机械5

摘要 数控铣床是重要的机械加工装备，在制造业中占有重要的地位，对国民经济的发展起着重要作用。其中，二维精密工作台是数控铣床的关键部件，二维精密工作台对数控铣床的加工精度和产品质量有着重要的影响，进行数控铣床二维精密工作台设计具有重要的经济价值与社会意义。 本设计的主要任务是研究数控铣床二维精密工作台主要结构，主要包括工作台的结构设计以及电机驱动电路的设计。 工作台结构设计的原则是参考现有的数控铣床工作台的结构，在实现工作台的强度、刚度、尺寸等实用要求的同时尽量实现结构简化及优化。设计的步骤是首先确定总体尺寸，主要参考沉阳机床厂卓越型数控铣床的总体尺寸。并采用solidworks软件进行计算机辅助设计，利用模型进行模拟装配和干涉检查。其次，在具体结构设计上尽量选着供应商的标准件，减少对机加工的要求。最后，对结构设计中主要部件例如丝杠进行校核以及精度验算。 驱动电路设计部分，首先确定使用直流伺服电机，并根据电机的型号参数设计驱动电路。驱动电路采用MOS管组成的H桥进行功率驱动，采用PWM调速系统进行速度控制。 设计完成后，根据主要结构及尺寸关系，绘制二维的零件图，绘制驱动电路原理图。 关键词：数控铣床；工作台；直流伺服电机；PWM Abstract CNC milli
ng machi
ni
ng equipme
nt, occupies a
n importa
nt positio
n i
n the ma
nufacturi
ng sector plays a
n importa
nt role i
n the developme
nt of the
natio
nal eco
nomy. The two-dime
nsio
nal precisio
n stage is a key compo
ne
nt of CNC milli
ng machi
ne a
nd the quality of two-dime
nsio
nal precisio
n stage has a
n importa
nt i
nflue
nce o
n CNC milli
ng machi
ni
ng accuracy a
nd product quality, CNC milli
ng two-dime
nsio
nal precisio
n stage desig
n has a
n importa
nt eco
nomicvalue social sig
nifica
nce. The desig
n of the mai
n task is to study the CNC milli
ng two-dime
nsio
nal precisio
n stage the mai
n structure, i
ncludi
ng the structure of the table desig
n a
nd the desig
n of the motor drive circuit. The table structure desig
n pri
ncipleswith refere
nce to the existi
ng structure of the CNC milli
ng machi
ne table, the practical requireme
nts of the be
nch-stre
ngth, stiff
ness, size, etc. At the same time try to simplify the structure a
nd optimizatio
n. The desig
n procedure is to first determi
ne the overall size, the overall size of the She
nya
ng Machi
ne Tool Factory excelle
nce i
n CNC milli
ng machi
ne. Use Solidworks software for computer-aided desig
n, usi
ng the model to simulate the assembly a
nd i
nterfere
nce checki
ng. Seco
ndly, the specific structural desig
n as much as possible suppliers of sta
ndard parts, reduce machi
ni
ng requireme
nts. Fi
nally, the structural desig
n of the mai
n compo
ne
nts such as screw checki
ng a
nd accuracy checki
ng. The desig
n portio
n of the drive circuit, first of all determi
ned usi
ng a DC servo motor a
nd drive circuit accordi
ng to the motor model parameters. Drive circuit composed of MOS tra
nsistor H-bridge power driver a
nd PWM speed co
ntrol system for speed co
ntrol. Whe
n desig
n is complete, accordi
ng to the mai
n structure a
nd size relatio
nships, draw two-dime
nsio
nal parts diagram, draw driver circuit schematic. Keywords: CNC milli
ng machi
ne; table; DC servo motor; the PWM 目录 引言3 1国内外数控铣床发展情况与设计意义4 1.1国外数控铣床发展情况4 1.2国内数控铣床发展情况4 1.3设计意义4 2方案选择5 2.1伺服进给系统选择5 2.2伺服电机选择6 3伺服进给系统参数计算7 3.1传动系统设计7 3.2工作台外形尺寸及重量初步估算7 3.3滚珠丝杠选择及计算8 3.3.1滚珠丝杠精度8 3.3.2滚珠丝杠选择8 3.4丝杠支撑选择及计算11 3.5导轨副的选择及计算13 3.6选择伺服电动机14 3.6.1最大切削负载转矩计算14 3.6.2负载惯量计算15 3.6.3空载加速转矩计算16 3.7伺服系统增益16 3.8精度验算16 3.8.1伺服刚度KR 16 3.8.2滚珠丝杠的拉压刚度Ktmi
n 17 3.8.3丝杠轴承的轴向刚度Kba 17 3.8.4滚珠丝杠螺母的接触刚度KC 18 3.8.5联轴器扭转刚度K1 18 3.8.6综合刚度K 18 3.8.7弹性变形18 3.8.8定位误差验算18 4主要部件设计及校核18 4.1联轴器18 4.2键19 4.3支承件19 4.3.1床身结构20 4.3.2电机座20 4.4 T型槽工作台21 4.5检测装置21 5直流伺服电机驱动电路设计23 5.1总体方案概述23 5.2 H桥驱动原理23 5.3 PWM原理24 5.4 H桥驱动电路设计25 5.5自举驱动电路26 5.6脉宽信号产生电路29 6结论31 谢辞32 参考文献33 附录34