Gear Design

Selection of Gear Type

(Reprinted from Handbook of Gears, Stock drive products)

Selection of Gear Materials

(Reprinted from Handbook of Gears, Stock drive products)

Formulae for gear forces

(Reprinted from Design Data, PSG Tech,1995)

Gear Force Diagram

Spur Gear Design

(Reprinted from Design Data, PSG Tech,1995)

DESIGN OF SPUR GEAR

Spur Gear Fundamental

1. Determine HorsePower based on Lewis Formula

Metalic Spur Gears :

W = SFY . 600 / (P . [600 + V] )

where W = Tooth Load, Lbs

S = Safe Material Stress (static)Lbs per Sq.in

F = Face Width, In.

Y = Tooth Form Factor

P = Diametral Pitch

D = Pitch Diameter

V = Pitch Line Velocity, Ft. per Min. = 0.262 . PD . RPM

For Non-Metalic Gears

W = S.F.Y. {(150 /[200 + V]) + 0.25} / P

Horse Power Rating (HP_L) = W . D. RPM / 126000


2. Calculate Design Horse Power

Design HP = HP_L * Service Load factor

3. Select the Gear / pinion with horse power capacity equal to or more than Design HP.

Ref :"Handbook of Gears" -Stock drive products

Table 1.15 Ratings for Steel Spur Gears

Helical Gear Design

(Reprinted from Design Data, PSG Tech,1995)

HELICAL GEAR DESIGN

Helical Gear Fundamental

1. Determine HorsePower based on Lewis Formula

Same as Spur Gear Design except the inclusion of helix angle

HP_Helical = HP_Spur * cos(ψ)

2. Calculate Design Horse Power

Same as Spur Gear

3. Select the Gear / pinion with horse power capacity equal to or more than Design HP

From "Handbook of Gears" -Stock drive products

Table 1.18 Ratings for Hardened Steel Helical Gears