Machine Kinematics

Toothed Gearing

Question 1
Marks : +2 | -2
Pass Ratio : 100%
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
(r + R) sin φ/2
(r + R) cos φ/2
(r + R) tan φ/2
(r + R) cot φ/2
Explanation:
In case 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
Question 2
Marks : +2 | -2
Pass Ratio : 100%
The module is the reciprocal of
diametral pitch
circular pitch
pitch diameter
none of the mentioned
Explanation:
It is the ratio of the pitch circle diameter in millimeters to the number of teeth.
Question 3
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 4
Marks : +2 | -2
Pass Ratio : 100%
An imaginary circle which by pure rolling action, gives the same motion as the actual gear, is called
addendum circle
dedendum circle
pitch circle
clearance circle
Explanation:
Pitch circle is an imaginary circle which by pure rolling action, would give the same motion as the actual gear.
Question 5
Marks : +2 | -2
Pass Ratio : 50%
The type of gears used to connect two non-parallel non-intersecting shafts are
spur gears
helical gears
spiral gears
none of the mentioned
Explanation:
The two non-intersecting and non-parallel i.e. non-coplanar shaft connected by gears. These gears are called skew bevel gears or spiral gears and the arrangement is known as skew bevel gearing or spiral gearing. This type of gearing also have a line contact, the rotation of which about the axes generates the two pitch surfaces known as hyperboloids.
Question 6
Marks : +2 | -2
Pass Ratio : 20%
The maximum efficiency for spiral gears is
sin (θ + φ ) + 1/ cos (θ − φ ) + 1
cos (θ − φ) + 1/sin (θ + φ ) + 1
cos (θ + φ ) + 1/ cos (θ − φ ) + 1
cos (θ − φ) + 1/cos (θ + φ ) + 1
Explanation:
ηmax = cos (θ + φ ) + 1/ cos (θ − φ ) + 1
Question 7
Marks : +2 | -2
Pass Ratio : 50%
The maximum length of arc of contact for two mating gears, in order to avoid interference, is
(r + R) sin φ
(r + R) cos φ
(r + R) tan φ
none of the mentioned
Explanation:
Interference may only be prevented, if the addendum circles of the two mating gears cut the
Question 8
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 9
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 10
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.