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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 . :TlAL#
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A. radii of the pitch circles B. transmission ratio C. working pressure angle =hPG_4#
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(2) The main failure form of the closed gear drives with soft tooth surfaces is the . KjBOjD'I
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A. pitting of tooth surfaces B. breaking of gear tooth /MhS=gVxM
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C. wear of tooth surfaces D. agglutination of tooth surfaces qP&byEs"
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(3) The tooth form factor in calculation of the bending fatigue strength of tooth root is independent of the . Oy:QkV9
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A. tooth number B. modification coefficient C. module n}0za#G
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D. helix angle of helical gear Z(K
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(4) The contact fatigue strength of tooth surfaces can be improved by way of . 3mk=ZWwv
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A. adding module with not changing the diameter of reference circle lxo.,n)
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B. increasing the diameter of reference circle u1tq2"D8
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C. adding tooth number with not changing the diameter of reference circle "\4]X"3<+
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D. decreasing the diameter of reference circle c[&d @
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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.) "!xvpsy
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A. equalize strengths of the two gears B. smooth the gear drive RV(
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C. improve the contact strength of the smaller gear 'CS^2Z
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D. compensate possible mounting error and ensure the length of contact line y>@v>S
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(6) For a pair of involute spur cylindrical gears, if z1 < z2 , b1 > b2 , then . /z/hUa
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A. B. C. D. 6 lN?) <uQ
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(7) In a worm gear drive, the helix directions of the teeth of worm and worm gear are the same. ^?E^']H)5u
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A. certainly B. not always C. certainly not z
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(8) Because of , the general worm gear drives are not suitable for large power transmission. |}M~kJ)
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A. the larger transmission ratios B. the lower efficiency and the greater friction loss 1f+*Tmc5]Q
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C. the lower strength of worm gear D. the slower rotating velocity of worm gear g ^D)x[
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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 . t9-_a5>E\}
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A. B. C. D. ;6DR.2}?>
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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 . N5:D8oWWXR
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A. into the driving sheave B. into the driven sheave 1h#w"4
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C. out of the driving sheave D. out of the driven sheave Ln"+nKr
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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°. ~0VwF
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A. greater than B. equal to C. less than D. not less than -=-x>(pRW7
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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. !1ie:z>s
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A. slack side B. tight side D6C-x
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(13) In order to , the larger sprocket should normally have no more than 120 teeth. d&GK