[机械原理英文答案.ppt

4-2 Determine the type of the linkage and the type of the two side links AB and DC (crank or rocker) according to the Grashof criterion. Can the coupler BC rotate 360o with respect to the frame (Yes or No)? 4-4 In the revolute four-bar mechanism similar to the one in Fig.4-23(b), let LAB=60mm, LBC =130mm, LDC=140mm, LAD=200mm, and ?BAD=135o.(1) Determine the type of the revolute four-bar mechanism. Crank-Rocker 4-4(2) If the side link AB is a driver and rotates at a constant speed,(a) find the pressure angle ? and the transmission angle ? of the mechanism at that position. (b) find the angular stroke ?max of the link DC. (c) find the crank acute angle ? between the two limiting positions.(d) calculate the time ratio k . (e) will any dead-point occur during the whole cycle of the motion? No.(d) find the maximum pressure angle ?max and the minimum transmission angle ?min. ?min =min{?min?, ?min??} 不能只求?min? !!! (3) If the side link DC is a driver,(a) find the pressure angle ?’ and the transmission angle ?’ of the mechanism at that position. (b) will any dead-point occur during the whole cycle of the motion? If so, when? Yes. (c) find the maximum pressure angle ?max and the minimum transmission angle ?min. 若DC为原动件，图示两位置的?不是?min！！ 4-5 In the offset slider-crank mechanism shown in Fig.4-5, the driver crank AB rotates at a constant speed. Let LAB=120mm, LBC=250mm, offset e=60mm, and ?AB=60o. Find (1)the length of stroke H of the slider, (2) the crank acute angle ? (3) the time ratio k ,  (4) ? and ? at that position,(5) ?max and ?min. 4-3 In a revolute four-bar linkage ABCD, LBC=100mm, LDC =80mm, LAD=110mm. (1)Find the range of the values for the length LAB of link AB if the linkage is either (a) a crank-rocker mechanism with crank AB, or (b) a double-rocker mechanism. (2) Can the linkage be a double-crank mechanism by choosing LAB suitably? Why? 4-7 In the double-crank linkage ABCD shown in Fig.4-1(b), LAB=80mm, LBC=180mm, LDC=230mm, L