3265 普通CA6140车床的经济型数控改造
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普通CA6140车床的经济型数控改造
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普通CA6140车床的经济型数控改造1 绪论1.1课题背景1946年诞生了世界上第一台电子计算机，这表明人类创造了可增强和部分代替脑力劳动的工具。它与人类在农业、工业社会中创造的那些只是增强体力劳动的工具相比，起了质的飞跃，为人类进入信息社会奠定了基础。6年后，即在1952年，计算机技术应用到了机床上，在美国诞生了第一台数控机床。我国目前机床总量380余万台，而其中数控机床总数只有11.34万台，即我国机床数控化率不到3。近10年来，我国数控机床年产量约为0.60.8万台，年产值约为18亿元。机床的年产量数控化率为6。我国机床役龄10年以上的占60以上；10年以下的机床中，自动/半自动机床不到20，FMC/FMS等自动化生产线更屈指可数（美国和日本自动和半自动机床占60以上）。可见我们的大多数制造行业和企业的生产、加工装备绝大数是传统的机床，而且半数以上是役龄在10年以上的旧机床。用这种装备加工出来的产品普遍存在质量差、品种少、档次低、成本高、供货期长，从而在国际、国内市场上缺乏竞争力，直接影响一个企业的产品、市场、效益，影响企业的生存和发展。所以必须大力提高机床的数控化率。在美国、日本和德国等发达国家，它们的机床改造作为新的经济增长行业，生意盎然，正处在黄金时代。由于机床以及技术的不断进步，机床改造是个永恒的课题。我国的机床改造业，也从老的行业进入到以数控技术为主的新的行业。在美国、日本、德国，用数控技术改造机床和生产线具有广阔的市场，已形成了机床和生产线数控改造的新的行业。在美国，机床改造业称为机床再生（Remanufacturing）业。从事再生业的著名公司有：Bertsche工程公司、ayton机床公司、Devlieg-Bullavd（得宝）服务集团、US设备公司等。美国得宝公司已在中国开办公司。在日本，机床改造业称为机床改装（Retrofitting）业。从事改装业的著名公司有：大隈工程集团、岗三机械公司、千代田工机公司、野崎工程公司、滨田工程公司、山本工程公司等。1.2机床改造的内容及意义1.2.1研究意义企业要在当前市场需求多变，竞争激烈的环境中生存和发展就需要迅速地更新和开发出新产品，以最低价格、最好的质量、最短的时间去满足市场需求的不断变化。而普通机床已不适应多品种、小批量生产要求，数控机床则综合了数控技术、微电子技术、自动检测技术等先进技术，最适宜加工小批量、高精度、形状复杂、生产周期要求短的零件。当变更加工对象时只需要换零件加工程序，无需对机床作任何调整，因此能很好地满足产品频繁变化的加工要求。普通车床经过多次大修后，其零部件相互连接尺寸变化较大，主要传动零件几经更换和调整，故障率仍然较高，采用传统的修理方案很难达到大修验收标准，而且费用较高。因此合理选择数控系统是改造得以成功的主要环节。数控机床在机械加工行业中的应用越来越广泛。数控机床的发展，一方面是全功能、高性能；另一方面是简单实用的经济型数控机床，具有自动加工的基本功能，操作维修方便。经济型数控系统通常用的是开环步进控制系统，功率步进电机为驱动元件，无检测反馈机构，系统的定位精度一般可达0.01至0.02mm，已能满足CW6140车床改造后加工零件的精度要求。1.2.2主要研究内容及技术路线(1)纵向和横向滚珠丝杠的选型及校核。(2)纵向和横向步进电机的选择。(3)主轴交流伺服电机的选择与校核。(4)其他元件的选择。1.3 机床的经济型数控化改造主要解决的问题(1) 恢复原功能，对机床、生产线存在的故障部分进行诊断并恢复。(2) NC化，在普通机床上加数显装置，或加数控系统，改造成NC机床、CNC机床。(3) 翻新，为提高精度、效率和自动化程度，对机械、电气部分进行翻新，对机械部分重新装配加工，恢复原精度；对其不满足生产要求的CNC系统以最新CNC进行更新。(4) 技术更新或技术创新，为提高性能或档次，或为了使用新工艺、新技术，在原有基础上进行较大规模的技术更新或技术创新，较大幅度地提高水平和档次的更新改造。2 数控系统的选择数控系统主要有三种类型，改造时，应根据具体情况进行选择。2.1步进电机拖动的开环系统系统的伺服驱动装置主要是步进电机、功率步进电机、电液脉冲马达等。由数控系统送出的进给指令脉冲，经驱动电路控制和功率放大后，使步进电机转动，通过齿轮副与滚珠丝杠副驱动执行部件。只要控制指令脉冲的数量、频率以及通电顺序，便可控制执行部件运动的位移量、速度和运动方向。这种系统不需要将所测得的实际位置和速度反馈到输入端，故称该之为开环系统，该系统的位移精度主要决定于步进电机的角位移精度，齿轮丝杠等传动元件的节距精度，所以系统的位移精度较低。该系统结构简单，调试维修方便，工作可靠，成本低，易改装成功。2.2异步电动机或直流电机拖动，光栅测量反馈的闭环数控系统该系统与开环系统的区别是：由光栅、感应同步器等位置检测装置测得的实际位置反馈信号，随时与给定值进行比较，将两者的差值放大和变换，驱动执行机构，以给定的速度向着消除偏差的方向运动，直到给定位置与反馈的实际位置的差值等于零为止。闭环进给系统在结构上比开环进给系统复杂，成本也高，对环境室温要求严。设计和调试都比开环系统难。但是可以获得比开环进给系统更高的精度，更快的速度，驱动功率更大的特性指标。可根据产品技术要求，决定是否采用这种系统。2.3交/直流伺服电机拖动，编码器反馈的半闭环数控系统半闭环系统检测元件安装在中间传动件上，间接测量执行部件的位置。它只能补偿系统环路内部部分元件的误差，因此，它的精度比闭环系统的精度低，但是它的结构与调试都较闭环系统简单。在将角位移检测元件与速度检测元件和伺服电机作成一个整体时则无需考虑位置检测装置的安装问题。当前生产数控系统的公司厂家比较多，国外著名公司的如德国SIEMENS公司、日本FANUC公司；国内公司如中国珠峰公司、北京航天机床数控系统集团公司、华中数控公司和沈阳高档数控国家工程研究中心。选择数控系统时主要是根据数控改造后机床要达到的各种精度、驱动电机的功率和用户的要求,所以依据改造的具体要求选用上海通用数控公司KT400-T经济型车床数控系统和KT300步进驱动装置.3 机械部分的改造为了充分发挥数控系统的技术性能，保证改造后的车床在系统控制下重复定位精度，微机进给无爬行，使用寿命长、外型美观，机械部分作了如下改动。(1) 床身为了使改造后的机床有较高的开动率和精度保持性，除尽可能地减少电器和机械故障的同时，应充分考虑机床零件、部件的耐磨性，尤其是机床导轨的耐磨性。增加耐磨性的方法有1，增加导轨的表面强度如：淬火；2，降低摩擦系数等。当前国内外数控机床的床身等大件多采用普通铸铁。而导轨则采用淬硬的合金钢材料，其耐磨性比普通铸铁导轨高5至10倍。据此，在改造中利用旧床身，采用淬火制成导轨，贴塑用螺钉和粘剂固定在铸铁床身上。粘接前的导轨工作表面采用磨削加工，表面粗糙度Ra0.8mm，以提高粘接强度。(2) 主轴变速箱选用数控系统,主运动方式和传统机床一样都要求有十分宽广的变速范围（116）来保证加工时选择合理的切速，从而获得较高的生产率和表面质量,所以要根据具体情况对主轴边速箱进行改造。(3) 拖板拖板是数控系统直接控制的对象，不论是点位控制还是连续控制，对被加工零件的最后坐标精度将受拖板运动精度、灵敏度和稳定性的影响。对于应用步进电机作拖动元件的开环系统尤其是这样。因为数控系统发出的指令仅使拖板运动而没有位置检测和信号反馈，故实际移动值和系统指令值如果有差别就会造成加工误差。因此，除了拖板及其配件精度要求较高外，还应采取以下措施来满足传动精度和灵敏度要求。在传动装置的布局上采用减速齿轮箱来提高传动扭矩和传动精度(分辨率为0.01mm)。传动比计算公式为： （3-1）式中：为步进电机的步距角(度)；p为丝杠螺距，mm；为脉冲当量，即要求的分辨率，mm。在齿轮传动中，为提高正、反传动精度必须尽可能的消除配对齿轮之间的传动间隙，其方法有两种，柔性调整法和刚性调整法。柔性调整法是指调整之后的齿轮侧隙可以自动补偿的方法，在齿轮的齿厚和齿距有差异的情况下，仍可始终保持无侧隙啮合。但将影响其传动平稳性，而且这种调整法的结构比较复杂，传动刚度低。刚性调整法是指调整之后齿轮侧隙不能自动补偿的调整方法，它要求严格控制齿轮的齿厚及齿距误差，否则传动的灵活性将受到影响。但用这种方法调整的齿轮传动有较好的传动刚度，而且结构比较简单。在设备改造中应用的配对齿轮侧隙方法是刚性调整法。采用滚珠丝杠代替原滑动丝杠，提高传动灵敏性和降低功率、步进电机力矩损失。 (4) 自动换刀装置为了满足在一台机床上一次装夹完成多工序加工，可采用自动刀架。自动刀架不但可代替普通车床手动刀架，还可用作数控机床微机控制元件。刀架体积小，重复定位精度高，适用于强力车削并安全可靠。(5) 拖板箱采用数控系统控制。拆除原拖板箱，利用此位置安装新拖板箱，新拖板箱除固定在滚珠丝杠的螺母上。挂轮箱、走刀箱拆除，在此两个位置分别装控制螺纹加工的主轴脉冲编码器和拖板轴向伺服元件功率步进电机及减速箱。使改造后的机床外型美观、合理。改造后机床的启动、停机均由数控系统完成，故拆除原机床操纵杆，变向杠、立轴等杠杆零件。3.1 滚珠丝杠的选择3.1.1滚珠丝杠副的特点滚珠丝杠副具有与滚动轴承相似的特征。与滑动丝杠副或液压缸传动相比，有以下主要特点：（1） 传动效率高 滚珠丝杠的传动效率可达85%98%，为滑动丝杠副的24倍，由于滚珠丝杠副的传动效率高，对机械小型化，减少启动后的颤动和滞后时间以及节约能源等方面，都具有重要意义。（2） 运动平稳 滚珠丝杠副在工作过程中摩擦阻力小，灵敏度高，而且摩擦系数几乎与运动速度无关，启动摩擦力矩与运动时的摩擦力矩的差别很小。所以滚珠丝杠副运动平稳，启动时无颤动，低速时无爬行。（3） 传动可逆性 与滑动丝杠副相比，滚动丝杠副突出的特点是具有运动的可逆性。正逆传动的效率几乎可高达98%。滚珠丝杠副具有运动的可逆性，但是没有象滑动丝杠副那样运动具有自锁性。因此，在某些机构中，特别是垂直升降机构中使用滚珠丝杠副时，必须设置防止逆转的装置。（4） 可以预紧 通过对螺母施加预紧力能消除滚珠丝杠副的间隙，提高轴向接触刚度，但摩擦力矩却增加不大。（5） 定位精度和重复定位精度高 由于滚珠丝杠副具有传动效率高，运动平稳，可以预紧等特点，所以滚珠丝杠副在工作过程中温升较小，无爬行。并可消除轴向间隙和对丝杠进行预紧拉伸以补偿热膨胀，能获得较高的定位精度和重复定位精度。（6） 同步性好 用几套相同的滚珠丝杠副同时驱动相同的部件和装置时，由于反应灵敏，无阻滞，无滑移，其启动的同时性，运行中的速度和位移等，都具有准确的一致性，这就是所谓同步性好。（7） 使用寿命长 滚珠丝杠和螺母的材料均为合金钢，螺纹滚道经过热处理，并淬硬至HRC58-62,经磨削达到所需的精度和表面粗糙度。实践证明，滚珠丝杠副的使用寿命比普通滑动丝杠副高56倍。（8） 使用可靠，润滑简单，维修方便 与液压传动相比，滚珠丝杠副在正常使用条件下故障率低，维修保养也极为方便；通常只需进行一般的润滑与防尘。在特殊使用场合，如核反应堆中的滚珠丝杠副，可在无润滑状态下正常工作。3.1.2. 纵向滚珠丝杠螺母副的型号选择与校核步骤(1)最大工作载荷计算 滚珠丝杠上的工作载荷Fm (N) 是指滚珠丝杠副的在驱动工作台时滚珠丝杠所承受的轴向力，也叫做进给牵引力。它包括滚珠丝杠的走刀抗力及与移动体重力和作用在导轨上的其他切削分力相关的摩擦力。由于原普通CA6140车床的纵向导轨是三角形导轨，则用公式3-2计算工作载荷的大小。 （3-2）1）车削抗力分析 车削外圆时的切削抗力有Fx、Fy、Fz，主切削力Fz与切削速度方向一致，垂直向下，是计算车床主轴电机切削功率的主要依据。且深抗力Fy与纵向进给方向垂直，影响加工精度或已加工表面质量。进给抗力Fx与进给方向平行且相反指向，设计或校核进给系统是要用它。 纵切外圆时，车床的主切削力Fz可以用下式计算： （3-3） =5360(N)由知: Fz:Fx:Fy=1:0.25:0.4 (3-4)得 Fx=1340(N) Fy=2144(N)因为车刀装夹在拖板上的刀架内，车刀受到的车削抗力将传递到进给拖板和导轨上，车削作业时作用在进给拖板上的载荷Fl、Fv和Fc与车刀所受到的车削抗力有对应关系，因此，作用在进给拖板上的载荷可以按下式求出：拖板上的进给方向载荷 Fl=Fx=1340(N)拖板上的垂直方向载荷 Fv=Fz=5360(N)拖板上的横向载荷 Fc=Fy=2144(N)因此，最大工作载荷 =1.151340+0.04(5360+909.8) =1790.68(N)对于三角形导轨 K=1.15 ，f =0.030.05,选f =0.04(因为是贴塑导轨)，G是纵向、横向溜板箱和刀架的重量，选纵向、横向溜板箱的重量为75kg,刀架重量为15kg.(2)最大动载荷C的计算滚珠丝杠应根据额定动载荷Ca选用，可用式3-5计算：C=， (3-5) L为工作寿命，单位为10r,L=60nt/10;n为丝杠转速（r/min）,n=;v为最大切削力条件下的进给速度（m/min）,可取最高进给速度的1/21/3;L0为丝杠的基本导程，查资料得L。=12mm；fm为运转状态系数，因为此时是有冲击振动，所以取fm=1.5。V纵向=1.59mm/r 1400r/min=2226mm/minn纵向=v纵向1/2 /L。=22261/2 /12=92.75r/min L=60nt/10=6092.7515000 /10=83.5则 C= =1.51790.68=11740(N) 初选滚珠丝杆副的尺寸规格，相应的额定动载荷Ca不得小于最大动载荷C:因此有CaC=11740N.另外假如滚珠丝杠副有可能在静态或低速运转下工作并受载，那么还需考虑其另一种失效形式-滚珠接触面上的塑性变形。即要考虑滚珠丝杠的额定静载荷Coa是否充分地超过了滚珠丝杠的工作载荷Fm,一般使Coa/Fm=23.初选滚珠丝杠为：外循环，因为内循环较外循环丝杠贵，并且较难安装。考虑到简易经济改装，所以采用外循环。 因此初选滚珠丝杠的型号为CD638-3.5-E型，主要参数为Dw=4.763mm,L。=8mm,dm=63mm,=219，圈数列数3.51 (3) 纵向滚珠丝杠的校核1)传动效率计算 滚珠丝杠螺母副的传动效率为 = tg/tg(+)= tg 219/tg(219+10)=92% (3-6)2)刚度验算 滚珠丝杠副的轴向变形将引起导程发生变化，从而影响其定位精度和运动平稳性，滚珠丝杠副的轴向变形包括丝杠的拉压变形，丝杠与螺母之间滚道的接触变形，丝杠的扭转变形引起的纵向变形以及螺母座的变形和滚珠丝杠轴承的轴向接触变形。1_丝杠的拉压变形量11=FmL / EA (3-7)=1790.682280 / 20.610(31.5) = 0.0064mm2 滚珠与螺纹滚道间的接触变形量2 采用有预紧的方式，因此用公式 2= 0.0013 (3-8) = =0.0028mm在这里 =1/3Fm=1/31790.68=597NZ= dm/Dw=3.1463/4.763=41.53 Z=41.533.51=145.36丝杠的总变形量=1+2=0.0064+0.0028=0.0092mm4所以丝杠很稳定。3.1.3横向滚珠丝杠螺母副的型号选择与校核步骤(1)型号选择1) 最大工作载荷计算 由于导向为贴塑导轨，则：k=1.4 f =0.05 ，Fl为工作台进给方向载荷，Fl=2144N ， Fv=5360N ， Fc=1340N ，G=60kg ， t=15000h，最大工作载荷：F m=kFl+ f (Fv+2Fc+G) =1.42144+0.05(5360+21340+9.875) =3452.6N2)最大动负载的计算v横=1400r/min 0.79mm/r = 1106 mm/minn横丝= v横1/2 / L。纵=11061/2 / 5 =110.6r/minL=60nt/10=1106110.615000 /10=99.54C =fmFm=99.541.53352.6=23283.8N初选滚珠丝杠型号为:CD506-3.5-E其基本参数为 Dw =3.969mm ，=211，L。=6mm，dm=50mm，圈数列数3.51(2)横向滚珠丝杠的校核1)传动效率计算=tg /tg (+)=tg211/tg(211+10)=93%2)刚度验算1丝杠的拉压变形量1=FmL/EA = 3352.6320/20.61025 = 0.0026mm2滚珠与螺纹滚道间的接触变形量2=0.0013 =0.0013 = 0.0099mm 在这里 Fyj=1118NZ=dm/Dw=3.1450/3.969=39.56Z=39.563.51=138.48丝杠的总变形量=1+2=0.0026+0.0099=0.0125mm100mm时n=6m由结构确定，在这里均取3,d3为螺钉直径.（1）D=26时的尺寸 =n-d3-1 则d3=2.5 取M4的螺钉=26+2.52.5=32.25 =32.25+32.5=39.25=0.9D=0.926=23.4m=3（2）D=37d3=2.5mm 取M4的螺钉=37+6.25=43.25mm=43.25+7.5=50.75mm=0.937=33.3mmm=3mm3.4.2 通盖 图3-6 通盖=D+(22.5)d3+2S2(有套环)=D。+(2.53)d3 =(0.850.9)Dd。=d3+（12） D100mm时n=4D100mm时n=6m由结构确定，在这里均取3mm,d3为螺钉直径.（1）D=6通盖尺寸，内加密封圈d3取M4螺钉=32.5 =39.75=23.4 d=18m=3（2）D=37通盖尺寸 d3取M4螺钉=43.25 =50.75=33.3 d=25m=33.5 丝轴承的选型与校核3.5.1滚珠丝杠用轴承的选型选用型号 7602025TVP的60推力角接触轴承 轴径 d=25mm 外径d=52mm 宽度B=15mm 球径Dw=6.35mm 球数Z=16 动载荷Ca=22000N 静载荷Coa=44000N 预加载荷500N 极限转速2600r/min3.5.2 校核 大部分滚动轴承是由于疲劳点蚀而失效的。轴承中任一元件出现疲劳步剥落扩展迹象前院运转的总转数或一定转速下的工作小时数称为轴承寿命（指的是两个套圈间的相对转数或相对转速）。 同样的一批轴承载相同工作条件下运转，各轴承的实际寿命大不相同，最高和最低的可能相差数十倍。对一个具体轴承很难预知其确切寿命，但是一批轴承则服从一定的概率分布规律，用数理统计的方法处理数据可分析计算一定可靠度R或失效概率n下的轴承寿命。实际选择轴承时常以基本额定寿命为标准。轴承的基本额定寿命是指90%可靠度，常用材料和加工质量，常规运转条件下的寿命，以符号L10(r)或L10h(h)表示。不同可靠度，特殊轴承性能和运转条件时其寿命可对基本额定寿命进行修正，称为修正额定寿命。 标准中规定将基本额定寿命一百万转（10r）时轴承所能承受的恒定载荷取为基本额定动载荷C。也就是说，在基本额定动载荷作用下，轴承可以工作10r而不发生点蚀失效，其可靠度为90%。基本额定动载荷大，轴承抗疲劳的承载能力相应较强。径向基本额定动载荷Cr对向心轴承（角接触轴承除外）是指径向载荷，对角接触轴承则是指引起轴承套圈间产生相对径向位移时的载荷径向分量。对推力轴承，轴向基本额定动载荷Ca是指中心轴向载荷。(1) 当量载荷滚动轴承若同时承受径向和轴向联合载荷，为了计算轴承寿命时在相同条件下比较，需将实际工作载荷转化为当量动载荷。在当量动载荷作用下，轴承寿命与实际联合载荷下轴承的寿命相同。当量动载荷P的计算公式是：P= （3-14）表3.2 轴承滚动当量动载荷计算的X,Y值轴承类型 Fa/Cor e 单向轴承双列轴承Fa/FreFa/FreFa/FreFa/FreX Y XY XYXY 角接触球轴承=150.0150.381 00.441.4711.65 0.722.390.0290.41.401.572.280.0580.431.301.462.110.0870.461.231.3820.120.471.191.341.930.170.501.121.261.820.290.551.021.141.660.440.561.001.121.630.580.561.001.121.63当量动载荷式中Fr为径向载荷，N；Fa为轴向载荷，N；X，Y分别为径向动载荷系数和轴向动载荷系数，可由上表查出。 上表中，e是一个判断系数，它是适用于各种X,Y系数值的Fa/Fr极限值。试验证明，轴承Fa/Fre或 Fa/Fre时其X,Y值是不同的。单列向心轴承或角接触轴承当Fa/Fre时，Y=0,P=Fr,即轴向载荷对当量动载荷的影响可以不计。深沟球轴承和角接触球轴承的e值随Fa/Cor的增大而增大。Fa/Cor反映轴向载荷的相对大小，它通过接触角的变化而影响e值。=0的圆柱滚子轴承与滚针轴承只能承受径向力，当量动载荷Pr=Fr;而=90的推力轴承只能承受轴向力，其当量动载荷Pa=Fa。 由于机械工作时常具有振动和冲击，为此，轴承的当量动载荷应按下式计算： P=fd(XFr+Yfa)冲击载荷系数fd由表3.3选取表3.3：载荷性质 机器举例fd平稳运转或轻微冲击电机，水泵，通风机，汽轮机1.01.2中等冲击车辆，机床，起重机，冶金设备，内燃机1.21.8强大冲击破碎机，轧钢机，振动筛，工程机械，石油钻机1.83.0由于轴承载荷与纵向载荷之比：=0.25C 此轴承合乎要求另外由于横向丝杠与纵向丝杠采用同一轴承，且载荷小于纵向，因此同理可验证其是合理的。4 步进电机的选择4.1 纵向步进电机的选择4.1.1 确定系统的脉冲当量脉冲当量是指一个进给脉冲使机床执行部件产生的进给量，它是衡量数控机床加工精度的一个基本技术参数。因此，脉冲当量应根据机床精度的要求来确定，CA6140的定位精度为0.015mm，因此选用的脉冲当量为0.01mm/脉冲 0.005mm/脉冲。4.1.2步距角的选择根据步距角初步选步进电机型号，并从步进电机技术参数表中查到步距角b ，三种不同脉冲分配方式对应有两种步距角。步距角b 及减速比 i与脉冲当量p 和丝杠导程 L0 有关。初选电机型号时应合理选择b及i, 并满足： b (pi360)/L0 （4-1）由上式可知：b pi360/L0=3600.011/10=0.36初选电机型号为:90BYG5502具体参数如表4.1所示 表4.1： 纵向电机步距角相数驱动电压电流90BYG55020.36 550V3A静转矩空载起动频率空载运行频率转动惯量重量 5N.m 2200 3000040 kg.cm4.5kg图4-1 电机简图4.1.3矩频特性： =J=J10(N.cm) 由于：nmax=(r/min)则： Mka=J(N.cm)式中：J为传动系统各部件惯量折算到电机轴上的总等效转动惯量（kg.cm）;为电机最大角加速度（rad/s）;nmax为与运动部件最大快进速度对应的电机最大转速（r/min）;t为运动部件从静止启动加速到最大快进速度所需的时间（s）;vmax为运动部件最大快进速度（mm/min）; p为脉冲当量（mm/脉冲）；b为初选步进电机的步距角（）步，对于轴、轴承、齿轮、联轴器，丝杠等圆柱体的转动惯量计算公式为J=(kg.cm),对于钢材，材料密度为7.810(kg.cm),则上式转化为J=0.78DL10(kg.cm),式中：Mc为圆柱体质量（kg）;D为圆柱体直径（cm），JD为电动机转子转动惯量，可由资料查出。(1)丝杠的转动惯量Js Js=Js/i，i为丝杠与电机轴之间的总传动比由于i=1则: Js=0.78DL10=0.78(6.3)17010=208.9( kg.cm)(2)工作台质量折算工作台是移动部件，其移动质量惯量折算到滚珠丝杠轴上的转动量JG:JG=（）M( kg.cm),式中：L。为丝杠导程（cm）;M为工作台质量（kg）.由于L。=1cm,M=90kg则 ： JG=（）M=90=2.28( kg.cm)1）一对齿轮传动小齿轮装置在电机轴上转动惯量不用折算，为J1.大齿轮转动惯量J2折算到电机轴上为=J2()2）两对齿轮传动传动总速比i=i1i2,二级分速比为i1=z2/z1和i2=z4/z3.于是，齿轮1的转动惯量为J1,齿轮2和3装在中间轴上，其转动惯量要分别折算到电机轴上，分别为J2()和J3().齿轮4的转动惯量要进行二次折算或以总速比折算为：=J4()() （4-2）因此，可以得到这样的结论：在电机轴上的传动部件转动惯量不必折算，在其他轴上的传动部件转动惯量折算时除以该轴与电机轴之间的总传动比平方。由于减速机构为一对齿轮传动，且第一级i=1,则可分别求出各齿轮与轴的转动惯量如下：n=45,m=1.5的转动惯量J45,其分度圆直径d=451.5=67.5mmS=27mm 则:J45=0.786.7510=4.371 kg.cmn=40,m=1.5的转动惯量J40,其分度圆直径d=401.5=60mmS=27mm 则:J40=0.78610=2.73kg.cmn=30,m=1.5的转动惯量J30,其分度圆直径d=301.5=45mmS=27mm 则:J30=0.784.510=0.964 kg.cmn=45,m=1.5的转动惯量J45,其分度圆直径d=451.5=67.5mmS=30mm 则:J45=0.786.7510=4.9538 kg.cmn=50,m=1.5的转动惯量J50,其分度圆直径d=501.5=75mmS=30mm 则:J50=0.787.510=7.548 kg.cmn=60,m=1.5的转动惯量J60,其分度圆直径d=601.5=90mmS=30mm 则:J60=0.78910=15.66 kg.cm两输入输出轴的转动惯量为:J输入=0.781.81310=0.106 kg.cm ; L=130mmJ输出=0.782.51310=0.396 kg.cm ; L=130mm查表得：JD=4 kg.cm综上可知：J=JD+Js+JG+J30+J40+J60+J50+2J45 （4-3） =252.302 kg.cm又由于 V =1.461600=2236mm/min则：Mka=252.30210=41.1N.cm(3)力矩的折算：1）Mkf空载摩擦力矩Mkf= （4-4）式中：G为运动部件的总重力（N）； f为导轨摩擦系数；i为齿轮传动降速比；为传动系统总效率，一般取=0.70.85；L。为滚珠丝杠的基本导程（cm）。由于G=9010=900N, f=0.05, i=1, =0.85则Mkf =8.4N.cm2）M。附加摩擦力矩 M。=(1-。) （4-5）式中：Fyj为滚珠丝杠预加负载，即预紧力，一般取1/3Fm;Fm为进给牵引力（N）, 。为滚珠丝杠未预紧时的传动效率，一般取。0.9得 Fyj=1/3Fm=1/31728.8=576.3N又 L。=10mm ， =0.95则 M。=96.6 N.cm 则 =+M。=41.1+8.4+96.6=140 N.cm由于=则所选步进电机为五相十拍的经表查得 ：=0.951则 =1.67N.m=0.955=4.75N.m所以所选步进电机合乎要求4.1.4据步进电机的矩频特性计算加减速时间校核的快速性T=(fn-f0) （4-6）式中：T为加减速时间，Jr和Jl分别为转子，负载的转动惯量（kg.m）为电机得步距角（），Tcp,Tl为电机最大平均转矩，负载转矩（N.m）f。,fn为起始加速时，加速终了时的频率（Hz）由于 Jr=0.410 kg.m Jl=0.0252 kg.m =0.36Tcp=5 N.m Tl=1.67 N.m f0=2200Hz fn=30000Hz 则 T=(30000-2200) =1.2s1.5s所以选此步进电机能满足要求。矩频特性曲线4.2 横向步进电机的选择4.2.1步距角的确定b pi360/L。 (4-7） L。=6mm , i=1 , p=0.005 b 0.3 初选电机型号为:110BYG5602横向电机步距角相数驱动电压电流110BYG56020.3 580V3A静转矩空载起动频率空载运行频率转动惯量重量 16 N.m 2500 3500015kg.cm16kg图4-2 电机简图4.2.2距频特性(1)力矩的折算1)空载摩擦力矩Mkf =GfL。/2i G=6010=600N f=0.05 L。=6mm =0.8 =3.5(N.cm)2)附加摩擦力矩 M。=(1-。)(N.cm) Fyj=1/3Fm=1/33433.6=1144.5N L。=6 M。=115 N.cm(2)转动惯量的折算1)滚珠丝杠的转动惯量 Js=0.78DL10 D=4cm L=26cm Js=0.78DL10=0.78(4)2610 =5.19 N.cm2)工作台转动惯量 JG=M （4-8） L。=0.6cm M=60kg JG=M =60=0.54( kg.cm)(3)多脉冲减速装置的转动惯量折算Z=30 d=mz=1.530=45mm J=0.78D L10 =0.784.51.810 =0.58kg.cmZ=40 d=mz=1.540=60mm J=0.78D L10 =0.7861.810 =1.82kg.cmZ=45 d=mz=1.545=67.5mm J=0.78DL10 =0.786.751.810 =2.92kg.cmZ=50 d=mz=1.550=75mm J=0.78DL10 =0.787.51.810 =4.44kg.cmZ=60 d=mz=1.560=90mm J=0.78D L10 =0.7891.810 =9.2kg.cm又由于 J输入=0.106 kg.cm J输出=0.396 kg.cm JD=15.8 kg.cm则 J=Js+JG+JJ=58 kg.cm Mka= J10vmax=0.781600=1248mm/mint=1.5sp=0.005b=0.3 Mka=50 =7.257N.cm Mkq=Mka+Mkf+M0=7.527+3.5+115=125.7N.cm又 MkqMjmax步进电机为五相十拍=0.95 Mjmax=16N.mMkq=1.257N.m0.9516=15.2N.m所以此步进电机符合条件(4)上升时间校核 t=(fn-f0)Jr=1.5810 kg.mJl=5.810 kg.m=0.3 Tcp=16N.m Tl=1.257N.m f0=2500Hz fn=35000Hz t= (35000-2500) =0.086s1.5s合乎要求5 主轴交流伺服电机5.1主轴的变速范围 主轴能实现的最高转速与最低转速之比称为变速范围Rn, 即Rn=nmax/nmin,数控机床的工艺范围宽，切削速度与刀具，工件直径变化很大，所以主轴变速范围很宽。 由于 Nmax=1800 nmin=14Nmax/nj=2nj/nmin （5-1） 则 nj=113r/min这里nj为电动机的额定转速该机床主轴要求的恒功率调速范围Rn为：Rn=nmax/nj （5-2） =1800/113=15.9主轴电机的功率是：7.5kw5.2初选主轴电机的型号选主轴电机的型号为：SIMODRIVE系列交流主轴驱动系统型号为1HP6167-4CB4，连续负载PH/KW=14.5，间歇负载（60%）/kw=17.5kw,短时负载（20min）/kw=19.25kw,额定负载n/r.min=5000，最大转速nmax/r/min=8000,额定转矩277N.m,惯性矩0.206/kg.m晶体管PWM变频器型号为6SC6058-4AA025.3主轴电机的校核电动机恒功率调速范围：Rn=nmax/nmin=8000/500=16所以所选电动机型号的调速范围满足主轴所要求的调速范围。6元件的选择6.1 SZGDBM01光电编码器6.1.1 概述 SZGDBM01光电编码器，是常用的位移、角位移、长度、深度等机械量的检测器件，广泛用于化工、冶金、能源、轻工、纺织、电子、机械、汽车等行业。6.1.2：主要技术性能SZGDBM01的分类方法6.2数控刀架/AK21系列刀架：AK21160*4*4C安装图及尺寸： 型 号ABCL1L2H1HXX1yh12MH3H4NAK2116041261261464412252197016017011230.5132082/44AK211604C1171261463882732177016017011432132060/32主要参数：序号项 目AK2116044C 1刀台方(mm)1602工位数(个)43装刀基面高(mm)704装刀基准孔高(mm)/5单工位转位时间(s)3.246刀架转速(r/min)177最大切向力矩(N .m)5008最大颠覆力矩(N .m)12509重复定位精度(mm)0.00510毛重(Kg)3811净重(Kg)3012箱体尺寸(mm)560400353结论 这次毕业设计持续的时间为16周，时间相对于我们以前搞设计来说是非常非长的。这次我毕业设计的题目是：把普通车床设计成为经济型数控车床。刚刚接受到这个题目的时候，感觉很难，因为以前从来没有接触过这方面的设计，头脑里一个最基本的概念都没有，后来老师给我们大体上讲了一下基本过程，再经过我们两个星期的研究，终于有一点眉目，搞清楚了什么是脉冲当量，什么是滚珠丝杠等等，还有我们为什么要改造那些这些机构。经过几个星期资料搜集，包括车床的说明书等等，设计并进入了正式的轨道。 在生活逐渐自动化的今天，对加工制造的精度和加工效益都提出了很高的要求，因此对机床等加工设备提出了很高的要求。以前单一的靠手工操作的机床，在很大程度上已经不能满足现代化的要求，数控机床的改造已经成为一种必要。但这次机床的改造是在原有的机床上换掉部分零部件，使它具有数控机床的基本功能，如不用手工操作能自动控制进给量等。但又考虑到改造成的是经济型数控车床，所以在选材等方面，必须考虑到经济这一重要问题。因此在这次设计中有些选型可能精度不是很高，但是考虑到经济这一个重要的前提，就选择了相对比较实惠的型号。 因为我们以前的基础知识掌握得不牢固，在这次设计中确实是遇到了很多的问题，但在这过程中，我们又学会了很多东西，在以前的小设计中，有些能马马虎虎过去的问题，就糊里糊涂过去了，可这次是一切正规化，不能有半点含糊，因此压力又大了很多，但是只要有一个明确的目标，乐在其中，特别是把以前学过的知识又温习了一下，而且把很多门课程都串联在一起，形成一个大的框架，这样确实是有一种豁然开朗、焕然一新的感觉。 通过这最后的毕业设计，我从一开始的只要完成任务的心态到后来的主动去学习，去努力的学习态度，这是一个不小的进步，并且把以前学过的知识融会贯通，看到了自己的许多不足之处。老师在我们设计中也给我们提出了很高的要求，它要求我们每一个零部件都要按照标准去查手册。另外，我们也学会了互相帮助，互相学习，合作的团体精神，严格要求自己，形成严谨治学的学习态度，这将会带到我们以后的工作中去。参考文献 吴振彪主编机电综合设计指导中国人民大学出版社.2000 余英良主编机床数控改造设计与实例机械工业出版社1997 机床设计手册编写组编机床设计手册第一，三，四册机械工业出版社1998 明兴祖主编数控加工技术化学工业出版社2001 胡占齐，杨莉主编机床数控技术机械工业出版社1986 黄调，赵松年主编机电一体化技术基础及应用机械工业出社1999杨有君主编数字控制技术与数控机床机械工业出版社1999王先逵主编机械制造工艺学机械工业出版社2002廖念钊，古莹庵主编互换性与技术测量中国计量出版社200010. 中国机械工程学会，中国设计大典编委会李壮云主编中国机械设计大典第五卷江西科学技术出版社，200211陈碧秀等主编实用中小电机手册。辽宁科学技术出版社200012 王槐德主编. .中国标准出版社.2003.13 普通CA6140车床的说明书.14 The Numerial Control Engine Bed Trasforms.15 邱宣怀主编.高等教育出版社.2002.16 薛严成.上海科学技术出版社.1999.附表附表 1 说明书中各符号一览表名称符号单位步进电机的步距角b()/脉冲脉冲当量pmm滚珠丝杠导程L。mm转动惯量J千克/米平方车床的切削功率PmkW机床电机功率PeKW进给方向载荷Fl,FxN拖板上垂直方向载荷Fv,FzN拖板上横向方向载荷Fc,FyN扭矩MN.m传动效率变形量mm临界载荷FkN稳定系数nk最大静转矩MjmaxN.cm名义启动转矩MnqN.cm空载启动转矩MkqN.cm最大动负载CN额定静载荷CoaN额定动载荷CaN最大工作载荷FmN主轴恒功率调速范围Rnp电动机恒功率调速范围RpThe Numerical Control Engine Bed TransformsHarvey B.M ackeyFirst numerical control system development summary brief history and tendency In 1946 the first electronic accounting machine was born in the world, this indicated the humanity created has been possible to strengthen and partially to replace the mental labor the tool. It with the humanity these which in the agriculture, the industry society created only is strengthens the physical labor the tool to compare, got up the quantitive leap, entered the information society for the humanity to lay the foundation. After 6 years, in 1952, computer technology applied to the engine bed , the first numerical control engine bed were born in US. From this time on, the traditional engine bed has had the archery target change. Since nearly half century, the numerical control system has experienced two stages and six generation of development. 1.1 Numerical control (NC) stage (1952 1970) The early computer operating speed is low, was not big to then science computation and the data processing influence, but could not adapt the engine bed real-time control request. The people can not but use numeral logic circuit to build to become an engine bed special purpose computer to take the numerical control system, is called the hardware connection numerical control (HARD-WIRED NC), Jian Chengwei numerical control (NC). Along with the primary device development, this stage has had been through repeatedly three generations, namely 1952 first generation of - electron tube; 1959 second generation of - transistor; 1965 third generation - small scale integration electric circuit. 1.2 Computer numerical control (CNC) stage (in 1970 present) In 1970, the general minicomputer already appeared and the mass production. Thereupon transplants it takes the numerical control system the core part, from this time on entered the computer numerical control (CNC) the stage (which should have computer in front of the general two characters to abbreviate). In 1971, American INTEL Corporation in the world first time the computer two most cores part - logic units and the controller, used the large scale integrated circuit technology integration on together the chip, called it the microprocessor (MICROPROCESSOR), also might be called the central processing element (to be called CPU). The microprocessor is applied to 1974 in the numerical control system. This is because minicomputer function too strong, controlled an engine bed ability to have wealthily (therefore once uses in controlling the multi- Taiwan engine bed at that time, called it group control), was inferior to used the microprocessor economy to be reasonable. Moreover then small machine reliability was not ideal. The early microprocessor speed and the function although insufficiently are also high, but may solve through the multi-processor structure. Because the microprocessor is the general-purpose calculator core part, therefore still was called the computer numerical control. In 1990, PC machine (personal computer, domestic custom had called microcomputer) the performance has developed to the very high stage, may satisfiedly take the numerical control system core part the request. The numerical control system henceforth entered based on the PC stage. In brief, the computer numerical control stage has also experienced three generations. Namely 1970 fourth generation of - minicomputer; 1974 five dynasties - microprocessor and 1990 sixth generation - (overseas was called PC-BASED) based on PC. Also must point out, although overseas already renamed as the computer numerical control (namely CNC).Also must point out, although overseas already renamed as the computer numerical control (namely CNC), but our country still the custom called the numerical control (NC). Therefore we daily say numerical control, the materially already was refers to computer numerical control. 1.3 the numerical control future will develop tendency 1.3.1 open style continues to, to develop based on the PC sixth generation of direction The software and hardware resources has which based on PC are rich and so on the characteristic, the more numerical controls serial production factory can step onto this path. Uses PC machine to take at least its front end machine, processes the man-machine contact surface, the programming, the associationQuestion and so on net correspondence, undertakes the numerical control duty by the original system. PC machine has the friendly man-machine contact surface, will popularize to all numerical controls system. The long-distance communication, the long-distance diagnosis and the service will be more common. 1.3.2 approaches and the high accuracy development This is adapts the engine bed to be high speed and the high accuracy direction need to develop. 1.3.3 develops to the intellectualized direction Along with the artificial intelligence in the computer domain unceasing seepage and the development, the numerical control system intellectualized degree unceasingly will enhance. (1) applies the adaptive control technology The numerical control system can examine in the process some important information, and the automatic control system related parameter, achieves the improvement system running status the goal. (2) introduces the expert system instruction processing The skilled worker and experts experience, the processing general rule and the special rule store in the system, take the craft parameter database as the strut, the establishment has the artificial intelligence the expert system. (3) introduces the breakdown to diagnose the expert system (4) intellectualized numeral servo drive May through the automatic diagnosis load, but the automatic control parameter, causes the actuation system to obtain the best movement.Second, engine bed numerical control transformation necessity 2.1 microscopic looks at the transformation the necessity From on microscopic looked below that, the numerical control engine bed has the prominent superiority compared to the traditional engine bed, moreover these superiority come from the computer might which the numerical control system contains. 2.1.1 may process the traditional engine bed cannot process the curve, the curved surface and so on the complex components. Because the computer has the excellent operation ability, may the instant accurately calculate each coordinate axis instant to be supposed the movement physiological load of exercise, therefore may turn round the synthesis complex curve or the curved surface. 2.1.2 may realize the processing automation, moreover is the flexible automation, thus the efficiency may enhance 3 7 times compared to the traditional engine bed. Because the computer has the memory and the memory property, may the procedure which inputs remember and save, then the order which stipulated according to the procedure automatic carries out, thus realization automation. The numerical control engine bed so long as replaces a procedure, may realize another work piece processing automation, thus causes the single unit and the small batch of production can automate, therefore is called has realized flexible automation. 2.1.3 processings components precision high, size dispersion degree small, makes the assembly to be easy, no longer needs to make repairs.2.1.4 may realize the multi- working procedures centralism, reduces the components in engine bed between frequent transporting. 2.1.5 has auto-alarm, the automatic monitoring, automatic compensation and so on the many kinds of autonomy function, thus may realize long time nobody to safeguard the processing. 2.1.6 advantage which derives by above five. For example: Reduced workers labor intensity, saved the labor force (a person to be possible to safeguard the multi- Taiwan engine bed), reduced the work clothes, reduced the new product trial manufacturing cycle and the production cycle, might to the market demand make rapid reaction and so on. Above these superiority are the predecessor cannot imagine, is an extremely significant breakthrough. In addition, the engine bed numerical control carries out FMC (flexible manufacture unit), FMS (flexible manufacture system) as well as CIMS (computer integration manufacture system) and so on the enterprise becoming an information based society transformation foundation. The numerical control technology already became the manufacturing industry automation the core technology and the foundation technology. 2.2 great watches the transformation the necessity From on macroscopic looked that, the industry developed country armed forces, the airplane weapon industry, in the end of the 70s, at the beginning of the 80s started the large-scale application numerical control engine bed. Its essence is, uses the information technology to the traditional industry (including the armed forces, airplane weapon industry) carries on the technological transformations. Except that uses outside the numerical control engine bed, FMC, FMS in the manufacture process, but also includes in the product development carries out CAD, CAE, CAM, the hypothesized manufacture as well as carries out MIS in the production management (management information system), CIMS and so on. As well as increases the information technology in its production product, including artificial intelligence and so on content. Because uses the information technology to the country foreign troops, the airplane weapon industry carries on the thorough transformation (to call it becoming an information based society), finally causes them the product in the international military goods and in the goods for civilian use market the competitive power greatly is the enhancement. But we in the information technology transformation tradition industry aspect compared to the developed country to fall behind approximately for 20 years. Like in our country engine bed capacity, numerical control engine bed proportion (numerical control rate) to 1995 only then 1.9%, but Japan has reached 20.8% in 1994, therefore every year has the massive mechanical and electrical products import. This also on from on macroscopic explained the engine bed numerical control transformation necessity.Thord, the numerical control transformation content and superiorly lacks 3.1 Transformation industry starting In US, Japan and Germany and so on the developed country, their engine bed transforms took the new economical growth profession, thrives abundantly, is occupying the golden age. As a result of the engine bed as well as the technical unceasing progress, the engine bed transformation is the eternal topic. Our countrys engine bed transformation industry, also enters from the old profession to by the numerical control technology primarily new profession. In US, Japan, Germany, have the broad market with the numerical control technological transformations engine bed and the production line, has formed the engine bed and the production line numerical control transformation new profession. In US, the engine bed transformation industry is called the engine bed regeneration (Remanufacturing) industry. Is engaged in the regeneration industry famous company to include: The Bertsche engineering firm, the ayton engine bed company, Devlieg-Bullavd (are valuable) serves the group, the US equipment company and so on. The American valuable company has set up the company in China. In Japan, the engine bed transformation industry is called the engine bed to reequip (Retrofitting) industry. Is engaged in the reequipment industry famous company to include: Big indentation project group, hillock three mechanical companies, thousand substitute fields labor machine company, wild engineering firm, shore field engineering firm, mountain this engineering firm and so on.3.2 Numerical control transformation content The engine bed and the production line numerical control transformation main content has following several points: First is extensively recovers the function, to the engine bed, the production line has the breakdown partially to carry on the diagnosis and the restoration; Second is NC, the addend reveals the installment on the ordinary engine bed, or adds the numerical control system, transforms the NC engine bed, the CNC engine bed; Third is renovates, for increases the precision, the efficiency and the automaticity, to the machinery, the electricity partially carries on renovates, reassembles the processing to the machine part, extensively recovers the precision; Does not satisfy the production request to it the CNC system to carry on the renewal by newest CNC; Fourth is the technology renews or the technical innovation, for enhances the performance or the scale, or in order to use the new craft, the new technology, carries on the big scale in the original foundation the technology to renew or the technical innovation, the great scope raises the level and the scale renewal transformation. The new electrical system transforms after, how carries on the debugging as well as the determination reasonable approval standard, also is the technology preparatory work important link. The debugging work involves the machinery, the hydraulic pressure, the electricity, the control, and so on, therefore must carry on by the project person in charge, other personnel coordinate. The debugging step may conform to simplicity to numerous, from infancy to maturity, carries on from outside to in, after also may the partial overall situation, after first the subsystem the3.3 The numerical control transformation superiorly lacks 3.3.1 reduced investment costs, the date of delivery are shortWith purchases the new engine bed to compare, may save 60% 80% expense generally, the transformation expense is low. Large-scale, the special engine bed especially is specially obvious. The common large-scale engine bed transforms, only spends the new engine bed purchase expense 1/3, the date of delivery is short. But some peculiar circumstances, like the high speed main axle, the tray automatic switching unit manufacture and the installment too requires a lot of work, costs a great deal of money, often transforms the cost to enhance 2 3 times, with purchases the new engine bed to compare, only can economical invest about 50%. 3.3.2 machine capability stable are reliable, the structure is limited Uses foundation and so on lathe bed, column all is heavy but the firm casting component, but is not that kind of welding component, after the transformation engine bed performance high, the quality is good, may take the new equipment continues to use many years. But receives the original mechanism the limit, not suitably makes the unprecedented transformation. 3.3.3 familiar understood the equipment, is advantageous for the operation service When purchases the new equipment, did not understand whether the new equipment can satisfy its processing request. The transformation then otherwise, may precisely calculate the engine bed the processing ability; Moreover, because many years use, the operator already understood to the engine bed characteristic, uses and services the aspect to train the time in the operation short, effective is quick. The transformation engine bed as soon as installs, may realize the capacity load revolution. 3.3.4 may fully use the existing condition May fully use the existing ground, does not need to like buys when the new equipment such to have reto construct the ground. 3.3.5 may use the newest control technology enhances the production equipment the automated level and the efficiency, improves the equipment quality and the scale, alters to the old engine bed now the horizontal engine bed.Fourth, numerical control system choice When the numerical control system mainly has three kind of types, the transformation, should act according to the special details to carry on the choice. 4.1 Step-by-steps the open system which the electrical machinery drives This system servo drive mainly is step-by-steps the electrical machinery, the power step-by-steps the electrical machinery, the battery solution pulse motor and so on. Entering sends out which by the numerical control system for instruction pulse, after the actuation electric circuit control and the power enlargement, causes to step-by-step the electrical machinery rotation, through gear vice- and ball bearing guide screw vice- actuation executive component. So long as the control command pulse quantity, the frequency as well as the circular telegram order, then may control the executive component movement the displacement quantity, the speed and the heading. This kind of system does not need the physical location and the velocity feedback which obtains to the input end, therefore called it the open system, this system displacement precision mainly decided in step-by-steps the electrical machinery angular displacement precision, transmission part and so on gear guide screw pitches the precision, therefore the system displacement precision is low. This system structure simple, debugging service convenient, work reliable, cost low, is easy to reequip successfully. 4.2 The asynchronous motor or the direct current machine drive, diffraction grating survey feedback closed loop numerical control system This system and the open system difference is: Physical location feedback signal which by position detector set and so on the diffraction grating, induction synchromesh obtains, carries on the comparison as necessary with the given value, two interpolations enlargements and the transformation, the actuation implementing agency, by the speed which assigns turns towards the elimination deviation the direction movement, until assigns the position and the feedback physical location interpolation is equal to the zero. The closed loop enters for the systemEnters for the system complex in the structure compared to the split-ring, the cost is also high, requests strictly to the environment room temperature. The design and the debugging is all more difficult than the open system. But may obtain compared to the split-ring enters for a system higher precision, quicker speed, actuation power bigger characteristic target. May act according to the product specification, decided whether uses this kind of system. 4.3 The direct current servo electrical machinery drives, encoder feedback semi-closure link numerical control system Half closed-loop system examination part installs in among passes in the moving parts, indirectly surveys the executive component the position. It only can compensate a system ring circuit interior part of part the error, therefore, its precision compared to closed-loop system precision low, but its structure and the debugging all compares the closed-loop system to be simple. In makes the angular displacement examination part and the speed examination part and the servo electrical machinery time a whole then does not need to consider the position detector set installs the question. The current production numerical control system company factory quite are many, overseas famous company like German SIEMENS Corporation, Japanese FANUC Corporation; Native corporation like China Mount Everest Corporation, Beijing astronautics engine bed numerical control system group company, Central China numerical control company and Shenyang upscale numerical control country engineering research center. When choice numerical control system mainly is each kind of precision which the engine bed must achieve after the numerical control transformation, actuates the electrical machinery the power and users request.Fifth in the numerical control transformation the main mechanical part reequips the discussion A new numerical control engine bed, must achieve in the design that, Has the high static dynamic rigidity; Movement vice- between friction coefficient small, the transmission is ceaseless; The power is big; Is advantageous for the operation and the service. When engine bed numerical control transformation should meet the above requirements as far as possible. Cannot think the numerical control installment and the ordinary engine bed connects in has met the numerical control engine bed requirements together, but also should carry on the corresponding transformation to the major component to enable it to achieve the certain design request, can obtain the anticipated transformation goal. 5.1 skids guide rail Said to the numerical control lathe that, the guide rail besides should have the conventional lathe guidance precision and the technology capability, but also must have good bears the friction, the attrition characteristic, and the reduction but sends the dead area because of the friction drag. At the same time must have the enough rigidity, by reduces the guide rail to distort to processes the precision the influence, must have the reasonable guide rail protection and the lubrication. 5.2 gear The common engine bed gear mainly concentrates in the headstock and the gear box. In order to guarantee the transmission precision, on the numerical control engine bed uses the gear precision class is all higher than the ordinary engine bed. Must be able to achieve the ceaseless transmission in the structure, thus transforms time, the engine bed main gear must satisfy the numerical control engine bed the request, by guarantees the engine bed processing precision. 5.3 skids the guide screw and the ball bearing guide screw The guide screw transmission relates directly to the transmission chain precision. The guide screw selects mainly is decided requests and drives the torque request in the job precision. Is not used by job precision request Gao Shike skids the guide screw, but should inspect the original guide screw attrition situation, like the pitch error and the pitch accumulative error as well as matches the nut gap. The ordinary circumstances skid the guide screw to be supposed not to be lower than 6 levels, the nut gap oversized then replaces the nut. Uses skids the guide screw relative ball bearing guide screw price to be low, but satisfies the precision high components processing with difficulty. The ball bearing guide screw rubs loses slightly, the efficiency is high, its transmission efficiency may above 90%; Precision high, the life is long; When start moment of force and movement the moment of force approaches, may reduce the electrical machinery to start the moment of force. Therefore may satisfiedly compare the high accuracy components processing request.5.4 safe protection The effect must take the security as a premise. Transforms in the engine bed must take the corresponding measure according to the actual situation, cuts noticeable. The ball bearing guide screw vice- is the precision part, when the work must take strict precautions against the dust is specially the scrap and the hard sand grains enters the roller conveyer. On longitudinal guide screw also coca overall sheet iron safety mask. The big carriage with skids two end surfaces which the guide rail contacts to have to seal, prevented absolutely the flinty granulated foreign matter enters the sliding surface damage guide rail.Sixth, After the engine bed electrical system transformation, to operates, the programmers inevitably brings the new request. Therefore ahead of time carries on new system knowledge training to the operator and the programmers to be extremely important, after otherwise will affect the transformation the engine bed rapid investment production. The training content should include the new operation kneading board disposition, the function, the instruction meaning generally; New system functional scope, application method and with old system difference; Maintenance maintenance request; Programming standard and automated programming and so on. The key point is makes, gets a good grasp of the operating manual and the programming instruction booklet.the numerical control transforms se Transforms the scope according to each equipment differently, must beforehand design the connection partial transformations, if transforms completely, should design the electro-mechanical transformation connection, the operation kneading board control and the disposition, the interconnection partial contacts, the parameter measuring point, services the position and so on, the request operates and services conveniently, reasonable, the line moves towards, center the small junction smoothly few, the strong and the weak electrical noise is smallest, has the suitable allowance and so on. Partial transformation, but also needs to consider the new old system the performance match, the voltage polarity and the size transformation, install the position, the digital-analog conversion and so on, when the necessity must manufacture the transformation connection voluntarily.veral examples 1st, transforms the X53 milling machine with SIEMENS 810M In 1998, the company invested 200,000 Yuan, with German Simens the 810M numerical control system, the 611A exchange servo drive system sds was the X53 milling machine carries on X, Y, the Z three axle numerical control transformation to a companys model; Retained the original main axle system and the cooling system; The transformation three axle has used the roller lead screw and the gear drive organization on the machinery. The entire transformation work including the machine design, the electrical design, the PLC procedure establishment and the debugging, the engine bed overhaul, finally is the entire machine installment and the debugging. After the milling machine transforms, processing effective stroke X/Y/The Z axis respectively is 88.0/270/28 billion mm; Maximum speed X/Y/The Z axis respectively is 5000/1500/800 mm/Min; Manual speed X/Y/The Z axis respectively is 3000/1000/500 mm/Min; The engine bed processing precision achieves 0.001mm. The engine bed three coordinates linkage may complete each kind of complex curve or the curved surface processing.2nd, transforms the C6140 lathe with GSK980T and the exchange servo drive system sds In 2000, with Guangzhou numerical control plant production GSK980T numerical control system, the DA98 exchange servo unit and 4 locations automatic tool rests to an electrical machinery branch factory C6140 lathe X, the Z two axes carries on the numerical control transformation; Retained the original main axle system and the cooling system; The transformation two axes have used the roller lead screw and with the ambulacrum transmission system on the machinery. Entire transformation work including machine design, electrical design, engine bed overhaul and entire machine installment and debugging. After the lathe transforms, processing effective stroke X/The Z axis respectively is 3.90/73 million mm; Maximum speed X/The Z axis respectively is 120.0/3 million mm/Min; The manual speed is 400mm/Min; Manual is fast is X/The Z axis respectively is 120.0/3 million mm/Min; The engine bed smallest migration unit is 0.001mm.3rd, transforms the X53 milling machine with SIEMENS 802S In 2000, the company invests 120,000 Yuan, with German Simens the 802S numerical control system, step-by-steps the actuation system is the X53 milling machine carries on X, Y, the Z three axle numerical control transformation to companys another model; Retained the original main axle system and the cooling system; The transformation three axle has used the roller lead screw and the gear drive organization on the machinery. The entire transformation work including the machine design, the electrical design, the engine bed overhaul, finally is the entire machine installment and the debugging. After the milling machine transforms, processing effective stroke X/Y/The Z axis respectively is 63.0/240/28 billion mm; Maximum speed X/Y/The Z axis respectively is 3000/1000/600 mm/Min; Manual enters for speed X/Y/The Z axis respectively is 200.0/800/5 billion mm/Min; The smallest motion unit is 0.001mm.数控机床改造一、数控系统发展简史及趋势 1946年诞生了世界上第一台电子计算机，这表明人类创造了可增强和部分代替脑力劳动的工具。它与人类在农业、工业社会中创造的那些只是增强体力劳动的工具相比，起了质的飞跃，为人类进入信息社会奠定了基础。6年后，即在1952年，计算机技术应用到了机床上，在美国诞生了第一台数控机床。从此，传统机床产生了质的变化。近半个世纪以来，数控系统经历了两个阶段和六代的发展。 1.1、数控（NC）阶段（19521970年） 早期计算机的运算速度低，对当时的科学计算和数据处理影响还不大，但不能适应机床实时控制的要求。人们不得不采用数字逻辑电路搭成一台机床专用计算机作为数控系统，被称为硬件连接数控（HARD-WIRED NC），简称为数控（NC）。随着元器件的发展，这个阶段历经了三代，即1952年的第一代-电子管；1959年的第二代-晶体管；1965年的第三代-小规模集成电路。 1.2、计算机数控（CNC）阶段（1970年现在） 到1970年，通用小型计算机业已出现并成批生产。于是将它移植过来作为数控系统的核心部件，从此进入了计算机数控（CNC）阶段（把计算机前面应有的通用两个字省略了）。到1971年，美国INTEL公司在世界上第一次将计算机的两个最核心的部件-运算器和控制器，采用大规模集成电路技术集成在一块芯片上，称之为微处理器（MICROPROCESSOR），又可称为中央处理单元（简称CPU）。 到1974年微处理器被应用于数控系统。这是因为小型计算机功能太强，控制一台机床能力有富裕（故当时曾用于控制多台机床，称之为群控），不如采用微处理器经济合理。而且当时的小型机可靠性也不理想。早期的微处理器速度和功能虽还不够高，但可以通过多处理器结构来解决。由于微处理器是通用计算机的核心部件，故仍称为计算机数控。 到了1990年，PC机的性能已发展到很高的阶段，可以满足作为数控系统核心部件的要求。数控系统从此进入了基于PC的阶段。 总之，计算机数控阶段也经历了三代。即1970年的第四代-小型计算机；1974年的第五代-微处理器和1990年的第六代-基于PC（也就是为PC-BASED）。 1.3、数控未来发展的趋势 1.3.1继续向开放式、基于PC的第六代方向发展 基于PC所具有的开放性、低成本、高可靠性、软硬件资源丰富等特点，更多的数控系统生产厂家会走上这条道路。至少采用PC机作为它的前端机，来处理人机界面、编程、联网通信等问题，由原有的系统承担数控的任务。PC机所具有的友好的人机界面，
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