Sproket gears and timing belt design parameters 2

[dasiagud]

I recently receiced a piece of equipment having two timing gears. One is about 6 inches in diameter and the other is about 1.5 inches in diameter. A high torques stepping mmotor it attached to the smaller gear. The gears are seperated from each other about 1.5 inches. The problem appears that the timing belt does not grab enough sprokets on the smaller gear causing the belt to jump, because the larger gear is too close. The manufacturer claims that this is the way it's been designed as if that's the last word. Is there any documentaion or design criteria I could access that would give me all the pertinent design parameters for this type of system? I can't seem to find anything anywhere.

 

[waross]

You may not be running the belt tight enough.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[MikeHalloran]

Timing belt manufacturers provide the belt data in the engineering section of their catalogs. Many assembly manufacturers do not read that section until they have a field problem. I didn't; I do now.

Basic problem is that you have to use peak, not average, values in sizing stepper drives. Steppers are known to beat the crap out of anything they're attached to.

Fixes might include:
Longer center distance for more wrap.
Fixed idler for more wrap on the motor. (May require special belt with ground backside)
Modifications to the stepper drive circuit to moderate the motor's violence.
Belt with stronger teeth (different material, e.g. polyurethane)
Wider belt and pulleys.


Mike Halloran
Pembroke Pines, FL, USA