AndyMark CIMple Box Stripped Out

[BobbyVanNess]

For anyone still interested, the cause of the drivetrain malfunction was two completely stripped 12 tooth CIM motor gears. According to our lead pit mentor, we oiled it routinely throughout competition, but we must have let it slip this summer. Proper lubrication is certainly important to avoid things like this happening, we're just lucky it happened at the end of a demo, not at an offseason competition.

[sanddrag]

Originally Posted by bobby5150

For anyone still interested, the cause of the drivetrain malfunction was two completely stripped 12 tooth CIM motor gears. According to our lead pit mentor, we oiled it routinely throughout competition, but we must have let it slip this summer. Proper lubrication is certainly important to avoid things like this happening, we're just lucky it happened at the end of a demo, not at an offseason competition.

Oiled or greased?

[BobbyVanNess]

Originally Posted by sanddrag

Oiled or greased?

I'm not entirely sure, I wasn't in charge of that.

[PhantomPhyxer]

Is oli the right lubricant? I would suggest a gear grease developed for high gear pressure.

[pmangels17]

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.

[Adrian Clark]

Originally Posted by bobby5150

For anyone still interested, the cause of the drivetrain malfunction was two completely stripped 12 tooth CIM motor gears. According to our lead pit mentor, we oiled it routinely throughout competition, but we must have let it slip this summer. Proper lubrication is certainly important to avoid things like this happening, we're just lucky it happened at the end of a demo, not at an offseason competition.

I think many of us would like an explanation as to how exactly a stripped gear made your gearbox lock up.

[BobbyVanNess]

Originally Posted by Adrian Clark

I think many of us would like an explanation as to how exactly a stripped gear made your gearbox lock up.

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.

Originally Posted by sanddrag

Oiled or greased?

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

[BobbyVanNess]

Originally Posted by Adrian Clark

I think many of us would like an explanation as to how exactly a stripped gear made your gearbox lock up.

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.

Originally Posted by sanddrag

Oiled or greased?

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

[Spirator]

Photos would be great!

[1502]

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.

[Jon Stratis]

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.

[BobbyVanNess]

Originally Posted by Spirator

Photos would be great!

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

Originally Posted by 1502

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.

We're just lucky it didnt happen in competition

[JesseK]

1. How much did your robot weigh?
2. What was the sprocket reduction from the gearbox to the wheels?
3. What type of material (box tubing/KOP/Sheet metal) is your frame made out of?
4. How much did your robot weigh, with bumpers but without battery?
5. What size diameter were the wheels?

[BobbyVanNess]

Originally Posted by JesseK

1. How much did your robot weigh?
2. What was the sprocket reduction from the gearbox to the wheels?
3. What type of material (box tubing/KOP/Sheet metal) is your frame made out of?
4. How much did your robot weigh, with bumpers but without battery?
5. What size diameter were the wheels?

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.

[JesseK]

Originally Posted by bobby5150

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.

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.