1.计算拐臂O1C绕O1Z轴的转动惯量:
从图中可知:δ1=40mm;δ2=17mm;R1=37.5mm;r1=25mm;R2=20mm;r2=10mm;d=157mm;d1=80mm;2a=EF=57.2mm;
1) R1半圆的转动惯量J1:
∵ J0=M/2×R2=π×R4×γ×δ/4,
∴ J1=π×γ×δ1×(R14-r14)/4
=π×2.65×103×0.04×(0.03754-0.0254)/4
=1.32114×10-4 (kg·m2)
2) R2半圆的转动惯量J2:
R2绕O1Z轴的转动惯量J20Z:
J20Z:=π×γ×(δ1-δ2)×(R24-r24)/4
=π×2.65×103×(0.04-0.017)×(0.024-0.014)/4
=7.1805×10-6 (kg·m2)
M2=π×γ×(δ1-δ2)×(R22-r22)/2
=π×2.65×103×(0.04-0.017)×(0.022-0.012)/2
=2.8722×10-2 (kg)
J2=J20Z+M2d2 (平移定理)
J2=π×γ×(δ1-δ2)×(R24-r24)/4+π×γ×(δ1-δ2)×(R22-r22)×d2/2
=7.1805×10-6+2.8722×10-2 ×0.1572
=715.149×10-6 (kg·m2)
3) 梯形ABCD绕O1Z轴的转动惯量J3:
J3=J3x+J3y
J3x=d3×γ×(2×R1+3×2×R2)/12
=0.1573×γ×(2×0.0375+3×2×0.02)/12
=6.2886×10-5γ
J3y=d×γ×[(2×R2)3+2×R2×(2×R1)2+(2×R2)2×2×R1+(2×R1)3]/48=0.157×γ×[(2×0.02)3+2×0.02×
(2×0.0375)2+(2×0.02)2×2×0.0375+(2×0.0375)3]/48
=2.7177×10-6γ
J3=6.2886×10-5γ+2.7177×10-6γ=65.6037×10-6γ
上述式中γ为面密度(kg/m2)
考虑到梯形厚度为δ1-δ2=0.04-0.017=0.023mm
∴ J3=66.6037×10-6γ'×0.023
= 66.6037×10-6×2.65×103×0.023=3.9985×10-3(kg·m2)
式中γ'为体密度=2.65×103(kg/m3)
4) 梯形ABEF绕O1Z轴的转动惯量J4:
J4=J4x+J4y
J4x=d13×γ×(2×R1+3×2×a)/12
=0.083×γ×(2×0.0375+3×0.0572)/12
=1.05216×10-5γ
J4y=d1×γ×[(2×a)3+2×a×(2×R1)2+(2×a)2×2×R1+(2×R1)3]/48
=0.08×γ×[0.05723+0.0572×(2×0.0375)2+0.05722×2×0.0375+(2×0.0375)
3]/48
=1.96027×10-6γ
J4=1.05216×10-5γ+1.96027×10-6γ=12.48187×10-6γ
上述式中γ为面密度(kg·m2)
考虑到梯形厚度为δ2=0.017mm
∴ J4= 12.48187×10-6γ'×0.017
=12.48187×10-6×2.65×103×0.017=0.5623×10-3(kg·m2)
式中γ'为体密度=2.65×103(kg/m2)
5) 轴销的转动惯量J5:(分为两部分:高度为δ2的圆柱及高度为δ1-δ2的半圆柱绕可O1Z轴转动,可等效高度为δ'=δ2+(δ1-δ2)/2=(δ1+δ2)/2=(0.04+0.017)/2=0.0285mm的圆柱绕O1Z轴转动)
因此,J5=J5OZ+M5d2
J5=π×γ×δ'×r24/2+π×r22×δ'×γ×d2
=π×7.8×103×0.0285×0.014/2+π×0.012×0.0285×7.8×103×0.1572=3.492×10-6+1.7214×10-3=1.725×10-3 (kg·m2)
6) 传动轴O1Z的转动惯量J6:(M6=2.96kg)
J6=M6×r12/2=2.96×0.0252/2=9.25×10-4(kg·m2)
所以:JC=J1+J2+J3+J4+J5+J6
=(0.132114+0.715149+3.9985+0.5623+1.725+0.925)×10-3
=8.058×10-3(kg·m2)
2.计算拐臂O1A绕O1Z轴的转动惯量:
r
从图中可知:δ1=46mm;δ2=16mm;R1=35mm;r1=18mm;R2=22mm;r2=10mm;d=132mm;d1=60mm;2a=EF=58.2mm;
1) R1半圆的转动惯量J1:
∵ J0=M/2×R2=π×R4×γ×δ/4,
∴ J1=π×γ×δ1×(R14-r14)/4
=π×2.65×103×0.046×(0.0354-0.0184)/4
=1.3362×10-4 (kg·m2)
2) R2半圆的转动惯量J2:
R2绕O1Z轴的转动惯量J20Z:
J20Z:=π×γ×(δ1-δ2)×(R24-r24)/4
=π×2.65×103×(0.046-0.016)×(0.0224-0.014)/4
=1.4×10-5 (kg·m2)
M2=π×γ×(δ1-δ2)×(R22-r22)/2
=π×2.65×103×(0.046-0.016)×(0.0222-0.012)/2
=4.7953×10-2(kg)
J2=π×γ×(δ1-δ2)×(R24-r24)/4+π×γ×(δ1-δ2)×(R22-r22)×d2/2
=1.4×10-5+4.7953×10-2×0.1322=84.9533×10-5(kg·m2)
3) 梯形ABCD绕O1Z轴的转动惯量J3:
J3=J3x+J3y
J3x=d3×γ×(2×R1+3×2×R2)/12
=0.1323×γ×(2×0.035+3×2×0.022)/12
=3.8716×10-5γ
J3y=d×γ×[(2×R2)3+2×R2×(2×R1)2+(2×R2)2×2×R1+(2×R1)3]/48=
3+2×0.022×2+2×2×0.035+0.132×γ×[(2×0.022)(2×0.035)(2×0.022)(2×0.035)3]/48
=2.143×10-6γ
J3=3.8716×10-5γ+2.143×10-6γ=40.859×10-6γ
上述式中γ为面密度(kg/m2)
考虑到梯形厚度为δ1-δ2=0.046-0.016=0.03mm
∴ J3=40.859×10-6γ'×0.03
=40.859×10-6×2.65×103×0.03=3.2483×10-3(kg·m2)
式中γ'为体密度=2.65×103(kg/m2)
4) 梯形ABEF绕O1Z轴的转动惯量J4:
J4=J4x+J4y
J4x=d13×γ×(2×R1+3×2×a)/12
=0.063×γ×(2×0.035+3×0.0582)/12=4.4028×10-6γ
J4y=d1×γ×[(2×a)3+2×a×(2×R1)2+(2×a)2×2×R1+(2×R1)3]/48=0.06×γ×[0.05823+0.0582×(2×0.035)2+0.05822×2×0.035+(2×0.035)3]/48=1.328×10-6γ
J4=4.4028×10-6γ+1.328×10-6γ=5.7308×10-6γ
上述式中γ为面密度(kg/m2)
考虑到梯形厚度为δ2=0.016mm
∴ J4=5.7308×10-6γ'×0.016
=5.7308×10-6×2.65×103×0.016=0.243×10-3(kg·m2)
式中γ'为体密度=2.65×103(kg/m3)
5) 轴销的转动惯量J5:(分为两部分:高度为δ2的圆柱及高度为δ1-δ2的半圆柱绕可O1Z轴转动,可等效高度为δ'=δ2+(δ1-δ2)/2=(δ1+δ2)/2=(0.046+0.016)/2=0.031mm的圆柱绕O1Z轴转动)
因此,J5=J5OZ+M5d2
J5=π×γ×δ'×r24/2+π×r22×δ'×γ×d2=π×7.8×103×0.031×0.014/2+π×0.012×0.031×7.8×103×0.1322
=3.798×10-6+1.324×10-3=1.328×10-3 (kg·m2)
6) 传动轴O1Z的转动惯量J6:(M6=2.96kg)
J6=M6×r12/2=2.96×0.0182/2=4.7952×10-4(kg·m2)
所以:JA=J1+J2+J3+J4+J5+J6
=(0.13362+0.849533+3.2483+0.243+1.328+0.47952)×10-3=6.282×10-3(kg·m2)
3.计算拐臂O1B绕O1Z轴的转动惯量:
从图中可知:δ1=30mm;δ2=12mm;R1=30mm;r1=18mm;R2=15mm;r2=6mm;d=94mm;d1=40mm;2a=EF=47.2mm;
1) R2半圆的转动惯量J1:
R2绕O1Z轴的转动惯量J20Z:
J20Z:=π×γ×(δ1-δ2)×(R24-r24)/4
=π×7.8×103×(0.03-0.012)×(0.0154-0.00)/4
=5.4395×10-6(kg·m2)
M2=π×γ×(δ1-δ2)×(R22-r22)/2
=π×7.8×103×(0.03-0.012)×(0.0152-0.0062)/2
=4.1682×10-2(kg)
J1=π×γ×(δ1-δ2)×(R24-r24)/4+π×γ×(δ1-δ2)×(R22-r22)×d2/2=5.4395×10-6+4.1682×10-2×0.0942
=373.74×10-6(kg·m2)
2) 梯形ABCD绕O1Z轴的转动惯量J2:
J2=J2x+J2y
J2x=d3×γ×(2×R1+3×2×R2)/12
=0.0943×γ×(2×0.03+3×2×0.015)/12=1.03823×10-5γ
J2y=d×γ×[(2×R2)3+2×R2×(2×R1)2+(2×R2)2×2×R1+(2×R1)3]/48=0.094×γ×[(2×0.015)3+2×0.015×(2×0.03)2+(2×0.015)2×2×0.03+(2×0.03)
3]/48
=7.93125×10-7γ
J2=1.03823×10-5γ+7.93125×10-7γ=111.75425×10-7γ
上述式中γ为面密度(kg/m2)
考虑到梯形厚度为δ1-δ2=0.03-0.012=0.018mm
∴ J2=111.75425×10-7γ'×0.018
=111.75425×10-7×7.8×103×0.018=15.69×10-4(kg·m2)
式中γ'为体密度= 7.8×103(kg/m3)
3) 梯形ABEF绕O1Z轴的转动惯量J3:
J3=J3x+J3y
J3x=d13×γ×(2×R1+3×2×a)/12
=0.043×γ×(2×0.03+3×0.0472)/12=1.0752×10-6γ
J3y=d1×γ×[(2×a)3+2×a×(2×R1)2+(2×a)2×2×R1+(2×R1)3]/48=0.04
2+0.04722×2×0.03+3]/48=5.2062×10-7×γ×[0.04723+0.0472×(2×0.03)(2×0.03)
γ
J3=1.0752×10-6γ+5.2062×10-7γ=15.9582×10-7γ
上述式中γ为面密度(kg/m2)
考虑到梯形厚度为δ2=0.012mm
∴ J3=15.9582×10-7γ'×0.012
=15.9582×10-7×7.8×103×0.012=1.494×10-4(kg·m2)
式中γ'为体密度=7.8×103(kg/m3)
4) 轴销的转动惯量J4:(分为两部分:高度为δ2的圆柱及高度为δ1-δ2的半圆柱绕可O1Z轴转动,可等效高度为δ'=δ2+(δ1-δ2)/2=(δ1+δ2)/2=(0.03+0.012)/2=0.021mm的圆柱绕O1Z轴转动)
因此,J4=J4OZ+M4d2
J4=π×γ×δ'×r24/2+π×r22×δ'×γ×d2=π×7.8×103×0.021×0.00/2+π×0.0062×0.021×7.8×103×0.0942
=3.33456×10-7+1.637×10-4=1.×10-4(kg·m2)
所以:JB=J1+J2+J3+J4
=(0.37374+1.569+0.1494+0.1)×10-3
=2.25614×10-3(kg·m2)
二、等效质量计算:
根据机构的传动关系,可知以M点为等效点,其等效质量MVM
MVM=3M+3MC×(VC/Vm)2+3JC×(ω1/Vm)2+MA×(VA/Vm)2+JA×(ω2/Vm)
2+2×M×(V/V)2+2×M×(V/V)2+2×M×(V/V)2+2×3J×(ω3/V)BABmBBBmBCBmBm2+M×(V/V)2 DDm
通过计算可已知以下参数:
M1(压气缸)=10kg;M2(绝缘拉杆)=4(kg);
M3(矩形管)=(50×30-42×22)×3500×2.65=5.3424(kg)
M4(355长拉杆)=2.667(kg)
M5(工作缸活塞)=4.67(kg)
1M=10+2×M2=10+2=12(kg)
1MC=2×M2=2(kg)
11MA=2×M4=2×2.667=1.3335(kg)
11MB=2×M4+M5=2×2.667+4.67=6.0035(kg)
MBA=MBC=5.3424÷2=2.6712(kg)
MBB=5.3424。
根据传动关系,可推导初以下公式:
VM=
22dSr2siniL2(e2r2sini)-r2cosi(e2r2sini)di22dtdtL(ersin)222i
VD=
22dhr1siniL1(e1r1sini)r1cosi(e1r1sini)di22dtdtL1(e1r1sini)
由于A、B、C三点均是绕O1Z轴转动的,角速度:
ω1=VA/r1;ω2=VC/r2;ω3=VB/r3;
1
VM
(
)2
1VA22VC13VB()2()2
222=(VA×VM);VM=(VC×VM);VM=(VB×VM);
dididi且VA=r1×dt;VB=r3×dt;VC=r2×dt;
VC2siniL2V22(e2r2sini)-r2cosi(e2r2sini)2M()=[];
2L22(e2r2sini)VA(VM)2=[
r1r22L22(e2r2sini)2siniL2(ersin)222i-r2cosi(e2r2sini)]2;
VB(VM)2=[
r3r22L22(e2r2sini)2siniL2(ersin)222i-r2cosi(e2r2sini)]2;