Quote:
Originally Posted by happyWobot
If you mean the sound at the end of the video, yes, that sounds familiar.
Has it always made the noise since the case was constructed?
If not, is there any chance some students went on a bolt tightening exercise recently?
Did you tape over the small holes on the back side to prevent debris from getting in?
I experienced the noise with a brand new case. Took it apart and reconstructed it twice. Discovered that if I tightened the plastic cover too much the noise was louder. I had a second case that was also brand new purchased at the same time. It made not a sound. Both were constructed at the same time, in tandem, and were identical as best as I could observe. I let off on the case bolts just till the noise was barely noticeable, then installed it CIMs and all into the chassis.
It actually got quieter over time. I had several theories about what it was, first was that the tightening of the case was causing the plastic to deform in a way that made it come in contact with one of the gears. The second was that the weight of the CIMS were doing something similar to the plastic cover. The third thing was that if there was some sort of contact or vibration, that the plastic cover was magnifying the sound like a drum.
I know for certain it was not the gears. The gears were clean with freshly applied grease. With the cover off it did not make a peep when turned. The gearing is ridiculously simple, the shafts confirmed to be mounted into the bearings until firmly seated. With the cover on, once tightened all the way down, it would make that rattle. Like as if gear teeth were coming contact with some part of the cover.
If you find that the noise goes away by loosening the cover just a bit, tighten it back down until the noise starts again and then just back off a touch. We got through two qualifiers, a district Championship and worlds and never once had an issue with either one.
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As far as I know, it only started making that sound on Saturday. They both sounded like the first sound until then. We did tighten bolts last week, but they were the ones holding the plate to the chassis. The other gearbox sounded similar to the weird one yesterday morning, but not as 'bad'.
Also, what holes are you speaking of?
Quote:
Originally Posted by Jon K.
If you are still experiencing these sounds, I would definitely take the gearboxes off and double check the gears. It's highly unlikely that you have managed to sheer teeth off the steel gears in the TB Mini, but this is the year of the strange failures.
A couple of quick questions:
Did you run the gearboxes in for about 30 minutes prior to greasing them?
Have you done any maintenance on the gearboxes this season?
-Running outside might have introduced a foreign contaminant into the gearbox, and it might be worth cleaning the gearboxes out and greasing them again after checking the teeth.
Have you checked the tightness of the screws holding the CIM motors on?
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As for greasing, the gears already had some grease on them from previous years, so we didn't think much about regreasing them. We did take apart the gearbox in question at our regional because a key fell out (making one of the motors hot, indicating something was wrong). We took it apart, added a key, added a washer (to each CIM) to keep the keys in, then reassembled it and added it back onto the robot.