GEAR RATING CALCULATIONS 1

[sanjaychetan]

HI,
IN VARIOUS GEAR DESIGN BOOKS LIKE DUDLEY,RATED TORQUE OF MOTOR MULTIPLIED BY SUITABLE GEAR REDUCTION RATIO IS USED TO CALCULATE THE STATIC STRENGTH OF GEARS OF VARIOUS STAGES OF A GEAR BOX.HOWEVER PULLOUT TORQUE OF MOTOR(SAY SLIP RING MOTOR) MAY BE AS HIGH AS 3 TIMES THE RATED TORQUE.SO DURING STARTING OF DRIVE VARIOUS GEARS WILL BE LOADED TO 3 TIMES THE TORQUE FOR WHICH THEY ARE DESIGNED.SO SHOULDN'T THE GEAR STRENGTH BE CALCULATED ON THE BASIS OF PULL OUT TORQUE OF MOTOR?SOMEBODY MAY PLEASE THROW SOME LIGHT ON IT

 

[tygerdawg]

Perhaps it is something like this: Starting torque not equal to running torque. Starting torque must overcome friction, etc., also start turning all of the rotational inertia of your drive train and get it up to speed. After up to speed, running torque significantly less.

TygerDawg
Blue Technik LLC
Advanced Robotics & Automation Engineering

http://www.bluetechnik.com

 

[digger200]

Gear strength is based on fatigue cycles and the starting torque only happens relatively infrequently. Calculate the fatigue strength then see how the starting torque compares to the yield of that gear. Up the size then if neccassary