Machine Kinematics Multiple Choice Questions on “Types of Gear Trains”.
1. A fixed gear having 200 teeth is in mesh with another gear having 50 teeth. The two gears are connected by an arm. The number of turns made by the smaller gear for one revolution of arm about the centre of bigger gear is
a) 2
b) 4
c) 3
d) none of the mentioned
Answer: b
Clarification: N1 = 200
N2 = 50
Number of turns = N1/N2
= 200/50 = 4.
2. Number of teeth on a wheel per unit of its pitch diameter is called
a) module
b) diametral pitch
c) circular pitch
d) none of the mentioned
Answer: b
Clarification: None.
3. The type of gears used to connect two non parallel and non intersecting shafts is
a) Spur gear
b) Helical gear
c) Bevel gear
d) Spiral gear
Answer: d
Clarification: Spiral gear is used connect two non parallel and non intersecting shafts. Spur gear is used to connect two parallel and coplanar shafts.
4. To connect two parallel and coplanar shafts the following type of gearing is used
a) Spur gear
b) Bevel gear
c) Spiral gear
d) None of the mentioned
Answer: a
Clarification: Spiral gear is used connect two non parallel and non intersecting shafts. Spur gear is used to connect two parallel and coplanar shafts.
5. In which of the following type of gear train the first gear and the last gear are co-axial.
a) Simple gear train
b) Compound gear train
c) Reverted gear train
d) None of the mentioned
Answer: c
Clarification: When the axes of the first gear (i.e. first driver) and the last gear (i.e. last driven or follower) are co-axial, then the gear train is known as reverted gear train.
6. Which gear train is used for higher velocity ratios in a small space?
a) Simple gear train
b) Compound gear train
c) Reverted gear train
d) Epicyclic gear train
Answer: d
Clarification: The epicyclic gear trains are useful for transmitting high velocity ratios with gears of moderate size in a comparatively lesser space. The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc.
7. Which type of gear train is used in clock mechanism to join hour hand and minute hand?
a) Simple gear train
b) Compound gear train
c) Reverted gear train
d) Epicyclic gear train
Answer: d
Clarification: The epicyclic gear trains are used in the back gear of lathe, differential gears of the automobiles, hoists, pulley blocks, wrist watches etc.
8. The gear used to convert rotary motion into translating motion is
a) Worm and wheel
b) Crown gear
c) Rack and pinion
d) Spiral Bevel gear
Answer: c
Clarification: Rack and pinion gears are used to convert rotation into linear motion. The flat, toothed part is the rack and the gear is the pinion. A piston coaxial to the rack provides hydraulic assistance force, and an open centered rotary valve controls the assist level.
9. The circular pitch of a gear is given by
a) Πd/t
b) Πd/2t
c) 2Πd/t
d) Πd/3t
Answer: a
Clarification: The distance measured along the pitch circle from a point on one tooth to the corresponding point on an adjacent tooth is called circular pitch.
Pc = Πd/t
Where d=diameter of pitch circle
t=number of teeth.
10. In a simple gear train, if the number of idle gears is odd, then the motion of driven gear will
a) be opposite as that of driving gear
b) be same as that of driving gear
c) depend upon the number of teeth on the driving gear
d) none of the mentioned
Answer: b
Clarification: None.