# Machine Design Questions and Answers – Terminology of Spur Gears

«
»

This set of Advanced Machine Design Questions & Answers focuses on “Terminology of Spur Gears”.

1. In cycloidal gears contact area is
a) Comparatively smaller
b) Comparatively larger
c) Can’t be determined
d) None of the listed

Explanation: Convex flank on one tooth meets with concave on the other thus increasing the contact area.

2. Involute gears have greater contact area as compared to cycloidal gears.
a) True
b) False

Explanation: There is mating of two convex surfaces and hence lesser contact area.

3. Cycloidal teeth consist of
a) Hypocycloid curve
b) Epicycloid gear
c) Both hypocycloid curve and epicycloid curve
d) None of the mentioned

Explanation: It consist of both and thus are hard to manufacture.

4. Pressure angle remains constant in case of involute profile.
a) True
b) False

Explanation: The common normal always passes through the pitch point and thus maintain the constant inclination.

5. Pressure angle is _____ in case of cycloidal teeth.
a) Constant
b) Variable
c) zero
d) None of the listed

Explanation: Cycloidal teeth consist of two profiles.

6. Velocity ratio is the ratio angular velocity of driving gear to that of driven gear.
a) True
b) False

Explanation: Velocity ratio is simply the angular velocities ratio.

7. Velocity ratio and transmission ratio are the same thing.
a) True
b) False

Explanation: Transmission ratio is measured between first and last gear.

8. Contact ratio is always
a) =1
b) >1
c) <1
d) Can’t be determined

Explanation: Some overlapping is essential for continuous transfer of power.

9. Product of diametric pitch and circular pitch is?
a) π
b) 1/π
c) None of the listed
d) 2

Explanation: CP=πd/z and circular pitch=z/d.

10. Diameteral pitch is 5, then calculate module of the gear.
a) 0.2
b) 0.4
c) 5
d) 10