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 |

W_{k} |
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 | r_{A} |
Active root radius |

a’ | Shaft distance | s | Thickness |

b_{1} |
Facewidth of the pinion | Tooth thickness at the chord | |

b_{2} |
Facewidth of the wheel | s_{a} |
Tip thickness |

d | Pitch circle | s_{f} |
Tooth root thickness |

r | Radius | s_{b} |
Base tooth thickness |

d’ | Active pitch circle | s_{t},s_{n} |
Apparent – real tooth thickness |

r’ | Active pitch radius | Real tooth thickness at the chord | |

d_{a} |
Tip circle | s_{c} |
Constant chord |

r_{a} |
Tip radius | s_{o} |
Cutter thickness |

d_{f} |
Root diameter | v | Velocity |

r_{f} |
Root radius | v_{g} |
Sliding speed |

d_{b} |
Base diameter | v_{b} |
Displacement velocity at the active line |

r_{b} |
Base radius | v_{t} |
Tangential velocity |

e | Tooth space dimension | W | Measurement over k-teeth |

e_{t} |
Apparent tooth space dimension | W_{nk} |
Practical measurement over k-teeth |

e_{n} |
Real tooth space dimension | x_{1} |
Gear correction |

g_{f} |
Approaching length | x_{2} |
Wheel correction |

g_{a} |
Outgoing length | z_{1},z_{2} |
Number of teeth |

g_{a} |
Length of contact | z_{o} |
Number of teeth of the cutting tool |

g_{β} |
Length of overlap | z_{v} |
Virtual number of teeth |

h | Tooth depth | a | Pressure angle |

h_{a} |
Addendum | a_{o} |
Pressure angle of the cutting tool |

Addendum of the chord | a^{‘} |
Active pressure angle | |

h_{f} |
Dedendum | a_{M} |
Active pressure angle at a certain point |

h_{č} |
Addendum of the constant chord | a_{x} |
Axial pressure angle |

j_{n} |
Real clearance | a_{t} |
Transverse pressure angle |

j_{t} |
Apparent clearance | a_{n} |
Normal pressure angle |

m | Module | β | Primitive helix angle |

m_{o} |
Cutter module | β_{o} |
Mill helix angle |

m_{t} |
Apparent module | β’ | Active helix angle |

m’ | Active module | β_{b} |
Base helix angle |

m_{n} |
Normal module | e_{a} |
Transverse quotient |

m_{to} |
Apparent module of the cutter | e_{β} |
Overlap ratio |

m_{t}^{‘} |
Apparent active module | e_{g} |
Total quotient |

m_{x} |
Axial module | φ_{f} |
Starting angle |

p | Pitch | φ_{a} |
Finishing angle |

p_{o} |
Cutter pitch | φ_{a} |
Angle of contact |

p_{b} |
Base pitch | φ_{β} |
Overlap angle |

p_{t} |
Apparent pitch | φ_{g} |
Total angle of contact |

p_{n} |
Normal pitch | d | Reference cone angle |

p_{bt} |
Base apparent pitch | d_{a} |
Tip angle |

p_{bn} |
Normal base pitch | d_{f} |
Root angle |

p_{x} |
Axial pitch | υ_{a} |
Addendum angle |

p_{z} |
Tangential pitch | υ_{f} |
Dedendum angle |

r_{inv} |
Radius of the extreme involute point | υ | Tooth depth angle |