Belt Driven instead of Chain driven

[Hawiian Cadder]

Originally Posted by Chris is me

They do?



And what about the kit frame is imprecise at all? It's not like the kit holes are randomly placed.


Indeed true, though usually belt pulleys don't need separate hubs like smaller chain sprockets do.

Belts are workable just like chain but they require a bit more thought and design than a standard 35 chain drive-train to work. You also have to be careful with belt reductions to make sure you're not putting too much stress on the pulley teeth.

My wording was not as precise as it should have been, what I meant was the kit frame has some weaknesses in that it lacks rigidity. I also have found that the kit frame doesn't tend to stay perfectly square without a substantial amount of additional support (plywood, or larger gussets) so I would choose to use chain with the kit-bot purely because the flexing might cause damage to the belts, and if the frame warps into a parallelogram, the belts will wear out at an accelerated rate.

This white paper does a good job of quantifying the bending problems on a standard 2010 robot. the frame bent enough to throw #35 (i think) chain, so belts would be out of the question.

http://www.chiefdelphi.com/media/papers/2398

[Chris is me]

Originally Posted by Hawiian Cadder

This white paper does a good job of quantifying the bending problems on a standard 2010 robot. the frame bent enough to throw #35 (i think) chain, so belts would be out of the question.

The 2010 frame was substantially different than the 2011 frame, since the axle mounts were stood off several inches (6? 8? more?) from the actual chassis. The issue that really caused the bending and flex wasn't the kitbot profile as much as the modules that wheels were mounted to. The parts flexed relative to one another and your end result is thrown chain.

Belts require more or less the same amount of precision that 25 chain requires.

[kramarczyk]

Originally Posted by Hawiian Cadder

This white paper does a good job of quantifying the bending problems on a standard 2010 robot. the frame bent enough to throw #35 (i think) chain, so belts would be out of the question.

http://www.chiefdelphi.com/media/papers/2398

Yes, it was #35 chain thrown off that chassis, but be careful not to take this one data point as a universal problem with the kit chassis.

Originally Posted by Chris is me

The 2010 frame was substantially different than the 2011 frame, since the axle mounts were stood off several inches (6? 8? more?) from the actual chassis. The issue that really caused the bending and flex wasn't the kitbot profile as much as the modules that wheels were mounted to. The parts flexed relative to one another and your end result is thrown chain.

As Chris points out this is an issue of structure. In the case of the 2010 kitobt it is a lack of triangles supporting the chain path and the open section of the wheel risers that cause the problem.

The kit frame should only be one portion of your entire robot's structure. Step back and look at the whole robot. Use the other systems to reinforce the chassis and use the chassis to reinforce the other systems.

I used #25 chain on a kit frame this year with no issues.