陈晓南版机械设计基础第六章答案
第六章部分题解参考 6-9 试根据图6-52中注明的尺寸判断各铰链四杆机构的类型。
习题6-9图解 (a) ? , ,l,90,70,160l,l,110,40,150maxmin其余
最短杆为机架
? 该机构为双曲柄机构
(b) ? , ,l,100,70,170l,l,120,45,165maxmin其余
最短杆邻边为机架
? 该机构为曲柄摇杆机构
(c) ? , l,l,100,50,150,l,70,60,130maxmin其余
? 该机构为双摇杆机构
(d) ? , ,l,90,70,160l,l,100,50,150maxmin其余
最短杆对边为机架
? 该机构为双摇杆机构
6-10 在图6-53所示的四杆机构中,若,,。则b在什么范围内a,17c,8d,21
时机构有曲柄存在,它是哪个构件,
解 分析:?根据曲柄存在条件?,若存在曲柄,则b不能小于c;若b=c,则不满足曲柄存在条件?。
所以b一定大于c。
?若b,c,则四杆中c为最短杆,若有曲柄,则一定是DC杆。
b,d: ?,l,a,d l,l,b,cmaxmin其余
? b? a,d,c,17,21,8,30
b,d: ?,l,a,b l,l,d,cmaxmin其余
? b? d,c,a,21,8,17,12
结论:12?b?30时机构有曲柄存在,DC杆为曲柄 6-13 设计一脚踏轧棉机的曲柄摇杆机构。AD在铅垂线上,要求踏板CD在水平位置上下各摆动10?,
且=500mm,=1000mm。试用图解法求曲柄AB和连杆BC的长度。 llCDAD
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解 l,,AB,0.01,7.8,0.078 m,78 mmABl
l,,BC,0.01,111.5,1.115 m,1115 mmBCl
06-14 设计一曲柄摇杆机构。已知摇杆长度,摆角,行程速比系数。试根据l,100 mm,,,45K,1.254min
o?的条件确定其余三杆的尺寸。 40
K,11.25,1解 ,,180:,180:,,20:K,11.25,1
l,,AB,0.002,14.5,0.028 m,28 mm ABl
l,,BC,0.002,73.3,0.1466 m,146.6 mm BCl
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,,32.42:mino不满足?传力条件,重新设计 ,40min
l,,AB,0.002,16.9,0.0338 m,33.8 mmABl
l,,BC,0.002,54.3,0.1086 m,108.6 mmBCl
,,40.16:mino满足?传力条件 ,40min
6-15 设计一导杆机构。已知机架长度,行程速比系数,试用图解法求曲柄的长度。 l,100 mmK,1.41
K,11.4,1解 ,,180:,180:,,30:K,11.4,1
l,,AB,0.002,12.94,0.02588 m,25.88 mm ABl1
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6-16 设计一曲柄滑块机构。已知滑块的行程,偏距。行程速比系数。试用作s,50 mme,10 mmK,1.4
图法求出曲柄和连杆的长度。
K,11.4,1解 ,,180:,180:,,30:K,11.4,1
l,,AB,0.001,23.62,0.02362 m,23.62 mmABl2
l,,BC,0.001,39.47,0.03947 m,39.47 mmBCl22
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