Calculating Strength Proportions for Worm Gears

Input values:

Gearing ratio i

Driving worm

Input power P 1

Input speed n 1

Driven worm gear

Input power P 2

Input speed n 2

Calculated values

a) Driving worm

Output speed:

b) Driving worm gear

Output speed: n 1 = n 2 i

Metric units

Worm circumferential speed

 

ANSI with English units

Worm circumferential speed

 

Worm gear circumferential speed

 

Sliding speed

 

v k = v 1 / cos γ

Friction factor in gear

 

Friction angle

 

tg ρ z = μ z

a) Driving worm

Gear efficiency:

 

Output power:

 

P 2 = P 1 η

Metric units

Input moment:

 

Tangential/circumferential force:

 

ANSI with English units

Input moment:

 

Tangential/circumferential force:

 

Output moment:

 

T 2 = T 1 i η

b) Driving worm gear

Gear efficiency:

 

Output power:

 

P 1 = P 2 η

Metric units

Input moment:

 

Tangential/circumferential force:

 

ANSI with English units

Input moment:

 

Tangential/circumferential force:

 

Output moment:

 

Tangential/circumferential force

 

Axial force

 

F a1,2 = F t2,1

Radial force

 

Normal force