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Unread 04-09-2012, 22:53
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trilogy2826 trilogy2826 is offline
Mentor - 2826
AKA: Jake Fischer
FRC #2826 (Wave Robotics)
Team Role: Mentor
 
Join Date: Nov 2008
Rookie Year: 2006
Location: Oshkosh, WI
Posts: 113
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Re: Timing belt in drive success

2826 used XL belts with 18 tooth sprockets in an offseason 8WD. We used an idler tension system. All parts were SPD/SI. The result was an unmitigated disaster. The failure mode began with the belts skipping no mayter the tension applied, then the sprocket flanges popping off and the belts shifting over the sprocket edge, then shredding the belt.

We based our original belt decisions on anecdotes and basic CD research. Liking our lessons learned, we followed the design process and actually performed the proper load calculations. What resulted was that the sprockets were 60% too small and the XL tooth simply could not handle the dynamic load at the width by almost a factor of 3.

Lesson: Always do the math!