1 Outline Gear Theory Nomenclature Gear Trains Fundamental Law of Gearing Functionally, a gearset is a device to exchange torque for velocity P=Tω the angular velocity ratio of the gears of a gearset must remain constant throughout the mesh in out in out V r r m = = ω ω Towards the Involute Profile A belt connecting the two cylinders line of action, pressure angle φ The Involute Profile Meshing pressure angle, line of action, length of action, addendum Nomenclature Figure 11-8 N d p c π =
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Outline Fundamental Law of Gearing - University of Delaware · · 2006-05-08Gear Trains Fundamental Law of Gearing ... Gear Trains Simple Gear Trains. 3 ... gears-304-06.ppt
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1
OutlineGear TheoryNomenclatureGear Trains
Fundamental Law of GearingFunctionally, a gearset is a device to exchange torque for velocity
P=Tωthe angular velocity ratio of the gears of a gearset must remain constant throughout
the mesh
in
out
in
outV r
rm ==ωω
Towards the Involute ProfileA belt connecting the two cylinders
line of action, pressure angle φ
The Involute Profile
Meshing
pressure angle, line of action, length of action, addendum
Nomenclature
Figure 11-8
Ndpcπ
=
2
Pitches, Etc.
circular pitch (mm, in.)
base pitch (mm, in.)
diametral pitch (teeth/in.)
module (mm/teeth)
Ndpc
π=
φcoscb pp =
dNpd =
Ndm =
Velocity Ratiopitches must be equal for mating gears, therefore
in
out
in
outV N
Nrrm ±=±=
Contact Ratio
average number of teeth in contact at any one time =