SPUR GEAR

Question 1

a cylindrical gear whose tooth traces are straight lines parallel to the axis. Generally, it
transmits rotational motion and power between two axes

Answer 1

spur gear

Question 2

each of the projecting parts of a gear which are intended to ensure, by contact with the teeth
of another gear, that one of the other gear turns the other

Answer 2

gear tooth

Question 3

the quotient of the pitch, expressed in millimeters, to the number π (or the quotient of the
reference diameter, expressed in millimeters, to the number of teeth)

Answer 3

module

Question 4

the line of intersection of the pitch cylinder by a plane perpendicular to the axis of the gear

Answer 4

pitch circle

Question 5

the radial distance between the addendum circle and the pitch circle

Answer 5

addendum

Question 6

the circle that bounds the outer ends of the teeth

Answer 6

addendum circle

Question 7

the radial distance between the dedendum circle and the pitch circle

Answer 7

dedendum

Question 8

the line of intersection of the dedendum cylinder by a plane perpendicular to the axis of the
gear

Answer 8

dedendum circle

Question 9

the amount by which the dedendum in a given gear exceeds the addendum of its meshing
gear

Answer 9

clearance

Question 10

the diameter of the pitch circle

Answer 10

pitch diameter

Question 11

the diameter of the addendum circle

Answer 11

addendum diameter

Question 12

the diameter of the of the dedendum circle

Answer 12

dedendum diameter

Question 13

the radial distance between the addendum circle and the dedendum circle

Answer 13

tooth depth

Question 14

the length of the arc of the pitch circle between two consecutive corresponding profiles

Answer 14

circular pitch

Question 15

the width of the tooth measured along the circular pitch

Answer 15

tooth thickness

Question 16

the space between teeth measured along the pitch circle

Answer 16

tooth space

Question 17

the tooth space minus the tooth thickness

Answer 17

backlash

Question 18

the width over the toothed part of a gear, measured along a straight line generator of the
reference cylinder

Answer 18

face width

Question 19

the portion of the surface of a tooth lying between the tip surface and the root surface

Answer 19

tooth flank

Question 20

angle at the point where the profile cuts the pitch circle

Answer 20

pressure angle

Question 21

of an involute cylindrical gear, the “base circle” of the involutes forming the tooth profiles

Answer 21

base circle

Question 22

the line of intersection of a tooth flank with any defined surface cutting the reference surface

Answer 22

tooth profile

Question 23

the line of intersection of a flank with the reference surface

Answer 23

tooth trace

Question 24

a cylindrical gear of which every usable tooth profile is an arc of an involute to a circle

Answer 24

involute cylindrical gear

Question 25

a plane curve described by a point on a straight line (the "generating line"), which rolls out without slip on the base circle

Answer 25

involute to a circle

Question 26

Materials Spur gear materials shall be of ??? with an ultimate tensile strength of ??? and a Brinell Hardness Number of ??? respectively.

Answer 26

- hot-rolled steel designation 1045 and 3140 - 600 MPa and 724 MPa - 215 and 205

Question 27

Hunting tooth gear ratio When using a hunting tooth gear ratio, a particular tooth in the pinion must mesh once with every tooth on the meshing gear when the pinion has completed as many revolutions as the ???. This is done in order to distribute the wear more evenly. In a hunting tooth gear ratio, the teeth in a pair of meshing gears are such that ???. Hunting tooth gear ratios are obtained by having the ???. ??? is used when both gears are hardened or hardened and ground. It is also used for gear pairs that are subjected to high cyclic loads.

Answer 27

- number of teeth in the meshing gear - they do not have a common divisor - sum of the teeth in each pair equal to a prime number - Hunting tooth

Question 28

The following information shall be marked on the gear:

Answer 28

a) Type b) Module c) Number of teeth d) Manufacturer’s name and/or its trademark

Question 29

The following information shall be marked on the packaging:

Answer 29

e) Type f) Module g) Number of teeth h) Manufacturer’s name, trademark and address