Page 194 - Analysis and Design of Machine Elements

Analysis and Design of Machine Elements
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h a addendum, mm v pitch line velocity, m s −1
h F bending moment arm, mm x profile shift coefficient
h dedendum, mm Y tooth form factor
f Fa
i Speed or velocity ratio, Y stress correction factor
Sa
transmission ratio Y stress correction factor for testing
ST
j number of gear teeth meshing per gear
revolution Y helix angle factor for bending
K load factor stress
K application factor Y contact ratio factor for bending
A
K life factor for bending stress stress
FN
1/2
K life factor for contact stress Z elastic coefficient, MPa ,
HN E
−2 1/2
K trial load factor (N mm )
t
K dynamic factor Z zone factor
v H
K transverse load factor Z helix angle factor for contact

K face load factor stress
L contact length, mm Z contact ratio factor for contact

L h design life in hours, h stress
l lead, mm z number of teeth
m module, mm z virtual number of teeth
v
m m mean module , mm pressure angle, ∘
m n normal module, mm n normal pressure angle, ∘
m nt trialnormalmodule, mm t transverse pressure angle, ∘
m t transverse module, mm helix angle, ∘
N number of load cycles b helix angle at base circle, ∘
n rotational speed, rpm pressure angle at the tip of tooth, ∘
P transmitted power, kW pitch cone angle in a bevel gear, ∘
p axial pitch, mm contact ratio
a
p base pitch, mm transverse contact ratio
b a
p circular pitch, mm transverse contact ratio of a
c av
p normal circular pitch, mm virtual gear
n
p transverse circular pitch, mm face contact ratio, overlap ratio
t
Q gear accuracy grade in ISO/GB Poisson’s ratio
standard radius of curvature, mm
Q gear quality number in AGMA normal radius of curvature, mm
AGMA n
standard transverse radius of
t
R cone distance, mm curvature, mm
r radius of reference or pitch circle, bending stress, MPa
F
mm endurance limit for bending
Flim
r a radius of addendum circle, mm stress, MPa
r b radius of base circle, mm [ ] allowable bending stress, MPa
F
r bv developed back cone radius, mm H contact stress, MPa
S F safety factor for bending strength Hlim endurance limit for contact
S H safety factor for contact strength stress, MPa
s F root thickness of a tooth, mm [ ] allowable contact stress, MPa
H
T torque, N mm d face width factor
u teethratio,gearratio R face width factor of a bevel gear
u v virtualspurgearteeth ratio angular velocity, rad/ s −1