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Unread 10-09-2006, 20:17
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Madison Madison is offline
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Re: pic: Practice Mecanum Chassis

Quote:
Originally Posted by Mike Nawrot
Perhaps you can save some trouble by integrating the gearbox into the inner plate of the mecanum assy, and replace the sprocket with a gear, to eliminate the issue of tension all together. I don't know what capabilities your team has when it comes to milling out excess material in the gears, but if worst comes to worst, you can design a nice lightweight gear and outsource it to sdp-si. I'm not a fan of outsourcing in FIRST, but in the real world, outsourcing is useful, and if you don't have the machining capabilities, you have no other option. It's a very nicely designed module. Keep up the good work.
I considered this and decided against it because I'd like some ability to play with and vary the final drivetrain ratio. Changing sprockets and adjusting tension allows this to happen pretty quickly and painlessly.

The latest iteration follows; and please note that I'm dissatisfied with how ugly the gearboxes are.


I neglected to color the pivot in this shot, but it's the long 3/8" bolt sticking out from near the middle of the image. The blue represents chain -- #25 this time around rather than #35 helps to achieve some tighter clearances.

The ratio as shown is 12:40 in the gears and 18:72 through the sprockets for an overall ratio of 13.32:1. I'm pretty confident this will be on par with or lighter than the kit gearbox arrangement that provides a similar 12.75:1 output.
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