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HELICAL GEARS
GeometryKK N
K M K N
K M
Spur gearsSpur gears
Helical gears
HELICAL GEARS
Geometry and manufacturing
Primitive helix
Base helix
Base helix
Spur gear generation Helical gear generation
HELICAL GEARS
Geometry
costan
tantan bb
R
cos
HELICAL GEARS
Contact and force transmission
cos bN S
sin tanb bT NS
b
RNM
tantan LLs b
RNM cos
tan tanbM MT
tan
cosLs
cosT
R R
HELICAL GEARS
Definitions and properties
mRp 2
(Tangential) Pitch
cosppn
mZ
p ( g )
Normal (= orthogonal) Pitch
nn mp
n
cosmmn Normal module
costantan n Normal pressure angle
INCIDENT AXES TRANSMISSION
Spherical motion
Gear 2
Gear 1Gear 1
Bevel gearings
2
1
1
2
sinsin
BEVEL GEARS
Bevel gears
sσ1
μ
C
s2
s1
σ
ε
σ2
PrimitiveBase cone
Primitive cone
BEVEL GEARS
Bevel gears
PrimitiveBase cone
Primitive cone
SKEW AXES TRANSMISSION
Worm-gearsGear axisGear axis
Worm axis
SKEW AXES TRANSMISSION
Worm-gears
Gear axis2
G W
W
pR
G i
Z Wp p i
2 W R
W Z2
Rp
ZZ
pW= worm pitchp = gear pitchp = gear pitchi = worm threadsR = gear pitch radiusg pZ = gear teeth
SKEW AXES TRANSMISSION
Other solutions
Cylindrical gears with helical teethHypoidal gearing
(bevel gears with curve-shaped teeth)y g (bevel gears with curve shaped teeth)