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Unread 09-12-2014, 16:02
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Travis Covington Travis Covington is offline
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Re: pic: 3 CIM WCD Crazy Geabox

Quote:
Originally Posted by Chris is me View Post
What does dog shifting have to do with pinion loading at all? Almost all gearboxes have cantilevered motor pinions, including this one. The only time I've seen a fully supported first stage pinion is when a team pressed 3/8 hex sleeves onto their CIMs.

While the distance from the motor and thus bushings matters, it's still going to be a concern here. It might work, but be careful.

I do like the low profile design a lot, but cleanly integrating three motors into a gearbox without excessive extra weight is indeed quite the packaging challenge - you'll always compromise *something* in the design. So you'll probably always get some nitpick on CD
I think he was saying that the bending moment induced by the torsion on the pinion gear is less when the gear is closer to the mounting plate. This would decrease the bending moment and the likelihood of bending the CIM shaft. I recall seeing one bent shaft on our 2013 robot (caused by some significant shock loads in the PTO/hanging mechanism). We used the same mounting scheme in 2014 and saw no bent shafts.

The dog shifter design usually spaces out the pinion by one gears face width. The design he has shown can place the pinion almost directly against the mounting plate.
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2008-2017 - Engineering Mentor of Team 254
2001-2008 - Engineering Mentor of Team 968
1998-2001 - Mechanical Director/Driver/Member of Team 115
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