左侧 333抗弯截面系数 W,0.1d,0.1*35,4287.5mm 333抗扭截面系数 ,0.2d,0.2*35,8575mmWT 截面4左侧的弯矩M为 39,25 M,13862.85，N,mm,4976.4N,mm39 截面4上的扭矩为 T,59720N,mm2 截面上的弯曲应力 M4976.4 ,,MPa,1.16MPa,bW4287.5 截面上的扭转切应力 T597202 ,,,,6.96MPaT8575wT 轴的材料为45钢，调质处理。由表15-1查表，，,,640MPa,,275MPaB,1 。截面上由于轴肩而形成的理论应力集中系数和可查表。,155MPa,,,,1,, D40r1因为，,经插值后可查得,1.7，,1.26 ,,0.029,,1.14,,,,d35d35 又查表得材料敏感系数为 ， ,0.82,0.85qq,, 故有效应力集中系数按式为 k,1，q(,,1),1，0.82，(1.7,1),1.574,,, k,1，q(,,1),1，0.85，(1.26,1),1.221,,, 查表得尺寸系数 ，扭转尺寸系数 ， ,0.67,0.82,,,,轴按磨削加工表面质量系数 ,,0.92,,,,轴未经表面强化处理，即，则得综合系数 ,,1q 11.5741,k ,，,1,，,1,2.43,K0.670.92,,,, 11.2211,k ,，,1,，,1,1.58,K0.820.92,,,, 由文献[2]碳素钢的特性系数取， ,,0.1,,0.05,,于是计算安全系数的值如下 275,,1 ,,,97.6S,2.43*1.16，0.1*0，,,,K,am, 155,,1 ,,,27.33S,6.966.96，,,,K,am1.58*，0.05*,22 97.6，27.33SS,, ,,,26.32,,S,1.5Sca222297.6，27.33，SS,, 故可知其安全。 c)截面4右侧 333抗弯截面系数 W,0.1d,0.1*40,6400mm 333抗扭截面系数 ,0.2d,0.2*40,12800mmWT 截面4左侧的弯矩M为 39,25 M,13862.85，N,mm,4976.4N,mm39 截面4上的扭矩为 T,59720N,mm2 截面上的弯曲应力 M4976.4 ,,MPa,0.78MPa,bW6400 截面上的扭转切应力 T597202 ,,,,4.67MPaT12800wT kkk,,,，由附表3-8用插值法求出，并取，于过盈配合处的,0.8,,,,,, kkk,,,是得 ,3.13,0.8,0.8，3.13,2.504,,,,,, 轴按磨削加工，由附图3-4得表面质量数为 ,,,,0.91,, 轴未经表面强化处理，即，则得综合系数 ,,1q 11,k ,，,1,3.13，,1,3.2,K0.92,,,, 11,k ,，,1,2.504，,1,2.59,K0.92,,,, 所以轴在截面4右侧的安全系数为 275,,1 ,,,24.69S,3.2*0.78，0.1*0，,,,K,am, 155,,1 ,,,25.14S,4.674.67，,,,K,am2.59*，0.05*,22 24.69，25.14SS,, ,,,19.25,,S,1.5Sca222224.69，25.14，SS,, 故可知其安全。 3.4 蜗杆轴的设计 3.4.1 初步确定轴的最小直径 查表15-3得，当轴材料为45钢时可取， A,1120 P0.947513d,A3,112，mm,9.61mm min0n15001 查《机械零件设计手册》表GB/T 4323-2002 LT4型弹性套柱销联轴器，标准孔径d=20mm，即轴伸直径为=20mm 。轴孔长度L=52mm d1 联轴器的计算转矩,查表14-1，考虑到转矩变化很小，故取，T,KTK,1.5caA1A则 T,KT,1.5，6.03,9.045N,mcaA1 3.4.2蜗杆轴的结构设计 1)拟定轴上零件的装配方案如下图所示: 图3-3 蜗杆示意图 2)根据轴向定位要求，，1轴右端需要一台阶h,(0.07~0.1)dh,(1.4~2mm) d,24mm故取,考虑联轴器轴向定位(套筒定位)可靠以及端盖厚度的覆2 l,50mm盖，故取 1 由于2段用于左轴承定位(圆螺母定位)，取，故车削时应有退刀槽，宽,19mml2 度为2mm 3)初步选定滚动轴承，应同时受有径向力和轴向力的作用，故选用角接触球轴 承7306C轴承，参照要求选取圆锥滚子轴承30207，其尺寸 ,故取d,d,35mm，轴承采用右端轴肩定d，D，T,35mm，72mm，19mm39 位，右轴承左端采用轴肩定位，且由于轴承何齿轮润滑条件不同，应有挡油 环，取查表得角接触球轴承7306C定位轴肩高度，l,l,20mmd,3.5mm39 l,l,10mmd,d,40mm此，。 4848 l,80mm4)6段为蜗杆螺旋，取，由于齿顶圆直径为，取d,48mm6a1 d,d,30mml,l,51mm，取，右轴承右端用圆螺母轴向定位，取5757 ,。 d,25mml,20mm1010 3.5 减速器箱体及附件的设计 3.5.1 箱体的基本结构设计 箱体是减速器的一个重要零件，它用于支持和固定减速器中的各种零件，并保证传动件的啮合精度，使箱体有良好的润滑和密封。箱体的形状较为复杂，其重量约占减速器的一半，所以箱体结构对减速器的工作性能、加工工艺、材料消耗，重量及成本等有很大的影响。箱体结构与受力均较复杂，各部分民尺寸一般按经验公式在减速器装配草图的设计和绘制过程中确定。 3.5.2 箱体的材料及制造方法:选用铸铁，砂型铸造。 3.5.3 箱体各部分的尺寸 箱体各部分尺寸如下表 名 称 称 号 一级蜗杆减速器 计算结果 箱座壁厚 δ 0.04a+3mm?8mm 11 箱盖壁厚 δ 蜗杆在下0.85δ?8mm 9.5 1 机座凸缘厚度 b 1.5δ 16.5 机盖凸缘厚度 b 1.5δ 14 11 机座底凸缘厚度 b 2.5δ 27.5 2 地脚螺钉直径 d 0.036a+12mm 20 f 地脚螺钉数目 n 4 轴承旁连接螺栓直径 d 0.75 d 16 1f机座与机盖连接螺栓直径 d (0.5~0.6) d 10 2f连接螺栓的间距 dl 150~200mm 150 2 轴承端螺钉直径 d (0.4~0.5) d 8 3f窥视孔盖螺钉直径 d (0.3~0.4) d 8 4f 定位销直径 d (0.7~0.8) d 8 2d、d、d至外机壁距离 c 22,16,13 f1 21 d、d至缘边距离 c 20,11 f 22 轴承旁凸台半径 R c 20 12 凸台高度 h 根据低速轴承座外径确定 42 外机壁到轴承端面距离 l c+ c+(5~8)mm 48 112内机壁到轴承端面距离 l δ+ c+ c+(5~8)mm 56 212蜗轮齿顶圆与内机壁距离 ? ?1.2δ 13.2 1 蜗轮端面与内机壁的距离 ? ?δ 11 2 机座肋厚 m m?0.85δ 10 轴承端盖外径 D 轴承座孔直径+(5~5.5) d 116 23轴承端盖凸缘厚度 e (1~1.2) d 10 3 表3-2 箱体各部分尺寸如下表 第四章 轴承校核 4.1蜗杆轴滚动轴承计算 (1) 预期寿命 ,要求使用寿命=4年×300天×8小时=9600小时 Lh (2) 寿命计算 使用30207型圆锥滚子轴承 ，，， f,1.5C,63.5KNC,54.2KN,,10/3p0rr 轴颈，转速 d,35mmn,1500r/min由前面设计蜗轮求得:、 F,F,,112.75Nr1VNV1 F,F,338.15Nr2VNV2 F,F,326.01NrH1NH1 F,F,259.28NrH2NH2 22 F,F，F,334.96NrrVrH111 22 F,F，F,426.11NrrVrH222 (3) 计算轴向力 F,F,e,334.96，0.37,123.94Nd1r1 F,F,e,426.11，0.37,157.66Nd2r2 因为，所以有 F,201.6NF,201.6，123.94,352.54Naa1 F,F,157.66Na2d2(4) 求当量动载荷 P和P12 FFa1a2 ， ,1.05,e,0.35,eFFr1r2 33 P,f(XF，YF),1047.072N1P1r11a1 P,f(XF，YF),639.165N2P2r22a2 (5) 验算轴承寿命 ,1060nL60，120，9600h,3 因为,按式 C,P,1047，,3731NP,P121661010 106610C103731,3 L,(),(),9599.8,9600hh60nP60，12010471 值约等于预期寿命，所以要使这个减速器的低速轴正常使用，工作3.8求得的Lh 年要换一次轴承。 第五章 键的校核 5.1 蜗杆轴端和联轴器的联结的键 (1)选择的键为 b，h，L,12mm，8mm，56mm (2)校核键的强度 轴，键，轮毂都是钢，查表7-3可得钢的许用挤压应力为 [,],120MPa, 键的工作长度为， l,L,b,56,12,44mmK,0.5，h,4 332T,102，59.72，10 ,,,,16.97MPa,[,],110MPap,Kld4，44，40 故满足要求。 5.2 涡轮与轴联结的键 (1)选择的键为.根据轴的直径为50mm b，h，L,12mm，8mm，40mm (2)校核轴的强度 轴，键，轮毂都是钢，查表7-3可得钢的许用挤压应力为 [,],120MPa, 键的工作长度为， l,L,b,40,12,28mmK,0.5，h,4 332T,102，59.72，10 ,,,,21.33MPa,[,],110MPap,Kld4，28，50 故满足要求。 5.3 涡轮轴轴端和联轴器联结的键 (1)选择的键为.根据轴的直径为24mm b，h，L,10mm，8mm，70mm (2)校核轴的强度 轴，键，轮毂都是钢，查表7-3可得钢的许用挤压应力为[,],120MPa , 键的工作长度为， l,L,b,24,10,14mmK,0.5，h,4 35 332T,102，59.72，10 ,,,,88.87MPa,[,],110MPap,Kld4，14，24 故满足要求。 第6章 润滑和密封的设计 6.1 润滑 蜗轮采用浸油润滑,轴承采用脂润滑。 4 5蜗轮圆周速度v<5m/s所以采用浸油润滑;轴承Dpw?n=1.455×10?(2~3) ×10 所以采用脂润滑。浸油润滑不但起到润滑的作用，同时有助箱体散热。为了避免浸油的搅动功耗太大及保证齿轮啮合区的充分润滑，传动件浸入油中的深度不宜太深或太浅，设计的减速器的合适浸油深度H ~1)个齿高，但油面不应高 对于蜗杆下置一般为(0.751 于蜗杆轴承下方滚动体中心。油池太浅易激起箱底沉渣和油污，引起磨料磨损，也不易散热。取浸油深度H为10mm。换油时间为半年，主要取决于油中杂质多少及被氧化、1 被污染的程度。查手册选择L-CKB 150号工业齿轮润滑油。 6.2 密封 减速器需要密封的部位很多，有轴伸出处、轴承内侧、箱体接受能力合面和轴承盖、窥视孔和放油的接合面等处。 6.2.1 轴伸出处的密封 作用是使滚动轴承与箱外隔绝，防止润滑油漏出以及箱体外杂质、水及灰尘等侵入轴承室，避免轴承急剧磨损和腐蚀。由脂润滑选用毡圈密封，毡圈密封结构简单、价格便宜、安装方便、但对轴颈接触的磨损较严重，因而工耗大，毡圈寿命短。 6.2.2 轴承内侧的密封 该密封处选用挡油环密封，其作用用于脂润滑的轴承，防止过多的油进入轴承内，破坏脂的润滑效果。 6.2.3 盖与箱座接合面的密封的接合面上涂上密封胶 37 6.3 附件的设计 6.3.1 窥视孔盖和窥视孔 为了检查传动件的啮合、润滑、接触斑点、齿侧间隙及向箱内注油等，在箱盖顶部设置便于观察传动件啮合的位置并且有足够大的窥视孔，箱体上窥视孔处应凸出一块，以便加工出与孔盖的接触面。 6.3.2 排油孔、放油油塞、通气器、油标 为了换油及清洗箱体时排出油污，在箱座底部设有排油孔，并在其附近做出一小凹坑，以便攻丝及油污的汇集和排放，平时排油孔用油塞及封油垫封住。本设计中采用螺塞M14×1.5 。 为了检查减速器内的油面高度，应在箱体便于观察、油面较稳定的部位设置油标 致谢 39 参考文献 [1] 南京化工公司设计院，化工起重运输机手册[M]. 北京:石油工业出版社,1976,9. [2] 濮良贵，纪名刚.机械设计(第八版)[M].北京:西北工业大学机械原理及机械零件教研室，高 等教育出版社，2000( [3] 徐 灏. 机械设计手册第一版第三卷[M]. 北京:机械工业出版社,1991,9. [4] 周良德，朱泗芳等.现代工程图学[M].湖南:湖南科学技术出版社，2000,6. [5] 成大先. 机械设计手册——轴及其联轴器[M]. 北京: 化学工业出版社,2004，1. [6] 程乃士.减速器与变速器[M]. 北京[M]:机械工业出版社, 2006,10. [7] 陈铁鸣 .新编机械设计课程设计图册[M],北京:高等教育出版社,2003,7. [8] 成大先.机械设计手册(第四版)[M].北京:化学工业出版社，2002.1 [9] 吴宗泽，罗圣国等.机械设计课程设计手册(第3版)[M].北京:高等教育出版社，2006.5. [10] 罗迎社.材料力学[M].武汉理工大学出版社，2001.6. [11] 哈尔滨工业大学理论力学教研室.理论力学[M]. 北京:高等教育出版，2002. [12] 吴宗泽.机械零件设计手册[M].北京:机械工业出版社，2004. 40 41 附录2 英文文献原文 20.9 MACHINABILITY The machinability of a material usually defined in terms of four factors: 1、Surface finish and integrity of the machined part; 2、Tool life obtained; 3、Force and power requirements; 4、Chip control. Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone. Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below. 20.9.1 Machinability Of Steels Because steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels. Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in resulfurized steels. Phosphorus in steels has two major effects. It strengthens the ferrite, causing increased hardness. Harder steels result in better chip formation and surface finish. Note that soft steels can be difficult to machine, with built-up edge formation and poor surface finish. The second effect is that increased hardness causes the formation of short chips instead of continuous 41 stringy ones, thereby improving machinability. Leaded Steels. A high percentage of lead in steels solidifies at the tip of manganese sulfide inclusions. In non-resulfurized grades of steel, lead takes the form of dispersed fine particles. Lead is insoluble in iron, copper, and aluminum and their alloys. Because of its low shear strength, therefore, lead acts as a solid lubricant (Section 32.11) and is smeared over the tool-chip interface during cutting. This behavior has been verified by the presence of high concentrations of lead on the tool-side face of chips when machining leaded steels. When the temperature is sufficiently high-for instance, at high cutting speeds and feeds (Section 20.6)—the lead melts directly in front of the tool, acting as a liquid lubricant. In addition to this effect, lead lowers the shear stress in the primary shear zone, reducing cutting forces and power consumption. Lead can be used in every grade of steel, such as 10xx, 11xx, 12xx, 41xx, etc. Leaded steels are identified by the letter L between the second and third numerals (for example, 10L45). (Note that in stainless steels, similar use of the letter L means “low carbon,” a condition that improves their corrosion resistance.) However, because lead is a well-known toxin and a pollutant, there are serious environmental concerns about its use in steels (estimated at 4500 tons of lead consumption every year in the production of steels). Consequently, there is a continuing trend toward eliminating the use of lead in steels (lead-free steels). Bismuth and tin are now being investigated as possible substitutes for lead in steels. Calcium-Deoxidized Steels. An important development is calcium-deoxidized steels, in which oxide flakes of calcium silicates (CaSo) are formed. These flakes, in turn, reduce the strength of the secondary shear zone, decreasing tool-chip interface and wear. Temperature is correspondingly reduced. Consequently, these steels produce less crater wear, especially at high cutting speeds. Stainless Steels. Austenitic (300 series) steels are generally difficult to machine. Chatter can be s problem, necessitating machine tools with high stiffness. However, ferritic stainless steels (also 300 series) have good machinability. Martensitic (400 series) steels are abrasive, tend to form a built-up edge, and require tool materials with high hot hardness and crater-wear resistance. Precipitation-hardening stainless steels are strong and abrasive, requiring hard and abrasion-resistant tool materials. The Effects of Other Elements in Steels on Machinability. The presence of aluminum and silicon in steels is always harmful because these elements combine with oxygen to form 42 aluminum oxide and silicates, which are hard and abrasive. These compounds increase tool wear and reduce machinability. It is essential to produce and use clean steels. Carbon and manganese have various effects on the machinability of steels, depending on their composition. Plain low-carbon steels (less than 0.15% C) can produce poor surface finish by forming a built-up edge. Cast steels are more abrasive, although their machinability is similar to that of wrought steels. Tool and die steels are very difficult to machine and usually require annealing prior to machining. Machinability of most steels is improved by cold working, which hardens the material and reduces the tendency for built-up edge formation. Other alloying elements, such as nickel, chromium, molybdenum, and vanadium, which improve the properties of steels, generally reduce machinability. The effect of boron is negligible. Gaseous elements such as hydrogen and nitrogen can have particularly detrimental effects on the properties of steel. Oxygen has been shown to have a strong effect on the aspect ratio of the manganese sulfide inclusions; the higher the oxygen content, the lower the aspect ratio and the higher the machinability. In selecting various elements to improve machinability, we should consider the possible detrimental effects of these elements on the properties and strength of the machined part in service. At elevated temperatures, for example, lead causes embrittlement of steels (liquid-metal embrittlement, hot shortness; see Section 1.4.3), although at room temperature it has no effect on mechanical properties. Sulfur can severely reduce the hot workability of steels, because of the formation of iron sulfide, unless sufficient manganese is present to prevent such formation. At room temperature, the mechanical properties of resulfurized steels depend on the orientation of the deformed manganese sulfide inclusions (anisotropy). Rephosphorized steels are significantly less ductile, and are produced solely to improve machinability. 20.9.2 Machinability of Various Other Metals Aluminum is generally very easy to machine, although the softer grades tend to form a built-up edge, resulting in poor surface finish. High cutting speeds, high rake angles, and high relief angles are recommended. Wrought aluminum alloys with high silicon content and cast aluminum alloys may be abrasive; they require harder tool materials. Dimensional tolerance control may be a problem in machining aluminum, since it has a high thermal coefficient of expansion and a relatively low elastic modulus. 43 Beryllium is similar to cast irons. Because it is more abrasive and toxic, though, it requires machining in a controlled environment. Cast gray irons are generally machinable but are. Free carbides in castings reduce their machinability and cause tool chipping or fracture, necessitating tools with high toughness. Nodular and malleable irons are machinable with hard tool materials. Cobalt-based alloys are abrasive and highly work-hardening. They require sharp, abrasion-resistant tool materials and low feeds and speeds. Wrought copper can be difficult to machine because of built-up edge formation, although cast copper alloys are easy to machine. Brasses are easy to machine, especially with the addition pf lead (leaded free-machining brass). Bronzes are more difficult to machine than brass. Magnesium is very easy to machine, with good surface finish and prolonged tool life. However care should be exercised because of its high rate of oxidation and the danger of fire (the element is pyrophoric). Molybdenum is ductile and work-hardening, so it can produce poor surface finish. Sharp tools are necessary. Nickel-based alloys are work-hardening, abrasive, and strong at high temperatures. Their machinability is similar to that of stainless steels. Tantalum is very work-hardening, ductile, and soft. It produces a poor surface finish; tool wear is high. Titanium and its alloys have poor thermal conductivity (indeed, the lowest of all metals), causing significant temperature rise and built-up edge; they can be difficult to machine. Tungsten is brittle, strong, and very abrasive, so its machinability is low, although it greatly improves at elevated temperatures. Zirconium has good machinability. It requires a coolant-type cutting fluid, however, because of the explosion and fire. 20.9.3 Machinability of Various Materials Graphite is abrasive; it requires hard, abrasion-resistant, sharp tools. Thermoplastics generally have low thermal conductivity, low elastic modulus, and low softening temperature. Consequently, machining them requires tools with positive rake angles 44 (to reduce cutting forces), large relief angles, small depths of cut and feed, relatively high speeds, and proper support of the workpiece. Tools should be sharp. External cooling of the cutting zone may be necessary to keep the chips from becoming “gummy” and sticking to the tools. Cooling can usually be achieved with a jet of air, vapor mist, or water-soluble oils. Residual stresses may develop during machining. To relieve these stresses, machined parts can be annealed for a period of time at temperatures ranging from to (to), and then cooled slowly and uniformly to room 80:C160:C175:F315:F temperature. Thermosetting plastics are brittle and sensitive to thermal gradients during cutting. Their machinability is generally similar to that of thermoplastics. Because of the fibers present, reinforced plastics are very abrasive and are difficult to machine. Fiber tearing, pulling, and edge delamination are significant problems; they can lead to severe reduction in the load-carrying capacity of the component. Furthermore, machining of these materials requires careful removal of machining debris to avoid contact with and inhaling of the fibers. The machinability of ceramics has improved steadily with the development of nanoceramics (Section 8.2.5) and with the selection of appropriate processing parameters, such as ductile-regime cutting (Section 22.4.2). Metal-matrix and ceramic-matrix composites can be difficult to machine, depending on the properties of the individual components, i.e., reinforcing or whiskers, as well as the matrix material. 20.9.4 Thermally Assisted Machining Metals and alloys that are difficult to machine at room temperature can be machined more easily at elevated temperatures. In thermally assisted machining (hot machining), the source of heat—a torch, induction coil, high-energy beam (such as laser or electron beam), or plasma arc—is forces, (b) increased tool life, (c) use of inexpensive cutting-tool materials, (d) higher material-removal rates, and (e) reduced tendency for vibration and chatter. It may be difficult to heat and maintain a uniform temperature distribution within the workpiece. Also, the original microstructure of the workpiece may be adversely affected by elevated temperatures. Most applications of hot machining are in the turning of high-strength 45 metals and alloys, although experiments are in progress to machine ceramics such as silicon nitride. SUMMARY Machinability is usually defined in terms of surface finish, tool life, force and power requirements, and chip control. Machinability of materials depends not only on their intrinsic properties and microstructure, but also on proper selection and control of process variable. 46