立式钻床用轴均布多轴头设计【含CAD图纸】
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摘要 本文是立式钻床用轴均布多轴头设计,可调式多轴头各轴在圆周方向均布且方向可方便地沿直径方向同步调整,以适应多种小批量生产条件下法兰盘类零件的螺孔加工。固定试式多轴头是根据一个典型法兰盘类零件而设计的,用于零件中大批量生产要求。多轴头架的设计参数来源于一般的加工工艺条件,以适应更广阔的加工范围。针对工厂里多孔钻削时,孔径一般较小,多在10cm左右,而且大部分是箱体、法兰盘等,箱体、法兰盘多为铸造件,材料是铸铁,也有个别的被加工零件的材料是低碳钢。根据这些工件的切削条件,可以确定多轴头架的工艺主参数。主参数确定后便可以进行多轴头架的总体设计。多轴头架的传动原理是通过齿轮啮合增加钻削轴的轴数,以满足多孔加工的要求。通过二级齿轮啮合,输入轴和输出轴的转向没变,但由于齿轮分支传动,变成多根输出轴。为了保证加工生产条件的安全,加上多轴头工作时装隔离装置比较困难,所以必须严格校核轴头架的强度,以免发生事故或达不到加工要求。可以看出,改装后的多轴钻床,可以同时完成多个孔的钻、扩、铰等工序。工艺范围可以满足一般加工情况的孔类钻削要求。可调多轴头架可以起到提高生产效率、降低成本、提高孔系加工精度等作用。参照该调节原理可进行其他任意孔系加工装置的设计,还可以用于攻丝、扩、锪孔等加工装置。此外该装置具有结构简单、操作方便、应用范围广等特点,值得推广。关键词:立式 钻床 多轴头 可调 固定AbstractThe design of multiple spindles heads for drilling machine whose drills spindles are adjustable or fixed are introducedThe adjustable spindles of the multiple spindles heads are located evenly in the circuit and can be adjusted synchronism on the diameters direction to meet the small scale production needs of the screw hole manufacture for flange plate parts.And the fixed multiple spindles heads is design for the big scale production needs of the screw hole manufacture for flange plate parts,it cant be used to manufacture another farts, because its spindle distance is designed for the only part.The design of multiple spindles heads include three parts : the total design, the transfer system design , and the constructive designBecause of the un-development in our manufacture industry ,most companys plant lack of the machine to drill multiple holes at the same time , and its a waste of funding on the manufacturing facilities which will be laid after the parts are produced . so the economic multiple spindles heads enable the normal company to drill the multiple holes in a fast way .And same company gained the economic performance by the way of reequips the machine tools. Its the fact that the reequipped drilling machine can satisfy the process precision requirement .so the design is feasible.Based on the design of the multiple spindles heads , we can also design the others to the manufacture of the other flange plant parts.Key words: drilling machine ;adjustable; multiple spindles heads;目录前言11 概述.21.1 问题的提出.21.2 同行业概况.21.3 课题的意义.22. 总体方案设计4对工件进行工艺分析4检查图纸的完整性和正确性.4分析工件的结构特点.4分析工件的材料及加工性能.5工件的生产批量.5确定工件的加工方法5对被改装钻床的分析5总体布局6其他问题分析73. 齿轮可调式三轴头架的设计8齿轮可调式三轴头架的传动原理及调整方法8方案的工艺设计参数9Z535钻床动力所允许的工况条件.9确定用于钻削计算的极限值.13三轴头架的传动设计.16齿轮的设计验算16轴的设计与校核21轴承的校核计算35键的设计校核37螺栓的设计校核38夹头夹紧力的计算校核404. 润滑与密封435. 结束语446. 谢辞467. 参考文献.47前言我的毕业设计的题目是立式钻床可调式多轴头架的设计。在现阶段,我国制造也的发展状况,一方面零件精度、复杂度越来越高,另一方面我国的制造业中普遍存在社别老化的问题。虽然设备老化在现代工业中是不可避免的事情现在设备的设计更新实在太快了。而且,随着现代产品的小批量生产趋势,为了加工某个零件去购置一台新机床是不合适的。怎样利用现有设备高效快速地加工出新零件是一件很有实际应用价值的课题。在现代设计中,箱体类、钣金类的零件被广泛应用,在上面进行设计一系列孔是很多时候必须的工作。进行多孔钻削是现代加工中一个不可缺少的加工工序。但是在我国的大部分中小企业目前还不能很好的适应多孔钻削的生产要求,为了某个批量不是很大的零件购置响应的排钻甚至专用机床是取不了多大的经济效益的。针对各个企业里的钻床进行改装不失为一个经济易行同时能满足大部分精度要求的好方法。目前国内已有一些厂家通过改造现有的钻床设备使之具备加工多孔钻削的能力。一般情况下,都是采用加装多轴头架的方法,并学用适当的夹具便于多轴头架的装夹。由于改造机床多为了某个特定的零件,各种多轴头架各有各的特点。一改改装机床的工艺对象普遍狭窄的缺点,我这里设计了一个可调式的多轴头架,它的切削周向直径可调节,大大的扩大了它的加工范围。1. 概述1.1 问题的提出本次毕业设计任务的提出,是为适应目前我国大部分制造厂的实际生产状况。当前制造业设备更新特别快,大部分企业遇到同一端面的多孔钻削的零件时,为此购置专用设备又往往不经济的条件下,可以通过改造现有普通单轴钻床使之具有多轴钻削的能力。既解决了加工要求与现有设备的矛盾,又有效的利用了闲置机床,极大的提高了设备利用率,给企业带来了巨大的经济效益。1.2同行业概况在国内的相关企业中已经有一部分企业开始原有设备的改造以适应新的加工生产。其中有一些结构相对比较复杂,当然这与白加工零件的相关工艺参数有关。在法兰盘周向均布孔的加工上应用已经相当广泛。比如在郑州的一个汽车制造车间上,运用了改造后的钻床进行加工,取得了良好的经济效果。由于这些厂家的生产对象的特殊性,他们加工的孔径一般较大,改造后的钻床,除了加装多轴头架外,还需设计额外的夹具以减轻头架的重量对钻床的作用力影响及保证头架进给的精度。1.3课题的意义为了使广大的一般小型生产厂家具有同一端面的多孔加工能力,我设计了重量较轻,钻削轴均布的三轴头架。可以实现同时三孔位的加工,而且如果孔之间的距离有变化,可以随时进行孔距的调节,使它能够实现多孔位的加工,那样不仅可以节省时间、改善工人的劳动强度、提高劳动效率,而且对于机械行业也是一种革新。齿轮可调式三轴头架,因为它是一种可换的,而且是可以调节孔距的设备,所以适应生产过程中的小批量的生产。根据多孔的加工要求,确定机床的主要参数如下:最大钻孔深度(单侧钻) 50mm主轴数目 3主轴中心线至工作台面高 750mm主轴转速 1000r/min左右2. 总体方案设计总体方案是部件和零件的设计依据,对整个机床的设计影响较大。因此,在拟定总体方案的过程中,必须综合的考虑,使所定方案技术上先进,经济效果好。确定总体方案,包括下列内容:2.1对工件进行工艺分析 2.1.1 检查图纸的完整性和正确性 工件的图纸应能清晰的表达工件的形状结构,标注全部尺寸及技术要求,说明工件的材料和所需要的工件数量等。加工零件为典型的盘类零件,砂轮机端盖,如图: 图1 砂轮机端盖 2.1.2 分析工件的结构特点 工件的结构决定了它的安装方式和加工厂方法。要求用多轴头架加工的孔为精度要求不甚高的螺栓孔,在加工时,以大端面为基准装夹,根据批量的要求需另外设计专用夹具,以适应中批量的生产要求。2.1.3 分析工件的材料及加工性能工件的材料对加工方法有很大的影响。如材料的软硬对刀具进给量、走刀量都有较大的影响。砂轮机端盖的毛坯为铸件,材料是球墨铸铁,可根据相关手册计算加工时的加工参数,以此来确定多轴头架的设计参数。2.1.4 工件的生产批量被加工工件的生产批量的大小对改装方案的制定也有较大的影响。工件的批量大,改装后的机床的生产效率则要求高,若工件的批量小,则对机床的效率要求不高。工件批量大时要求要考虑机床的专用性,工件批量小时要求要考虑机床的通用性。砂轮机端盖的生产为中批量生产,设计周期短、经济的三轴头架十分适合它的生产批量加工条件。2.2 确定工件的加工方法 不同的加工方法可带来不同的经济效益,故工件加工工厂方法选择的是否合适,对钻床改装来说是非常重要的,他不仅关系到改装形式,还直接影响改装后机床加工质量的优劣、生产效率的高低等。所以确定工件加工方法时,应考虑以下主要问题:(1)加工表面要求的精度和粗糙度;(2)工件的生产批量;(3)工件的结构形状和尺寸(4)钻床改装的实际可能性。2.3 对被改装钻床的分析 分析被改装钻床时包括的主要内容有:(1)分析机床能否适应改装要求;(2)调查和了解机床的使用情况;(3)考虑机床的动力情况;(4)分析改装后机床的强度和刚度问题。Z535型立式钻床是一种传统的立式钻床,在机械制造和维修中的单件、小批量生产中,对中小型零件进行钻孔、扩孔、铰孔、锪孔及攻螺纹等加工工艺上得到了普遍的应用。但由于其为单孔钻床,对多孔钻削的加工比较麻烦,很费工时,给操作者增加了劳动强度。为此,为了挖掘设备潜力,将其改装成多头钻床,根据在实际加工中的要求,同一加工平面三孔或四孔加工比较常见,设计了齿轮十多轴头架,以便于更高效的使用Z535立式钻床。在完成一批生产任务后,三轴头架可以从钻床上拆下来,立式钻床恢复原貌,不会影响钻床原来的参数。当参数发生改变、被加工工件尺寸发生变化时,可调式头架的钻削主轴轴距可以调节,适应被加工工件上孔距在一范围内的变化,从而扩大了三轴头架的使用范围。有关Z535钻床的动力参数将在以下内容进行详尽的分析计算。2.4 总体布局 一般包括:分配运动、选择传动形式和支承形式的位置、拟定从布局上改善机床性能和技术经济指标的措施等。最后,绘制多轴头架与机床的总联系尺寸图,以表达所才用的总体布局,规定联系尺寸,并确定主要的技术参数。查相关的机床手册,得到Z535的相关联系尺寸,列于下表(单位:mm)最大钻孔直径d35最大钻孔深度h175从主轴端面到工作台端面H0750从主轴中心到导轨距离A175从工作台T型槽中心到凸肩距离B160凸肩高度h0-3工作台最大升高325主轴箱最大垂直移动量200主轴最大行程225主轴外径尺寸40d4锥孔莫式号数4号2.5其他问题分析在制定改装方案时,除了以上各因素外,还要注意维护要方便、制造和装陪要简单、结构要紧凑、通用化程度要高、外型要平整协调等,同时也要考虑因地制宜的改装问题。考虑到在钻床上安装了三轴头架之后,再装上钻头,钻头前端到被加工工件之间必须留有一定的高度用于进刀用,在加上工件孔的深度,钻头架的垂直尺寸必须满足一定的范围。根据钻床外的联系尺寸、钻头长度和一般被加工工件的尺寸,钻头架的垂直尺寸应在400mm左右。3. 齿轮可调式三轴头架的设计3.1 齿轮可调式三轴头架的传动原理及调整方法可调式三轴头架的传动原理如图1所示。主轴1由钻床主轴来带动旋转,经齿轮副2与3和3与5,使小轴4(即钻削主轴)得到动力旋转,于是带动钻头进行钻削。钻削孔径的调整通过改变两小轴4的中心距来实现,即使两小轴4的中心距等于被加工孔的孔径。在调整时(参见图1),首先松开六角螺母,然后转动支架使之带动介轮轴一起在本体中转动,直至三小轴的中心距调整到所要求的尺寸为止,再将六角螺母拧紧。 图1 三轴头架传动原理图 图2 传动原理简图1.主轴 2.中心轮 3.介轮 4.小轴 5.小齿轮3.2方案的工艺设计参数 3.2.1 Z535钻床动力所允许的工况条件 多轴头架是根据加工工件的需要进行设计的,与之相配套的立钻动力是否够用,设计前必须验证。常用的验证方法有两种:一是类比法,即加工同类零件机床动力进行比较,以此决定所选用的动力是否能满足要求,另一种是计算法,将计算所得的切削功率与配套机床的动力进行比较,以此决定配套机床的动力是否够用。 应用公式计算切削速度、切削力和切削功率,根据设计儿女物说明书的要求,最大孔径为,此时在各种工况条件下的V、F、P。考虑到齿轮传动有功率损失,单根钻削轴能承受的最大功率(Z535的额定功率围4.5kw)=1.33kw(1) 用高速钻头钻孔时查机械加工工艺师手册(以下简称工艺师)表28-14高速钢钻头钻削结构钢(),当d=10mm时,最大进给速度为f=0.25mm/r,对应的切削速度 V=15m/min 轴向力 F=3010N转矩 T=10.03Nm功率 P=0.51KW=1.33KW查工艺师表28-15高速钢钻头钻削灰铸铁(190HBS),当d=10mm时,最大的进给速度为f=0.60mm/r,对应的切削速度 V=12m/min 轴向力 F=3765N转矩 T=13.93Nm功率 P=0.52KW170HBS),这里按f=0.25mm/r计算查表得 有 满足功率要求。则用硬质合金钻头YG8钻削时,3.2.2 确定用于钻削计算的极限值由于以上所计算的进给量是在机床功率允许的最大值,此时转速为最小值,而在多轴头架中从主轴到钻削主轴是升速运动,可以充分发挥Z535的各级转速对比各种工况下的钻削速度,小轴钻削速度为:(1) 高速钢钻头钻削加工碳素结构钢()时v=16.1m/min n=v/D=16.1/0.010=512.7r/min (2) 高速钢钻头加工灰铸铁(190HBS)时v=13.4m/minn=v/D=13.4/0.010=426.8r/min (3) 用硬质合金钻头YG8加工灰铸铁(190HBS)时v=47.4m/minn=v/D=47.4/0.010=1509.6r/min对比可以看出在钻床所允许的功率下,工作最低转速为426.8 r/min,根据有关手册查得Z535钻床的各级转速为:68、100、140、190、275、400、530、750、1100r/min 为了减小轴头架的尺寸,防止头架过重,应尽量缩小头架的传动比,取主轴最低转速为140r/min进行升速,此时钻削轴转速为426.8r/min 则总的传动比为:考虑钻头都有一定的转向,一般为右旋,为了使钻削主轴与机床主轴的转动方向一致(都为右旋),采用两级齿轮传动。如果把传动比分配的合理,传动系统结构紧凑、重量轻、对机床的作用力就小,润滑条件也好。若分配不合理,可能会造成种种不便,因此分配传动比时要考虑以下原则:(1) 各级传动比应在每一级传动的范围内,各类传动比允许的推荐值可参见实用机械设计手册(以下简称实用手册)表1-3:(2) 各级传动尺寸要协调合理。 取 总传动比 为保证头架总体尺寸不至于过大,取小齿轮的齿数取Z3=20,根据有关资料的设计经验,取模数m=2则个齿轮的尺寸为: 小齿轮 Z3=20 mm 介轮 mm 中心轮 齿轮齿数确定后,算得传动比误差,总齿数比为:传动比误差为: 误差在内,满足误差要求。 图3 三轴头架的俯视图则轴头架的工艺尺寸(见图3)(1) 进行正式的三孔加工时 但由于支架的尺寸影响,不可能达到理论最小均布直径,根据支架的外型尺寸,头架能够加工的最小均布直径为50mm.(20) 作双轴头架使用,钻削双孔时 但是,作用轴头架使用时算的是达不到的,因为钻削主轴支架的厚度限制,具体尺寸在装配图完全确定后才能确定。(约为50mm)3.3三轴头架的传动设计3.3.1齿轮的设计演算(参考机械设计工程学I) (!)选择齿轮的材料 查表817 小齿轮选用40Cr调制处理 介轮选用45调质处理 中心轮选用45正火处理(2) 对中心轮进行齿根弯曲强度校核计算 由式(866) 确定齿轮传动精度等级,小齿轮的转速算得为426.8r/min以上,最高达1000r/min左右,小齿轮的圆周速度 参考表814,815选取齿宽系数 查表823按齿轮相对轴承为悬臂布置小齿轮转矩,按最大值计算为T3=13.1Nm(高速钢钻头钻削灰铸铁时),根据介轮受力分析 载荷系数K 由式(854)得 使用系数 查表8-20动载荷系数 查表8-57齿向载荷分布系数 查表8-60齿间载荷分布系数 查表8-55及=0得 查表8-21并查值则动载荷系数K=1.251.071.111.15=1.71齿型动载荷系数 查图8-67得 中心轮 介轮 应力修正系数 查图8-68 中心轮 介轮 重合度系数 由式8-67 =0.25+0.75/=0.25+0.75/1.72=0.69 许用弯曲应力 由式8-71 =/ 弯曲疲劳极限 查图8-72应力循环次数由式8-70 得)= 弯曲寿命系数 查图8-73 尺寸系数 查图8-74 安全系数 查图8-27 则 =39011/1.3=300N/mm =46011/1.3=354N/mm又因为中心轮齿宽 介轮齿宽较大,在计算时按 (已经取得比实际值大,若校核安全,则肯定安全)故 (3) 对小齿轮进行齿面接触疲劳强度校核计算 由式8-63得 齿宽系数查表8-23,按齿轮相对轴承为悬臂布置,取齿宽 介轮齿宽暂取,实际不止这尺寸,则按照他校核安全,则介轮肯定安全。 小齿齿宽 小齿轮转矩 (注:为极大值) 载荷系数K 由式(854)得 使用系数 查表8-20动载荷系数 查表8-57齿向载荷分布系数 查表8-60齿间载荷分布系数 查表8-55及=0得 查表8-21并查值则载荷系数弹性系数 查表8-22节点影响系数 查表8-64重合度系数 查表8-65()许用接触应力 式8-69得 接触疲劳极限应力、查图8-69 应力循环次数由式8-70 得 (已算得) 则查图8-70得接触强度的寿命系数、(不允许有点蚀) 硬化系数 查图8-71及说明 接触强度安全系数 查表8-27,按一般可靠度查得 取 =57011/1.1=518N/mm =148011/1.1=1345N/mm 齿数比 故 3.3.2轴的设计与校核 (1)小轴的设计校核 1)小轴最大转矩 2)作用在齿轮的力 圆周力 径向力 3)确定轴的最小直径 选取轴的材料为45钢调质处理,按式4-2初估轴的最小直径,查表4-2取A=115,可得 高速钢钻头钻削碳素钢时 高速钢钻头钻削灰铸铁时 硬质合金钻头钻削灰铸铁时 当轴上开有键槽时会削弱轴的强度,要适当增大轴的直径。轴段上有一个键槽时,轴径增大35%,故 4)轴的结构设计 A 拟定轴上零件的装配方案(见图4) B 按轴向定位要求确定各轴段直径和长度 轴段1 齿轮左端用弹簧挡圈定位,按轴段1的直径,取挡圈直径D=18.5mm(GB894.1-86).取. 轴段2 该轴段安装滚动轴承。此轴承主要承受切削力,即轴向力,选用单向推力轴承,取轴段直径,选用8205型单向推力轴承,尺寸dDT=254715.取齿轮垫圈的厚度为2mm,铜套的长度取为45mm, 轴段3 该轴段为夹头,起加紧钻头的作用,其具体尺寸有相关标准,此处不再详细分析。 图4 小轴的装配简图 5)轴上零件的周向定位 齿轮与轴的周向定位采用A型普通平键,尺寸为,为了保证齿轮与轴有良好的对中性,取齿轮与轴的配合为。 滚动轴承与轴的周向定位是采用过渡配合保证的,此轴段公差取为。 6)确定轴上零件圆角和倒角尺寸 各轴肩处的圆角半径见图3,轴端倒角取。 7)轴的强度校核 A)求轴的载荷 首先根据轴的结构图作出计算简图,在确定轴承支点位置时,因其只承受轴向力,对轴的强度无影响,而铜套与轴的配合段可视为墙壁。 根据轴的计算简图作出轴的弯矩图、扭矩图和当量弯矩图。从轴的结构图和弯矩图可以看出,A截面的当量弯矩最大,是轴的危险截面。 A截面处的、及的数值如下 弯矩 和 水平面 垂直面 合成弯矩 扭矩 当量弯矩 B)校核轴的强度 轴的材料为45钢,调质处理,由表4-1查得 ,则,即5865N/mm,取,轴的计算应力为 根据计算结果可知,该轴满足强度要求。 小轴的受力分析简图(3) 介轮轴的设计校核1) 求轴上的转矩2) 求作用在齿轮上的力 圆周力 径向力 3) 确定轴的最小直径选取轴的材料为45钢调质处理,按式4-2初估轴的最小直径,查表4-2取A=115,可得 4) 轴的结构设计拟定轴上零件的装配繁方案(见图5)A 按轴向定位要求确定各轴段直径和长度 轴段1左端用螺母定位,螺纹选用M20,配合螺母选用M20,规格为GB6172-86,m=10,螺纹长度为l=18mm,L=18+4=22mm. 轴段2 固定介轮轴用,为保证其垂直度、同轴度不受影响齿轮齿轮啮合,选L=24mm,d=22mm. 轴肩3 与螺母拧紧相互作用,另外,由于2、4段的表面粗糙度有要求,留有退刀槽,轴肩取L=4mm,则L=4+2+2=8mm,d=38mm. 轴段4 轴段长度为齿轮长度与小轴铜套长度及垫圈之和L=66+2=2+39+6=111mm,直径取d=22mm。 图5介轮轴的装配简图 B 轴上零件的周向定位 与小轴架用的销联接,选取d=4mm,L=22+220=62mm。而铜套与轴之间用间隙配合,功能相当于滑动轴承,配合取H7/h6,轴段2取H7/g6 C 确定轴上零件圆角和倒角尺寸 各轴肩处的圆角半径见图3,轴端倒角取。5) 轴的强度校核A 求轴的载荷 首先根据轴的结构图作出计算简图,因为各力均是由齿轮上传递过来的,所以对只论受力分析时,。根据轴的计算简图作出弯矩图,不承受扭矩,从结构图和弯矩图中看出在退刀槽处的弯矩最大,是轴的危险截面。 水平面 垂直面 合成弯矩 B)校核轴的强度 轴的材料为45钢,调质处理,由表4-1查得 ,则,即5865N/mm,取,轴的计算应力为 根据计算结果可知,该轴满足强度要求。 介轮轴的受力分析简图(4) 中心轴的设计校核1) 求轴上的转矩 2)求作用在齿轮上的力 圆周力 径向力 3)确定轴的最小直径选取轴的材料为45钢调质处理,按式4-2初估轴的最小直径,查表4-2取A=115,可得 当轴上开有键槽时会削弱轴的强度,要适当增大轴的直径。轴上有一个键槽时,轴径增大35%,故 4) A拟定轴上零件的装配繁方案(见图6)B按轴向定位要求确定各轴段直径和长度 轴段1跟机床主轴的4号莫氏锥度配合,锥度长103mm,加上过渡部分总长L=103+7=120mm,大端直径为31.926mm。 轴段2 对轴承进行密封防尘,选用毡圈55JB/ZQ4606-86,取,即L=16mm,比轴承外圈略小,比毡圈内径略大,有助于紧固零件。 轴段3 该轴段安装滚动轴承,考虑轴承承受径向力之外还要承受头架的重量,选择角接触球轴承。取轴段直径d=35mm,选用36207型角接触球轴承,尺寸。为了安装轴承,左端用轴肩定位,取m=3mm,则L=3+17+20+17+4=61mm. 轴段4 该轴段安装齿轮,左端用轴肩定位,右端用弹性挡圈定位,取轴段直径d=32mm,已知齿宽20mm,为了更好地压紧齿轮,按挡圈的配合要求,l=19.9mm,L=20+1+3=24mm。 图6 中心轴的装配简图C 轴上零件的周向定位 齿轮与轴的周向定位采用A型普通平键,尺寸为,为了保证齿轮与轴有良好的对中性,取齿轮与轴的配合为。 滚动轴承与轴的周向定位是采用过渡配合保证的,因此轴段直径尺寸公差取为。 D 确定轴上圆角和倒角尺寸 各轴肩处的圆角半径见图3,轴端倒角取5)轴的强度校核A 求轴的载荷 首先根据轴的结构图作出计算简图,在确定轴承支点位置时,从手册中查取a值(轴承的支反力作用点与轴承的距离)。对于36207型角接触球轴承,查得,因此轴的支承跨矩 L=15.7+20+15.7=51.4mm轴的悬臂距 L=(17-15.7)+4+10=15.3mm中心轮与三个介轮啮合,而且介轮均布。 水平面 以A为支点 以B为支点 垂直面 以A为支点 以B为支点 根据轴的计算简图作出轴的弯矩图、扭矩图和当量弯矩图。从轴的结构图和弯矩图可以看出,右轴承右侧的当量弯矩较大,虽然B处弯矩最大,但在轴承内孔内,应力集中不明显,故校核C处。 B 计算危险截面应力 C处弯矩 扭矩 抗弯截面系数 抗扭截面系数 截面上的弯曲应力 截面上的弯曲应力 弯曲应力幅 弯曲平均应力 扭转剪应力的应力幅与平均应力幅相等 C 确定影响系数 轴的材料围45钢,调质处理,由表4-1查得 配合边缘有效应力集中系数、查表得、 尺寸系数、,根据轴截面为圆截面查图4-18得、 表面质量系数、,据,表面的加工反复法为磨削,查图4-19 材料弯曲、扭转的特性系数 、 取, 由上面结果可知 有查表4-4中许用安全系数值,则可知该轴安全。三根轴的工作图见零件图。 中心轴的受力简图3.3.3 轴承的校核计算 (1)中心轴上36207型角接触球轴承的校核 1) 计算轴承支反力 合成支反力 2) 轴承的派生轴向力 由式5-8,估计A(轴向力即头架重力)为200N,取e=0.38 得 3) 轴承所承受的轴向载荷 因 由式5-10 4)轴承当量动载荷(1) 因 ,查表5-12 , 式5-7 (2) 查表5-12 式5-7 5) 轴承的动载荷要求,接受力要求轴承应当具有的当量动载荷,由表5-9、表5-10得,按式5-6 =8912.5Cr=23500 36207型角接触球轴承校核安全(2) 小轴上8205型单向推力轴承的校核 由于单向推力轴承只承受轴向力,在钻削时,(硬质合金YG8钻削灰铸铁时)则 (查表5-16,旋转轴承的安全系数取1.2),合格。3.3.4 键的校核计算 (1)小轴上的平键校核 选用的是6616,A型平键。由式2-49,得 查表2-21(轴联接的许用挤压应力)按有轻微冲击载荷取,校核合格。(3) 中心轴上的平键校核选用的是10818A型平键,有 稍微有些危险,改为采用双键,成对称布置,考虑到制造误差使键上载荷分布不均,按1.5个键计算,安全。 3.3.5螺栓的设计校核计算(参考机械设计工程学) 在多轴头架中,只有介轮周上的螺纹比较重要,需要进行校核。(1) 螺栓材料及其性能等级螺栓材料 45钢性能等级 查表27选6.8级,(2) 螺栓受力分析计算螺栓在头架中只承受介轮轴往下的零件(介轮轴、介轮、支架、小齿轮、小轴及钻头)的重力,经过估算,承受的重量约为5.5kg。受力为P=5.59.8=53.9N 螺栓工作拉力 由式2-15 F=P/Z=53.9/1=53.9N残余预紧力 查表2-5选 螺栓总拉力 由式 2-26相对刚度系数 查表2-6 螺栓预紧力 由式2-27/=86.24-53.90.3=70.07N (3)初定螺栓直径 选安全系数 查表2-11 许用拉应力 由式2-33 所需螺栓小径 由式2-29 cm 螺栓大径 查有关手册并根据轴的直径 取 d=20mm,其d1=17.294mm (4)螺栓疲劳强度校核螺栓尺寸系数 查表2-9 螺栓材料的疲劳极限 应力幅安全系数 查表2-11 应力集中系数 查表2-10 螺栓许用应力幅 由式2-36 螺栓应力幅 由式 2-303.3.6 夹头夹紧力的计算校核 在小轴上的夹头必须能够夹紧转头,避免钻削时打滑二无法进行加工。满足的条件的是弹簧夹头与钻头柄部产生的磨檫力能与钻削时的扭矩平衡。由于螺母的拧紧力是夹紧的主要作用力,通过反向计算螺母的拧紧力来校核螺母的疲劳强度。(1) 弹簧夹头夹紧力的计算查相关手册,弹簧夹头的夹紧力W在无轴向定位时 式中 W 总的径向夹紧力 P 轴向作用力,这里是由螺母产生的拧紧力 弹簧夹爪锥角之半 夹爪与工件之间的磨檫角 R 夹爪的变形阻力 K 系数(当夹爪的瓣数为4时,K=200)H 夹头弯曲部分的壁厚D 夹头弯曲部分的外径 夹爪与工件间的直径间隙L 夹爪根部至锥面中点的距离 必须满足 即 (2) 螺母的受力分析P 是螺母的总拉力相对刚度系数 查表2-6 =0.3螺母所需预紧力 由式 2-27(3) 确定螺母直径选用安全系数 查表2-11 许用拉应力 由式2-33所需螺栓小径 由式 2-29 螺栓大径 查相关手册并根据轴的直径 取 d=48mm,其=42.588mm(4) 螺栓疲劳强度校核 螺栓尺寸系数 查表2-9 插值 螺栓材料的疲劳极限 应力幅安全系数 查表 2-10 螺栓许用应力幅 由式2-36 螺栓应力幅 由式2-30满足疲劳强度要求。 4.润滑与密封 作为一个齿轮传动机构,为避免齿轮表面直接接触,以减小磨檫,减轻磨损,降低工作表面温度,应对齿轮进行适当的润滑,润滑方式应该根据轮齿速度来选择。在可调式三轴头架中,最高转速在1000r/min左右,对于分度圆最大的中心轮半径,它的最高齿轮速度是主轴在1100r/min工作时的速度,此时,查机械设计工程学表4-2应采用油浴润滑,但由于头架加工时位置摆放的特殊性竖直安装,采用油浴润滑很难实现,而压力喷油润滑又因为支架的尺寸太小也不好布置,所以 采用人工定期润滑,这是本次设计改进的地方之一。头架中轴孔连接的部位都必须密封防尘及防止漏油,由于齿轮在工作时相当于平放,头架下端的密封显得格外重要,而且属于动密封,加上轴与孔之间的配合的限制,只能采用接触式密封。5.结束语 本次毕业设计现已经接近尾声,共历时近两个多月。回顾整个设计过程,深觉的受益匪浅,通过这次毕业设计,不仅提高了我对四年来所学的各种知识的综合运用能力,还使我学到了书本所不能获取的知识,在看待问题核处理问题方面有了新的认识与方法,让我学会了用不同的立场去思考问题。在本次设计中,我做的主要是立式钻床可调式多轴头架的设计,对于钻床来说,它是一中常用的机床设备,但是它的加工能力却只局限在单一孔的加工,如果能够在它的轴头部分加一种装备,使它能够实现多孔位的加工,那样不仅可以节省时间、改善工人的劳动强度、提高劳动效率,而且对于机械行业也是一种革新,而我这次的课题就是要设计这样的一种装备,经过查阅资料及指导老师的细心帮助,这次设计基本达到了预期的目的,我设计成了一种可调式的三轴头架,可以实现同时三孔位的加工,而且如果孔之间的距离有变化,可以随时进行孔距的调节,基本达到了预期的效果。通过本次的毕业设计,不仅锻炼了自己查阅资料的能力,让我熟悉了有关技术政策,熟练的运用国家标准、规范手册、图册等工具书进行设计计算、数据处理、编写技术文件的独立工作能力。还让我感到了团体的力量,遇到问题时,通过同学之间的讨论、分析和指导老师的指导,最终总能得到满意的结果。对于目前我们所掌握的知识、实际的实践经验以及设计的时间,设计一种机床装备一个人不可能独立完成,需要我们彼此通力合作,才能真正的发挥团体的力量。这次毕业设计使我建立了正确的设计思想,初步掌握了解决本专业工程技术问题的方法和手段,从而,让我受到了一次工程师般的训练,相信在以后的学习、工作中一定会大有用处的。本次毕业设计,我得到了指导老师焦锋老师的精心指导,以及机制教研组其他老师的耐心指导和批评指正,给我提出了许多宝贵的意见和建议,在此表示由衷的感谢!还有在设计过程中,给予我莫大帮助的同学们也表示深深的谢意! 6.谢辞此次毕业设计中,我所设计的题目是立式钻床的可调式的多轴头架,在整个设计过程中,指导教师焦锋老师付出了很大的心血,从开始制定设计日程表到去焦作博克液压件厂、焦作制动器厂和系实验室实地考察实习,从图纸的绘制到说明书的整理,都在指导老师的指导下有条不紊的进行。在平时的设计中,焦老师深入设计教室,到我们学生中间来,就设计过程中存在的问题及时提出改进方案和建议,同时针对设计中中存在的问题给予详细而准确的解答,并且时时不忘督导我们按设计日程进行设计。正是由于有了焦老师的诸多帮助,我的毕业设计顺利进行直至结束。焦老师渊博的专业知识和丰富的生产时间经验,严谨务实的学术精神也在深深的感染着我,为我在以后的工作中树立了榜样,在此,我向焦老师表达我由衷的感谢。另外,在设计过程中,也得到了刘传绍老师、童景玲老师、李新老师等其他机制教研室老师的指导帮助,在此也表示由衷的感谢。同时在设计中和同教室的同学们进行了讨论,得到了他们的帮助,在此也表示感谢。谢谢你们!7.参考文献(1) 杨叔子 主编 机械加工工艺手册 机械工业出版社 2001(2) 吴相宪 王正为 黄玉堂 主编 实用机械设计手册 中国矿大出版社1993(3) 王洪欣 李木 刘秉忠 主编 机械设计工程学中国矿大出版社、2001(4) 唐大放 冯小宁 杨现卿 主编 机械设计工程学 中国矿大出版社2001(5) 陈榕林 张磊 主编 巧改机床 中国农业机械出版社1985(6) 中国纺织大学工程图学教研室主编 画法几何及工程制图上海科学技术出版社 1997(7) 孔庆华 刘传绍 主编 极限配合与测量技术基础 同济大学出版社 2002(8) 史美堂 主编 金属材料及热处理 上海科学技术出版社 1983(9) 苏翼林 主编 材料力学 高等教育出版社 1980(10) 顾崇衔 主编 机械制造工艺学 陕西科学技术出版社 1999(11) 濮良鬼 纪名刚 主编 机械设计 高等教育出版社 196051540 Research on the structure of green-product integration development system Jiang Jibin, Wu Qisheng, Lin Jiuguang, Liu Zhifeng, Liu Guangfu Hefei University of Technology, Hefei 230009, China ABSTRACT In order to conduct green design effectively and scientifically, it is an important premise to build Green- product Integration Development System orienting product life-cycle. In this paper, viewed from practicality and integration, current green products design tools are firstly analyzed, the structure of current accessible green-product integration development system is secondly discussed, and the strategy of system development from practicality and integration is lastly brought forward. * 1 SUMMARY Green-product is compatible with environment, resource and energy. Its green attribute is implemented on its whole life- cycle. Green-product development means that its function and structure. are designed and the green degree of the life-cycles different stage is virtually designed and assessed its digital- product stage. So the demands of time, quality, cost etc. are fulfilled on the precise of meeting environment and resources demands. There are many design tools about green-product design now. But most of them which are on theoretic stage arent integrated with traditional design tools such as CAD, CAM etc and can not support the enterprises product development. This paper studies on the structure of current accessible green-product integration development system and discusses the strategy of system development on the base of analyzing the specialties of green-product development from practicality and integration. The aims that different computer aided tools can fulfill are not the same as each others. For example CAD mainly completes products geometrical modeling. On the contrary, different aims of functions decide the structure of diverse system. So at the beginning of implementing system development, only to know well the functional aim of established system to be fulfilled, and only to apply those aim to instructing system planning and software development, can one assure the system to be established meeting functional demand. The aims of traditional designs theories and methods are to meet products function, quality, time, and cost. These * This project is supported by the Nation Natural Science Foundation of China 59935120 demands include the functions of satisfying customers, need, high quality, short manufacturing cycle, and low cost. Green design adds environmental aim comparing to traditional design and is centered by environmental protection. As to eliminate the potential negative effect, it emphasizes on the bondage between products fundamental attributes and environmental attributes. The environmental aim is a wide concept. It includes a series of problems such as ecological environment, resource, and the utility of energy etc. The problem about ecological environment means that it affects ecologically environment on its whole life-cycle. For example, polluted air and used water generated on manufacturing procedure affect ecological environment, whats more, the products which are disposed can affect ecological environment also. The utility of resource means the capacity of resource , especial non- recycle resource is utilized comprehensively and optimized. Then the aim is very important because resource is increasingly scarce. Though products green attribute is important when it is on manufacturing, using and disposed stage, it is decided on product development (digital product or blueprint) stage. Then we can achieve the goat of products minimum affect on ecological environment, minimum energy consumption, maximal resource using if only if we understand it well and regard environment as one aim by rational design of product structure when we is developing products. We can make a conclusion from above analysis: Green- product development not only includes traditional design which is applied to fulfill products function but also carries out environmental capability design., so the computer aided system which is applied to support Green-product development has characters of multi-tool and integration, and this point must to be considered when the structure of green- product development system is planned. 2 THE STRUCTURE OF CURRENT GREEN PRODUCT DESIGN TOOL The research about green product has been widely carried out since Alting introduced life-cycle engineering in 1993. Many research institutes and universities have studied and developed some green product design tools while many theories have been pointed out after many years research. Those tools not only validated these theories pointed out but also supported designers informational design tools. The current main green design tools is listed on section 3.5.2 in References1, and by analysis on those tools, the structure of the system is mainly divided into two style: single-tool structure and integration structure. This section will analyze their characters and applied field as to support theoretically the structure of green product development system which is based on uniform product model introduced in this paper. 541 2.1 Single-tool Structure Green design references to the analysis and estimate of products green attributes in life-cycle. It is a multi-fact and multi-attribute decision-making process. Early green design tools adopted single-tool structure and developed operating tools for a particular design content. The system existed alone and could not communicate with other design tools. For example, DFDS(Design For Disassembly System)developed by HeFei University of Technology belongs to this kind of structures. Figure 1 The Structure of DFDS Figure 1 is the structure of DFDS. This system acquires information about the structure, assembling and parts, and constructs product net-graphic model by information inputting system. It calculates parts disassembly direction and creates products disassembly sequence by some relative algorithm about applied graphic and analyzing disassembly plan which is based on net-graph model. Then it estimates products sustainability by analyzing disassembly time and disassembly problems. It finally creates files about estimating result which are supplied to the designers , and to be applied to modify products design. The research and development of DFDS supply an aided tool which can analyze the ability of disassembly for designers. DFDS can achieve interactive disassembly and prompt the research and development of sustainability design and green design. But the system adopts single-tool structure, it has some disadvantages. Many years research on CAD that indicates information about product structure, geometry, and assembly is so much , complicated and diverse that it is difficult to be expressed by simple data structure. DFDS is developed by VC+, because the data structure which is used to store product information is limited, it is too difficult to acquire entirely information, and it is only applied to several parts; It is not integrated with development tools such as CAD etc. Then it results to input information again and again and not feedback the estimating result automatically. The visual-ability of product and disassemblys process is limited. Whats more, its operation is relatively abstract. 2.2 Integration Structure Integration structure regards information integration as the aim. It realizes the integration of product development process and supports the information exchange and transfer among CAx (CAD, CAPP etc) and DFx (DFA, DFD etc.) by being supplied uniform data model (product model or management model). According to data model, the structure of product integration development system is divided into two categories: (1) Integration structure based on uniform product data model This structure plans every life-cycle development tool as a whole system. Product development is based on uniform product data model. It can achieve systemic high integration and shared information of a system. It is shown in figure 2(a). It constructs product integration development system platform by encapsulating development tools with uniform application interface. Different users carry out different product developments basing on this platform. The interactive action between development platform and product model is implement by product data management. Then they achieve information exchanging between development tools and shared information and integration in the process of product development. The essence of this system is product integration model which is applied to exchange, save, pigeonhole of product data in the whole life-cycle. Integration structure which is based on uniform product data model references to uniform and product integration model including life-cycle information about the product. It discards every development tools special database. At the same time, it constructs semantic relation between different tool data by managing product model data. Then it avoids dates redundancy and non-consistence between dates. Whats more, the advantage of product model with applied public data format is that it can reduce the developments of data- exchange processor. So researchers can spare more time to realizing the function of development tools, but not realizing system integrative data exchange. (a) (b) Figure2 The System of Integration Structure (2) integration structure based on uniform data management model The structure is based on PDM(Product Data Management), and integrates many functional software on uniform PDM platform, and achieves integration management of information and process. It is Data-exchange processor PDM system Integration product model Product data managemen Development system platform Specialty product model Specialty product model Product information Analysis result Information inputting Information modeling Disassembly planning Base information Part information Assembly information Net graph model Layer relation Disassembly direction Disassembly sequence Product Data Base Product model User interface DFA DFD DFx CAD CAPP CAx Development Tools basal model Applied basal model Professional applied model Knowledge base Knowledge Resource Universal knowledge Professional knowledge 542 shown on figure 2(b). PDM usually adopts product data and model management based on product structure model. There is plenty of redundant dates in applied files because on product structure model only proscribes the relation between professional product model and each applied system. The consistence check of files content can not been carried out by product dates management system either. Low-layer applied systems is forced to establish Mechanism of input and output conformed by standards such as STEP and IGES etc. because it lacks an integrative data model. On the other hand, the work amount is very large. So it is difficult to assure veracity of transforming data from one systemic product model to another. 3 THE STRUCTURE OF GREEN PRODUCT INTEGRATION DEVELOPMENT SYSTEM Green attribute is the essential character of green product. Because what green attribute references to mainly is manufacturing, using, and disposing which are on life-cycles material stage. So it usually adopts simulating way on the digital stage of product development. It also constructs virtual manufacturing, using and disposed environment on computer and predicts future green products character. In the future it appraises product green attribute on the basis of product and modifies irrational design affecting green attribute. The product to be developed finally reaches scheduled green aims. On the other hand, product development references to other simulating characters besides green attribute such as sustainability and manufacturing-ability of product. Those characters need digital product model too. So product model with uniform structure, no redundant information and oriented the whole life-cycle are the bases of realizing green product development , and it must to be considered carefully when researchers are planning product development system. According as above discussions, we think that the integration system based on uniform product data model should be preferred structure. What is shown in figure 4 is the structure of integration development system based on uniform product model. This system mainly consists of some components. Figure3 The Structure of Green Product Integration Development System (1) Development tool Product development system supplies correspondent supporting development tools when product is oriented for different applied demands in life-cycle. They are computer aided tools (CAx) and Design for X tools (DFx), and CAx is a platform that can meet demands in special fields of product design. Such as CAD, CAPP and CAM etc, modeling product and planning manufacturing process can be finished on this platform; DFx developed on the basis of CAx is technology and a tools that can meet life- cycle demands, it considers thoroughly what product affects on later procedure of product design stage, such as assembly- ability, manufacturing-ability and maintain-ability etc, designers consider as many factors as possible which can affect function by appraising every CAx designing results and rational decisions. Then it makes product achieve an optimum aim that synthesizes each functional index in the whole life- cycle. (2) Product model and model management Product model is the object manipulated by design activity. It is the essence of green design, and is the data and information set of product. We consider it consists of different layer model from figure 4. The first model is basal model which is not relative to concrete application, such as product geometrical model. The second model is applied basal model which references to applied function, such as precision model and resource & environment model. The third model is professional applied model for particular application, such as Finite-Element net model. Effective application of product model need supporting from management model. Management model and product model are usually combined into one functional unit. It can realize interactive information between development tool and product model by controlling information exchange and storing. Then shared and integrated information among all development tools can be achieved. Model management mainly consists of data management which is based on product structure and the mechanism of transforming model information into applied requirement information. (3) Knowledge base and knowledge management Knowledge base stores much information about all sorts of applied knowledge which references to product development. These information is the applied basis of every development tool and necessary for designing and estimating project. All information is divided into three layers by its specialties and universal character. The first layer is knowledge which is related to project and applied field. Such as design rule of axial parts and the rule of selecting cutting parameters. The second is knowledge which is related to particular product design. Such as enterprise standard and knowledge about enterprise manufacturing resource. The third is knowledge which is independent of application. Such as material standards and mechanical drawing standards. The storing and utility of knowledge data is realized by knowledge management system. These knowledge for product design applied demand which supports the being carried out project is delivered to development tool by knowledge management system interface. (4) User interface Each development tool(CAx and DFx), product model and knowledge base are encapsulated as a uniform development platform for designers. Each development tool can be harmoniously applied to process of product development by user interface. By user interface, the storing and acquiring of data and knowledge is controlled consistently, and then the uniformly management of process and information is realized. So it is possible to realize integrated and parallel product development. One important character of this structure is the model based on uniform product. Each life-cycle development tool and shared information is realized by enclosure of user interface. Then it can ensure that developed product achieves not only traditional structure and function aim but also environmental green aim. So green product can be successively developed. 4 THE IMPLEMENT STRATEGY OF GREEN PRODUCT INTEGRATION DEVELOPMENT SYSTEM Pro/E and UGII which are both commercial supporting software supply functional module such as design, model, analyze, NC programming and manufacture etc. They emphasize on product structure and manufacturing process, and they havent functional module such as about analysis and estimating environment affected by product and dont 543 support correspondent green design tool. But This sort of system is open and integrated partially. Viz. The system supplies three-dimension modeling. Uniform product data model can be constructed by the software. and at any moment, product geometrical and functional description can be acquired for product development tools, such as CAPP and Finite-Element analysis, etc. The system supplies customization modeling. It supplies input interface of project applied information about tolerance and material attribute, and makes a technical basis for constructing product model which includes life-cycle information. The system can be extended and is an open system. User applied system that is seamlessly integrated with the system Figure4 the structure of DFDS can realize user special function demand with listed development tools. So the paper introduces the implement strategy that the third-party develops green design functional tool on the basis of commercial supporting software platform, and increases and expands the system function, such as DFD etc., adapts the system to green products development. UGII for DFD is a system which is developed on UG platform with the strategy, as figure 4. Its prototype comes from figure 1, and it divides DFDS functional model into UG functional menu and is integrated into UG user interface. Net information that is applied to disassembly analysis can be acquired from UG product model. DFD analysis result is reflected directly on product model. The system adds disassembly process simulating too. So application-ability of the system is strengthened. Now the system is on trial stage and is highly assessed by enterprises. 5 CONCLUSION The research on the structure of green-product integration development system is systemic and whole planning for the system function, character and running ways. It is applied to decide developed software final operation model and applied field. The research of structure of green-product integration development system aims to select a appropriate system structure and framework model, and it assures that green design and estimation on each life-cycle stage are realized by the system. So product green attribute is implemented on the whole life-cycle. 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