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Unread 16-11-2014, 19:03
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Joe Johnson Joe Johnson is offline
Engineer at Medrobotics
AKA: Dr. Joe
FRC #0088 (TJ2)
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Re: [Behind the Lines] Ep. 3 with Ken Stafford on Motors and Gearboxes!

Quote:
Originally Posted by Jared View Post
Out of curiosity, why do you say this? I agree that they aren't the easiest gearbox to get right, but I don't think they're impossible. You can get some really huge reductions. We had success with putting a worm gear reduction in a 2" x 2" aluminum square tube with .125" wall. We drove the thing with three CIM motors, so I don't think the typical FRC planetaries would have worked in that situation.

I agree with all your other comments, especially the note about the CIM motors. They're big and heavy, but when you consider how long some teams stall them for on their drives, it's very impressive that they last as long as they do.
Worm gears are hard to get right. If you know what you're doing, sure, you can make it work and you will get some benefit. I think that the percentage of teams that will net out to a positive is under 1%.

Perhaps my thoughts will evolve on this. I used to be dead set against bevel gears as well, which are nearly as hard, but which also provide a very nice benefit for certain kind of swerve implementations, so if you are careful and you really want that particular swerve, I think you can come out ahead. But, worm gears are harder and have other negatives so I just don't see benefits outweighing the costs and risks.

YMMV.

Joe J..
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