Banebot Gearbox

[chris31]

we believe they will support two CIM motors.

Umm. Does that mean they didnt test them?

[NeedMoreEngines]

Originally Posted by chris31

Umm. Does that mean they didnt test them?

Dunno. That's all they wrote to me so I sent a second message for some numbers and things.

All I gotta say is - YOU BETTER HOPE THIS THING WORKS!!!


sorry banebots. I like your company name. I just don't like your indecisiveness.

Here's my reasoning. If FIRST made the switch from those big square single-speeds of the past 2 years to these BB planetaries, they've got to be substantial enough. For them to replace something THAT GOOD, these new ones are probably just as good.

sorry FIRST. I think it's cool that your company name is an acronym. I just don't like your choice of gear reduction devices.

[Nitroxextreme]

Has anyone tryed to put a big cim in the BB tranny?... and if so what kind of modifications did you have to make?

[Bochek]

By the sounds of things team 2200 will be getting 2 of thoes doubble cim adapters. as well as 2 more Cim's

Only time will tell how well the BB trannies hold up.

- Bochek

[Gdeaver]

Our team may go with the 56 BB and 2 cim adapter. We will be supporting the shaft if this is the teams choice.

[wdw_mkr87]

i was wondering what the 80/20 to 1/2 aluminum square stock was in weight

we may go with a 6 wheel design and need to cut down on weght got any ideas

[ewankoff]

Our team is also questioning the possibility of these transmissions with the 2 cim adaptor to fail. So instead of hoping and praying were going with 4 individual trannies. Our design will provide redundancy and safe guards to prevent chronic failure.

[banebots]

This is a post by BaneBots

The 56mm gearbox and 2 motor adapter were tested independently by BaneBots and FIRST.

The only issue we are currently aware of is with mounting the CIM motor to the 56mm gearbox. We have seen that in some instances the pinion extends too far into the gearbox and causes the gearbox to bind. We have identified three things that may cause this:

1) There is grease between the stages that temporarily holds the stages too far apart. This can usually be resolved by turning the gearbox a few times by hand or removing the internal gears and reinserting them. DO NOT REMOVE THE GREASE FROM THE GEARS.

2) The pinion spacer is to long. If the pinion extends beyond the shaft the spacer is too long. The easiest fix this issue is to shorten the spacer so that the pinion is flush with the end of the shaft.

3) The motor mounting plate is too thin or shaft is too long. We have recently seen small variances in the thickness of the mounting plate and the length of the CIM motor shaft. If the pinion is flush with the end of the motor shaft and there is still a problem, this is likely the problem. There are two ways to address this problem. You can either shorten the CIM shaft and spacer or you can add a thin spacer between the gearbox and the motor mounting plate.

With proper correction, the mounting problem does not affect the reliability of the gearbox. We do not know of any reliability issues with either the gearbox or the two motor adapter.

Please keep the following two points in mind:
- Either support the gearbox shaft or keep the load as close to the face of the gearbox as possible.
- Do not depend on the gearboxes to support the weight of the motors - support the CIM motors.

If you are having a problem with any of our products, please contact us for assistance - www.banebots.com/contact.

BaneBots

[Ken Patton]

Thanks for the detailed info on the fixes - its good to hear the scoop from the source.

Hopefully this isn't too off-topic..... do you have any efficiency data for the gearbox with the CIMs? Or, short of that, perhaps a measured free-speed value based on testing of a gearbox?

Thanks,
Ken

[Jeremiah H]

We just tested a prototype using the Banebot trannies, Kit sprockets, and kit AndyMark wheels. One CIM per gearbox.
<These figures are the best I have. These numbers were exchanged quite a lot tonight and they may very well be off a little>
My figures were as follows:
CIM-5370 rpm->tranny (12:1) ->sprockets (1.625:1)->AndyMark wheel
Gives you ~ 7.3 fps
When we timed it (free wheeling up off the ground) we came up with~6.75, which gives you about 92% efficiency, and from that we figured that the gearbox shaft was turning such that a directly mounted wheel would give you ~ 10.8 fps. That doesn't take into account loss in the chain and sprockets.
This was timed off of our slower motor, so others' figures may not line up. If anyone finds a big discrepancy, please let me know.
Hope this helps! Good luck!

[free_rider_151]

It's a 2.5mm wrench. If you use the 3/32" wrench, when you tighten it, it will strip out.
~Olav
team 2039

[Bochek]

Team 2200 had the bot driving around today and encountered a problem with the BB gearbox,

the screws that hold the case together. (4 on each end of the case)

One of them was not lined up properly when drilled. So when the bolt was installed the case was flexing enough to cause the gears to bind.

The simple temporary fix was to remove the screw.

- Bochek

[Alex698]

Originally Posted by Nick 568

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!

We are having the same problem. How much did you grind down your bushing anyways? Thank you!

[Richard Wallace]

Originally Posted by Alex698

We are having the same problem. How much did you grind down your bushing anyways? Thank you!

Looking at #38 above, I'd say you should grind the spacer until the pinion gear is flush with the end of the CIM shaft. If you still have interference then the shaft is too long -- shorten it or shim between CIM and gearbox.

[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.