机原习题集(双语)

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2-1Please draw the kinematic diagrams of the mechanisms shown below 。

(a)

(b)

(c)

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2-2 Please calculate the DOF of mechanisms as follows, can you point out these mechanisms have a determined motion or not ? (The link with arrow is driving link)

（c）

（d）

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3-1 Please confirm the location of the instant centres of mechanisms as follows （Using the sign ij P ）

。

4-1According to the link dimension ,determine the type of four-bar linkage holding different link as frame？

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4-2 In a revolute four-bar linkage ABCD shown as below b=100mm c=80mm d=110mm

(1)Find the range of the values for the length L AB of link AB if the linkage is either (a) crank-rocker mechanism with crank AB ,or(b) a double-rocker mechanism.

(2) Can the linkage be a double-crank mechanism by choosing L AB suitably?Why?

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4-3 In the double-crank linkage ABCD shown as below L AB =80mm L BC =180mm L CD =230mm L AD=200 The driver BC rotates at a constant speed. Find the minimum transmission angle

γof the linkage

min

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4-4 In the revolute four-bar linkage ABCD Let link AD is the frame L AB =60mm L BC =130mm L CD =140mm L AD=200mm and 0

∠=

BAD

135

(1)Determine the type of the revolute four-bar

mechanism

(2) If the side link AB is a driver and rotates at a

constant speed

(a)find the pressure angle αand transmission angle γ

of the mechanism at that position

(b) Find the angular

ϕstroke of the link CD

max

(c) Find the crank acute angleθbetween the two

limiting positions

(d) Calculate the time ratio K

(e) Will any dead-point occur during the whole cycle of

the motion?

(f) Find the maximum pressure angle

α and the

max

minimum transmission angle

γ

min

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4-5 Design the revolute four-bar linkage ABCD according to the figure as below:

Let the length of rocker L CD =75mm , L AD=100mm and Link AD is the frame , the time ratio K=1.5 , The angle between one limiting position of rocker and the frame 0

45

∠=

CDA

Calculate the length of L AB、L BC（has two results）

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4-6 Design the offset slider-crank mechanism ABC according to the figure as below: The crank AB is the driver, Let the length of crank L AB =25mm, The offset e=10mm, The maximum pressure angle 0max 30α= Find the stroke H of the slider and the crank acute angle

θ between the two limiting positions.

11 4-7 图所示为一牛头刨床的主传动机构，已知mm l AB 75=，mm l DE 100= ，行程速比系数K=2，刨头5的行程H=300mm ，要求在整个行程中，推动刨头5有较小的压力角，试设计此机构。