Re: AndyMark CIMple Box Stripped Out
 

Sorry it took me a while to get back to you. It is possible the metal shavings got wedged between the gears, or the CIM gears which were stripped didn't mesh with the output gear. Also, when I said it locked up, I meant it provided heavy resistance and wouldn't turn over without seizing.

Greased with a high pressure lithium grease, as I have come to find out.

Re: AndyMark CIMple Box Stripped Out
 

Sorry it took me a while to get back to you. It is possible the metal shavings got wedged between the gears, or the CIM gears which were stripped didn't mesh with the output gear. Also, when I said it locked up, I meant it provided heavy resistance and wouldn't turn over without seizing.

Greased with a high pressure lithium grease, as I have come to find out.

Re: AndyMark CIMple Box Stripped Out
 

Photos would be great!

Re: AndyMark CIMple Box Stripped Out
 

The little tubes of grease that come with the CIMple boxes work great. We have a stash of them since we usually build transmissions and don't open the cimple boxes, but if you have some, those are great. We actually had the same issue this year at SBPLI, but we greased it a lot and it spun like a pro.

Re: AndyMark CIMple Box Stripped Out
 

We had the same problem. One must not have been lubed up as much as the others. We had it lock up and we came to find out that both sets of gears had about 90% of the teeth gone and their shavings mixed in with some grease at the bottom of the box. :ahh:

Re: AndyMark CIMple Box Stripped Out
 

We've found that you can't put too much grease in a CIMple box... literally! If there's too much in there, it'll work its way out in the first few minutes of running it - just turn everything up, wipe off what comes out, and you're good to go.

Re: AndyMark CIMple Box Stripped Out
 

Actually I posted an image of it before, heres the link:
http://postimage.org/image/l4hxqnftx/
Thanks for your interest

We're just lucky it didnt happen in competition :P

Re: AndyMark CIMple Box Stripped Out
 

Re: AndyMark CIMple Box Stripped Out
 

I dont have the specifics at hand, but I'll try my best.

Our robot was 119.9lbs w/o bumpers or battery.
I cant remember exactly what it was, but it would top out around 10fps.
1" aluminum box tubing 1/8th" thick.
With the bumpers, I believe it weighed around 130lbs.
We used the 6" kit wheels.

Re: AndyMark CIMple Box Stripped Out
 

Nothing seems out of the ordinary here. Weight/Gearing aren't out of wack (good speed for a heavy bot). A frame with that tubing can be crazy stiff if welded properly.

How crazy were your drivers during your competitions? Where there many instances of slamming the robot controls the opposite direction when the bot was at full speed?

Also, is there any possibility that the output shaft bearing popped out slightly (the one in the plastic, where the encoder goes)? Any sort of lateral stress on the CIMple box output shaft (over-tension on chain, massive shifts in control that are opposite the robot's momentum which 'snap' the chain into high tension) can lead to fatigue in the plastic over time that causes the bearing to unseat. This could cause the opposite bearing on the output shaft (the one in the metal) to seize, which could then cause the CIM gears to shred. It only takes 1-2 degrees of bearing misalignment for these bearings to become VERY inefficient; any more and they probably did seize.

Re: AndyMark CIMple Box Stripped Out
 

That does look like classic lack of lubrication. I know we have done it before ourselves.

Re: AndyMark CIMple Box Stripped Out
 

I measured the components of the CIMple gearbox including the 56T gear and output shaft. These parts are made to a loose fit tolerance. This in both the fit to the bearings and the fit to the 56T gear. Much looser than anything I have designed. It seems it would take quite a bit of misalignment for anything to bind.

Question - Is the 56T gear plated in your gearboxes?

Re: AndyMark CIMple Box Stripped Out
 

The image strongly implies not enough lube in the gearbox. You REALLY need to pack those things with grease and make sure they stay lubricated. Some teams use a clear spray-on lubricant that makes their gearbox look ungreased, but don't let that fool you - you need grease.

Re: AndyMark CIMple Box Stripped Out
 

I second the cyclical fatigue motion. Constant running would likely not shred the gears, but high stress cyclic loading would cause them to fatigue and eventually the teeth would fracture. Perhaps your drivers were cycling the controls back and forth when the gearbox seized up to get the robot moving and this resulted in the gears becoming stripped.

Just a thought.