FINAL

Question 1

height of tooth above pitch circle or the distance
between the pitch circle and the top of the tooth,

Answer 1

Addendum

Question 2

the circle that bounds
the outer ends of the teeth.

Answer 2

Addendum Circle ( or Outside Circle)

Question 3

arc of the pitch circle through which a tooth travels from the first point of contact with the rating tooth to the point where the contact ceases.

Answer 3

Arc of Action

Question 4

arc of the circle through which a tooth travels
from the point of contact with the mating tooth to the pitch point.

Answer 4

Arc of Approach

Question 5

arc of the pitch circle through which a tooth travels from its contact with the mating tooth at the pitch point to the point where the contact ceases.

Answer 5

Arc of Recess

Question 6

in a pair of gears it is the plane that contains the two axes. in a single gear, it may be any plane containing the axis and the given point.

Answer 6

Axial Plane

Question 7

the amount by which the width of a tooth space
exceeds the thickness of the engaging tooth on the pitch circles.

Answer 7

Backlash

Question 8

the circle from which an involute tooth is
generated or developed.

Answer 8

Base Circle

Question 9

the angle, at the base cylinder if an involute
gear, that the tooth maxes with the gear axis.

Answer 9

Base Helix Angle

Question 10

In an involute gear it is the pitch on the base circle
or along the line of action.

Answer 10

Base Pitch

Question 11

is the base pitch in the normal plane.

Answer 11

Normal Base Pitch

Question 12

the distance between the parallel axes of spur gears and parallel helical gears, or between the crossed axes of helical gears and worm gears. Also it is the distance between the centers of the pitch circles.

Answer 12

Center Distance

Question 13

in a worm gear this is the plane perpendicular to the gear axis and contains the common perpendicular of the gear and the worm axes.

Answer 13

Central Plane

Question 14

the height from the top of the tooth to
the chord subtending the circular-thickness arc.

Answer 14

Chordal Addendum

Question 15

length of the chord subtended by the circular thickness arc (the dimension obtained when a gear tooth caliper is used to measure the thickness at the pitch circle.

Answer 15

Chordal Thickness

Question 16

length of the arc of the pitch circle between the
centers or other corresponding points of adjacent teeth.

Answer 16

Circular Pitch

Question 17

is the circular pitch in the normal
plane.

Answer 17

Normal Circular Pitch

Question 18

the length of the arc between the two
sides of a gear tooth, on the pitch circles unless otherwise specified.

Answer 18

Circular Thickness

Question 19

is the base pitch in the axial plane.

Answer 19

Axial Base Pitch

Question 20

is the circular thickness in the
normal plane.

Answer 20

Normal Circular Thickness

Question 21

the amount by which the dedendum exceeds the addendum of the mating tooth. It is also the radial distance between the top of’a tooth and the bottoms of the mating tooth space.
-the dedendum minus the mating addendum.

Answer 21

Clearance

Question 22

the smallest diameter on a gear tooth with
which the mating gear makes contact.

Answer 22

Central Diameter

Question 23

the ratio of the arc of action to the circular pitch. It is sometimes thought-of as the average number of teeth in contact. For involute gears, the contact ratio is obtain most directly as the ratio of the length of action to the base pitch.

Answer 23

Contact Ratio

Question 24

the curve formed by the path of a point on a circle as it rolls along a straight line. When this circle rolls along the outer side of another circle, the curve is called an Epicycloid: When it rolls along the inner side of another circle it is called a Hypocycloid

Answer 24

Cycloid

Question 25

the depth of tooth space below the pitch circle or the radial dimension between the pitch circle and the bottoms of the tooth space.

Answer 25

Dedendum

Question 26

the ratio of the number of teeth to the number
of millimeters of pitch diameter.

Answer 26

Diametral Pitch

Question 27

is the diametral pitch as calculated in the normal plane and is equal to the diametral pitch divided by the cosine of the helix angle.

Answer 27

Normal Diametral Pitch

Question 28

that portion of the face width that actually comes into contact with mating teeth, as occasionally one member of a pair of gears may have a greater face width than the other.

Answer 28

Effective Face Width

Question 29

the actual torque ratio of a gear set divided by its
gear ratio.

Answer 29

Efficiency

Question 30

a gear with teeth on the outer cylindrical
surface.

Answer 30

External Gear

Question 31

that surface of the tooth which is between the
pitch circle to the top of the tooth.

Answer 31

Face of Tooth