Machine Kinematics

Toothed Gearing

Question 1
Marks : +2 | -2
Pass Ratio : 33%
The product of the diametral pitch and circular pitch is equal to
1
1/Ï€
Ï€
2Ï€
Explanation:
Diametral pitch, pd = T/D = π/pc
Question 2
Marks : +2 | -2
Pass Ratio : 33%
Which is the incorrect relationship of gears?
Circular pitch × Diametral pitch = π
Module = P.C.D/No.of teeth
Dedendum = 1.157 module
Addendum = 2.157 module
Explanation:
None.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
If the module of a gear be m, the number of teeth T and pitch circle diameter D, then
m = D/T
D = T/m
m = D/2T
none of the mentioned
Explanation:
Module, m = D /T.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
For a speed ratio of 100, smallest gear box is obtained by using
a pair of spur gears
a pair of helical and a pair of spur gear compounded
a pair of bevel and a pair of spur gear compounded
a pair of helical and a pair of worm gear compounded
Explanation:
None.
Question 5
Marks : +2 | -2
Pass Ratio : 50%
Involute profile is preferred to cyloidal because
the profile is easy to cut
only one curve is required to cut
the rack has straight line profile and hence can be cut accurately
none of the mentioned
Explanation:
The face and flank of involute teeth are generated by a single curve where as in cycloidal
Question 6
Marks : +2 | -2
Pass Ratio : 25%
The condition of correct gearing is
pitch line velocities of teeth be same
radius of curvature of two profiles be same
common normal to the pitch surface cuts the line of centres at a fixed point
none of the mentioned
Explanation:
The fundamental condition of correct gearing is the common normal at the point of contact between a pair of teeth must always pass through the pitch point.
Question 7
Marks : +2 | -2
Pass Ratio : 50%
Mitre gears are used for
great speed reduction
equal speed
minimum axial thrust
minimum backlash
Explanation:
When equal bevel gears (having equal teeth) connect two shafts whose axes are mutually perpendicular, then the bevel gears are known as mitres.
Question 8
Marks : +2 | -2
Pass Ratio : 50%
The ratio of face width to transverse pitch of a helical gear with α as the helix angle is normally
more than 1.15/tan α
more than 1.05/tan α
more than 1/tan α
none of the mentioned
Explanation:
None.
Question 9
Marks : +2 | -2
Pass Ratio : 20%
The size of a gear is usually specified by
pressure angle
circular pitch
diametral pitch
pitch circle diameter
Explanation:
Pitch circle diameter is the diameter of the pitch circle. The size of the gear is usually specified by the pitch circle diameter. It is also known as pitch diameter.
Question 10
Marks : +2 | -2
Pass Ratio : 20%
Law of gearing is satisfied if
two surfaces slide smoothly
common normal at the point of contact passes through the pitch point on the line joining the centres of rotation
number of teeth = P.C.D. / module
addendum is greater than dedendum
Explanation:
Law of gearing says that the common normal at the point of contact between a pair of teeth must always pass through the pitch point.