Banebot Gearbox

[chris31]

We tried to take the metal plate off like your supposed to but couldnt get them off. Anyone know what size we need. Nothing we had worked and the ones that looked like they fit just would slip. They seem to be in there very tight.

[Jeff 801]

FYI the allen screws are English I don't remember the size but I assembled them not to long ago

[Nick 568]

I'm not meaning to hi-jack this thread, but has anyone else had problems with their gearbox jamming? One of the boxes is fine, but the other ones keeps jamming up. We have taken it apart and re-assembled it numerous times to no avail.


P.S. the allen wrench size is: 3/32" for the plate.

[chris31]

Originally Posted by Nick 568

P.S. the allen wrench size is: 3/32" for the plate.

Much appreciated. If i can figure out where we put our allen wrenches ill let you know if ours jam. Maybe put some grease on em.

[Nick 568]

Thanks, we've added more grease, but still nothing. I look forward to your response though!

UPDATE: We figured out what the problem was, apparently, the bushing was too long on one of the motors, so we ground it down on the lathe and all is well!

[chris31]

Using 3/32" only works for half of them for us. The others use something large than that but its smaller than the 1/8" wrench. Its so annoying. Im going to have to see if I have a 7/64" wrench or figure out what the heck is wrong with these screws.

[sanddrag]

Has anyone pulled one apart? Is there only that one bearing I can see from the outside? I'm guessing it wouldn't be wise to slap a wheel smack on there without another bearing eh?

[Ben Piecuch]

I haven't pulled apart the gearbox yet, but I was wondering the same thing. Dr Joe, care to give an answer to this?

While picking up the KOP at the Manchester Kickoff, I noticed that FIRST had built a couple practice bots. One robot used the new Banebot Trannies, and left the drive shaft fully cantilevered. Below you can find a picture. I was quite surprised to see if used in this configuration.



I don't think I'll be using it in this configuration, but YMMV.

BEN

[Gdeaver]

I too have concerns about shaft loading on the BB trans. If we were to use the 2 cim adapter and use 2 sprockets to duplicate last years 4 motor 4 wheel drive kit bot, can the 56mm trans take that shaft load and input? Has it been tested. Is the bearing support necessary for a 2 sprocket load? Can the 56 mm trans handle 2 cims? Would a safer bet be 4 cims 4 trans? Joe any comments?

[Joe Johnson]

I hate cantilevered loads. But I learn to live with them if their is good support for the shaft and if the loads are not too great.

So... ...my first recommendation is that you figure out a way to support the end of the shaft if you can. In fact, I recommended that FIRST put the bearing plate in the kit.

But...

There ARE two bearings supporting the output shaft but the bearings are side by side so things are kind of in a gray area. Yes I think is okay to have some side load on these shafts, but I would not suggest teams cantilevering load if the sprocket or gear is going to be far out on the shaft.

You can probably get away with it is you have a single sprocket and are not using the encoder (which spaces the load out).

Joe J.

[chris31]

Thank you for your reply but can you answer why a 3/32" allen srench only works on half my screws? As of right now my only solution is to cut them out and buy and replace them with new ones from BB.

[NeedMoreEngines]

Originally Posted by Gdeaver

I too have concerns about shaft loading on the BB trans. If we were to use the 2 cim adapter and use 2 sprockets to duplicate last years 4 motor 4 wheel drive kit bot, can the 56mm trans take that shaft load and input? Has it been tested. Is the bearing support necessary for a 2 sprocket load? Can the 56 mm trans handle 2 cims? Would a safer bet be 4 cims 4 trans? Joe any comments?

I actually emailed BaneBots tech support for EXACTLY this question. Here is their response:

The two motor adapter does not change the gear reduction so in a best case [assuming no mechanical loss] the RPM would be the same as with 1 CIM motor and the torque would be twice that of a single CIM motor.

The 56mm gearbox and two motor adapter was specifically designed for FIRST applications and we believe they will support two CIM motors.

BaneBots

I don't know though---It doesn't seem like that little sucker can handle those two big CIMs. I'd hate to find out the wrong way.

[chris31]

we believe they will support two CIM motors.

Umm. Does that mean they didnt test them?

[Joe Johnson]

Originally Posted by Ben Piecuch

I haven't pulled apart the gearbox yet, but I was wondering the same thing. Dr Joe, care to give an answer to this?

While picking up the KOP at the Manchester Kickoff, I noticed that FIRST had built a couple practice bots. One robot used the new Banebot Trannies, and left the drive shaft fully cantilevered. Below you can find a picture. I was quite surprised to see if used in this configuration.



I don't think I'll be using it in this configuration, but YMMV.

BEN

Whoa! I don't know how I missed seeing that picture earlier but to me, that is about the scariest picture I have seen in a long time.

Perhaps the bearings inside that gearbox are better than I thought, but I would have never never never hung a sprocket that far out on that shaft.

I am thinking that the only way they got away with it was that they weren't really using it in competition and they must not have had the grippiest of tires.

Looking at that picture sends shivers down my spine! Really -- read this post for more on my views of emotion and engineering.

Joe J.

[Otaku]

Originally Posted by sanddrag

Has anyone pulled one apart? Is there only that one bearing I can see from the outside? I'm guessing it wouldn't be wise to slap a wheel smack on there without another bearing eh?

I'm not aware of exactly how strong the gearbox is, however I would not suggest direct drive without added support.

That being said, BaneBots sells the bearing plates with the same mounting holes as the transmission itself, meaning all you have to do is get one of those and figure out where you're going to mount it.

I do suggest, however, running a chain drive system. Even if it's short. The weight of the chains and added mounting hardware shouldn't be too much (say, 5lbs for a 4-wheel setup and some heavy chain), plus if a motor or gearbox fails and you don't have time to take it out, just disconnect the power, take a link out of the chain, and take the chain off, leaving the corresponding wheel free to move.