XK6125数控铣床总体及横向进给传动机构设计(全套含CAD图纸)
下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985毕 业 设 计 (论 文 )XK6125 数控铣床总体及横向进给传动机构设计所 在 学 院专 业班 级姓 名学 号指 导 老 师年 月 日下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985I摘 要本论文是对 XK6125数控铣床总体及横向进给传动机构设计,其内容包括:进给伺服系统机械部分设计与计算、步进电动机的计算与选型、铣床改造的结构特点、安装调整中应注意的问题等。对普通铣床进行数控改造符合我国国情,即适合我国目前的经济水平、教育水平和生产水平,又是国内许多企业提高生产设备自动化水平和精密程度的主要途径,在我国有着广阔的市场。从另一个角度来说,该设计既有机床结构方面内容,又有机加工方面内容,还有数控技术方面的内容,有利于将大学所学的知识进行综合运用。虽然设计者未曾系统的学习过机床设计的课程,但通过该设计拓宽了知识面,增强了实践能力,对普通机床和数控机床都有了进一步的了解。关键词:横向进给系统,数控化改造,机床改造,铣床下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985IIAbstractThe present paper is to XK6125 for feed system of NC transformation, its contents include: feed servo system of mechanical part design and calculation, and the calculation of the stepper motor selection, Miller structure characteristics, installation and adjustment should pay attention to the problem. On the common milling machine numerical control transformation in line with Chinas national conditions, that is suitable for Chinas current economic level, educational level and the level of production, but also many domestic enterprises to improve the level of automated production equipment and precision degree of the main way, has the broad market in our country. From another perspective, the design is a machine tool structure in terms of content, but also organic processing aspects, CNC technical content, the university knowledge to make comprehensive use of. Although the designers have not studied the machine design course, but through the design to broaden the knowledge, enhances the ability of practice, the general machine tools and CNC machine tools have a further understanding.KeyWords: horizontal feed system, NC transformation, transformation of machine tools, milling machine下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985III目录摘 要 .IAbstract .II目录 .III第 1 章 数控机床发展概述.11.1 数控机床发展概述 .11.2 数控机床的组成及分类 .11.2.1 数控机床的组成 .11.2.2 数控机床的分类 .31.3 数控机床的特点及应用范围 .41.3.1 数控机床的特点 .41.3.2 数控机床的应用范围 .4第 2 章 数控机床总体方案的制订及比较.52.1 课题要求 .52.1.1 题目名称(包括主要技术参数)及技术要求 .52.1.2 课题内容及工作量 .52.2 设计原则 .52.3 总结构设计 .62.3.1 数控机床的机构设计要求 .62.3.2 提高机床的结构刚度 .62.3.3 提高进给运动的平稳性和精度 .7第 3 章 确定切削用量及选择刀具.83.1 刀具选择 .83.2 切削用量确定 .83.3 切削三要素 .93.4 加工精度和表面粗糙度 .93.5 刀具材料 .12第 4 章 传动系统图的设计计算.13IV4.1 传动系统设计 .134.1.1 参数的拟定 .134.1.2 传动结构或结构网的选择 .134.1.3 转速图拟定 .154.1.4 齿轮齿数的确定及传动系统图的绘制 .184.2 传动件的估算与验算 .224.2.1 传动轴的估算和验算 .224.2.2 齿轮模数的估算与验算 .244.3 展开图设计 .294.3.1 结构实际的内容及技术要求 .294.3.2 齿轮块的设计 .314.3.3 传动轴设计 .334.3.4 主轴组件设计 .364.4 制动器设计 .414.5 截面图设计 .424.5.1 轴的空间布置 .424.5.2 润滑 .434.5.3 箱体设计的有关问题 .44第 5 章 横向进给传动机构装配图零件图的设计计算.455.1 进给伺服系统的设计 .455.1.1 对进给伺服系统的基本要求 .455.1.2 进给伺服系统的设计要求 .455.1.3 进给伺服系统的动态响应特性及伺服性能分析 .465.2 横向进给滚珠丝杠副设计 .465.2.1 导程确定 .465.2.2 确定丝杆的等效转速 .465.2.3 估计工作台质量及负重 .475.2.4 确定丝杆的等效负载 .475.2.5 确定丝杆所受的最大动载荷 .47下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985V5.2.6 精度的选择 .485.2.7 选择滚珠丝杆型号 .495.3 校核 .495.3.1 临界压缩负荷验证 .495.3.2 临界转速验证 .505.3.3 丝杆拉压振动与扭转振动的固有频率 .515.4 电机的选择 .515.4.1 电机轴的转动惯量 .525.4.2 电机扭矩计算 .52总结与展望.54参考文献.55致 谢.56VI下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985VII下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 119709851第 1 章 数控机床发展概述1.1 数控机床发展概述随着社会生产和科学技术的发展,机械产品日趋精密复杂,且需频繁改型。特别是在宇航、造船、军事等领域所需的零件,精度要求高,形状复杂,批量小。普通机床已不能适应这些需求。为了满足上述要求,一种新型的机床数字程序控制机床(简称数控机床)应运而生。最早进行数控机床研制的是美国人。1952 年,美国麻省理工学院成功地研制出一套三坐标联动,利用脉冲乘法器原理的数控机床。但这台数控机床仅是一台试验性的机床,当时用的电子元件是电子管。直到 1954 年 11 月,第一台工业用的数控机床才生产出来。从此以后,世界上其他一些工业国家也多开始开发、生产及应用数控机床。我国数控机床的研制是从 1958 年起步的。1965 年国内开始研制晶体管数控系统。从 70 年代开始,数控技术广泛应用于车、铣、钻、镗、磨、齿轮加工、点加工等领域,数控加工中心在上海、北京研制成功。在这一时期,数控线切割机床由于结构简单,使用方便、价格低廉,在模具加工中得到了推广。80 年代,我国从日本及美国、德国引进一些新技术。这使我国的数控机床在性能和质量上产生了一个质的飞跃。1985 年,我国数控机床品种有了新的发展。早期的数控机床控制系统采用电子管,体积大、功耗高,只在军事部门应用。只有在微处理机用于数控机床后,才真正使数控机床得到了普及。目前数控技术的主要发展趋势是:实现高速度,搞可靠性,高精度,大功率,多功能;采用微处理机和微型计算机,向着增强功能、降低造价、方便使用的目标进展;积极应用计算技术、系统工程理论和控制技术的最新成果,像这综合自动化方向变革。1.2 数控机床的组成及分类1.2.1 数控机床的组成数控机床的种类繁多,但从组成一台完整的数控机床上讲,它由控制介质、数控装置、伺服系统和机床本体丝大部分以及辅助设备组成。(1)控制介质2控制介质是指零件加工信息传送到数控装置去的信息载体。控制介质有多种形式,它随着数控装置的类型不同而不同,常用的有穿孔纸带、穿孔卡、磁带、磁盘等。另外,随着 CAD/CAM 技术的发展,有些数控设备利用 CAD/CAM 软件在其他计算机上编程,然后通过计算机与数控系统通信,将程序和数据直接传送给数控装置。(2)数控装备数控装置是数控机床的控制中心。它由输入装置、控制装置和输出装置等组成。如图(2)所示,划线框内位数控装置。输入装置受控制介质上的信息,经过识别与译码之后,送到控制运算器。这些信息将作为控制与运算的原始依据。控制运算器根据输入装置送来的信息进行运算,并将控制命令输送往输出装置。输出装置将控制器发出的控制命令送到伺服系统,经功率放大,驱动机床完成相应的动作。(3)伺服系统伺服系统,亦称随动系统,是一种能够跟踪输入的指令信号进行动作,从而获得精确的位置、速度或力输出的自动控制系统。它是数控机床的执行机构,包括驱动和执行两大部分。伺服系统接受数控系统的指令信息,并按照指令信息的要求带动机床移动部件运动,以加工出符合要求的零件。指令信息是以脉冲信息体现的,每一脉冲使机床移动部件产生的位移叫脉冲当量(常用的脉冲当量为 0.001mm0.01mm)。从自动控制理论的角度来分析,无论多么复杂的伺服系统,都是有一些功能元件组成的。目前数控机床的伺服系统中,常用的位移执行机构有功率步进电机、直流伺服电动机和交流伺服电动机,后两者都带有光电编码器等位置测量元件。(4)机床本体机床本体是数控机床的主体,是用于完成各种切削加工的机械部分,它是在原有的普通机床的基础上改进而得到的,具有以下特点:1)数控机床采用了高性能的主轴及伺服系统传动系统,机械传动结构简化,传动链较短。2)数控机床机械结构具有较高的刚度,阻尼精度及耐磨性,热变形小。3)更多地采用高效传动部件,如滚动丝杠副,直线滚动导轨等。下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 119709853除了上述四个主要部分外,数控机床还有一些辅助装置和附属设备,如电器,液压,气动系统与冷却、排屑、照明、储运等装置以及编程机、对刀块等。1.2.2 数控机床的分类(1)按控制系统的特点分类1)点位控制数控机床点位控制机床的特点是只控制移动部件的终点位置,即控制移动部件由一个位置到另一个位置的精确定位,而对它们运动过程中的轨迹没有严格的要求,在移动和定位过程中不进行任何加工。2)线控制数控机床直线控制数控机床的特点是刀具相对于工件的运动不仅要控制两点键的准确位置(距离) ,还要控制两点之间移动的速度和轨迹。3)廓控制数控机床轮廓控制又称连续控制,大多数数控机床具有轮廓控制功能。其特点是能同时控制两个以上的轴,具有插补功能。4)执行机构的控制方式分类开环控制系统它是指不带反馈装置的控制系统。闭环控制系统它是指在机床的运动部件上安装位移测量装置,将加工中测量到的实际位置值反馈到数控装置中,与输入值的指令相比较,用比较的差值控制移动部件,直到差值为零,即实现移动部件的精确定位。半闭环控制系统它是在开环控制系统的丝杠上或进给电动机的轴上装有角位移检测装置。(2)按工艺要求金属切削类数控机床金属成型类数控机床数控特种加工机床其它类的数控机床(3)按数控机床的性能分类档数控机床中档数控机床高档数控机床41.3 数控机床的特点及应用范围1.3.1 数控机床的特点数控机床是一个装有程序控制系统的机床。它是一种高度机电一体化的产品。特点如下:(1)工精度高(2)工生产率高(3)减轻劳动强度、改善劳动条件(4)良好的经济效益(5)有利于生产管理的现代化1.3.2 数控机床的应用范围从最经济的方面出发,数控机床适用于加工:(1)多品种小批量零件;(2)结构较复杂,精度要求较高的零件;(3)需要频繁改型的零件;(4)价格昂贵,不容许报废的关键零件;(5)需要小生产周期的急需零件。下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 119709855第 2 章 数控机床总体方案的制订及比较2.1 课题要求2.1.1 题目名称(包括主要技术参数)及技术要求1、主轴转速:25-1450 转/分 2、工作台尺寸(长宽): 1100mm250mm 3、工作台最大行程: 纵向 700mm 横向 280mm 垂直 360mm 4、快速移动速度: 10m/min5、工作台定位精度 x、y、z 0.03mm;工作台重复定位精度 x、y、z 0.02mm;6、纵向、横向及垂直进给为微机控制,采用步进电机或伺服电机驱动,滚珠丝杠传动,脉冲当量 0.010mm/脉冲。7、实现功能:铣削平面、斜面、沟槽、齿轮等。8、操作要求:起动、点动、单步运行、自动循环、暂停、停止2.1.2 课题内容及工作量(1) 机床尺寸联系图 A0 一张(2) 机床传动系统图 A0 一张(3) 横向进给伺服系统 装配图 A0 一张(4)计说明书一份 1 万字以上注:全部图纸用计算机绘制,说明书由计算机输出。2.2 设计原则根据设计要求和铣床的具体情况,课题的基本设计方案如下:(1)机床采用连续控制系统,定位方式采用增量坐标控制。(2)考虑到机床加工精度要求不高,为了简化结构,降低成本,采用步进电机开环伺服系统驱动。(3)进给传动的设计是机床设计的重点,数控机床必须有精确的进给传动系,才会有高的精度和表面质量。考虑到电机步距角和丝杠导程只能按标准选用,为达到分辨率 0.01mm 的要求,需采用齿轮降速传动,利用电子控制系统消除误差。6(4)为了保证一定的传动精度和平稳性,又要求机构紧凑,所以选用丝杠螺母副。为提高传动刚度和消除间隙,采用有预加载荷的结构。(5)传动系统要加上脉动装置。以上为基本的设计方案,除了这些,课题应注意机床的几何精度的修正,数控指令的显示和使用等。2.3 总结构设计2.3.1 数控机床的机构设计要求数控机床的结构设计要求主要有以下方面:(1)有良好的抗振性能和很大的额定切削功率、高的静、动态刚度;(2)有较高的热稳定性和较高的几何精度、传动精度、定位精度;(3)有数控系统及其介质。下面我们详述数控机床结构设计的主要要求2.3.2 提高机床的结构刚度机床的刚度是指切削力和其它力作用下,抵抗变形的能力。机床在切削过程当中,要承受各种外力的作用,承受的静态力有运动部件和被加工零件的自重;承受的动态力有:切削力、驱动力、加减速时引起的惯性力、摩擦阻力等。组成机床的结构部件在这种力作用下将产生变形。如固定连接表面或啮合运动表面的接触变形;各支撑零件不得弯曲和扭转变形,以及某些支撑件的局部变形等,这些变形都会直接或间接的引起刀具和工件之间的相对位移,从而导致工件的加工误差,或者影响机床切削过程的特性。(1)选择及布置隔板和筋条床身的静刚度是直接影响机床的加工精度和其生产率的主要因素之一。而静刚度及固有频率,是影响动刚度的重要因素。支承件的隔板和筋条的合理性,可提高构件的静、动刚度。(2)结构刚度与普通机床相比,数控机床应有更高的静、动刚度,更好的抗振性。机床的导轨和支承件往往是局部刚度最弱的部分,在本次设计中,采用双臂联接形式,X 、Y 轴导轨较窄。下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 119709857(3)采用焊接结构的构件采用钢板和型钢而不采用铸件的原因:1)钢的弹性模量约为铸铁的两倍,因此采用钢板焊接结构床身有利于提高固有频率。在形状和轮廓尺寸相同的前提下,如要求焊接件与铸件的刚度相同,则焊接件的臂厚只需铸件的一半。2)如果要求局部刚度相同,因局部刚度与臂厚的三次方成正比,所以焊接件的臂厚只需铸件的 80%左右。3)钢可以提高构件的谐振频率使共振不易发生。4)钢板焊接能将构件做成全封闭的箱形结构,提高刚度。焊接结构床身的突出优点是制造周期短,一般比铸铁快 1.7-3.5 倍。省去了制作木模和铸造工序,不易出废品。焊接结构设计灵活,便于产品更新、改进结构。焊接件能达到与铸件相同,甚至更好的结构特性,可提高抗弯截面惯性矩,减少质量。合理的结构布局可以提高刚度,机床的工作头部分由于重力作用将会使机床立柱产生弯曲变形,切削力将使立柱产生弯曲和扭转变形。这些变形将影响到加工精度。故本次设计中将采取通过在立柱上方安装两组定滑轮来平衡重力的方法,来减少立柱的变形,提高机床的刚度。2.3.3 提高进给运动的平稳性和精度数控机床各坐标轴进给运动的精度极大的影响零件的加工精度。在开环进给系统中运动精度取决于系统各组成环节,特别是机械传动部件的精度;在闭环和半闭环进给系统中,位置监测装置的分辨率对运动精度有决定性的影响,但是机械传动部件的特性对运动精度也有一定的影响。通常在开环进给系统中,设定的脉冲当量为 0.01mm时,实际的定位精度最好的情况也只能达到 0.025。在闭环进给系统中,设定的脉冲当量(或称最小设定单位)一般为 0.001mm,实际上定位精度只能达到 0.003mm,当指令进给系统做单步进给(即每次移动 0.001mm)时,开始一两个单步指令,进给部件并不动作,到第三个单步指令时才突跳一段距离,以后又如此重复。这些现象都是因为进给系统的低速爬行现象引起的,而低速爬行现象又决定于机械传动部件的特性。本设计采取的方案有:(1)减少静、动摩擦系数之差(2)提高系统的传动刚度。8第 3 章 确定切削用量及选择刀具3.1 刀具选择(一)刀具选择:铣平面:硬质合金端铣刀或立铣刀,尽是采用二次走刀。凸台、凹槽、箱口面:立铣刀。毛坯表面或粗加工孔:镶硬质合金刀片的玉米铣刀(粗皮刀) 。立体型面和变斜角轮廓外形:球刀、环形刀、锥形刀、盘形刀。(二)原则:安装调整方便、刚性好、耐用和精度高。尽是用较短刀柄,保证刚性。(三)排序原则减少刀具数量;装夹一次,尽是加工完;即使刀具规格相同,粗、精加工刀具分开;先铣后钻;精加工,先曲面后二维轮廓;尽可能自动换刀。3.2 切削用量确定粗:效率;半精、精:质量、兼顾效率。1、主轴转速 n:根据线速度 v 确定:V= (端铣: 150m/min;周铣:30m/min)0D2、切深 t:最好是 t 等于加工余量。3、切宽 L:与刀具直径成正比,与切深成反比。L0.60.9d粗加工:大切深、大进给、低切速。精加工:小切深、小进给、高切速。下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 1197098593.3 切削三要素主轴转速、切削深度、进给速度。少切削,快进给。3.4 加工精度和表面粗糙度1、加工精度:尺寸精度、形状精度、位置精度。(1)尺寸精度:公差与配合国家标准(GB1800 1804-97) 。IT01、IT0、IT1 、IT2IT18。新公差等级与旧公差等级的对照及应用旧精度等级新公差等级轴 孔加工方法 应用IT01IT2 研磨用于量块、量仪制造IT3IT4无研磨用于精密仪表、精密机件的光整加工IT5 1 无IT6 2 1研磨、珩磨、精磨、精铰、精拉IT7 3 2IT8 34磨削、拉削、铰孔、精车、精镗、精铣、粉末冶金用于一般精密配合。IT7 IT6在机床和较精密的机器、仪器制造中用得最为普遍IT9 4IT10 5车、镗、铣、刨、插用于一般要求。主要用于长度尺寸的配合外,如键和键槽的配合IT11 6IT12IT13 7粗车、粗镗、粗铣、粗刨、插、钻、冲压、压铸用于不重要的配合。IT12 IT13也用于非配合10IT14 8 冲压、压铸IT15IT18 912铸、锻、焊、气割用于非配合(2)形状精度:零件上的线、面要素的实际形状相对于理想形状的准确程度。国家标准(GB11821184-80)规定了六项形状公差:直线度、平面度、圆度、圆柱度、线轮廓度、面轮廓度。(3)位置公差:零件上点、线、面要素的实际位置相对于理想位置的准确程度。国家标准(GB11821184-80)规定了八项位置公差:定向:平行度、垂直度、倾斜度。定位:同轴度、对称度、位置度。跳动:圆跳动、全跳动。2、表面粗糙度:表面上微小峰谷高低程度。国家标准(GB3503-83、GB103183、GB131-83)轮廓算术平均偏差:Ra 或近似于 Ral1ldxy0|)(| n1iY|微观不平十点高度:Rz ( + )51iYp51iv在常用数值范围内(Ra0.256.3m,Rz0.125m) ,在图样上应优先选用 Ra。表面粗糙度 Ra、Rz 允许值及加工方法表Ra(m) Rz(m)表面要求表面特征第 1系列第 2系列第 1系列第 2系列加工方法旧国际光洁度级别代号1600不加毛坯表面清除 1250下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985111000800630500工 毛刺100 40080 32063 250明显可见的刀纹 50 200140 16032 125可见刀纹 25 100 220 8016.0 63粗加工微见刀纹 12.5 50粗车粗铣粗刨钻粗锉310 408 32可见加工痕迹 6.3 25 45 204 16微见加工痕迹 3.2 12.5 52.5 102 8半精加工不见加工痕迹 1.6半精车精车精铣精刨粗磨 61.25 6.31.00 5可辨加工痕迹的方向 0.8 470.63 3.20.5 2.5微辨加工痕迹的方向 0.4 2.080.32 1.6精加工不辨加工痕迹 0.25 1.25精铰刮精拉精磨912的方向 0.2 1.000.16 0.800.125 0. 63暗光泽面 0.1 0.50 100.080 0.400.063 0.32亮光泽面 0.05 0.25 110.040 0.200.032 0.16镜状光泽面 0.025 0.125 120.020 0.100.016 0.080雾状光泽面 0.012 0.063精密磨削珩磨研磨超精加工抛光130.010 0.0500.008 0.040精密加工镜面0.025 0.032镜面磨削研磨143.5 刀具材料碳素工具钢 T10A、T12A:HRC60-64,200-250, V8m/min。合金工具钢 CrWMn、9SiCr:350-400,V10m/min。高速钢 W18Cr4V、W6Mo5Cr4V2 :HRC62-67,550-600,V 30m/min;110W1.5Mo9.5Cr4Vco8、W6Mo5Cr4V2Al :HRC68-70,6004、硬质合金:HRA89-93(HRC74-82) ,850-1000,V100-300m/min。另外,还有新型硬质合金、陶瓷材料、人造金刚石、立方氮化硼等。下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985第 4 章 传动系统图的设计计算4.1 传动系统设计4.1.1 参数的拟定已知课题要求的主轴转速:25-1450 转/分,而根据机床主轴变速标准数列的要求,无 1450 这个标准数据,所以拟采用 30-1500 转/分,这样这个转速范围正好可以包含25-1450 转/分,而又可以满足主传动变速要求选定公比,确定各级传送机床常用的公比 为 1.26 或 1.41,考虑适当减少相对速度损失,这里取公比为 =1.26,根据给出的条件:主运动部分 Z=18 级,根据标准数列表,确定各级转速为:(30,37.5,47.5,60,75,95,118,150,190,235,300,375,475,600,750,950,1180,1500R/min).4.1.2 传动结构或结构网的选择1,确定变数组数目和各变数组中传动副的数目该机床的变数范围较大,必须经过较长的传动链减速才能把电机的转速降到主轴所需的转速。级数为 Z 的传动系统由若干个传动副组成,各传动组分别有 . 1z2. 个传动副,即 Z= 。传动副数由于结构的限制,通常采用 P=2 或3z123z3,即变速 Z 应为 2 或 3 的因子:Z= xab因此,这里 18=3x3x2,共需三个变速组。2,传动组传动顺序的安排18 级转速传动系统的传动组,可以排成:3x3x2,或 3x2x3。选择传动组安排方式时,要考虑到机床主轴变速率的具体结构,装置和性能。I 轴如果安置制动的电磁离和器时,为减少轴向尺寸。第一传动组的传动副数不能多,以2 为宜,有时甚至用一个定比传动副;主轴对加工精度,表面粗糙度的影响很大,因此主轴上齿轮少些为好,最后一个传动组的传动副选用 2 ,或一个定比传动副。这里,根据前多后少的原则,选择 18=3x3x2 方案。143,传动系统的扩大顺序安排对于 18=3x3x2 的传动,有 3!=6 种可能安排,亦即有 6 种机构副和对应的结构网,传动方案中,扩大顺序与传动顺序可以一致, ,结构式 18= x x 的传动中,1392扩大顺序与传动顺序一致,称为顺序扩大传动,而,18= x x 的传动顺序不一致,39根据“前密后疏”的原则,选择 18= x x 的结构式。13924 验算变速组的变速范围齿轮的最小传动 1/4,最大传动比 2,决定了一个传动组的最大变minUmaxU速范围 = /maxYin因此,可按下表,确定传动方案:根据传动比及指数 x, 的值x公比极限值传动比指数1.26x 值: =1/ =1/4minUx6值 : = =2a 3(x+ )值: = inr=8x9因此,可选择 18= x x 的传动方案。13925、最后扩大传动组的选择:正常连续顺序扩大传动(串联式)的传动式为:Z= *1z21z32最后扩大传动组的变速范围为:r= =123()z(/2)z按 原则,导出系统的最大收效 Z 和变速范围为:8r3z2 3下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985151.26 Z=18 R=50 Z=12 R=12.7因此,传动方案 18=3*3*2 符合上述条件,其结构网如下图 4.1:图 4.1 结构网图4.1.3 转速图拟定运动参数确定后,主轴各级转速就已知,切削耗能确定电机功率。在此基础上,选择电机的型号,分配个变速组的最小传动比;拟定转速图,确定各中间轴的转速。1,主电机的选择中型机床上,一般都采用交流异步电动机为动力源,可在下列中选用,在选择电机型号时,应注意:(1)电机的 N:根据机床切削能力的要求确定电机功率,但电机产品的功率已标准化,因此,按要求应选取相近的标准值。(2)电机的转速 dn异步电动机的转速有:3000,1500,1000,750,r/min,这取决于电动机的极对数 P=60f/p=60x50/p ( r/min)dn机床中最常用的是 1500 r/min 和 3000r/min 两种,选用是要使电机转速与主轴最高速度 和工轴转速相近为宜,以免采用过大或过小的降速传动。max根据以上要求,我们选择功率为 7.5KW,转速为 1500r/min 的电机,查表,16其型号为 Y132M-4,其主要性能如下表电机型号额定功率KW 荷载转速r/min同步转速r/minY132M-47.5KW 1440 15002、分配最小传动比,拟定转速图(1) 轴的转速:轴从电机得到运动,经传动系统转化为主轴各级转速,电机转速和主轴最小转速应相近,显然,从动件在高速运转下功率工作时所受扭矩最小来考虑, 轴转速不宜将电机转速降得太低。弱轴上装有离合器等零件时,高速下摩檫损耗,发热都将成为突出矛盾,因此, 轴转速也不宜也太高, 轴转速一般取 7001000r/min左右较合适。因此,使中间变速组降速缓慢。以减少结构的径向尺寸,在电机轴 I 到主传动系统前端轴 增加一对 26/54 的降速齿轮副,这样,也有利于变型机床的设计,改变降速齿轮传动副的传动比,就可以将主轴 18 级转速一起提高或降低。(2)中间轴的转速对于中间传动轴的转速的考虑原则是:妥善解决结构尺寸大小和噪音,振动等性能要求之间的矛盾。中间传动轴转速较高时,中间传动轴和齿轮承受扭矩小,可以使轴径和齿轮模数小些: d , m 从而可使结构紧凑。但这样引起空载功率 和噪音加大:4M3 pL=1/ (3.5 +c n)KWN空 610nda主式中:C 系数,两支承滚动轴承和滑动轴承 C=8.5,三支承滚动轴承 C=10;所有中间轴轴径的平均值;da主轴前后轴径的平均值主中间传动轴的转速之和nn主轴转速(r/min)下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 1197098517=20lg -KpL610lg()4.5(1tan)(ancmzqmz 主 主式中:( 所有中间传动齿轮的分度圆直径的平均值 mm;主轴上齿轮分度圆直径的平均值 mm;()z主q传到主轴上所经过的齿轮对数主轴齿轮螺旋角,K系数,根据机床类型及制造水平选取,我国中型车床,铣床 =3.5,铣床1c 1cK=50.5从上述经验公式可知,主轴 n 和中间传动轴的转速和 对机床噪音和发热的关系,确定中间轴转速时,应结合实际情况做相应的修正。a,对高速轻载或精密机床,中间轴转速宜取低些b,控制齿轮圆周速度 v 取 =90mm,后轴颈1mD852平均轴颈 取 d=27mm.58721mD2), 主轴内孔直径 d 的确定主轴内孔主要用于通过棒料夹紧刀具或工件的控杆,冷却管等,大型,重型机床的空心主轴还可以减轻重量. 确定孔径 d 的原则是在满足对空心主轴孔径的要求和最小壁厚要求以及不削弱主轴刚度的要求下尽量去大些。由材料力学知,轴刚度 K 与抗弯截面惯性矩 I 成正比 ,与直径之间有下列关系:41()KIdD空 空实 实由上式可知,当 时,空心主轴的刚度 与实心主轴的刚度 相差甚/0.56dDK空 K实小,即内孔对主轴刚度降低的影响很小, 当 时,刚度降低约 25%.因此,为了不至/0.7d于过分地削弱主轴刚度,一般应使 另外 ,还应考虑主轴的颈外壁厚是否足够. /.推荐: 铣床,d= 拉杆直径+(5-10)mm. 根据铣床的主参数, 取 d=29mm.则 4022。满足要求 ./27/90.3dD3), 主轴悬伸量 a 的确定主轴悬伸量 a 是指主轴前端大炮前支承径向反力作用中点(一般为前径向支承中点)的距离,它主要取决于主轴端部结构型式和尺寸(大多都有轴端标准),前支承的轴承配置和密封装置等. 有的还与机床其它结构参数有关,如工作台的行程等. 因此主要由结构设计确定。参考同类机床和,取 则悬伸量 a=63mm。 1/0.7,aD4), 主轴跨距 的确定l根据,计算前支承刚度.1.41.457070920/AKDNm计算综合变量=311Optimal Design of Compliant Trailing Edge for Shape ChangingAbstract: Adaptive wings have long used smooth morphing technique of compliant leading an d trailing edge to improve their aerodynamic characteristicsThis paper introduces a systematic approach to design compliant structures to carry out required shape changes under distributed pressure loadsIn order to minimize the deviation of the deformed shape from the target shape,this method uses M ATLAB and ANSYS to optimize the distributed compliant mechanisms by way of the ground approach and genetic algorithm (GA)to remove the elements possessive of very low stressesIn the optimization process,man y factors should be considered such as air loads,input displacements,and geometric nonlinearities。Direct search method is used to locally optimize the dimension an d input displacement after the GA optimization。The resultant structure could make its shape change from 0 to 93degreesTheexperimental data of the model confirm s the feasibility of this approachKeywords: adaptive wing;compliant mechanism;genetic algorithm ;topology optimization;distributed pressure load;geometric nonlinearity1 Introduction:As conventional airfoil contours are usually designed with specific lift coefficients and M ach numbers,they could not change in accordance with the environment changingSiclari and Austin indicated that the variable camber trailing edge would produce the drag about sixty percent less than the conventional fixed camber airfoilThere are three methods used to design able camber wingsOf themone is conventional hinged mechanism,which,however, will create discontinuities over the wings surface leading to earlier airflow separation an d drag increase The others are smart material and the compliant mechanism,of which both could realize smooth shape changingNevertheless,compared to the compliant mechanism,the smartmaterialmade actuators have many disadvantages,such as deficient in energy ,slow in response,strong in hysteresis, limited by temperature,and difficult to control too many actuatorsMusolff from Industry University of Berlin 12used NiTi shapememoryalloy wire to make an adaptive variable camber wing,which could quickly change its shape,but could not perform highly frequent alteration because of its resilience depend en ton the heat exchange with the outside environment。Compliant mechanism is a kind of one-piece flexible structure,which can transfer motion and power through its own elastic deformationIt is not only flexible enough to deform,but also has enough stiffness to withstand external loadsThanks to its jointfree nature,it does not have the trouble some problems confronted by conventional mechanism such as friction,lubrication,noise and recoiling,thereby achieving smooth shape changing.In 1 994,Kota ,a professor from University of Michigan,firstly pointed out that compliant mechanism could be used to control static shape changing under the sponsorship of the Air Force Of ice of Scientific Research in USASaggere and Kotasuggested a new method to design compliant adaptive structures,which made the least square errors between the shapechanged curve and the target curve as the objective function for optimizationBased on their work,Lu put forward a load pathrepresentation methodHowever, her work was limited to only linear analysis under consideration of nodal loadsGood from Virginia Polytechnic Institute of State University used the compliant mechanism and the Moving Asymptotes method to design the fuselage tail within the allowable range of its tip maximal deflectionKota and He trick in2004 designed a compliant trailing edge on the baseof the F16s data,which can change from 0。to 15。and obtained a patentCampanile from German Aerospace Center presented a modal procedure to design synthetic flexible mechanisms for airfoil shape control,and pointed out that the future research should take into account the air load and the geometric nonlinearityBuhl from Riso National Laboratory of the Wind Energy Department in Denmark used the SIM P method and geometrically nonlinear finite element method to design compliant trailing edge flapsFlxSys Inc in 2006 produced an adaptive compliant wing,which stood the test on the White Knight airplaneThe results 13indicated that the compliant trailing edge could change+10 In China,the research of adaptive wing has been concentrated on smart material and conventional mechanismFew people,it seems,have worked on designing adaptive wings with the compliant mechanismYang is an exceptionHe analyzed the active aeroelastic wings based on the aeroservoelasticity technologyChen and Huang separately investigated the morphing of the compliant leading edge from the viewpoints of discreteness and continuity.This paper presents a method to design the shape changeable structure by MATLAB and ANSYS associated with distributed compliant mechanism on the base of the ground structure approach and genetic algorithm (GA)taking into account the external distributed loads and geometric nonlinearity.2 Optimization Process:21 Defining the trailing edge model and objective functionAs shown in Fig1,both curves represent two ideal shapes of the trailing edge in the different flying statesOne side point)of the structure is supposed to be fixed,and the other side point) to be sliding horizontally. Firstly, the design domain should be defined by the initial curve shapethe input location and the boundary conditionsThenit is divided with abeam element network simulating the birds feather as shown in Fig2This is termed the partial ground structure method.Fig1 Initial shape and target shape Fig2 Discretization of the design domain The simplest and most effective way to manufacture the planar compliant mechanism is to use wirecutting technologyIn the optimization program,all the elements are of rectangular beams with the same width equal to the thickness of the material,every beams height being a design variable14In order to make the structures deformation come close to the target shape curve, the least square error(LSE)between the deformed curve and the target curve is defined as the objective functionLSE is the sum of squares of position differences of various points along the curves Its expression is where I (=1, 2,P)is the number of the points along the curves ,P is the total number of points and are the coordinates of it h node on the target and deformed boundary curve respectivelyThe constraints are Where J (=1, 2, )is the number of elements,miss the tota1 number of elements,h i the dimension variable,h min and hmax are the lower and upper bounds of the element beam height for all elements with the value dependent on manufacturing,h b the height of the boundary elements, the maximumnoda1 deformation of the nodes on the curve boundary when the input point is inactive,and should be smaller thandto ensure structure stiffness,d the allowable maximum displacement when the input point is inactive,Omax the maximum stress of al1 the elements which must be smaller than Tj to prevent yielding,T j the topology variable equal to 1,or else0 when the element is eliminated22 GA optimizationGA is an optimization method which simulates the heuristic selection rule in nature, where the fittest living things have the most chance to survive,but the inferior ones also have the opportunity to exist Different from the continuous optimization method,it does not require the gradient-based information of the objective function.15Every element could be expressed as a topology variable and a dimension variable Therefore,each individua1 could be coded as followswhere ,2 is the number of elements except the boundary onesWith the same heights,the boundary elements throughout the optimizing process arerepresented by only one variable,h b.The fitness is the criterion of the GA optimization It could be transformed from the objective function into where is a coefficient deciding the compulsive selection of the betterindividua1The smaller the value,the more different would be between the two individualsfitness thus increasing the compulsiveness of choosing the individual of higher fitnessThe selection of control parameters plays an important role in the convergence of the GAGenerally speakingthe cross probability ranges 040099;the mutation probability is 0000 01-001and the number of individuals 1 0200The variable would be updated through the crossover and mutation,so the possible design could generate in the GA process23 Finite element analysis(FEA)Because of the limited design variables and the target function,the optimization module of FEA software could not be used to design the compliant morphing mechanismTherefore ,this paper programmed the GA in MATLAB and the FEA in ANSYSIn the FEA,taking only account of geometric nonlinearities and the material being of linear elasticity, ANSYS could solve the node displacements and the element stressesThen by deleting the elements with low stress,the fitness could be calculatedFig3 shows the detailed process 16Fig3 Flowchart of the structural optimization program24 Second optimizationAlthough the GA could optimize the topology and dimension simultaneously in a large solution space,the dimension usually could not directly converge to the optimizationIn order to solve this problem,after the GA,the Direct Search methodshould be used to find the best values of the input displacement and the dimensions of the elements which remain in the results after the GAFor morphing of compliant mechanism,Fig3describes the whole optimization processIt mainly contains initialization of the design domain,FEA ,GA optimization and second optimization.3 Presentation of Results:Adopted from Ref,the sizes of the initial and the target trailing edge are reduced by sixty percent ,I1ab1e 1 lists the design parameters.Because the displacement is used as the input,the nonlinear analysis could hardly converge and the stress of the initia1 solutions is very largeWhich should be considered after thirtieth generation.17Table 1 Design parameters Fig4 and Fig5 illustrate the results from the GA optimization and the second optimization respectivelyFig4 Results after the GA optimization Fig5 Results after the second optimizationForm Table 2,it could be found that through the second optimization of the input displacement and the dimension,the LSE is reduced by 1352 8mmand improved by 313 The altered angle is increased by 1049 3Table 2 Results after the two optimization 18Fig6 Stability of final optimal structureFig6 shows the influences of the parameters when the outside distributed pressure load changes from 0 to 1 0 Nmm and the input displacement remains 1 1389 7 mm on the optimal structureIt could be seen that the optimal structure has a good stability if the load is kept in the range Of 05 NmmAs the external load exceeds 5 Nmm,the max stress is likely to exceed the yield stress19Because this optimization program is based on the M ATLAB and ANSYSin order to verify the results an attempt is made to introduce the analytical results of the optimized structure into ANSYS and PATRAN respectively, and then a comparison is made between themAs shown in Fig7 and Fig8,the two altered shapes are in good agreement:for in ANSYS the tip displacement is 5497mm and in PATRRAN 5450mmThe minor difference between them is from the softwareFig7 Results of FEA in ANSYS Fig8 Results of FEA in PATRANOn the other hand,a model is made by wirecutting technology to verify the analytical resultsThe material of the mode1identical with that of the design,is 5 mm thickIn the experiment,the distributed pressure load is assumed to be zero The input displacement 11389 7mm with the required input load 146 NFig9 shows the model and the experimental resultThe altered angle is measured93 。 and the tip displacement 53mmThe altered shape well accords to the optimized resultIf a displacement of 113897mm is imposed on the model,the theoretical tip displacement is 54796 mm Because of the friction there is between the model and the experiment table a tiny difference will take place between the measured data and the calculated results20Fig9 The model and experimental result4 Conclusions:Proved by the simulation and experiments,the proposed method to design morphing compliant mechanism is effectual in turning out a trailing edge with required morphing effects and ability of withstanding external loadsThe combination of MATLAB and ANSYS in the optimization renders the program simple and universa1There is no need for frequent changes of the rigid matrixIt also avoids the complexity of programming the nonlinear FEA and the transforming distributed loads into nodal loadsUsing the mixed code,the topology and the dimension could simultaneously be optimized by the GARemoving the free elements after the FEA could speed up the optimizationThe second optimization could improve the GA results
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