中国石油大(北京)机械原理考研习题Homework.ppt

7-７ Shown below is a hoist. The teeth numbers of all the gears are: Z1=20, Z2=50, Z2’=15, Z3=30, Z3’=1, Z4=40, Z4’=18, Z5=52. Find the train ratio i15 and point out the rotating direction of the handle to raise the weight. 7-8 Shown below is the gear train in a clock. S, M and H denote the pointers of second, minute and hour, respectively. The given numbers of teeth are Z1=Z2’=8, Z2=64, Z3’=12, Z4’=15. If the modules of gear 4 and gear 5 are equal, find the numbers of teeth Z3, Z4, and Z5. 7-9. Shown in Fig.7-19 is a differential gear train with Z1=15, Z2=25, Z2’=20, Z3=60, n1=200 r/min, n3=50 r/min. Find nH when（1）n1 and n3 are in the same direction; (2) n1 and n3 are in the opposite directions. 常见错误1： 常见错误2： When n1 and n3 are in the same direction， 常见错误3： When n1 and n3 are in the same direction， 常见错误4： When n1 and n3 are in the opposite direction， 7-10 Shown below is a gear train in which gear 3 engages with gears 2 and 4 simultaneously. What kind of gear train is it? If Z1=34, Z2=Z3=20, and Z4=74, find the train ratio i1H. 常见错误： 错将此行星轮系当成复合轮系 7-11 Shown below is a gear train with Z1=16, Z2= Z2’ =25, Z3=57, Z4=56. Find the train ratio i14. (a) In the In planetary gear train 1-2-3-H, (b) In the differential gear train 1-2=2’-4-H, 常见错误：1、齿数比前面的正负号。 7-12 In the combined gear train shown below, Z1=36, Z2=60, Z3=23, Z4=49, Z4’=69, Z5=31, Z6=131, Z7=94, Z8=36, Z9=167, n1=3549 r/min. Find both the magnitude and the direction of nH. (a) In ordinary gear train 1-2-3-4 (b) In the differential gear train 4’-5-6-7: (c) In planetary gear train 6-7-8-H 7-13 In the combined gear train shown below, Z1= Z5= Z6=17, Z2=18, Z2’=27, Z3=34, Z4=51. n1=110 r/min. Find both the magnitude and the direction of n6. (a) In differential gear train 1-2-2’-3-6 : (b) In planetary gear train 4-5-6-3 常见错误： 两个基本周转轮系的系杆是不一样的。共用同一代号H引起混淆。 常见错误： 7-14. Sho