Related Resources: calculators

Helical Gears Shafts Parallel Exact Exact Center Distance Design Equations and Calculator

Machine Design and Engineering
Mechanical Gear Design and Engineering

Helical Gears Shafts Parallel, Center Distance Exact Design Equations and Calculator

The first step in helical gear design is to determine the desired direction of the thrust. When the direction of the thrust has been determined and the relative positions of the driver and driven gears are known, then the direction of helix (right- or left-hand) may be found

Related: Helical Gears Shafts Parallel Center Distance Exact Design Equations and Calculator

 

Preview Helical Gears Shafts Parallel, Center Distance Exact Design Calculator

Pitch diameter of large gear formula

D = N / ( P_n cos α )

where

cos α = ( N + n ) / ( 2 * Pn * C )

Pitch diameter of small gear formula 

d = n / ( P_n cos α )

Outside diameter of large gear

O = D + 2 / P_n

Outside diameter of small gear

o = d + 2 / P_n

Number of teeth marked on formed milling cutter (large gear)

T = N / cos³α

Number of teeth marked on formed milling cutter (small gear)

t = n / cos³α

Lead of helix on large gear

L = π D cot α

Lead of helix on small gear

l = πd cot α

Center distance (if not right, vary α)

C = 1⁄2 (D + d)

Where:

C = approximate center distance
P_n  = normal diametral pitch
N = number of teeth in large gear
n = number of teeth in small gear
α = angle of helix 

References:

Machinerys Handbook, 29th Edition