减速箱(南宁)正面孔专用机床设计说明书
减速箱(南宁)正面孔专用机床设计说明书,减速,南宁,面孔,脸孔,专用,机床,设计,说明书,仿单
减速箱(南宁)正面孔专用机床设计The deceleration box(nan ning) positive bore appropriation tool machine design前言组合机床是以通用部件为基础,配以少量专用部件,对一种或若干中工件按预先确定的工序进行加工的机床。它能够对工件进行多刃多轴多面多工位同时加工。在组合机床上可以完成钻孔、扩孔、镗孔、攻丝、车削、铣削、磨削及液压等工序,随着组合机床的发展它能完成的工艺范围将日益扩大。组合机床所使用的通用部件具有特定功能,按标准化、系列化、通用化原则设计制造的组合机床基础部件,每种通用部件有合理的规格尺寸系列,有适用的技术参数和完善的配套关系。组合机床与通用机床、其它机床比较具有以下特点:(1)组合机床上的通用部件和特征零件越占全部机床零部件的70%-80%,因此设计和制造周期短,经济效益好。(2)用于组合机床采用多刀加工,机床自动化程度高,因此比通用机床生产效率高,产品质量稳定,劳动强度低。(3)组合机床的通用部件是经过周密设计和长期生产实践考验的,又有专门厂家成批生产,它与一般专用机床比较,其结构稳定,工作可靠,使用和维修容易。(4)组合机床加工工件,采用专用夹具,组合刀具和导向装置等,产品加工质量靠工艺装备保证,对操作工人的技术水平要求不高。(5)当机床被加工的产品更新时,专用机床的大部分的部件报废,组合机床的通用部件是根据国家检验设计的,并等效于国际检验,因此其通用部件可以重复使用,不必另行设计和制造。(6)组合机床易于联成组合机床自动线,以适应大规模和自动化生产需要。目前,我国组合机床以广泛用于大批量生产和使用,例如:汽车、拖拉机等。减速箱(南宁)正面孔专用机床设计摘要:组合机床及其自动线所使用的通用部件是具有特定功能,按标准化,系列化,通用化原则设计、制造的组合机床基础部件。每种通用部件有合理的规格尺寸系列,有适用的技术参数和完善的配套关系。组合机床是以通用部件为基础,配以少量专用部件,对一种或若干中工件按预先确定的工序进行加工的机床。它能够对工件进行多刃多轴多面多工位同时加工。在组合机床上可以完成钻孔、扩孔、镗孔、攻丝、车削、铣削、磨削及液压等工序,随着组合机床的发展它能完成的工艺范围将日益扩大。关键词: 组合机床 通用部件 工序Abstract:The aggregate machine-tool and its the general part which uses fromthe generatrix has the specific function, according tostandardization, seriation, universalized principle design,manufacture aggregate machine-tool foundation part. Each kind ofgeneral part has the reasonable specification size series, has thesuitable technical parameter and the consummation necessary relations. Can complete to drill a hole, expand bore, Tang bore, offend silk, car to pare in The aggregate machine-tool, the Xian pare, whet to pare and the liquid press an etc. work preface, will extend day by day along with the craft scope that it can complete of the develop of the aggregate machine-tool.Key word: Aggregate machine-tool In general use parts Work preface目 录第一章 通用部件简介 11 .通用部件分类 12.动力滑台与动力箱23.组合机床支承部件2第二章 组合机床的总体设计的步骤41组合机床工艺方案的制定42确定切削用量及选择刀具53组合机床总体设计三图一卡6第三章组合机床多轴箱设计121概述122多轴箱的设计12 第四章夹具的设计 16总结17致谢18参考文献19 第一章 通用部件简介一.通用部件的分类 通用部件已列为国家标准,并等效为国际标准,设计时应贯彻执行国家标准。我国有些企业有内部标准,但其主要技术参数及部件和联系尺寸必须统一执行国家标准,以实现部件通用化标准。1.动力部件(1)主运动动力部件用来实现组合机床的切削运动。例如:刀具的回转运动。动力箱:1DT121DT25,适用小型组合机床;1 DT321DT80,适用大型组合机床。多轴箱:主轴固定多轴箱;主轴可调多轴箱。(2)进给运动部件实现刀具的进给运动。液压滑台:1HY系列液压滑台;1HYA系列长台面型液压滑台;1HYS系列液压十字滑台。机械滑台:1HJ系列机械滑台;1HJC系列机械滑台;NC-1HJ系列交流伺服数机械滑台。(3)既能实现主运动,又能实现进给运动的部件。动力头:1LHJb系列机械滑套式动力头;1LXJB系列箱体移动式机械动力头;LHF系列风动动力头;1LZY系列多轴转塔动力头。(4)为单轴头变化主轴转速的跨系列通用部件:1XG系列传动装置。2.输送部件 输送部件是将工件由一个工位输送到另一个工位的部件:1AHY系列液压回转台工作台;1HYA系列长台面型液压滑台。3.支承部件支承部件是可用来安装组合机床其它部件,它包括1CC系列滑台,侧底座;1CD系列立柱侧底座;1CL系列立柱及中间底座等。4.控制部件 控制部件用来控制组合机床行动循环。5.辅助部件 除上述部件外的部件称辅助部件,主要指用于润滑、冷却和排屑等部件。二.动力滑台与动力箱1.动力滑台是由滑座、滑鞍和驱动装置等组成,是实现组合机床直线进给运动的动力部件。 动力滑台的用途:根据被加工工件的工艺要求,可以在滑台上安装动力箱、钻削头、铣削头和镗孔车端面头等各种部件,以完成对工件的钻孔、扩孔、铰孔、螳孔、倒角、削端面、车端面、铣削及攻丝等工序,有时也作为输送部件使用,配置多工位组合机床。2.1TD系列动力箱的用途 动力箱是将电动机的动力传递给多轴箱的动力部件。动力箱安装在滑台或其它进给部件的结合面上,动力箱前端结合面上安装多轴箱,动力箱的输出轴驱动动力箱的每个主轴及传动轴,使多轴箱完成各种工艺切削运动。 1DT系列动力箱分两种:第一种根据用于配置小型组合机床,其型号为1DT121DT25,本规格的动力箱输出轴有两种传动形式,I型用输出轴安装的平键,齿轮输出转矩;II型用输出轴端面键输出转矩。第二种动力箱用于配置大型组合机床,其规格为1DT321DT80,其输出轴只有平键,齿轮一种输出转矩的形式。三.组合机床支承部件 组合机床支承部件包括中间底座,侧底座,立柱,立柱底座,支架及垫块等。支承部件主要用来安装动力部件及其它工作部件是组合机床的基础部件。支承部件应用于足够的刚度,以保证各部件之间相对位置精度长期正确,从而保证组合机床的加工精度。 组合机床的支承部件采用组合式,例如:卧式组合机床的床身,由中间底座与侧底座装配而成,而立式组合机床的床身由立柱及立柱底座装配而成。此种装配结构优点是加工和装配工艺性好,调整和运输比较方便。但是,组合式结构减弱了床身的整体刚性,这一缺点通常用加强部件之间的连接刚度来补偿。1.1CC系列滑台侧底座1CC系列滑台侧底座用于安装1HY系列液压滑台及各种机械滑台侧底座长度按滑台行程长度分型并与其配套。滑座安装在侧底座上,侧底座与中间底座用螺钉及销(或键)连接成一体,滑台与侧底座之间装有5mm厚的调整垫。采用调整垫铁对机床的制造和维修都方便。因为当滑座导轨磨损后,或重新组装机床时,只须取下滑台将导轨面重新修刮或修磨,再重新更换调整垫厚度,可使机床达到应有精度。 侧底座的顶面具有与滑座结合的平面外在其周围有收集冷却液或润滑油用的沟槽,用管道将油液引回存储槽中,侧底座的另一侧面有电气壁盒,以供安装电器元件用。一般电器壁盒与冷却液存储箱不应靠近,以防电气元件潮湿。 为了便于支承部件及整台机床运输,侧底座应用走丝吊孔或吊环螺钉孔及放入撬杠用的底面凹槽。2.中间底座中间底座用于安装运输部件和夹具等的支承部件。它可以与侧底座支架和立柱等相接。 中间底座在配置组合机床时,往往不能用一种系列满足不同使用要求,因此,中间底座无标准化系列,尚须根据具体情况设计专用的中间底座。 中间底座分为安装固定夹具和安装回转工作台的两种类型。 根据组合机床配置形式的不同,中间底座多种多样。总之,随着组合机床形式不同,中间底座在结构,尺寸方面就有不同的要求。 中间底座的高度为560mm,也可选用630mm或710mm,本次设计底座选用560mm。第二章 组合机床的总体设计一.组合机床工艺方案的制定 工艺方案制定的正确与否,将决定机床能否达到体积小,重量轻,结构简单。为了使工艺方案制定得合理,先进,必须认真分析被加工零件图纸开始,深入现场全面了解被加工零件的结构特点,加工部位,尺寸精度,表面粗糙度和技术要求,定位、夹紧要求,工艺方法和加工过程所采用的刀具、辅具,切削用量及生产率要求等,分析优缺点。 1.零件的工艺分析 被加工零件为减速箱(南宁)正面孔的钻孔,且要一次加工完成,因此需在专用机床上加工,并要保证它们之间的粗糙度和位置精度要求。2工件的定位基准选择 箱体类零件是机械加工中工序多,精度要求高的零件,这类零件一般都有较高的精度的孔要加工,又常要在几次安装下进行。因此,定位基准选择“一面两销”进行,其原因: a可简单的消除工件的六个自由度,使工件获得稳定可靠的定位。 b有同时加工零件五个表面的可能,即能高度集中工序,又有利于提高各面孔的位置精度。 c“一面两销”可作为零件从粗加工到精加工全部工序的定位基准,使零件整个工艺过程基准统一,从而减少由基准转换带来的累积误差,有利于保证零件加工精度。 d易于实现自动化定位,并有利于防止切屑落于定位基面上。3.夹紧方案的制定 夹紧机构由夹紧动力,中间传动机构,夹紧元件三部分组成,夹紧动力用于产生力源,并将作用力传给中间传动机构。采用中间传动机构可改变作用力的大小和方向,同时能产生的锁作用,以保证在加工过程中,当力源消失时,工件在切削力或振动作用下仍能可靠夹紧。夹紧元件刚用以承受由中间传动机构传递的夹紧力。并与工件直接接触而执行夹紧动作。工件夹紧时,夹紧装置应重点解决下列问题:(1)夹紧装置在对工件夹紧时,不应破坏工件的定位应正确选择夹紧力的方向及着力点。(2)夹紧力的大小应可靠,适当。要保证工件在夹紧后的变形和受压表面的损坏不能超过允许的范围。(3)结构简单合理,夹紧动作迅速,操作方便,省力,安全。(4)夹紧力或夹紧行程在一定范围内可调整或补偿。二.确定切削用量及选择刀具 切削用量选择是否合理,对组合机床的加工精度、生产率、刀具的耐用度、机床的布局及正常工作均有很大的影响。组合机床切削用量的选择特点: 1.在大多数情况下,组合机床为多轴,多刀,多面同时加工,因此切削用量,根据经验应比一般万能机床单刀加工低30%左右。 2.组合机床多轴箱下,所有刀具共用一个进给系统,通常为标准动力滑台,工作时,要求所以的刀具的每分钟进给量相同,且等于动力滑台的分钟进给量。a 由于工件材料:HT330 HBS:190230 5孔深15mm 查钻孔切削速度查得:铸铁:v=1018m/min. (1) 5孔的计算: f=0.1mm/r 由L/D=15/5=3.0选取v=10m/min 查表得Kv=0.9 计算硬度 可得:切削力F=26Df0.8HB0.63=1572.237N切削扭矩: =10D1.9f0.8HB0.63=2574.054Nmm 切削功率: KW刀具耐用度: 三.组合机床总体设计三图一卡1.被加工零件工序图 被加工零件的工序图是根据选定的工艺方案,表示一台组合机床或自动线完成的工艺内容,加工部位尺寸、精度、表面粗糙度及技术要求,加工用定位基准,夹紧符号及被加工零件的材料、硬度、重量等表示。不能用客户提供的图纸,而需在原零件图的基础上,突出被加工的内容,加上必要的说明绘制而成的,它是组合机床设计的主要依据,也是制造,使用,检验和调整机床的重要技术元件,图上应表示出:(1)被加工零件的形状和轮廓尺寸及本机床设计有关的部位的结构形状及尺寸。(2)加工用定位基准,夹紧部位及夹紧方向,以便依此进行夹具的定位支承,限位,夹紧,导向装置的设计。(3)本道工序加工部位尺寸、精度、表面粗糙度、形状位置尺寸及技术要求,还包括本道工序对前道工序提出的要求。(4)必要的文字说明,如被加工零件的编号名称,硬度,重量,加工余量等。 减速箱箱体的工序图见图2.加工示意图 1.加工示意图的作用和内容 零件的加工工艺方案要通过加工示意图反映出来,加工示意图表示被加工零件在机床尚的加工过程,刀具辅具的布置状况以及工件,夹具,刀具等机床各部件间的相对位置关系,机床的工作行程及工作循环等。因此,加工示意图是组合机床设计的主要图纸之一。在总体设计中占据重要地位。它是刀具,辅具,夹具,多轴箱,液压电气装置设计及通用部件选择的主要原始资料;也是整台组合机床布局和性能的原始要求,同时还是调整机床刀具及成车的依据,其内容为:(1)应反映机床的加工方法,加工条件及加工过程。(2)根据加工部位特点及加工要求,决定刀具类型,数量,结构,尺寸(直径和长度),包括镗削加工是膛杆直径和长度。(3)决定主轴的结构类型,规格尺寸及外伸长度。(4)选择标准或设计专用的接杆,浮动卡头,导向装置,攻丝靠模装置,刀杆托架等,并决定它们的结构参数及尺寸。(5)标明主轴,接杆,夹具(导向)与工件之间的联系尺寸,配合及精度。(6)根据机床要求的生产率及刀具,材料特点等,合理正确定并标注各主轴的切削用量。2.加工示意图零件的选择(1)刀具的选择刀具的选择要求考虑工件加工尺寸精度,切削的排除,及生产率要求等因素。 由机械加工工艺设计手册表11.29选择:莫氏锥柄长麻花钻:(2)初定主轴类型、尺寸、外伸长度和选择接杆主轴形式主要取决于进给力和主轴刀具系统结构的需要。主轴尺寸规格应根据选定的切削用量计算出切削转矩, 由d=5mm 查表3-5得:确定主轴直径d=20mm.(3)弹簧涨套:T0631-41 。(4)除刚性主轴外,组合机床主轴与刀具之间常用两种连接:一是接杆连接,也称刚性连接,用于单导向进行钻、扩、铰及倒角加工;二是浮动卡头连接,也称浮动连接,用于长导向、双导向和多导向进行镗、扩、铰孔,以减少主轴位置误差及主轴径向跳动对加工精度的影响。 选接杆: T0635-01 B型。减速箱箱体的加工示意图见图3.影响联系尺寸的关键刀具 保证加工终了时,多轴箱端面到工件端面之间的尺寸最小,来确定全部刀具,接杆,导向,刀具托架及工件之间的联系尺寸。其中,须标注主轴端部外径和内孔径,外伸长度,刀具各段直径及长度,导向的直径,长度配合,工件至夹具之间须标注工件距离导套端面的距离,还需标注刀具托架与夹具之间的尺寸,工件本身及加工部位的尺寸和精度等。4.动力部件的工作循环动力部件的工作循环是指:加工时,动力部件从原始位置开始到加工终了位置又返回到原始位置的动力过程。一般包括快速引进,工作进给,快速退回等动作,有时还有中间停止,多次往复进给,跳跃进给,死挡铁停留等特殊要求,这是根据具体的加工工艺需要确定的。5.动力部件的工作行程(1)工作进给长度L应等于工件加工部位长度与刀具切入长度和切出长度之和。参考组合机床设计表317得:切入长度 =5mm.由表324得:9mm.(2)快速退回和攻退长度之和等于快速引进和进给长度之和。其长度按加工具体要求而定。5快进取91mm;工进29mm;快退取120mm。(3)动力部件总行程长度除了应保证要求的工作循环工作过程外,还要考虑装卸调整刀具方便,及考虑前备量。前备量取20mm 。3.尺寸联系图一般来说,组合机床是由标准的通用部件动力滑台、动力箱、各种工艺、切削头、侧底座、立柱底座及中间底座加上专用部件多轴箱、刀具、辅具系统、夹具、液电、冷却、润滑、排屑系统组合装配而成的。联系尺寸图的主要内容为:(1)以适当数量的视图按同一比例画出机床各主要组成部件的外形轮廓及相关位置,表明机床的配置型式及总体布局,主视图的选择应与机床实际加工状态一致。(2)图上应尽量减少在必要的线条及尺寸应标注,但反映部件的联系,专用部件及主要轮廓尺寸,运动部件的极限位置及行程尺寸必须完全。(3)为便于开展局部设计,联系尺寸图上应标注通用部件的规格,代号,电动机型号,功率及转速,并说明机床部件的分组情况及总行程。组合机床的动力部件是配置组合机床的基础,它主要包括用以实现刀具主轴旋转主运动的动力箱,各种工艺切削用量及进给运动的运功动滑台。影响动力部件选择的主要因素为:切削功率,进给力,进给速度,行程,多轴箱轮廓,尺寸,动力滑台的精度和导轨材料,综合这些因素,根据具体加工要求正确合理选择动力部件动力滑台和动力箱,并以其为基础进行通用部件配置。根据前面算的再查组合机床设计表214选1DT12动力箱,电动机功率:P=0.75KW,电动机转速:n=1400r/min,驱动轴转速:n=950r/min.动力箱输出轴距底面高度为99.5mm。 由表23结合附表1:选液压动力滑台1HY25 ,台面宽:B=250mm,面长:500mm,行程长:H250mm,导轨为铸铁材料,允许最大进给力:8000N,快速行程速度:12mm,工进速度32800mm/min。 配套通用部件:滑台侧底座其型号:1CC251,高度h=560mm,宽度=450mm,长度L900mm计算多轴箱轮廓尺寸标准的通用钻,镗类多轴箱的厚度有两种尺寸规格,卧式为325mm绘制机床联系尺寸图时,重要确定的尺寸是多轴箱的宽度B和高度H及最低主轴高度:B=b+ H=h+式中:b工件再宽度方向相距最远的两孔距离(mm) 最边缘主轴中心距箱外壁的距离(mm) h工件在高度方向相距最远的两孔距离(mm) 最低主轴高度。为保证多轴箱有排布齿轮的足够空间,推荐b170100 mm,取b1=175mm,=230mm,H=984mm,h3=250mm,h4=560mm,h7=5mm,推荐85140 mm。 =h2+H-(0.5+h3+h7+h4)61.5984(0.5+250+5+560)=230mm B=b+2b1=47+1752=397mm根据上述计算值,按多轴箱轮廓尺寸系列标准最后确定多轴箱轮廓尺寸由P012表41,取BH=400320mm。动力箱以及底面与动力滑台定位连接,在机床长度方向上,通常动力箱后端面应与滑台后端面平齐安装。动力滑台与滑座在机床长度方向的相对位置由加工终了时滑台前端面到滑座前面的距离决定,是在机床长度方向上各部件联系尺寸的可调环节;对于通用的标准动力滑台,尺寸的最大范围为50mm,是动力滑台,滑座本身结构决定的滑台前端面到滑台前端面的最小距离与前备量两者之和。前者通常不应小于1520mm,后者用补偿刀具重磨后轴向可调的尺寸并用于弥补机床制造和安装误差前备量取20mm;刚203050mm。为便于机床的调整和维修,滑台与侧底座在机床长度方向上的相对位置由滑座前端面到侧底座前端面的距离决定。若采用的侧底座为标准型,则可由组合机床通用部件联系尺寸标准中查得;若不能采用标准型侧底座则可根据具体情况而定,取110mm。由于只钻正面孔中间底座轮廓尺寸其长度方向尺寸可根据实际情况确定.综合起来本次设计取:L=800mm4.机床生产率计算卡 机床负荷率等。根据选定得机床工作循环所需要的工作行程长度,切削用量,动力部件的速度及工进速度等;就可以计算机床的生产率并编制生产率计算卡;用以反映机床的加工过程;完成每一动作所需的时间,切削用量,机床生产率等1.理想生产率Q1指定成年生产纲领A(包括备量及废品率在内)所需求的机床生产率。它与全年工时总数有关,一般情况下,单班制生产K取2350h,两班制生产取4600h,则Q1=(件/h)2.实际生产率Q指所设计机床每小时实际可以生产的零件数量Q=60/求出:生产一个零件所需的时间(min)=t切+t辅=(L1/Vf1+L2/Vf2+T停)+(L顺进/Vfk+L快退/Vfk+T移+t卸装)=2.567minQ=60/=60/2.567=23.37(件/h)3.机床负荷率负当Q1Q时,计算二者的比值即为负荷率h负=Q1/Q则h负=8.5/23.37=0.3644.机床生产率计算卡机床生产率计算卡 见图第三章 组合机床多轴箱设计1.概述多轴箱是组合机床的主要部件之一,按专用要求进行设计,由通用零件组成。其主要作用是根据被加工零件的加工要求,安排各主轴位置,并将动力和运动由电机或动力部件传给各工作主轴,使之得到要求的转速和转向。多轴箱按其结构大小,可分为大型多轴箱和小型多轴箱两类。大型又分为通用多轴箱和专用多轴箱两种。通用多轴箱主要由箱体,主轴,传动轴,齿轮,轴套等零件和通用(专用)的附加机构组成。在多轴箱体前后壁之间可安排厚度为24mm的齿轮三排或32mm的齿轮两排;在多轴箱体后壁之间可安排一或两排齿轮。通用多轴箱体厚度为180mm,用于卧式的多轴箱前盖厚度为55mm(基型),用于立式的多轴箱前盖并作油池,加厚为70mm,基型后盖厚度为90mm,其余三种厚度的后盖(50,100,125mm),可根据多轴箱内传动系统安排动力部件与多轴箱的具体连接情况而定。2.多轴箱的设计多轴箱是组合机床的重要部件之一,它关系到整台组合机床质量的好坏。具体设计时,需根据“三图一卡”,仔细分析研究零件的加工部件,工艺要求,确定多轴箱与被加工零件,机床其它部分的相互关系。1.绘制多轴箱设计原始依据图根据“三图一卡”整理编汇,内容包括多轴箱设计的原始要求和已知条件。在编制此图时从“三图一卡”中已知:(1)多轴箱轮廓尺寸400mm320mm(2)工件轮廓尺寸及各孔位置尺寸(3)工件与多轴箱相对位置尺寸多轴箱图一般应包括以下内容:(1)所有主轴的位置尺寸及工件与多轴箱的相对尺寸,在标注主轴的位置及相关尺寸时,首先要注意多轴箱和被加工零件在机床上是面对面摆放的,因此多轴箱横截面上的水平方向尺寸因与被加工零件工序图的水平方向相反;其次,多轴箱上的坐标尺寸基准和被加工零件工序图的尺寸基准相常不相重合,应根据多轴箱和被加工零件的相对位置找出统一基准,并标注出其相对位置关系尺寸.(2)在图中标注主轴转向由于标注刀具多为右旋,因此要求主轴一般为逆时针旋转。(3)图中应标出多轴箱的外形尺寸.(4)列表标明工件材料,加工表面要求,并标出各主轴的工序内容,主轴外伸部分尺寸和切削用量等.(5)注明动力箱型号,功率P,转速机和其它主要参数.2.主轴直径和齿轮模树的初步确定m(30-32) (mm)3.传动系统的设计与计算(1)对传动系统的一般要求1) 尽量用一根中间轴带动很多根主轴,当齿轮齿合中心距不符合标准时,可用变位齿轮或略变传动比的方法解决.2) 一般情况下,尽量不采用主轴带动主轴的方案,因为会增加主动轴的负荷,如遇到主轴分布密集而切削负荷又不大时,为了减少中心轴,也可用一根主轴带1-2根或更多根主轴的传动方案.3) 为使结构紧凑多轴箱体的齿轮传动副的最佳传动比为1-1.5,在多轴箱后盖内的第IV排(或第V排)齿轮,根据需要,其传动比可以取大些,但一般不超过33.5。4) 根据转速与转距成反比的道理,一般情况下如驱动轴转速较高时,可采用逐步降速传动,如驱动轴转速较低时可先使速度升高一点再降速,这样可使传动链前面几根轴齿轮上的齿轮应尽量安排靠近前支承,以减少主轴的扭转变形。5)粗加工切削力大,主轴上的齿轮应尽量安排靠近前支承,以减少主轴的扭转变形。6)齿轮安排数可按下面方法安排:不同轴上齿轮不相碰,可放在箱体内同一排上。不同轴上齿轮与轴或轴套不相碰,可放在箱体内不同排上。齿轮与轴相碰,可放在后盖内。4计算主轴和传动轴的齿数驱动轴上齿数有一定限制(2126) 取22,m=3则总传动比:i=637/960=2/3 3个主轴的速度都是=637r/min 驱动轴=950r/min1)假设,m=2, 驱动轴 22, m3, 2)中间传动轴mm, m=2 得 ; , mm,所以,所以 有上面的假设得: 所以,要求的转速为637r/min.转速的相对误差在5%以,所以设计符合要求。 3)用中间传动轴8兼做调整手柄轴。其转速如下r/min,轴8转速较高,操作省力,位置适当,可满足要求。4)采用R12-2型叶片泵,由中间轴7经一对齿轮传动,r/min在400800r/min范围之内满足要求。5. 计算传动轴得直径轴1,2,3: , 取d=20mm同理可得:轴4,5,7 :d=10.6mm, 取d=20mm 轴6: d=18.7mm, 取d=30mm 轴0: d=10.6mm 取d=20mm.由于轴8是手柄轴。手柄轴可适当取大点,所以轴8取d=30mm.6多轴箱的总图设计1通用多轴箱总图的设计通用多轴箱总图的设计包括绘制主视图,展开图,侧视图,和编列装配图表以及制定技术条件。2多轴箱主要零件图的设计 多轴箱的零件绝大多数是通用件,标准件和外购件。需要设计的零件图,只是变位齿轮,专用轴,套以及箱体补充加工图,此外还要编制多轴箱明细表。第四章夹具的设计机床夹具是在机床上所使用的一种辅助装置,用它来准确迅速地确定工件与机床刀具间地相对位置,即将工件定位及夹紧,以完成加工所需地相对运动。使用夹具地最终目的是保证产品质量,改善工人劳动条件,提高生产效率,降低产品成本。1减速箱箱体的定位基准的选择由零件图可知,零件底部的孔已经加工,因此,以减速箱箱体的下表面作为主要定位基面。为了提高加工效率,决定采用液压式伸缩销定位,同时为了缩短辅助时间采用液压夹紧。2 夹紧力的计算 查机床夹具设计手册表1211 工件以平面定位,夹紧力与切削力方向垂直。 其中为基本安全系数1,2 为加工性质系数1,2 为刀具钝化系数1 为断续切削系数10.16 0.7 2.5则2750N 现选用前法兰式夹紧液压缸,查机床夹具设计手册: , 故本夹具可安全工作。 设计总结 毕业设计是对我们四年学习和知识的融汇、运用和贯通,是迅速提高我们实践经验的一条重要途径。在实践中教导我们发现问题,以及怎样分析问题并最终解决问题。让我们的综合能力有所提高,扎实巩固专业基础知识。毕业设计是对学生进行工程师基本训练的重要环节。通过毕业设计我们能巩固,熟悉并综合运用所学知识;培养理论联系实际的学风;掌握零件机械加工工艺规程编制,专用工艺装备及组合机床的基本技能;学会查阅,运用各种技术资料,手册。初步掌握对专业范围的生产技术问题进行分析综合研究的能力;使学生受到比较全面训练。 为了顺利完成这次毕业设计,学校组织我们到扬州柴油机厂、扬州亚星等单位参观实习。在实地学习中增强了感性认识,拓宽了知识面,取得了一定的实际生产经验和此次设计相关的技术资料。另外,图书馆的有关资料对我的设计提供了科学的数据和有价值的参考。 工艺设计是产品设计和产品制造间的纽扣和桥梁。合理的工艺设计不仅可以经济有效地生产产品,而且也是一个企业生存发展的必要条件。就个人而言,我希望通过这次毕业设计一方面能进一步培养我独立思考的能力,另一方面能提高我与同学们互助协作的能力,为以后工作打下良好基础,为伟大祖国建设贡献我的力量。致谢经过近三个月的忙碌,毕业论文工作已经接近了尾声。毕业设计的完成,同时也意味着大学生涯的结束。在设计和写作说明书的过程中,由于经验不足、知识匮乏,难免有许多疏漏和错误。谢谢指导老师的督促,谢谢小组同学的帮助,才能按时完成毕业设计和论文。首先要感谢我的毕业设计指导老师王志老师,其次要感谢大学四年来所有的任课老师,为我们打下了机械专业知识的基础,你们教给我的人生道理,教给我的知识能让我在今后的工作学习中受益颇丰。同时还要感谢设计小组的全体同学,正是因为有了你们的鼓励,此次毕业设计才会顺利完成。另外,我要感谢毕业设计参考文献的原作者。这些专家、学者的研究成果,为我的毕业设计和写作说明书提供了许多帮助。最后,我要感谢机械工程学院和我的母校江苏大学四年来对我的大力栽培。 谢谢!参考文献【1】 金正华主编 组合机床及其调整与使用 机械工业出版社 1990【2】 黑龙江人民出版社 组合机床设计与制造 1982【3】 赵如福主编 金属机械加工工艺人员手册第三版 上海科技出版社 1982【4】 周泽华主编 金属切削原理第二版 上海科学出版社 1993【5】 谢家瀛主编 组合机床设计简明手册 机械工业出版社 【6】 大连组合机床研究所编 组合机床与自动化加工技术 【7】 丛凤延,迟建山主编 组合机床设计 上海科学技术出版社【8】 组合机床编写小组编 组合机床讲义 北京:国防工业出版社 1975【9】 大连组合机床研究所编 组合机床设计参考图册 北京:机械工业出版社 1990【10】中华人民共和国国家标准 GB 6477.1-6477.16_86 金属切削机床术语 北京:中国标准出版社 198823 LATHEThe basic machines that are designed primarily to do turning, facing and boring are called lathes. Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathe can do boring, facing, drilling, and reaming in addition to turning, their versatility permits several operations to be performed with a single setup of the workpiece. This accounts for the fact that lathes of various types are more widely used in manufacturing than any other machine tool Lathes in various forms have existed for more than two thousand years. Modem lathes date from about 1797, when Henry Maudsley developed one with a lea&crew. It provided controlled, mechanical feed of the tool. This ingenious Englishman also developed a changegear system that could connect the motions of the spindle and lea&crew and thus enable threads to be cut. Lathe Construction. The essential components of a lathe are depicted in the block diagram. These are the bed, headstock assembly, tailstock assembly, carriage assembly, quick-change gear box, and the lea&crew and feed rod. The bed is the backbone of a lathe. It usually is made of well-normalized or aged gray or nodular cast iron and provides a heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets. Because several other components are mounted and/or move on the ways they must be made with precision to assure accuracy of alignment. Similarly, proper precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The ways on most modem lathes are surface hardened to offer greater resistance to wear and abrasion. The headstock is mounted in a fixed position on the inner ways at one end of the lathe bed. It provides a powered means of rotating the work at various speeds. It consists, essentially, of a hollow spindle, mounted in accurate bearings? And a set of transmission gears similar to a truck transmission through which the spindle can be rotated at a number of speeds. Most lathes provide from eight to eighteen speeds, usually in a geometric ratio, and on modem lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types, A longitudinal hole extends through the spindle so that long bar stock can be fed through it.The size of this hole is an important size dimension of a lathe because it determines the maximum size of bar stock that can be machined when the material must be fed through the spinale. The inner end of the spindle protrudes from the gear box and contains a means for mounting various types of chucks, face plates, and dog plates on it. Whereas small lathes often employ a threaded section to which the chucks are screwed, most large lathes utilize either cam-lock or key-drive taper noses. These provide a large-diameter taper that assures the accurate alignment of the chuck, and a mechanism that permits the chuck or face plate to be locked or unlocked in position without the necessity of having to rotate these heavy attachments. Power is supplied to the spindle by means of an electric motor through a V-belt or silent-chain drive. Most modem lathes have motors of from 5 to15 horsepower to provide adequate power for carbide and ceramic tools at their high cutting speeds. The tailstock assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location. An upper casting fits on the lower one and can be moved transversely upon it on some type of keyed ways. This transverse motion pemfits aligning the tailstock and headstock spindles and provides a method of tuming tapers. The third major component of the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 2 to sinches in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a handwheel and screw. The open end of the quill hole terminates in a morse. taper in which a lathe center, or various tools such as drills, can be held. A graduated scale, several inches in length, usually is engraved on the outside of the quill to aid in controlling its motion in and out of the upper casting. A locking device permits clamping the quill in any desired position. The carriage assembly provides the means for mounting and moving cutting tools. The carriage is a reianvely fiat H-shaped casting that rests and moves on the outer set of ways on the bed. The transverse bar of the carriage contains ways on which the cross slide is mounted and can be moved by means of a feed screw that is controlled by a small handwheel and a graduated dial. Through the cross slide a means is provided for moving the lathe tool in the direction normal to the axis of rotation of the work. On most lathes the tool post actually is mounted on a compound rest. This consists of a base, which is mounted on the cross slide so that it can be pivoted about a vertical axis, and an .upper casting. The upper casting is mounted on ways on this base .so that it can be moved back and forth and controlled by means of a short lead screw operated by a handwheel and a calibrated dial. Manual and powered motion for the carriage, and powered motion for the cross slide, is provided by mechanisms within the apron, attached to the front of the carriage. Manual movement of the carriage along the bed is effected by turning a handwheel on the front of the apron, which is geared to a pinion on the back side. This pinion engages a rack that is attached beneath the upper front edge of the bed in an inverted position. To impart powered movement to the carriage and cross slide, a rotating feed rod is provided. The feed rod, which contains a keyway throughout most of its length, passes throughthe two reversing bevel pinions and is keyed to them. Either pinion cam be brought into mesh with a mating bevel gear by means of the reversing lever on the front of the apron and thus provide forward or reverse power to the carriage. Suitable clutches connect either the rack pinion or the cross-shde screw to provide longitudinal motion of the carriage or transverse motion of cross slide. For cutting threads, a second means of longitudinal drive is provided by a lead screw. Whereas motion of the carriage when driven by the feed-rod mechanism takes place through a friction clutch in which shppage is possible, motion through the lead screw is by a direct, mechanical connection between the apron and the lead screw, s This is achieved by a split nut. By means of a clamping lever on the front of the apron, the split nut can be closed around the lead screw. With the split nut closed, the carriage is moved along the lead screw by direct drive without possibility of slippage. Modern lathes have a quick-change gear box. The input end of this gear box is driven from the lathe spindle by means of suitable gearing. The output end of the gear box is connected to the feed rod and lead screw. Thus, through this gear train, leading from the spindle to the quick-change gear box, thence to the lead screw and feed rod, and then to the carriage, the cutting tool can be made to move a specific distance, either longitudinally or transversely, for each revolution of the spindle. A typical lathe provides, through the feed rod, forty-eight feeds ranging from 0.002 inch to 0.118 inch per revolution of the spindle, and, through tne lead screw, leads for cutting forty-eight different threads from 1.5 to 92 per inch. On some older and some cheaper lathes, one or two gears in the gear train between the spindle and the change gear box must be changed in order to obtain a full range of threads and feeds. MILLING Milling is a basic machining process in which the surface is generated by the progressive formation and removal of chips of material from the workpiece as it is fed to a rotating cutter in a direction perpendicular to the axis of the cutter. In some cases the workpiece is stationary and the cutter is fed to the work. In most instances a multiple-tooth cutter is used so that the metal removal rate is high, and frequently the desired surface is obtained in a single pass of the work. The tool used in milling is known as a milling cutter. It usually consists of a cylindrical body which rotates on its axis and contains equally spaced peripheral teeth that intermittently engage and cut the workpiece. 1 In some cases the teeth extend part way across one or bothends of the cylinder. Because the milling principle provides rapid metal removal and can produce good surface finish, it is particularly well-suited for mass-production work, and excellent milling machines have been developed for this purpose. However, very accurate and versatile millingmachines of a general-purpose nature also have been developed that are widely used in jobshop and tool and die work. A shop that is equipped with a milling machine and an engine lathe can machine almost any type of product of suitable size. Types of Milling Operations. Milling operations can be classified into two broad categories, each of which has several variations: 1. In peripheral milling a surface is generated by teeth located in the periphery of the cutter body; the surface is parallel with the axis of rotation of the cutter. Both flat and formed surfaces can be produced by this method. The cross section of the resulting surface corresponds to the axial contour of the cutter. This procedure often is called slab milling. 2. In face milling the generated flat surface is at right angles to the cutter axis and is the combined result of the actions of the portions of the teeth located on both the periphery and the face of the cutter. 2 The major portion of the cutting is done by the peripheral portions of the teeth with the face portions providing a finishing action. The basic concepts of peripheral and face milling are illustrated in Fig. 16-1. Peripheral milling operations usually are performed on machines having horizontal spindles, whereas face milling is done on both horizontal- and vertical-spindle machines. Surface Generation in Mimng. Surfaces can be generated in milling by two distinctly different methods depicted in Fig. 16-2. Note that in up milling the cutter rotates againsi the direction of feed the workpiece, whereas in down milling the rotation is in the same direction as the feed. As shown in Fig. 16-2, the method of chip formation is quite different in the two cases. In up milling the c hip is very thin at the beginning, where the tooth first contacts the work, and increases in thickness, becoming a maximum where the tooth leaves the work. The cutter tends to push the work along and lift it upward from Tool-work relationshios in peripheral and face milling the table. This action tends to eliminate any effect of looseness in the feed screw and nut of the milling machine table and results in a smooth cut. However, the action also tends to loosen the work from the clamping device so that greater clamping forcers must be employed. In addition, the smoothness of the generated surface depends greatly on the sharpness of the cutting edges. In down milling, maximum chip thickness cecum close to the point at which the tooth contacts the work. Because the relative motion tends to pull the workpiece into the cutter, all possibility of looseness in the table feed screw must be eliminated if down milling is to be used. It should never be attempted on machines that are not designed for this type of milling. Inasmush as the material yields in approximately a tangential direction at the end of the tooth engagement, there is much less tendency for the machined surface to show tooth marks than when up milling is used. Another considerable advantage of down milling is that the cutting force tends to hold the work against the machine table, permitting lower clamping force to be employed. 3 This is particularly advantageous when milling thin workpiece or when taking heavy cuts. Sometimes a disadvantage of down milling is that the cutter teeth strike against the surface of the work at the beginning of each chip. When the workpiece has a hard surface, such as castings do, this may cause the teeth to dull rapidly. Milling Cutters. Milling cutters can be classified several ways. One method is to group them into two broad classes, based on tooth relief, as follows: 1. Profile-cutters have relief provided on each tooth by grinding a small land back of the cutting edge. The cutting edge may be straight or curved. 2. In form or cam-reheved cutters the cross section of each tooth is an eccentric curve behind the cutting edge, thus providing relief. All sections of the eccentric relief, parallel with the cutting edge, must have the same contour as the cutting edge. Cutters of this type are sharpened by grinding only the face of the teeth, with the contour of the cutting edge thus remaining unchanged. Another useful method of classification is according to the method of mounting the cutter. Arbor cutters are those that have a center hole so they can be mounted on an arbor. Shank cutters have either tapered or straight integral shank. Those with tapered shanks can be mounted directly in the milling machine spindle, whereas straight-shank cutters are held in a chuck. Facing cutters usually are bolted to the end of a stub arbor. The common types of milling cutters, classified by this system are as follows: Types of Milling Cutters. Hain milling cutters are cylindrical or disk-shaped, having straight or helical teeth on the periphery. They are used for milling flat surfaces. This type of operation is called plain or slab milling. Each tooth in a helical cutter engages the work gradually, and usually more than one tooth cuts at a given time. This reduces shock and chattering tendencies and promotes a smoother surface. Consequently, this type of cutter usually is preferred over one with straight teeth. Side milling cutters are similar to plain milling cutters except that the teeth extend radially part way across one or both ends of the cylinder toward the :center. The teeth may be either straight or helical. Frequently these cutters are relatively narrow, being disklike in shape. Two or more side milling cutters often are spaced on an arbor to make simultaneous, parallel cuts, in an operation called straddle milling. Interlocking slotting cutters consist of two cutters similar to side mills, but made to operate as a unit for milling slots. The two cutters are adjusted to the desired width by inserting shims between them. Staggered-tooth milling cutters are narrow cylindrical cutters having staggered teeth, and with alternate teeth having opposite helix angles. They are ground to cut only on the periphery, but each tooth also has chip clearance ground on the protruding side. These cutters have a free cutting action that makes them particnlarly effective in milling deep slots. Metal-slitting saws are thin, plain milling cutters, usually from 1/32 to 3/16 inch thick, which have their sides slightly dished to provide clearance and prevent binding. They usually have more teeth per inch of diameter than ordinary plain milling cutters and are used for milling deep, narrow slots and for cutting-off operations.车床用与车外圆、端面和镗孔等加工的机床叫车床。车削很少在其他种类的机床上进行,因为其他机床都不能像车床那样方便地进行车削加工。由于车床除了用于车外圆外还能用于镗孔、车端面、钻孔和铰孔,车床的多功能性可以使工件在一次定位安装中完成多种加工。这就是在生产中普遍使用各种车床比其他种类的机床都要多的原因。两千多年前就已经有了车床。现代车床可以追溯到大约17刃年,那时亨利莫德斯利发明了一种具有丝杠的车床。这种车床可以控制工具的机械进给。这位聪明的英国人还发明了一种把主轴和丝杠相连接的变速装置,这样就可以切削螺纹。车床的主要部件:床身、主轴箱组件、尾架组件、拖板组件、变速齿轮箱、丝杠和光杠。床身是车床的基础件。它通常是由经过充分正火或时效处理的灰铸铁或者球墨铸铁制成,它是一个坚固的刚性框架,所有其他主要部件都安装在床身上。通常在床身上面有内外两组平行的导轨。一些制造厂生产的四个条导轨都采用倒“V”形,而另一些制造厂则将倒V”形导轨和平面导轨相结合。由于其他的部件要安装在导轨上并(或)在导轨上移动,导轨要经过精密加工,以保证其装配精度。同样地,在操作中应该小心,以避免损伤导轨。导轨上的任何误差,常常会使整个机床的精度遭到破坏。大多数现代车床的导轨要进行表面淬火处理,以减小磨损和擦伤,具有更大的耐磨性。主轴箱安装在床身一端内导轨的固定位置上。它提供动力,使工件在各种速度下旋转。它基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮类似于卡车变速箱所组成,通过变速齿轮,主轴可以在许多种转速下旋转。大多数车床有818种转速,一般按等比级数排列。在现代车床上只需扳动24个手柄,就能得到全部挡位的转速。目前发展的趋势是通过电气的或机械的装置进行无级变速。由于车床的精度在很大程度上取决于主轴,因此主轴的结构尺寸较大,通常安装在紧密配合的重型圆锥滚子轴承或球轴承中。主轴中有一个贯穿全长的通孔,长棒料可以通过该孔送料。主轴孔的大小是车床的一个重要尺寸,因为当工件必须通过主轴孔供料时,它确定了能够加工棒料毛坯的最大外径尺寸。主轴的内端从主轴箱中凸出,其上可以安装多种卡盘、花盘和挡块。而小型的车床常带有螺纹截面供安装卡盘之用。很多大车床使用偏心夹或键动圆锥轴头。这些附件组成了一个大直径的圆锥体,以保证对卡盘进行精确地装配,并且不用旋转这些笨重的附件就可以锁定或松开卡盘或花盘。主轴由电动机经V带或无声链装置提供动力。大多数现代车床都装有515马力的电动机,为硬质合金和金属陶瓷合金刀具提供足够的动力,进行高速切削。尾座组件主要由三部分组成。底座与床身的内侧导轨配合,并可以在导轨上做纵向移动,底座上有一个可以使整个尾座组件夹紧在任意位置上的装置。尾座安装在底座上,可以沿键槽在底座上横向移动,使尾座与主轴箱中的主轴对中并为切削圆锥体提供方便。尾座组件的第三部分是尾座套筒,它是一个直径通常在23英寸之间的钢制空心圆柱轴。通过手轮和螺杆,尾座套筒可以在尾座体中纵向移入和移出几英寸。活动套筒的开口一端具有莫氏锥度,可以用于安装顶尖或诸如钻头之类的各种刀具。通常在活动套筒的外表面刻有几英寸长的刻度,以控制尾座的前后移动。锁定装置可以使套筒在所需要的位置上夹紧。拖板组件用于安装和移动切削工具。拖板是一个相对平滑钓H形铸件,安装在床身外侧导轨上,并可在上面移动。大拖板上有横向导轨,使横向拖板可以安装在上面,并通过丝杠使其运动,丝杠由一个小手柄和刻度盘控制。横拖板可以带动刀具垂直于工件的旋转轴线切削。大多数车床的刀架安装在复式刀座上,刀座上有底座,底座安装在横拖板上。可绕垂直轴和上刀架转动;上刀架安装在底座上,可用手轮和刻度盘控制一个短丝杠使其前后移动。溜板箱装在大拖板前面,通过溜板箱内的机械装置可以手动和动力驱动大拖板以及动力驱动横拖板。通过转动溜板箱前的手轮,可以手动操作拖板沿床身移动。手轮的另一端与溜板箱背面的小齿轮连接,小齿轮与齿条啮合,齿条倒装在床身前上边缘的下面。利用光杠可以将动力传递给大拖板和横拖板。光杠上有一个几乎贯穿于整个光杠的键槽,光杠通过两个转向相反并用键连接的锥齿轮传递动力。通过溜板箱前的换向手柄可使啮合齿轮与其中的一个锥齿轮啮合,为大拖板提供“向前”或“向后”的动力。适当的离合器或者与齿条小齿轮连接或者与横拖板的螺杆连接,使拖板纵向移动或使横拖板横向移动。对于螺纹加工,丝杠提供了第二种纵向移动的方法。光杠通过摩擦离合器驱动拖板移动,离合器可能会产生打滑现象。而丝杠产生的运动是通过溜板箱与丝杠之间的直接机械连接来实现的,对开螺母可以实现这种连接。通过溜板箱前面的夹紧手柄可以使对开螺母紧紧包合丝杠。当对开螺母闭合时,可以沿丝杠直接驱动拖板,而不会出现打滑的可能性。现代车床有一个变速齿轮箱,齿轮箱的输入端由车床主轴通过合适的齿轮传动来驱动。齿轮箱的输出端与光杠和丝杠连接。主轴就是这样通过齿轮传动链驱动变速齿轮箱,再带动丝杠和光杠,然后带动拖板,刀具就可以按主轴的转数纵向地或横向地精确移动。一台典型的车床的主轴每旋转一圈,通过光杠可以获得从0叩2到0118英寸尺寸范围内的48种进给量;而使用丝杠可以车削从15到92牙英寸范围内的48种不同螺纹。一些老式的或价廉的车床为了能够得到所有的进给量和加工出所有螺纹,必须更换主轴和变速齿轮箱之间的齿轮系中的一个或两个齿轮。铣削铣削是机械加工的一个基础方法。在这一加工过程中,当工件沿垂直于旋转刀具轴线方向进给时,在工件上形成并去除切屑从而逐渐地铣出表面。有时候,工件是固定的,而刀具处于进给状态。在大多数情况下,使用多齿刀具,金属切削量大,只需一次铣削就可以获得所期望的表面。在铣削加工中使用的刀具称做铣刀。它通常是一个绕其轴线旋转并且周边带有同间距齿的圆柱体,铣刀齿间歇性接触并切削工件。在某些情况下,铣刀上的刀齿会高出圆柱体的一端或两端。 由于铣削切削金属速度很快,并且能产生良好的表面光洁度,故特别适合大规模生产加工。为了实现这一目的,已经制造出了质量一流的铣床。然而在机修车间和工具模具加工中也已经广泛地使用了非常精确的多功能通用的铣床。车间里拥有一台铣床和一台普通车床就能加工出具有适合尺寸的各种产品。 铣削操作类型:铣削操作可以分成两大种类,每一类又有多种类型。 1圆周铣削 在圆周铣削中,使用的铣刀刀齿固定在刀体的圆周面上,工件铣削表面与旋转刀具轴线平行,从而加工表面。使用这种方法可以加工出平面和成型表面,加工中表面横截面与刀具的轴向外轮廓相一致。这种加工过程常被称为平面铣削。 2端面铣削 铣削平面与刀具的轴线垂直,被加工平面是刀具位于周边和端面的齿综合作用形成的。刀具周边齿完成铣削的主要任务,而端面齿用于精铣。 圆周铣削和端面铣削的基本概念,圆周铣削通常使用卧式铣床,而端铣削则既可在卧式铣床又可以在立式铣床上进行。 铣削面的形成:铣削时可以采用两种完全不同的方法。应注意,在逆铣时,铣刀旋转方向与工件进给方向相反,而在顺铣时铣刀旋转与工件进给方向相同。在逆铣过程中,当铣刀齿刚切人工件时,切屑是非常薄的,然后渐渐增厚,在刀齿离开工件的地方,切屑最厚。在两种铣削方法中,切屑的形成是不同的,逆铣过程中,刀具有推动工什丌使工件从工作台上提升的趋势,这种作用有助于消除铣床工作台进给螺杆和螺母间的间隙,从而形成平稳的切削。然而,这种作用也有造成工件与夹紧装置之间的松动的趋势,这时应施加更大的夹紧力。此外,铣削表面的平整度主要取决于切削刃的锋利程度。 顺铣时,最大切屑厚度产生于靠近刀具与工件接触点处。由于相对运动趋于把工件拉向铣刀,如果采用顺铣法,要消除工作台进给螺杆可能产生的松动。因此,对于不能用于顺铣的铣床,不要采用顺铣方法。因为在铣刀结束切削时,处于切线方向的被切材料发生屈服,所以与逆铣相比,顺铣的被加工表面没有什么切痕。顺铣的另一个优势是切削力趋于将工件压紧在工作台上,因此对工件的夹紧力可以小于逆铣。这一优势可以用于铣削较薄的工件或进行强力切削。顺铣的弱点是铣刀齿刚一切削每片铁屑时,刀齿会撞击工件的表面。如果工件表面坚硬,像铸件,就会使刀齿迅速地变钝。铣刀 铣刀分类有多种方法,一种方法是根据刀具后角将铣刀分为两大类: 1仿形铣刀 每个刀齿在切削刃的背面磨了一个很小的棱面形成后角,切削刃可以是直线或曲线的。 2成形或凸轮形后角铣刀 每个齿的横截面在切削刃的背面呈偏心曲线状,以产生后角。偏心后角的各面与切削刃平行,具有切削刃的相同形状。这种类型的铣刀仅需磨削齿的前刀面就可以变得锋利,只要切削刃的外形保持不变,铣刀的另一种分类方法是根据铣刀安装的方法进行分类。心轴铣刀带有一个中心孔以使铣刀安装在心轴上。带柄铣刀有一锥柄或直柄轴,含锥形轴柄的铣刀可以直接安装在铣床的主轴上,而直柄轴的铣刀则是夹持在卡盘里。平面铣刀通常用螺栓固定在刀轴的末端上。 根据这种分类方法,通用型的铣刀可分类如下:
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