Thread: 4146 Swerve CAD
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Unread 27-12-2013, 20:32
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Re: 4146 Swerve CAD

Quote:
Originally Posted by glennword View Post
1. I just redesigned with the WCP/VexPro Miter gears (see attachment) which cut a quarter inch out of the width and length of the footprint of the bottom module. I initially hesitated to do this because it required me to make custom shafts, but it worked out in the end.
Custom machined shafts aren't necessary if you are using gears with a hex bore. Take a look at some of the products vexpro offers, in particular, these shafts and the hex-bore bearings listed at the top of this page.

I would echo the point that the bearing supporting the wheel module wont cut it. If you are familiar with free body diagrams, draw one (for the wheel module) in the state where the robot is pushing against a wall to see why. Most teams with successful coaxial swerve drives have two bearings to support the wheel module to handle the load.

Another point that hasn't been mentioned yet: For the CIM powering the drive wheel, you have two chain stages, both appear to be geared 1:1. If you use the chain stages of the transmission to provide more reduction, you will have less stress on other components. A big sprocket on the wheel and a small sprocket driving it will make the bevel gears see less stress, and decrease the likelihood of those parts failing. If you put a reduction in both of your chain stages, you may even be able to remove a gear stage from the CIM gearbox (in most cases, the fewer stages a gearbox has, the more efficient it is).
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