第五章平面连杆机构动力分析

jyθ'3CR'30R22S3，m3，JS3θ'21θ2φRR'20θ'20B3R30R'Smθ2，2，JS210φ3R1θ1SR31，m1，JS1R10R4DAφ1θ4x图6 铰链四杆机构的动力学分析 已知：

Ri,Ri0,R'i0,?i,?'i,?i,?i,?i,Si,mi,JSi(i?1,2,3)M,F

i,Fxiyi(i?2,3)求：F

xi?1,i,Fyi?1,i(i?1,2,3),Fx4,1,Fy4,1,M1解：Fxi?1,i=Fi，i?1

一、构件CD 的受力分析

FFy3y2,3θ'M33R'30Fx3S3，m3，JS3Fx2,3θ3R3R30Fy4,3φ3Fx4,3图9 构件CD的受力分析

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??Fx3?Fx2?,3Fx?4ax,m333?Fy3?F2?,3Fy?4ay,m333 ?y?M3?FR?x2,'3sin(3?0??')3?Fy3R'cos(2?,3??3')0

33??Fx4,R3sin(30???)3?Fy3Rcos(4?,3??3)033???JS3?3

二、构件BC的受力分析

Fy3,2Fx3,2Fθ'2y1,2R2Fy2φθ2R'20M22RFx2F20S2x1,2S2，m2，J图8 构件BC的受力分析

??Fx2?Fx1?,F2x?3a,m2x22 ?F?y2?Fy1?,F2y?3a,m2y22

?M2?Fx1R,2si2?n0(??2?F)y2R1?,c2?o?s20(2)2???Fx3,R2's2i0?n?(?2?F'y2)R3,?2'??c20os?(JS?2'2) 未知量6个： Fx1,,2Fy,1,F2x,F2y,3,Fx2,, 3Fy 方程6个

??Fx1,??F?2y1,?2 (F ?)??Fx2,??F?3y2?? ,3?Fx4,???3?Fy4,??3

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22??m2ax2?Fx2??m??2ay2?Fy2? ( A)??JS2???2?M2???m? 3ax3?Fx3??ma?F??3y3y3?J?M?S3???33????1?0 [G] ???R20si?n(?2??0??0??0 F(?)G[?1]A ()0-10010?102?)R2?0c?o?s(2?R2)??2?'0siRn2(2?'??)20'c2os(2010100100R'30sin(??3?')3?R'cos(3?0??')3Rsin(3??3?0)0?0?')0??0?

?1??R???)?3cos(33??07

033

三、原动件受力分析

Fy2,1θ'1Fx2,1ay1φ\1FR1R'10ax1y4,1θ1MR10S1，m1，J11φ1JOFx4,1图7 原动件AB的受力分析

??Fx4,?1Fx?2a,1mx11 ??Fx4,?1Fx?2a,1mx11

?M1?Fx2R,1si?1n?Fy1R2c?,o1s11???JO?1??Fx4,?1axm1?1Fx2,1 ?F?y4,?1aym1?1Fy2,1?M1?JO?1?Fx2,sR1in?1?1yFRc2,o?

1s11M1为电机的驱动力矩 注意：

方程求解从从动件开始，依基本杆组列方程组，因为基本杆组是静定的。

Fy1,4M4Fy3,4Fx1,4Fx3,4Fy4Fx4图10 机架的受力分析

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