Connecting 4in omni wheels to a cimbox

[Topperbotics]

We have a 4in omni wheel (am-0385) that we are trying to attach to a CIMple box in the center of our drive train. Is there a specific part we need for a spacer? How do we actually put the wheel onto the shaft? Thanks!

[Lil' Lavery]

Assuming you're attempting to direct drive your wheel, the easiest/simplest way would be to remove the bearing from the wheel and use a 1/2" keyed hub, along with shaft collars to retain the wheel. However, this may change depending on exactly how you want to set up your drivetrain. Perhaps you could provide some more specifics on how you're setting up your drive?

[Topperbotics]

We are setting up a slide drive train with omni wheels. The one we are working on attaching is the middle wheel.

[Topperbotics]

We are also concerned that the wheel will not extend beneath the gearbox. Do you have any tips on this?

[Lil' Lavery]

Originally Posted by Topperbotics

We are also concerned that the wheel will not extend beneath the gearbox. Do you have any tips on this?

To address you concern, a 4" diameter wheel will just barely extend beyond the top and bottom of a CIMple box if mounted directly to the output shaft. In all likelyhood, any mounting hardware you use will end up extending beyond the edge of the wheel, and even the compliance of the carpet may cause issues with the razor thin margin for error.

My tip is simple, don't mount the wheel directly to the output shaft of the CIMple box. Use additional gears, chains, or belts from the output shaft of the CIMple box to power the wheel on another shaft. This serves two purposes:
A) You no longer have to worry about the dimensions of the gearbox and the wheel
B) You can add additional reduction

Point B is particularly important. Assuming you're using a CIM (or MiniCIM) as the drive motor, a 4.67:1 reduction is not enough for FRC drive applications (assuming you're anywhere near the weight limit). With such a small reduction, the load on the motor will be quite high. As a result, the motor will spin at a lower RPM and draw significant current. This will put a strain on your battery and quite possibly cause you to trip the 40A breaker for that motor if you run the motor for a prolonged period.

I'd suggest reading some of the terrific resources out there on designing a drive system for FRC applications.
http://www.chiefdelphi.com/media/papers/2429
http://www.chiefdelphi.com/media/papers/1378
http://www.chiefdelphi.com/media/papers/2597
http://www.chiefdelphi.com/media/papers/2755
http://www.chiefdelphi.com/media/papers/2274