1、China University Petroleum, Beijing, 2006-2007, Semester 1Test paper (A) of Mechanisms and machine Theory. (Closed book) No.1234567Total ScoreScoreClass             Name           Student ID No.  

2、;             1. In a crank-slider mechanism shown in the figure, the crank is the driving link. the stroke H of the slider is 50mm, the coefficient of travel of travel speed variation K =1.5, the offset e=20mm. Please calculate : (20%)1) T

3、he crank acute angle between the two limiting positions，2) The dimensions of crank a, coupler b，3) The maximum pressure angle aMAX. of the mechanism，4) Will the dead-point occur if the slider is driving link?評分標(biāo)準(zhǔn)：此題每題分） 圖畫對二極限位置之夾角可得3分，寫出公式k=(180º+)/( 180º-) 可得分。結(jié)果1分） 計(jì)算方法可不同，必要公式和中間過程4分，結(jié)

4、果分） 寫對表達(dá)式即可得分，位置對，但結(jié)果錯(cuò)誤扣分。） 答對得分，錯(cuò)不得分。2. Draw the kinematic diagram of the mechanism.(8%) 評分標(biāo)準(zhǔn)：每錯(cuò)一處運(yùn)動副扣分，未按比例畫圖不扣分3. In the combined gear train shown below, Z1=17, Z2=68, Z3=23, Z4=19. Z4 =20, Z5=24. Find the train ratio i15. (10%)Solution:In the ordinary gear train 1-2： In the planetary gear train

5、3-4=4-5-2: 評分標(biāo)準(zhǔn)：） 公式分，公式中丟“”扣1分，） 公式5分） 結(jié)果1分。4. The fig. shown is an involute spur gear set: the driving gear 1 rotates at angular velocity 1, ra1 and ra2 are the radii of both addendum circle of gear1 and gear 2 respectively, rb1 and rb2 are the radii of both base circle of gear1 and gear 2. module

6、 m4mm，pressure angle20°，l0.001m/mm . Draw in the figure and point out the following: (20%)1) The actual line of action B1B2 graphically, 2) The theoretical line of action N1N2 graphically, 3) Measure the actual line of action B1B2,Calculate the contact ratio according the definition of contact

7、ratio ea=B1B2/Pb pb=pmcosa評分標(biāo)準(zhǔn)： ） 找對B1B2即可得分，否則不得分。） 找對N1N2可得6分，N1N2方向反扣分） 量得B1B2 可得2分，寫出的定義式得分5. Calculate the degree of freedom of the mechanism shown( the formula should be given). Add the serial numbers to the links and indicate compound hinge, passive DOF, redundant constraint before the calcul

8、ation of the DOF. What is the condition for the mechanisms to have determined motion?(10%)評分標(biāo)準(zhǔn)n=8 分 pL=11 分 pH=1 分F=3n2pLpH=3×8-2×11-1 分1 分 機(jī)構(gòu)有確定運(yùn)動的條件為：原動件數(shù)與機(jī)構(gòu)的自由度數(shù)相等。 分 指示對 compound hinge, passive DOF, redundant constraint 共分6. A mechanical system runs at a periodic fluctuated speed with

9、a angular period of T=2,a rotating link is selected as an equivalent link. The equivalent driven moment Mr on the equivalent link are given functions of the rotating angle j as shown in the figure. and the equivalent input moment Md on the equivalent link is constant. The equivalent moment of inerti

10、a Je can be neglected. The average speed is nm =1000 r/min. The allowable coefficient of speed fluctuation is d=0.0112% 1) Find the equivalent input moment Md,2) Calculate the maximum increment of work DWmax,3) Calculate the minimum moment of inertia of the flywheel JF .Suppose E0=E0Ea=E0-F1= E0+0.5

11、×0.25p×30=E0+15p/4 Eb=Ea+F2= E015p/4Ec=Eb-F3= E0+15p/4 Ed=Ec+F4= E015p/4Ef= E0 Emax= Ea = E0+15p/4Emin= Eb = E015p/4 評分標(biāo)準(zhǔn)：此題每題4分1） 計(jì)算對Md=30Nm得分. 寫出Wd=Wr但結(jié)果算錯(cuò)扣分2） 計(jì)算對DWma得分. 解題方法對或畫能量示意圖方法對僅計(jì)算結(jié)果算錯(cuò)扣分3） 寫對JF的表達(dá)式且計(jì)算結(jié)果全對得4分，寫對JF的表達(dá)式且計(jì)算結(jié)果錯(cuò)扣分。7. The fig. shown is a plate cam with a translating of

12、fset roller follower. The cam contour consists of four arcs. Using a graphical method, indicate: (20%) 1) The pitch curve of the cam and 2) The radius of prime circle rP, 3) The cam angle for rise 0, the cam angle for outer dwell S , the cam angle for return 0', the cam angle for inner dwell S'，4) The lift h of the follower , 5) Fin