157.21mmР140mmР210mmР105mmР52.5mmР2.1.3 机构运动速度分析Р已知:n1=90r/min;机构处于B,分析速度。Р 图6 机构位置图Р = rad/s = =9.425 rad/s 逆时针Р = ·lAB = 9.425×0.069015=0.650m/sР = + Р大小? 0.65 ?Р方向⊥CD ⊥AB ⊥BCР选取比例尺μv=0.004m/(mm/s),作速度多边形Р 图7 速度多边形Р=· =0.03/0.05=0.600m/sР=· =0.009/0.05=0.180m/sР=· =0.45/0.05=0.900m/sР =· =0.44/0.05=0.880m/sР=·=0.01/0.05=0.200m/sР=·=0.031/0.05mm=0.620m/sР=·=0.022/0.05mm=0.440m/sР∴==0.18/0.314425=0.572rad/s (逆时针)Рω==0.60/0.140=4.290rad/s (顺时针)Рω==0.20/0.0525=3.809rad/s (顺时针) Р 表3 速度表Р项目Р数值Р0.650Р0.600Р0.900Р0.880Р0.620Р0.44Р9.425Р0.572Р4.290Р3.809Р单位Рm/sРRad/sР2.1.4机构运动加速度分析:РaB=ω12LAB=9.4252×0.069015=6.130m/s2РanCB=ω22LBC=0.5722×0. 314425=0.103m/s2РanCD=ω32LCD=4.2902×0.14=2.577m/s2 РanFE =ω42LEF=3.8092×0.0525=0.762m/s2Р= anCD+ atCD= aB + atCB + anCBР大小: ? √? √? √Р方向: ? C→D ⊥CD B→A ⊥BC C→B
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