Minimum Number of Teeth on a Pinion for Involute Rack in Order to Avoid Interference

Question 1
Marks : +2 | -2
Pass Ratio : 100%
In a simple train of wheels, if the number of intermediate wheels is odd, the motion of the follower will be same as that of the driver.
True
False
Explanation:
The speed ratio (or velocity ratio) of gear train is the ratio of the speed of the driver to
Question 2
Marks : +2 | -2
Pass Ratio : 100%
In gears, interference takes place when
the tip of a tooth of a mating gear digs into the portion between base and root circles
gears do not move smoothly in the absence of lubrication
pitch of the gears is not same
gear teeth are undercut
Explanation:
Interference occurs when the number of teeth on the smaller of the two meshing gears is less than a required minimum.
Question 3
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An involute pinion and gear are in mesh. If both have the same size of addendum, then there will be an interference between the
tip of the gear tooth and flank of pinion
tip of the pinion and flank of gear
flanks of both gear and pinion
tip of both gear and pinion
Explanation:
The phenomenon when the tip of a tooth under cuts the root on its mating gear, is known as interference.
Question 4
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The maximum efficiency of spiral gears is
sin (Ï´ + ɸ) + 1/cos(Ï´ – ɸ) +1
cos(Ï´ – ɸ) +1/sin (Ï´ + ɸ) + 1
cos (Ï´ + ɸ) + 1/cos(Ï´ – ɸ) +1
cos(Ï´ – ɸ) +1/cos (Ï´ + ɸ) + 1
Explanation:
The maximum efficiency of spiral gears is
Question 5
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The minimum number of teeth on the pinion which will mesh with any gear without interference for 200 full depth involute teeth will be
12
14
18
24
Explanation:
The minimum number of teeth on the pinion in order to avoid interference for 14.50 full depth involute are 32 and for 200 full depth involute teeth are 18.
Question 6
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When the addenda on pinion and wheel is such that the path of approach and path of recess are half of their maximum possible values, then the length of the path of contact is given by
(r2 + R2) cosɸ/2
(r2 + R2) sinɸ/2
(r + R) cosɸ/2
(r + R) sinɸ/2
Explanation:
None.
Question 7
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The interference may only be avoided if the addendum circles of the two mating gears cut the common tangent to the base circles between the points of tangency.
True
False
Explanation:
None.
Question 8
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The contact ratio for gears is
zero
less than one
greater than one
infinity
Explanation:
The theoretical minimum value for the contact ratio is one, that is there must always be at least one
Question 9
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Which of the following statement is correct for involute gears?
The interference is inherently absent
The variation in centre distance of shafts increases radial force
A convex flank is always in contact with concave flank
The pressure angle is constant throughout the teeth engagement
Explanation:
None.
Question 10
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Pass Ratio : 100%
In a simple train of wheels, the velocity ratio _____________ the intermediate wheels.
depends upon
is independent of
is equal to
none of the mentioned
Explanation:
The speed ratio (or velocity ratio) of gear train is the ratio of the speed of the driver to