Quote:
Originally Posted by zsm150
Do you check that your cims are in the right position for the size pinion you are using? We had a similar problem in week 2 turns out one of our students put the cims in the position for a 12T pinion but we are using 11T.
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The 12T and 11T pinions use the same "inboard" mounting holes on the CIMs.
We had the locking issue at our event on practice day, and eventually it came to the sheered off 50T gear. Looking at the gearbox it was obvious the issue was that the CIMs were mounted on this outboard hole. We thought at the time this was due to incorrect assembly, proceeded to replace it with a steel 50T gear, putting the CIM's in the inboard hole.
After inspecting the other gearbox, it appeared atleast one of the CIM's were in the outboard hole. Sure enough the next match (thankfully our last one of the day) it started locking, and the gear had sheered right off. This gearbox we know for a fact was infact assembled correctly with the CIM's mounted to the "inboard" hole. (We know this because this process was recorded on video for a reveal video, and it's clear that the gearbox was infact assembled using the inboard hole.
This leads us to suspect that perhaps the CIM's are able to shift from inboard to outboard throughout use without the bolt coming out?
Both gears have been replaced with steel gears, and red loctite was used on the inboard/outboard CIM mounting bolt.
I've attached a picture of one of the gears - at least what is left of it.
http://i.imgur.com/mVv31n4.jpg?1
Personally, I'd rather see a separate mounting hole on the gearbox plates rather than two holes side by side. This issue cost us an RP, and a match. We're open to talking to WCP's Engineers to see what can be done. We haven't emailed them yet because our robot is bagged, and understand there is a huge backlog on emails.