《飞剪机构分析与设计》补充资料(doc 8页).doc

补充资料一、 正弦飞剪机构的设计1、 建立机构设计的计算模型e、f为由刀刃安装确定的结构尺寸，h为刀刃重合量。刀刃E的位置方程：xE=acosj1+eABn1EFhefdj1j10xyaxEyEyE=asinj1.刀刃E的速度方程：xE= -aw1sinj1yE=aw1cosj1.剪切角j01：cosj01=（a-h）/a曲柄半径a：要求开始剪切的刀刃速度yE为dvt，由此得到：dvt = aw1（a-h）/aa= dvt/w1+h 。轭架结构尺寸d：d=a+e+h+f。2、 计算实例：已知：vt=2m/s,L=1m, h=5mm,d=1.025,v刀0.05。曲柄角速度：w1=2pvt/L=2p2/1=4p/ s曲柄半径：a= dvt/w1+h=1.0252000/（4p）+5=168.1338mm。剪切角j01：cosj01=（a-h）/a=（168.1338-5）/168.1338=0.97026188j01=-14.0080140轭架结构尺寸d：若取e=f=250md=a+e+h+f=168+250+5+250=673mm。校验机器性能刀刃剪钢速度：xE= -aw1sinj1=-1684psin(-14.0080140)=511.02mm/s.yE=vEt=aw1cosj1.=1684pcos(-14.0080140)=2047.7248mm/s=VFtd=2047.7248/2000=1.0239。v刀=0。二、摆动导杆飞剪机构的设计1、运动分析位移方程acosj1+s cosj3=dasinj1+s sinj3=0由此得：s=d2+a2-2adcosj30.5.j3=arctanasinj1/( d- acosj1)C12dACBw1A34ayxdefsdFDhj1j10B0j3速度方程-aw1sinj1-sw3sinj3+scosj3=0aw1cosj1+s w3cosj3+ssinj3=0s=aw1sin(j1 -j3)w3=-aw1cos(j1 -j3)/s刀刃位置：xE=a cosj1+ecosj3yE=a sinj1+esinj3xF=d-fcosj3yF=-fsinj3刀刃速度：xE=-aw1 sinj1-ew3sinj3yE=a w1cosj1+ew3cosj3xF=fw3sinj3yF=-fw3cosj32、 机构尺寸设计已知刀刃结构尺寸e、d。由于刀刃与钢材速度同步，当j1=j01剪钢时：dvt=yE=a w1cosj01+ew3cosj03dvt=yF=-fw3cosj03两式联立得：cosj01=(e+f) dvt /( a w1 f)当剪钢时j1=j01由AB0C得：cosj01=a2+d2-(e+f)2/(2ad);其中由下式确定：d=a+e+f-h设p=e+f由以上cosj01两式联立得：a=-B(B2-4C)0.5/2.B=(p-h)-pdvt/(fw1)C=h2/2-ph -(p-h)pdvt /( fw1)求出后，得：d=a+e+f-h摇杆摆角y=2arcsin(a/d).3、 计算实例已知e=f=250mm,p=500mm, d=1.025, vt =2000mm/s, h =5mm, w1=4p (1/s),L=1000mm.曲柄角速度：w1=2pvt/L=2p2/1=4p/ s按下式计算曲柄半径：a=-B(B2-4C)0.5/2.B=(p-h)-pdvt/(fw1)C=h2/2-ph -(p-h)pdvt /( fw1)B=（500-5）-5001.0252000/(2504p)=169.6C=25/2-5005-(500-5)5001.0252000/(2504p)= -163558.9.a=-169.6169.62+4163558.9 0.5/2=328.5mm.机架结构尺寸d： d=a+e-h+f=328.5+250-5+250=823.5mm。剪切角j01：cosj01=(e+f) dvt /( a w1 f)=5001.0252000/(328.54p250)=0.9932.j01=6.6834.摇杆摆角:y=2arcsin(a/d)=2arcsin(328.5/823.5)=47.0198校验机器性能刀刃剪钢速度：s=d2+a2-2adcosj30.5.j3=arctanasinj1/( d- acosj1)s=823.52+328.52-2328.5823.5cos6.68340.5=499.1918mmj3=arctan328.5sin6.6834/( 823.5- 328.5cos6.6834)= arctan0.07689j3=4.3968w3=-aw1cos(j1 -j3)/sw3=-328.54pcosj(6.6834 -4.3968)/499.1918=-8.2553.yE=a w1cosj1+ew3cosj3yF=-fw3cosj3yE=328.54pcos6.6834+250(-8.2553)cos4.3968yE=2042.2490mm/syF=-250(-8.2553)cos4.3968=2057.7612mm/sv刀=(2042.2490+2057.7612)/2=2050.0001mm/sd=2050.0001/2000=1.025.v刀=(2057.7612m -2042.2490)/2050.0001=0.0076三、 双滑块六杆飞剪机构的设计h013dCAh02a0GDC0aba+b1、机构相对尺寸确定给定参数：导杆及摇杆摆角a、b，机架长度比k0= h02/ h01.取a0=1。由图得：c0/sina=( h01+ h02)/sin(a+b),c0 = h01 ( 1+k 0) sina/sin(a+b);c0 = a0( 1+k 0) /sin(a+b);两式联立：h01= a0 /sina。h02= k0 h012、机构绝对尺寸确定令l=e+fa=k1dVt/w1.比例尺m= a / a0.得机构绝对尺寸c、h1、h2.C3Bw145j1j3S3j5ayDEFef2hh13dCAh2xGC由图得：l=e+f=h2-a-c+h.e=f=l/23、 切角j1的确定确定剪切角j1的有两种方法：（1）试凑法；（2）牛顿拉甫辛法。（1）试凑法：按j1cos-1(a-h/2)/a初定剪切角，按该角进行运动分析，求出lBC, 若lBC与l=e+f的相对误差不大于5%，则认可。（2）牛顿拉甫辛法由回路ABG、ABCD得：f1= a cosj1+h1-s3 cosj3=0f2= a sinj1-s3 sinj3=0f3= a cosj1+l cosj3-h2-c cosj5=0f4= a sinj1+l sinj3-c sinj5=0初定j1、j3、j5、S3，按下式求出其近似值。4、确定最终机构尺寸运动分析求出刀刃速度V刀，得实际的k1=V刀/aw1,再从新求曲柄半径a*及机构最终尺寸。5、实例已知a=15、b=30，机架长度比k0= 1.5.a0=1。d=1.025, vt =2000mm/s, h =5mm, w1=4p (1/s).机构相对尺寸h01= a0 /sina=3.86。h02= k0 h01=5.796.c0 = a0( 1+k 0) /sin(a+b)=3.536.机构绝对尺寸取k1=1.2, Vt =2000mm/s,d=1.02, h =5mm.a=k1dVt/w1.=195mm.m= a / a0=195.由此得绝对尺寸：c=689mm,h1=753mm,h2=1130mm.e+f=h2+h-a-c252mm. e=f=126mm.用牛顿拉甫辛法求剪切角j1。计算结果：f1=0.000019,f2=0.000434,f3=0.000005,f4=0.000075fai1=11.607341,fai3=2.379909,fai5=175.863550,s3=944.827087,f1=0.000019,f2=0.000434,f3=0.000005,f4=0.000075numb=10j1=11.6, j3=2.38, j5=175.86,s3=944.8mm,运动分析确定机构最终尺寸V刀=（yE+yF）/2=2771.4818mm/s.K*1=aw1/ V刀=0.88416.a*=k*1 dvt/w1=144mm.m*= a*/a=0.736.c*=507mm,h*1=554mm,h*2=832mm;按最终尺寸计算的机构性能xE=787.53mm,YE=32.713mm,xf=787.53mm,yF=32.76mm;xE=372.54mm/s,YE=2004.07118mm/s,xf=-177.29136mm/s,yF=2075.92882mm/s;V刀=（yE+yF）/2=2040mm/s; d=1.02; V刀=0.035d=1.02.求真实的k*1值：k*1=aw1/ V刀=1.0466.重新求曲柄半径：a*= k*1 dVt /w1=1.04661.022000/(4p)170mm.按比例尺求机构最终尺寸：m*= a*/ a=0.85.a*= 170mm, b*=bm*=850mm, h*=hm*=340mm, e*=em