Page 198 - Analysis and Design of Machine Elements

Analysis and Design of Machine Elements
176
Face width
Top land

Face

Addendum Addendum circle
Circular pitch
Tooth Width Pitch circle Flank
Dedendum thickness
of space
Bottom land
Clearance circle
Root fillet
Clearance
Dedendum circle
(a)
Pinion O 1
r b1 r 1
ω 1
N 1
Pressure angle α α Common tangent
Addendum circle
P
T 1 T 2 Centre distance
a
Pressure line
α r b2 N 2
r 2 Pitch circle
ω 2
Base circle
Gear Dedendum circle
O 2
(b)
Figure 8.1 Geometry and terminology of spur gears. Source: Budynas and Nisbett 2011, Figure 13.5,
p. 676. Reproduced with permission of McGraw-Hill.

7) Centre distance, a. Centre distance is the distance between the centres of the pitch
circles of the mating pinion and gear. For standard installation, the centre distance is
1
a = (d + d ) (8.2)
1
2
2
8) Circular pitch, p . Circular pitch is the distance along the pitch circle between corre-
c
sponding points of adjacent teeth, and is equal to the sum of space width and tooth