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Unread 27-12-2011, 16:20
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Garret Garret is offline
Standing on the Shoulders of Giants
AKA: Garret Smalley
FRC #0691 (Hart District Robotics)
Team Role: Mentor
 
Join Date: Dec 2009
Rookie Year: 2008
Location: Goleta, CA (UCSB)
Posts: 203
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Re: pic: I was bored... so I designed this.

Quote:
1) The keyway would not be compatible with the needle bearings.
2)The counter thrust for the thrust bearing at the wheel would be by the needle bearing housing or the frame member, which is not good. A preloaded pair of angular contact bearings would be better. There is no particular side thrust to keep the thrust bearing loaded.
I did not realize that, but now that I think about that it makes sense. I will change that, I was working on a version that used an angular contact bearing. I have not worked with them before so I wasn't sure how to approach them.

Quote:
3) The gear separating force from the tooth meshing + the torque from the robot weight will be bending the vertical plate. It may be better to continue the removable vertical plate down the the lower shaft, so that the wheel shaft is not cantilevered.
I had a version of this that has that plate extended down to the wheel shaft. On the newest version I have completely removed the cantilever (replaced the modules with our current modules)

Quote:
4) Why is the wheel contact patch offset from the pivot axis? My understanding is that you want to avoid the turning force from a wheel drag moment seen at the pivot. This moment could cause twisting, scuffing, excessive drive resistance and problems with rigging to drive straight.
That is a problem I have fixed that in the newest version.

Thanks for the comments, they have been very helpful.

Here is the newest version so far.
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