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Unread 30-12-2015, 12:50
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Re: pic: Inverted CIM Gearbox V3

Quote:
Originally Posted by cbale2000 View Post
Have teams actually gotten away with cantilevering gearbox gears like this on competition machines? Maybe it's just me, but it seems like a REALLY bad idea, and I've been seeing more and more of it lately.
What about it seems like a bad idea?
EDIT: I just noticed theres only one bearing. This is a bad idea. If there was a second bearing, it would likely be okay for the following reasons.

Cantilevering the gear has no effect on torsional loads, and the gear/shaft has no significant axial loading, so we only need to worry about radial loading on shaft and bearings.

Three CIMs have a combined stall torque of around 1000 in-oz, and pinions have a pitch radius of around .3 inches, so the tangential force at the pitch circle is around 3000 oz or 190 lbs force. FRC gears have a pressure angle of 14.5 degrees, so the radial load is 190 x tan 14.5, which is 50 lbs.

50 lbs is less than a cantilevered wheel will experience on a WCD and these shafts do not commonly bend.

Last edited by Jared : 30-12-2015 at 12:53.
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