pic: 865 flipped CIM WCD gearbox

[mman1506]

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[Joey Milia]

I like it

What are the tooth counts of the belt and pulleys you're using?

Also, are you doing anything to protect the cims from impact?

Definitely loving the compactness. I've always been a bit nervous to use belts in a drive transmission, but it looks like you've pulled it off pretty successfully. Props to you for this great design! Is there any reason you didn't lighten the plates?

[mman1506]

Originally Posted by Joey Milia

I like it

What are the tooth counts of the belt and pulleys you're using?

Also, are you doing anything to protect the cims from impact?

Thanks,
the pulleys are 24 and 30 tooth and the belt is a 50 tooth.

The omni sticks out past the CIM motor by about a 1/4 of an inch so that should give it some protection from side impacts. We've been considering some sort of "splitter" to prevent something getting in front of the gearbox or a polycarb bumper outside of the transportation area.

[Joey Milia]

Ah ok cool, in the pic it looks like the cims stick past the wheel so I was worried. I just noticed you said the belts were gt3, were did you sorce them?

[mman1506]

Originally Posted by Andrew Lawrence

Definitely loving the compactness. I've always been a bit nervous to use belts in a drive transmission, but it looks like you've pulled it off pretty successfully. Props to you for this great design! Is there any reason you didn't lighten the plates?

We were originally going to have the CIM mount plate waterjet cut where ON/OFF cycles are a big factor of machine wear. While we ended up laser cutting them we decided against a lightening pattern due to minimal weight savings and the potential of impact to the gearbox.

[mman1506]

Originally Posted by Joey Milia

Ah ok cool, in the pic it looks like the cims stick past the wheel so I was worried. I just noticed you said the belts were gt3, were did you sorce them?

My mistake, the belts are GT2 from SDP-SI

[mman1506]

I thought I'd update this post with a long term review for those who are looking to do something similar.

I'm happy to report that we had zero issues with the gearbox after three competitions. There doesn't appear to be any significant belt wear and the CIMs have held up fine after bashing them numerous times.

We also added grayhill encoders for our 3rd competion using the "cheesy poof method" into the input reduction shaft.