Quote:
Originally Posted by Cory
I'm not trying to denigrate what 192 did last year, because they made a gorgeous, highly functional gearbox, but it should also be asked "what advantage does 192's gearbox design hold over a COTS or modified COTS solution?"
Moving the motors out of the way isn't a good enough reason for most teams, IMO. What is all that extra work and potential compromise of reliability really buying you? An extra 8" in the interior of your robot that you probably don't really need anyways?
192 had the benefit of doing something similar (with worm gears) to OP's design in 2012. They didn't do it again after that. They have at least 4 revs of their 2014 gearbox (as I recall they made 2 prototypes in the 2012 offseason, plus the 2013 gearbox, then the 2014 gearbox).
There are so many better obstacles for most teams to tackle than making custom gearboxes. If 254 were starting a new team right now, I highly doubt we would make custom gearboxes. Maybe custom sideplates to get the right ratio, but that's about it. The stuff that's out there now is so high quality that if you have any question about your ability to solve every other aspect of the game challenge, you really shouldn't be going custom.
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Advantages:
-2.5lbs less total
-Extra bellypan space (especially with the smaller size this last year)
-Easy motor/gearbox removal (no need to pocket the bellypan as much to pull out the gearbox)
-Money. For a WCP gearbox it's $300 without cims. A non-COTS option with shifter shaft might be half that.
Maybe 254 doesn't need the space, but 115 would have absolutely adored a few extra square inches last year.
Disadvantages:
-Manufacturing time. If designed properly, this can be reduced to a couple hours on a mill early in the season. For our team, it's not a problem to quickly churn out a couple custom gearbox plates on our mill and machine 2x1 sides in a few days while the drivetrain is deisgned. Plus, we would have to wait a couple days for COTS gearboxes anyway, so instead we can just wait for shifter parts.
I open-source all of my designs, so it doesn't need to be redesigned each year. I'm remaking my 192 gearbox clone to be easier to machine and use COTS shifter parts right now.
However, any custom gearbox should be deisgned and tested pre-season. It's too dangerous for many teams to do otherwise.
While 192 made several revisions, it is relatively easy to copy their design because they've done all the hard work in the basic design. The hardest part of a design IMO is coming up with the overall design first. After that, it all falls into place in CAD.