pic: Am I Doing It Right Guys?

ballshifter
minicim
vexpro
775pro
frc5712

#1



Saw lots of 775Pro Drive and MiniCIM Drive threads over past few months, so when the AM DeCIMate was released I thought to myself “Why not both”?

Thoughts?


#2

Did you design that cover for the DeCIMate gears or is that somewhere on AndyMark’s website?


#3

My design, I figured with the amount of grease required to keep the gears lubricated it would be helpful. As it turned out, I had to pack the gearboxes with grease (Red Tacky) several times, even with the covers on, just to keep the gears from throwing the grease off the gears immediately.

I’d be happy to upload the model somewhere if people are interested.


#4

I would be interested in using the cover if you want to share the CAD. My team is looking at using these gearboxes and I couldn’t find any cover pre-designed (even though the assembly directions mention one).


#5

Here you go:

https://www.thingiverse.com/thing:2763971


#6

I find it interesting that the DeCIMate Assembly Guide explicitly mentions a 3D-Printed case on page 5, but I find no mention of this on AM’s website. Even still, this is awesome!


#7

Interesting, we bought ours already assembled so I never bothered to look at the guide. I like how the one shown in the guide holds the spacers in place, but I think I still prefer the overall shape of mine tbh.


#8

:rolleyes:] You’re not doing it right. There should be a 775Pro on one slot of the DeCIMate instead of the Redline. The other slot should have a Redline./:rolleyes:]

I kid, I kid, that’s definitely an interesting configuration. If you do end up using that be sure to post back with how it held up!


#9

Sorry about that! For now, here is the official AndyMark one I designed. We should have it on a page in the 3D printing section of the website up soon.


#10

Thank you! I was just looking through it for once my team’s DeCIMates come and noticed there wasn’t a link. I definetly like the idea of having a cover over the gears to keep grease in and dirt out.


#11

Heh, not a bad idea actually… :rolleyes:

Honestly I would have preferred using 775Pros (simply because Redlines are still somewhat unproven), but we didn’t have any way to press-fit the pinion gears onto them in our shop so it was easier to just used the pre-assembled gearboxes from AndyMark.

I definitely plan to use these in this configuration on our robot, the real question is for how long. I am a little concerned about wear on the DeCIMate gears, we did the recommended 30 minute no-lube run-in and now the gears seem to have quite a bit of backlash when changing directions. I’m hoping this is expected behavior and that the lubricant we added will prevent further wear.


#12

Also, change one of the MiniCIMs to a regular CIM.


#13

Would that set a record for “most motor types in one gearbox”?


#14

My team is using the 775 Pros since the Redlines are new, we just use a vise usually to press fit them, thats what we did last year with pulleys.


#15

It almost certainly would if they also changed the shifter to a servo instead of a piston.


#16

Everything old becomes new again:


#17

Nah man, door latch actuator.


#18

I have actually been wondering about using these, but unless you’re using a solenoid-type actuator (which have limited power under the solenoid rules and might not be strong enough), wouldn’t you run into issues stalling the motor? :confused:


#19

Yes unless the actuator had it’s own detent built in or you added your own detent. Every lock actuator I’ve seen had no detent (plunger was free-moving when not powered) as they used the door lock mechanism itself as the detent.


#20

I hate to necro a post this old, but I figured I’d actually post an update on how this configuration worked for us this past season (since you asked); better late than never right?

So, first off, we ran with the gearbox configuration I posted in the OP the entire season. Overall, they worked well and delivered the performance we were expecting. There were a few, relatively minor, issues that we encountered however…

  • We did end up replacing the “worse” of the two DeCIMate’s after our first competition due to gear wear. This was mostly a result of the initial wear we experienced from the AM run-in procedure I mentioned previously. The gearbox still worked fine but we replaced it as a precaution.
  • The system did pull a LOT of current at stall (our record was over 400A according to PDP logs), especially in High Gear (as would be expected). Ideally we would have implemented current-triggered downshifting, but we were able to mitigate it with some driver training (practicing down-shifting right before you hit something helps a lot).
  • We had issues with the mounting screws on the Redlines coming loose at Detroit Worlds (our fault for not securing them with Loctite when they were initially assembled). The lack of accessibility to these screws (due to where and how we mounted the DeCIMates) also made it difficult to correct these issues at the competition (while trying to avoid taking the gearboxes completely apart).

Overall, would I consider using this gearbox arrangement again? Perhaps, but probably only for a game that required a LOT of pushing power (2014 comes to mind), in retrospect it was overkill for this years game (though I don’t think it hurt us either). That said, with the new NEO brushless motors that were just released, it might make a configuration like this obsolete anyways.