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Unread 05-07-2007, 21:19
dbell dbell is offline
Mentor for team#3937 (Breakaway!)
AKA: David Bell
FRC #1519 (Mechanical Mayhem)
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Join Date: Nov 2006
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Location: Manchester,NH/Edmond, OK/Searcy, AR
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Re: pic: DeWalt drive base: side module

Quote:
Originally Posted by AdamHeard View Post
Those sprockets could be narrower though and probably save at least 1/2".
Yes, i could make the sprockets narrower,(they are currently .75in wide) which would allow the plates to be closer together. Right now i don't have a real big reason to do that though.


Quote:
Originally posted by Lil' Lavery
Why not only have 1 DeWalt on each side, linked to both CIM motors? It would require a little more modification, but it seems like it would save size and weight.
Several reasons: First of all i am using 4 dewalts because i know how to directly connect the CIM to the DeWalt, using the white paper. Making a gearbox to adapt 2 CIMs to one DeWalt would be something i have never done before. I think this would be possible though.
Another reason is because it would not really save that much weight. Each dewalt only weighs 1.5lbs and adding a 2-CIM adapter could add that much.
Also it wouldn't really save space because currently they only take a few inches at the ends. Which also distributes the weight well.
And finally because "this way when one of them fails, you still have drive on that side....." (posted by squirrel)


Quote:
Originally posted by Bill_Hancoc
from my experience dewalts require further reduction from the output shaft before it gets down to a usable speed. We usually run a chain reduction.
Feel free to correct me if im wrong, but thats what we have always done.
Quote:
Originally posted by Greg Needel
the reduction ratios of the NBD modification are 3:1, 4:1, 12:1. (12:1 being the same as the Banebots transmission this year) It would seem a bit fast to direct drive the wheels but wheel size plays a big factor in this (the smaller the wheel the more realistic this becomes), although I wouldn't do it as a cim motor at 3:1 reduction with 6 inch wheels would go ~46.5 ft/sec
Quote:
Originally posted by newton418
Definitely. Unless you want to have ~2" diameter wheels (in which case, the CIM would be the part touching the ground), you should really consider a reduction. My experience has been that an additional reduction in the ballpark of 4:1 (for a 7.5" diameter wheel) provides sufficient torque in 1st gear (for pushing/wheel slip), and plenty of speed in 2nd and 3rd.
You guys are all correct.
I forgot to make this clear.
I am planning on adding the last stage to the DeWalt gearboxes. To my knowledge this stage is 4:1. This should be a good speed with the current 6 inch wheels i have. I have not yet tested adding this part of the dewalts so it may not be realistic. I'll see.

Thanks for your comments!
DB
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