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Unread 17-12-2012, 14:02
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FRC #3310 (Black Hawk Robotics)
Team Role: Engineer
 
Join Date: Jan 2012
Rookie Year: 2012
Location: Texas
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Re: Incorporating the vex ball shifter into a WCD Drive

Quote:
Originally Posted by jb1403 View Post
What are the gears that you are using in the third stage, standard IFI ones? One of the possible issue's I noticed with IFI's third stage is that it sits below the bottom of the plastic housing from the previous two stages, causing an issue if you want to mount the housing to the bottom of a robot with very little clearance. I was thinking about changing up the gear ratio and was wondering if that is what you did.
In the CAD file he is using 34/50 for the 3rd stage. With 4" wheels this gives a theoretical 7.6/17.2 fps. If you drop down to the next IFI option of 24/60 that gives you 4.5/10.1 fps. It'd be nice to have something in between... like 30/54 which gives 6.2/14.1 fps except IFI does not have a 54T gear. It shouldn't be too hard to find a 54T gear from another source.

Having the gear hanging below the bottom of the frame shouldn't be an issue for traversing perpendicular bumps as the gear is concentric with the wheel. Parallel "ruts" might be an issue... regardless wouldn't be a bad idea to extend the mounting plates and create a guard. I really like the low CG of this design.