1、机械原理大作业凸轮结构20 凸轮机构设计题目要求:试用计算机辅助设计完成下列偏置直动推杆盘形凸轮机构的设计,已知数据如下各表所示。凸轮沿逆时针方向作匀速转动。表一 偏置直动滚子推杆盘形凸轮机构的已知参数升程/mm升程运动角/。升程运动规律升程许用压力角/。回程运动角/。回程运动规律回程许用压力角/。远休止角/。近休止角/。70120余弦加速度3590正弦加速度656090要求:1)确定凸轮推杆的升程、回程运动方程,并绘制推杆位移、速度、加速度线图。2)绘制凸轮机构的线图;3)确定凸轮基圆半径和偏距;4)确定滚子半径;5)绘制凸轮理论廓线和实际廓线。推杆运动规律:(取)1)推程运动规律:由余弦加
2、速度运动公式可得2)回程运动规律:正弦加速度运动公式可得试中:T=经带入计算可得:s1 = 0.035*(1 - cos(1.5*x);v1=0.105/2 * w * sin(1.5 * x);a1 = 0.1575/2 * w2 .* cos(1.5*x);s3 = 0.070*(3 - 2*z/pi + 1/(2*pi).*sin (4*z - 4* pi);v3 = -0.140/pi * w .* (1 - cos(4*z - 4* pi);a3 = 0.56 * w2/pi .*sin(4*z - 4* pi);三 计算程序(matlab)(1)推杆位移、速度、加速度线图编程;a.
3、位移与转角曲线w = 2*pi/3x = 0:(pi/100):(2*pi/3);s1 = 0.035*(1 - cos(1.5*x);v1=0.105/2 * w * sin(1.5 * x);a1 = 0.1575/2 * w2 .* cos(1.5*x);y = (2*pi/3):(pi/100):(pi);s2 = 0.070;v2=0;a2 = 0;z = (pi ):(pi/100):(3*pi/2);s3 = 0.070*(3 - 2*z/pi + 1/(2*pi).*sin (4*z - 4* pi);v3 = -0.140/pi * w .* (1 - cos(4*z - 4
4、* pi);a3 = 0.56 * w2/pi .*sin(4*z - 4* pi);c = (3*pi/2):(pi/100):( 2*pi);s4 = 0;v4 = 0;a4 = 0;plot(x,s1,b,y,s2,b,z,s3,b,c,s4,b)xlabel(转角/rad)ylabel(位移/m/)title(位移与转角曲线)b.速度与转角曲线w = 2*pi/3x = 0:(pi/100):(2*pi/3);s1 = 0.035*(1 - cos(1.5*x);v1=0.105/2 * w * sin(1.5 * x);a1 = 0.1575/2 * w2 .* cos(1.5*x)
5、;y = (2*pi/3):(pi/100):(pi);s2 = 0.070;v2=0;a2 = 0;z = (pi ):(pi/100):(3*pi/2);s3 = 0.07*(3 - 2*z/pi + 1/(2*pi).*sin (4*z - 4* pi);v3 = -0.140/pi * w .* (1 - cos(4*z - 4* pi);a3 = 0.56 * w2/pi .*sin(4*z - 4* pi);c = (3*pi/2):(pi/100):( 2*pi);s4 = 0;v4 = 0;a4 = 0;plot(x,v1,g,y,v2,g,z,v3,g ,c,v4,g)xla
6、bel(转角/rad)ylabel(速度/(m/s)title(速度与转角曲线)c.加速度与位移转角曲线w = 2*pi/3x = 0:(pi/100):(2*pi/3);s1 = 0.035*(1 - cos(1.5*x);v1=0.105/2 * w * sin(1.5 * x);a1 = 0.1575/2 * w2 .* cos(1.5*x);y = (2*pi/3):(pi/100):(pi);s2 = 0.070;v2=0;a2 = 0;z = (pi):(pi/100):(3*pi/2);s3 = 0.070*(3 - 2*z/pi + 1/(2*pi).*sin (4*z - 4
7、* pi);v3 = -0.140/pi * w .* (1 - cos(4*z - 4* pi);a3 = 0.56 * w2/pi .*sin(4*z - 4* pi);c = (3*pi/2):(pi/100):( 2*pi);s4 = 0;v4 = 0;a4 = 0;plot(x,a1,r,y,a2,r,z,a3,r ,c,a4,r)xlabel(转角/rad)ylabel(加速度/(m2/s)title(加速度与转角曲线)(2)凸轮机构的线图编程;w = 2*pi/3x = 0:(pi/100):(2*pi/3);s1 = 35*(1 - cos(1.5*x);news1 = 35*
8、1.5*sin(1.5*x);y = (2*pi/3):(pi/100):(pi);s2 = 70;news2 = 0;z = (pi ):(pi/100):(3*pi/2);s3=70*(3 - 2*z/pi + 1/(2*pi).*sin (4*z - 4* pi);news3 =-140/pi * w .* (1 - cos(4*z - 4* pi);c = (3*pi/2):(pi/100):( 2*pi);s4 = 0;news4 = 0; plot(news1,s1,b,news2,s2,b,news3,s3,b,news4,s4,b)xlabel(ds/dp);ylabel(位移
9、s/mm)title(ds/dp 与位移s曲线)grid(3)确定基圆半径和偏距;(4)经过对凸轮机构的线图分析确定其偏距e=17,s=70,基圆半径r0=32,得s0=50;a.先求凸轮理论轮廓曲线,程序如下:w = 2*pi/3;s0 = 50;s = 70;e = 17;x = 0:(pi/100):(2*pi/3);x1 = (s + s0)*cos(x)-e*sin(x);y1 = (s0 + s)*sin(x) - e*cos(x);y = (2*pi/3):(pi/100):(pi);x2 = (s + s0)*cos(y)-e*sin(y);y2 = (s0 + s)*sin(
10、y) - e*cos(y);z = (pi):(pi/100):(3*pi/2);x3 = (s + s0)*cos(z)-e*sin(z);y3 = (s0 + s)*sin(z) - e*cos(z);c = (3*pi/2):(pi/100):( 2*pi);x4 = (s + s0)*cos(c)-e*sin(c);y4 = (s0 + s)*sin(c) - e*cos(c);plot(x1,y1,b,x2,y2,b,x3,y3,b,x4,y4,b);xlabel(x/mm)ylabel(y/mm)title(理轮轮曲线)b.再通过该廓线求其最小曲率半径,程序如下:v=;syms x
11、1 x2 x3 x4 x5 s0 = 50; e = 20; s1 = 35*(1 - cos(1.5*x1);t1 = (s1 + s0)*cos(x1)-e*sin(x1); y1 = (s0 + s1)*sin(x1) - e*cos(x1); tx1=diff(t1,x1); txx1=diff(t1,x1,2); yx1=diff(y1,x1); yxx1=diff(y1,x1,2);for xx1= 0:(pi/100):(2*pi/3); k1=subs(abs(tx1*yxx1-txx1*yx1)/(tx12+yx12)1.5),x1,xx1); v=v,1/k1;end s2
12、 = 70;t2 = (s2 + s0)*cos(x2)-e*sin(x2); y2 = (s0 + s2)*sin(x2) - e*cos(x2); tx2=diff(t2,x2); txx2=diff(t2,x2,2); yx2=diff(y2,x2); yxx2=diff(y2,x2,2);for xx2=(2*pi/3):(pi/100):(pi); k2=subs(abs(tx2*yxx2-txx2*yx2)/(tx22+yx22)1.5),x2,xx2); v=v,1/k2;end s3 = 110*(10/3- 2*x3/pi + 1/(2*pi).*sin (4*x3 - 14
13、* pi/3);t3 = (s3 + s0)*cos(x3)-e*sin(x3); y3 = (s0 + s3)*sin(x3) - e*cos(x3); tx3=diff(t3,x3); txx3=diff(t3,x3,2); yx3=diff(y3,x3); yxx3=diff(y3,x3,2);for xx3=(pi):(pi/100):(3*pi/2); k3=subs(abs(tx3*yxx3-txx3*yx3)/(tx32+yx32)1.5),x3,xx3); v=v,1/k3;end s4 = 0;t4 = (s4 + s0)*cos(x4)-e*sin(x4); y4 = (s
14、0 + s4)*sin(x4) - e*cos(x4); tx4=diff(t4,x4); txx4=diff(t4,x4,2); yx4=diff(y4,x4); yxx4=diff(y4,x4,2);for xx4=(3*pi/2):(pi/100):( 2*pi); k4=subs(abs(tx4*yxx4-txx4*yx4)/(tx42+yx42)1.5),x4,xx4); v=v,1/k4;endmin(v)(3)凸轮的理论廓线和其包络线;由基圆半径确定其滚子的半径为r=8mm,其他参数保持不变;a.凸轮的理论廓线w = 2*pi/3;s0 = 50;s = 70;e = 17;x
15、= 0:(pi/100):(2*pi/3);x1 = (s + s0)*cos(x)-e*sin(x);y1 = (s0 + s)*sin(x) - e*cos(x);y = (2*pi/3):(pi/100):(pi);x2 = (s + s0)*cos(y)-e*sin(y);y2 = (s0 + s)*sin(y) - e*cos(y);z = (pi ):(pi/100):(3*pi/2);x3 = (s + s0)*cos(z)-e*sin(z);y3 = (s0 + s)*sin(z) - e*cos(z);c = (3*pi/2):(pi/100):( 2*pi);x4 = (s
16、 + s0)*cos(c)-e*sin(c);y4 = (s0 + s)*sin(c) - e*cos(c);plot(x1,y1,b,x2,y2,b,x3,y3,b,x4,y4,b);xlabel(x/mm)ylabel(y/mm)title(理轮轮曲线)b.凸轮的包络线w = 2*pi/3;s0 = 50;e = 17;r = 8;x = 0:(pi/100):(2*pi/3);s1 = 35*(1 - cos(1.5*x);x1 = (s1 + s0).*cos(x) - e*sin(x);y1 = (s0 + s1).*sin(x) - e*cos(x);n1 = -(35*1.5*s
17、in(x) + s0).*sin(x) -e*cos(x);m1 = (s0 + 35*1.5*sin(x) ).*cos(x) + e*sin(x);xt1 = x1+(r*m1)./(sqrt(n1.2+m1.2);yt1 = y1 - (r*n1)./sqrt(m1.2 +n1.2);xw1 = x1 - (r*m1)./sqrt(m1.2 +n1.2);yw1 = y1 + (r*n1)./sqrt(m1.2 +n1.2);y = (2*pi/3):(pi/100):(pi);s2 = 70;x2 = (s2 + s0).*cos(y)-e*sin(y);y2 = (s0 + s2).
18、*sin(y) - e*cos(y);n2 = -s0.*sin(y)-e*cos(y);m2 = s0 .*cos(y) + e*sin(y);xt2 = x2 + (r*m2)./sqrt(m2.2+n2.2);yt2 = y2 - (r*n2)./sqrt(m2.2+n2.2);xw2 = x2 - (r*m2)./sqrt(m2.2+n2.2);yw2 = y2 + (r*n2)./sqrt(m2.2+n2.2);z = (pi ):(pi/100):(3*pi/2);s3 = 70*(3- 2*z/pi + 1/(2*pi).*sin (4*z - 4* pi);x3 = (s3 +
19、 s0).*cos(z)-e*sin(z);y3 = (s0 + s3).*sin(z) - e*cos(z);n3 = -(140/pi *cos(4*z - 4*pi) + s0).*sin(z)-e*cos(z);m3 = (s0 + 140/pi *cos(4*z - 4*pi).*cos(z) + e*sin(z);xt3= x3 + (r*m3)./sqrt(m3.2+n3.2);yt3 = y3 - (r*n3)./sqrt(m3.2+n3.2);xw3 = x3 -(r* m3)./sqrt(n3.2+m3.2);yw3 = y3 + (r*n3)./sqrt(n3.2+m3.
20、2);c = (3*pi/2):(pi/100):( 2*pi);s4 = 0;x4 = (s4 + s0).*cos(c)-e*sin(c);y4 = s0 .*sin(c) - e*cos(c);n4 = - s0.*sin(c)-e*cos(c);m4 = s0 .*cos(c) + e*sin(c);xt4= x4 + (r*m4)./sqrt(m4.2+n4.2);yt4 = y4 - (r*n4)./sqrt(m4.2+n4.2);xw4 = x4 - (r*m4)./sqrt(n4.2+m4.2);yw4 = y4 + (r*n4)./sqrt(n4.2+m4.2);plot(xw1,yw1,b,xw2,yw2,b,xw3,yw3,b,xw4,yw4,b)xlabel(x/mm)ylabel(y/mm)title(凸轮的包络线)grid
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