Simple Gear Selection Procedure

Simple Gear Selection Procedure

The Lewis formula, in the form given by $\sigma =W_{t}/FmY$ can be used in a provisional spur gear selection procedure for a given transmission power, input, and output speeds. The procedure is outlined as follows:

Select the number of teeth for the pinion and the gear to give the required gear ratio. Note that the minimum number of teeth permissible when using a pressure angle of 20° is 18.
Use either the standard teeth numbers or as listed in a stock gear catalog.
Select a material. This will be limited to those listed in the stock gear catalogs.
Select a module, m from standard or as listed in a stock gear catalog
Calculate the pitch diameter, d = mN.
Calculate the pitch line velocity, $V=(d/2)\times n\times (2\pi /60)$
Calculate the dynamic factor, $K_{v}=6.1/6.1+V$
Calculate the transmitted load, W_t = Power/V.
Calculate an acceptable face width using the Lewis formula in the form $F =\frac{W_{t}}{K_{v}mY\sigma _{p}}$

References:

CHILDS, PETER R. N. MECHANICAL DESIGN ENGINEERING HANDBOOK. BUTTERWORTH-HEINEMANN LTD, 2014.

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