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(1) The center distance separability of a pair of involute spur cylindrical gears implies that a change in center distance does not affect the . |UN#utw{^Y
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A. radii of the pitch circles B. transmission ratio C. working pressure angle i8.OM*[f
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(2) The main failure form of the closed gear drives with soft tooth surfaces is the . d4
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A. pitting of tooth surfaces B. breaking of gear tooth =h}PL22
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C. wear of tooth surfaces D. agglutination of tooth surfaces ~HXZ-
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(3) The tooth form factor in calculation of the bending fatigue strength of tooth root is independent of the . uU1q?|4
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A. tooth number B. modification coefficient C. module b
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D. helix angle of helical gear E /V`NqC
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(4) The contact fatigue strength of tooth surfaces can be improved by way of . A{Q~@1
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A. adding module with not changing the diameter of reference circle /
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B. increasing the diameter of reference circle ; T WYO
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C. adding tooth number with not changing the diameter of reference circle IO?6F@(
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D. decreasing the diameter of reference circle 66cPo
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(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.)
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A. equalize strengths of the two gears B. smooth the gear drive SMh[7lU`
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C. improve the contact strength of the smaller gear S;S_<GX
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D. compensate possible mounting error and ensure the length of contact line P
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(6) For a pair of involute spur cylindrical gears, if z1 < z2 , b1 > b2 , then . oOK&+r7
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(7) In a worm gear drive, the helix directions of the teeth of worm and worm gear are the same. XJi^gT N
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A. certainly B. not always C. certainly not [7SR2^uf<j
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(8) Because of , the general worm gear drives are not suitable for large power transmission. A+F@JpV
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A. the larger transmission ratios B. the lower efficiency and the greater friction loss L\X2Olfz1
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C. the lower strength of worm gear D. the slower rotating velocity of worm gear kc70HrG
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(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 . h^"OC$
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(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 . "+:IA|1wD
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A. into the driving sheave B. into the driven sheave iu6NIy7D
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C. out of the driving sheave D. out of the driven sheave -|~tZuf
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(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°. ,,[pc
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A. greater than B. equal to C. less than D. not less than 73OYHp_j
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(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. g}=opw6z
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A. slack side B. tight side @-QDp`QtI
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(13) In order to , the larger sprocket should normally have no more than 120 teeth. L cpz(W^
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A. reduce moving nonuniformity of a chain drive
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B. ensure the strength of the sprocket teeth C. limit the transmission ratio 5b^`M
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D. reduce the possibility that the chain falls off from the sprockets due to wear out of the d2e4=/A%
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(14) In order to reduce velocity nonuniformity of a chain drive, we should take . #n8jn#
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A. the less z1 and the larger p B. the more z1 and the larger p 9G@
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