Contents - Index

Gear_Lewis_Factor

Gear_Lewis_Factor(N, Tooth$)

The function Gear_Lewis_Factor returns the Lewis factor (sometimes called Y - the Lewis Form Factor) associated with the tooth profile.  

Inputs:

N - number of teeth

Tooth$ - string indicating the tooth profile

 '14.5 degree involute' for 14.5 degree pressure angle involute tooth

 '20 degree involute' for 20 degree pressure angle involute tooth

Output:

Returns the dimensionless Lewis Form Factor (Y)

Example:  

$UnitSystem SI Mass J K Pa

$Load Mechanical Design

N=20 [-]

Tooth$='20 degree involute'

Y=gear_lewis_factor(N, Tooth$)

{Solution:

Y = 0.3192}

Reference:  Budynas, R.G. and J. Keith Nisbett, Shigley's Mechanical Engineering Design, 11th Edition, McGraw Hill, New York, (2020).

The function uses curve fits to data found in  https://www.engineersedge.com/gears/lewis-factor.htm.

Gear Design