hehe

haha

在哪呢????

where

引用

引用第4楼鱼的自行车于2007-10-31 09:56发表的“”: `Q>qmf_Fi  
努力为自己的梦想奋斗 ,大家加油

]==S?_.B3n  

没链接上吧

xiexie

看不到什么东西啊 edfb7prfTl  
9f3rMPVh(  
(ZD~Q_O-  
(1)       The center distance separability of a pair of involute spur cylindrical gears implies that a change in center distance does not affect the     . Ce@"+k+w  
B[7Fq[.mh  
A. radii of the pitch circles     B. transmission ratio     C. working pressure angle .oe\wJS6  
|I=GI]I  
(2)       The main failure form of the closed gear drives with soft tooth surfaces is the       . FND+Ok&  
I=4G+h5p  
A. pitting of tooth surfaces     B. breaking of gear tooth =O~Y6|  
U%aDkC+M  
C. wear of tooth surfaces     D. agglutination of tooth surfaces hJ*#t<.<P;  
Qs8Rb]%|  
(3)       The tooth form factor in calculation of the bending fatigue strength of tooth root is independent of the       . ,o6,(jJU  
rTA#4.*&  
A. tooth number   B. modification coefficient   C. module 8MBvp*  
Lz`_&&6  
D. helix angle of helical gear *XluVochrb  
.|2[!7CXH  
(4)       The contact fatigue strength of tooth surfaces can be improved by way of     . &B} ,xcNO  
C9nCSbGMY{  
A. adding module with not changing the diameter of reference circle ME'LZ"VT  
zB#.EW  
B. increasing the diameter of reference circle \_t[\&.a}  
o(oD8Ni  
C. adding tooth number with not changing the diameter of reference circle \-{2E  
7G 3e  
D. decreasing the diameter of reference circle fWl #CI\]  
>$;,1N $bd  
(5)       In design of cylindrical gear drives, b1 = b2 +(5~10)mm is recommended on purpose to       . (Where b1, b2 are the face widths of tooth of the smaller gear and the large gear respectively.) J
'
'lOj(@  
$x(p:+TI\4  
A. equalize strengths of the two gears         B. smooth the gear drive O\}w&BE:h  
P+Sgbtc  
C. improve the contact strength of the smaller gear w,;ox2  
lrK?&a9AB  
D. compensate possible mounting error and ensure the length of contact line
9K=K,6 b  
k3& /Ei5  
(6)       For a pair of involute spur cylindrical gears, if z1 < z2 , b1 > b2 , then     . t7,**
$ST  
FOS*X  
A.     B.     C.     D. N'I9J?e Q  
`6pz9j]  
(7)       In a worm gear drive, the helix directions of the teeth of worm and worm gear are     the same. ,gIeQ!+vy  
f:ep~5] G  
A. certainly       B. not always       C. certainly not {5JYu  
F-2Q3+7$  
(8)       Because of       , the general worm gear drives are not suitable for large power transmission. @Qd5a(5WM  
X92I==-w  
A. the larger transmission ratios   B. the lower efficiency and the greater friction loss /n3SE0Y  
)H%RwV#  
C. the lower strength of worm gear   D. the slower rotating velocity of worm gear xhncQhf\  
g\@zQ^O?  
(9)       In a belt drive, if v1, v2 are the pitch circle velocities of the driving pulley and the driven pulley respectively, v is the belt velocity, then       . tCQf `  
2o~UA\:+=  
A.   B.   C.   D. g
X/?  
$A>]lL o0  
(10)   In a belt drive, if the smaller sheave is a driver, then the maximum stress of belt is located at the position of going     . k(_^Lq f-  
&}FWpo!  
A. into the driving sheave       B. into the driven sheave sUpSXG-W/@  
hIwqSKq9  
C. out of the driving sheave       D. out of the driven sheave ^6 \@$  
v8K4u)  
(11)   In a V-belt drive, if the wedge angle of V-belt is 40°，then the groove angle of V-belt sheaves should be     40°. `6o5[2V  
,ydn]0SS  
A. greater than     B. equal to     C. less than     D. not less than 1"U.- I@  
]u "x=S93  
(12)   When the centerline of the two sheaves for a belt drive is horizontal, in order to increase the loading capacity, the preferred arrangement is with the       on top. / (Ryh
6M  
Qz([\Xx:  
A. slack side   B. tight side BU=Ta$#BZ  
]wV_xZ)l^A  
(13)   In order to     , the larger sprocket should normally have no more than 120 teeth. USbFUHdDc  
&5R-bYGW  
A. reduce moving nonuniformity of a chain drive kl#)0yqN0  
y(jd$GM|  
B. ensure the strength of the sprocket teeth     C. limit the transmission ratio JO\KTWtjO  
kj '  
D. reduce the possibility that the chain falls off from the sprockets due to wear out of the  ie <m)  
k]yv#Pa  
chain $ZnVs@:S  
0Y/k/)Ul]  
(14)   In order to reduce velocity nonuniformity of a chain drive, we should take       . ?,
FL"ye  
eLk:
">kj  
A. the less z1 and the larger p     B. the more z1 and the larger p u1/q8'RW  
(t"rzH  
C. the less z1 and the smaller p     D. the more z1 and the smaller p }xytV5a^  
Fzn#>`qG  
(Where z1 is the tooth number of the smaller sprocket, p is the chain pitch) 'jBtBFzP-  
bE2{^5 iG  
(15)   In design of a chain drive, the pitch number of the chain should be     . _OR[RGy  
n16TQe"8  
A. even number   B. odd number   C. prime number Ct}rj-L<i  
mJS-x-@  
D. integral multiple of the tooth number of the smaller sprocket lu V_  
d$v{oC}  
6>-Gi  
q@iZo,Yk  
2. (6 points) Shown in the figure is the simplified fatigue limit stress diagram of an element. [
300F=R  
szD BfGd%j  
If the maximum working stress of the element is 180MPa, the minimum working stress is -80MPa. Find the angle q between the abscissa and the line connecting the working stress point to the origin. IR<*OnKn  
_tVrLb7`s  
!6{b)P  
[NguQ]B.  
+/2:  
?iNihE  
3. (9 points) Shown in the figure is the translating follower velocity curve of a plate cam mechanism. u"M^qRhD  
Op:7Ed T#  
(1)   Draw acceleration curve of the follower schematically. %'<m[wf^ o  
R3} Z"  
(2)   Indicate the positions where the impulses exist, and determine the types of the impulses (rigid impulse or soft impulse). zd#/zUPI  
b:(*C  
(3)   For the position F, determine whether the inertia force exists on the follower and whether the impulse exists. ~CL^%\K  
a+{95"4  
^)|1T#Tz  
'Z(4Wuwb  
cE0Kvqe`  
sy.U]QG  
> VWH bo  
-QUvd1S40  
)0NE_AZ?  
SgocHpyg  
$N1UEvC%Q  
fr<, LC.  
4. (8 points) Shown in the figure is a pair of external spur involute gears. a7UfRG  
x9!vtrM\Zr  
  The driving gear 1 rotates clockwise with angular velocity while the driven gear 2 rotates counterclockwise with angular velocity . , are the radii of the base circles. , are the radii of the addendum circles. , are the radii of the pitch circles. Label the theoretical line of action , the actual line of action , the working pressure angle and the pressure angles on the addendum circles , . (l3P<[[?  
&Kgl\;}  
0jN?5j  
enGjom  
D>Qc/+  
R_2JP C  
5. (10 points) For the elastic sliding and the slipping of belt drives, state briefly: 2!35Tj"RFE  
,@Izx  
(1)   the causes of producing the elastic sliding and the slipping. V5{^R+_)Ya  
LGm>x  
(2)   influence of the elastic sliding and the slipping on belt drives. !~&vcz0>)9  
Gq/f|43}@O  
(3)   Can the elastic sliding and the slipping be avoided? Why? zU9G:jH  
bNG;`VZ%  
B|Rnh;B-  
JL4\%
 
H0 YxPk)  
I~$LIdzw  
ji[O?  
;$y(Tvd;  
]r{-K63P{!  
oO4 Wwi  
^ )Lh5   
zOpl #%"  
6.Nu[-?  
h7-! q@  
Ne<"o]_M  
kN4nRW9z  
aPq9^S*  
U/2g N H  
g< cR/  
bUC-}  
u , %mVd  
*Rv e
R?kO  
uD&!]E3  
<_02)6j  
bh&,*Y6=  
*hAeA+:  
,epKt(vl  
Q/6T?
{\U7  
(XJehdB0  
XnQd(B`M  
h'<}
N  
mD:d,,~  
6. (10 points) A transmission system is as shown in the figure. Eo\#*Cv*  
H*3f8A&@s  
The links 1, 5 are worms. The links 2, 6 are worm gears. The links 3, 4 are helical gears. The links 7, 8 are bevel gears. The worm 1 is a driver. The rotation direction of the bevel gear 8 is as shown in the figure. The directions of the two axial forces acting on each middle axis are opposite. -
vI?b#  
5j`"@C5;O  
(1)   Label the rotating direction of the worm 1. p2
PD';"  
j3VM!/  
(2)   Label the helix directions of the teeth of the helical gears 3, 4 and the worm gears 2, 6. -8qLshQ  
TH/!z,(>  
EuqmA7s8A  
"uCx.Q9ef  
]y$D@/L@  
m^h"VH,   
%96JH YcX  

OekcU%C  
+Bv{A3E9  
/^qCJp`  
7. (12 points) A planar cam-linkage mechanism is as shown in the figure with the working resistant force Q acting on the slider 4. Q <zL;AJ  
LLg ']9  
  The magnitude of friction angle j (corresponding to the sliding pair and the higher pair) and the dashed friction circles (corresponding to all the revolute pairs) are as shown in the figure. The eccentric cam 1 is a driver and rotates clockwise. The masses of all the links are neglected. j*Q/
vY!T  
@.T'  
(1)   Label the action lines of the resultant forces of all the pairs for the position shown. iBxCk^  
OCo=h|qBp  
(2)   Label the rotation angle d of the cam 1 during which the point C moves from its highest position to the position shown in the figure. Give the graphing steps and all the graphical lines. I1kx3CwJ{P  
W!I"rdo; V  
6<NaME  
(SoV2[|  

O?D*<rwD  
6YrkS;_HS  
&pK1S>t  
?;+=bKw0  
i5|A\Wv"  
v%/_*69a  
8. (15 points) In the gear-linkage mechanism shown in the figure, the link 1 is a driver and rotates clockwise; the gear 4 is an output link. `BMg\2Ud*
 
 #It{B  
(1)   Calculate the DOF of the mechanism and give the detailed calculating process. gx4`pH;B\  
?nB).fc  
(2)   List the calculating expressions for finding the angular velocity ratios and for the position shown, using the method of instant centers. Determine the rotating directions of and . !s?vj
<  
G#)>D$Ck#  
(3)   Replace the higher pair with lower pairs for the position shown. 9/{+,RpC  
f<uLbJ6  
(4)   Disconnect the Assur groups from the mechanism and draw up their outlines. Determine the grade of each Assur group and the grade of the mechanism. /^DDU!=(<  
EHcqj;@m  
"xa<Q%hk  
%$Wt"~WE"O  
+0.$w  
_V1O =iu-  
6 t*pV [  
CP|N
2rb  
G!8O*4+A  
|Ag~k? QC  
rV"<1y:g  
6*S|$lo9B  
xFHc+m' m~  
oS/<)>\Gv  
f&js, NU"  
&tj0Z:  
6;l{9cRgc  
w-AF5%gX  
0 4x[@f`  
^p|MkB?uM  
!Jh-v  
8,a&i:C  
F6}Pwz[c  
I$n 0aR6  
aM9^V MOb  
?#<Fxme  
9. (15 points) An offset crank-slider mechanism is as shown in the figure. ES;7_ .q  
Lf3Ri/@ p  
If the stroke of the slider 3 is H =500mm, the coefficient of travel speed variation is K =1.4, the ratio of the length of the crank AB to the length of the coupler BC is l = a/b =1/3. * Od_Cl  
hW~,Uqy  
(1)   Find a, b, e (the offset). w+=>b  
lV
?rC z  
(2)   If the working stroke of the mechanism is the slower stroke during which the slider 3 moves from its left limiting position to its right limiting position, determine the rotation direction of the crank 1. YKJk)%;+w  
VSx[{yn  
(3)   Find the minimum transmission angle gmin of the mechanism, and indicate the corresponding position of the crank 1.

？？