Standardization of symbols

Symbols – geometry c Relative at the constant chord
a Centre distance d
b Facewidth e Outside
c Bottom clearance f At the root
d Diameter g
e Tooth interval h Tooth depth
f Coefficient of friction i Inside
g Contact length j Relative clearance
h Tooth depth k
i Ratio l Longitudinal direction of the gear
j Tooth clearance m Average
k Number of teeth spanned n Real
l Length o
m Module p Relative with the pitch
n Number of rotational speeds per minute q
p Pitch r Radial
r Radius s Relative with the tooth thickness
s Tooth thickness t Apparently
t Time u
u Gear ratio v Virtual
v Linear velocity w
w x Axial
x Correction coefficient y
y Correction coefficient at the center distance z From the angle
z Number of teeth or teeth a From the pressure angle overlap
inva Involute a β From the helical angle overlap
a Pressure angle g Total overlap
β Helix angle e
g Helix angle at the reference cylinder Σ Relative at the shaft angle
d Reference angle 0 Relative with the tool
e Coefficient of contact 1 Relative with the pinion
η Half reference angle 2 Relative with the wheel
λ Wavelength of the undulation ()’ From the action
μ Angle of friction (ˉ) Relative to the chord
r Radius of curvature bij Additional value
σ Stress gew Required value
τ Angular pitch of mutual wheel dia Diagram value
φ Angle of contact eff Effective value
ψ Half angle tooth thickness inv Relative to the involute
ω Angular velocity lim Limiting value
Σ Shaft angle max Maximum value
P Diametrical pitch min Minimum value
Wk Dimension across the teeth per Periodic value
Additional indexes the Theoretical value
a From the tip tot Total value
b From the basis adm Permissible value


Symbols – combined R Primitive describing
a Normal center distance rA Active root radius
a’ Shaft distance s Thickness
b1 Facewidth of the pinion Image103 Tooth thickness at the chord
b2 Facewidth of the wheel sa Tip thickness
d Pitch circle sf Tooth root thickness
r Radius sb Base tooth thickness
d’ Active pitch circle st,sn Apparent – real tooth thickness
r’ Active pitch radius Image104 Real tooth thickness at the chord
da Tip circle sc Constant chord
ra Tip radius so Cutter thickness
df Root diameter v Velocity
rf Root radius vg Sliding speed
db Base diameter vb Displacement velocity at the active line
rb Base radius vt Tangential velocity
e Tooth space dimension W Measurement over k-teeth
et Apparent tooth space dimension Wnk Practical measurement over k-teeth
en Real tooth space dimension x1 Gear correction
gf Approaching length x2 Wheel correction
ga Outgoing length z1,z2 Number of teeth
ga Length of contact zo Number of teeth of the cutting tool
gβ Length of overlap zv Virtual number of teeth
h Tooth depth a Pressure angle
ha Addendum ao Pressure angle of the cutting tool
Image105 Addendum of the chord a Active pressure angle
hf Dedendum aM Active pressure angle at a certain point
hč Addendum of the constant chord ax Axial pressure angle
jn Real clearance at Transverse pressure angle
jt Apparent clearance an Normal pressure angle
m Module β Primitive helix angle
mo Cutter module βo Mill helix angle
mt Apparent module β’ Active helix angle
m’ Active module βb Base helix angle
mn Normal module ea Transverse quotient
mto Apparent module of the cutter eβ Overlap ratio
mt Apparent active module eg Total quotient
mx Axial module φf Starting angle
p Pitch φa Finishing angle
po Cutter pitch φa Angle of contact
pb Base pitch φβ Overlap angle
pt Apparent pitch φg Total angle of contact
pn Normal pitch d Reference cone angle
pbt Base apparent pitch da Tip angle
pbn Normal base pitch df Root angle
px Axial pitch υa Addendum angle
pz Tangential pitch υf Dedendum angle
rinv Radius of the extreme involute point υ Tooth depth angle