how can I calculate the efficiency of worm gear system?

[aliesmal110]

Hi all

I want to select a motor for a worm gear system with 1:104 ratio.I know that the output torque is 208 N.M
for calculating the input torque I know that I must use this formula:
Tin=Tout/reduction ratio/efficiency
so
Tin=208/104/efficiency
but I don't know how can I find the value of the effieciency of my worm gear system.
thanks to eny one could help me

 

[drawoh]

aliesmal110,

Your machine design textbook from college should have a good explanation of the forces on a worm gear system.

--
JHG

 

[bithkits]

Maybe this will help you on your way:

http://www.roymech.co.uk/Useful_Tables/Drive/Worm_Gears.html

Mechatronics Engineer from South Africa.

 

[tbuelna]

aliesmal110-

Your question should be more specific. First, high ratio worm gear drives typically have fairly low input-to-output efficiency, and this efficiency can vary greatly depending upon the particular system design (ie. oil or grease lubrication, rolling element vs. plain bearings, etc.) and the operating conditions at which the efficiency is being measured. When sizing a motor, you need to take into account the increased torque needed at start up, and the gear drive system mechanical losses at the combined worst-case operating conditions.

Unfortunately, what you'll discover with the size of motor needed for your 104:1 worm gear drive once you take into account all of the worst-case conditions, is that the motor will be far larger than you imagined.

Best of luck to you.
Terry

 

[drawoh]

tbuelna,

Someone on this site quoted or made up a quick rule of thumb that a worm drive's efficiency was 100% minus the gear ratio. Obviously, this does not help the OP one bit.

--
JHG

 

[tbuelna]

drawoh,

I guess the problem with free advice is that often it is only worth what you paid for it.

Terry

 

[chumet1]

gear ratio that big for a worm gear system?? hasnt crossed my path. high ratio worm gears are not efficient transmitters of power. these effiencies range from around 40-98% but usually such efficiencies are approximations from experience thats why people come up with some form of rule of thumb. for your system i would take the lowest to be on the safe side