HELICAL GEAR

Question 1

cylindrical gear whose tooth traces are helices, it transmits rotational motion and power
between two parallel axes

Answer 1

helical gear

Question 2

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

Answer 2

gear tooth

Question 3

quotient of the circular pitch, expressed in millimeters, to the number π (or the quotient of the
diametral pitch, expressed in millimeters, to the number of teeth)

Answer 3

module

Question 4

quotient of the normal circular pitch (expressed in millimeters)and the number π, where the
normal circular pitch is the product of the circular pitch and the cosine of the helix angle

Answer 4

normal module

Question 5

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

Answer 5

pitch circle

Question 6

radial distance between the addendum circle and the pitch circle

Answer 6

addendum

Question 7

circle that bounds the outer ends of the teeth

Answer 7

addendum circle

Question 8

radial distance between the dedendum circle and the pitch circle

Answer 8

dedendum

Question 9

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

Answer 9

dedendum circle

Question 10

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

Answer 10

clearance

Question 11

diameter of the pitch circle

Answer 11

pitch diameter

Question 12

diameter of the addendum circle

Answer 12

addendum diameter

Question 13

diameter of the of the dedendum circle

Answer 13

dedendum diameter

Question 14

radial distance between the addendum circle and the dedendum circle

Answer 14

tooth depth

Question 15

length of the arc of the pitch circle between two consecutive corresponding points of adjacent
teeth

Answer 15

circular pitch

Question 16

length of the arc, living between the tooth traces of two consecutive corresponding flanks of a
cylindrical normal helix

Answer 16

normal circular pitch

Question 17

width of the tooth measured along the circular pitch

Answer 17

tooth thickness

Question 18

space between teeth measured along the pitch circle (

Answer 18

tooth space

Question 19

difference between the tooth space and the tooth thickness

Answer 19

backlash

Question 20

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

Answer 20

face width

Question 21

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

Answer 21

tooth flank

Question 22

pressure angle at the point where the profile cuts the pitch circle

Answer 22

pressure angle

Question 23

pressure angle at a point on a tooth trace

Answer 23

normal pressure angle

Question 24

curve whose tangents are inclined at a constant angle to the axis of the cylinder

Answer 24

helix

Question 25

in a cylinder on which helix is considered, a helix which is perpendicular to that helix

Answer 25

normal helix

Question 26

acute angle between the tooth trace and the generator of any imaginary cylinder or cone coaxial with a gear whose tooth trace is under consideration

Answer 26

helix angle

Question 27

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

Answer 27

base circle

Question 28

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

Answer 28

tooth profile

Question 29

the line of intersection of a flank with the reference surface

Answer 29

tooth trace

Question 30

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

Answer 30

involute cylindrical gear

Question 31

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

Answer 31

involute to a circle

Question 32

The following information shall be marked on the gear and /or its packaging:

Answer 32

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