pic: Coaxial Swerve drive, lightened.

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[Joe_Widen]

That looks super cool. Instead of all that machining to make it lighter, you could try just using a thinner plate, such as 1/8'' or 3/16" (it looks like you have 1/4''). You can never have to many speed holes though.

[Tytus Gerrish]

allot of sharp edges i see. this thing is awfully tall. you know how much side load those bushings are taking and how much shear that creates between those plates up there? i know modules that i make out of legos that are that tall don't last long. it would be nice if it were supported closer to the Axel.

[Madison]

I've been curious as to why you've opted to mill pockets into the plates rather than entirely cut out large sections. Any insight?

The reasons for the lightening style is structure. As a whole, the entire module is only 8 inches tall, from the top of the power transmission shaft to the bottom of the tread.

The plates used are 1/4", and it can't be any thinner, as it's held together with bolts. As for sideload issues, Inventor 11's stress analysis tells me that it can take about 900 pounds of sideload as a whole, which just might be enough for a FIRST bot.

[Joe_Widen]

You could try using Al tubing and be crafty with the cnc mill. It would have zero bolts (...gasp....). Thats how im designing mine atleast. No fancy stuff, no coaxial, just plain old spur gears and motor mounted on each module. Fancy gears are not my friend, especially after using worm gears (a thousand and one to many headaches there), although, I think helical gears are crazy cool. Good Luck to ya.

[Nuttyman54]

Originally Posted by Joe_Widen

You could try using Al tubing and be crafty with the cnc mill. It would have zero bolts (...gasp....).

Maintinence would be a pain though, even more so w/ the extra stuff due to the coaxial design

The gear sytem for said module is a set of bevel gears (under martin sprocket as miter gears.) They give me a 1:1 ratio, which matches all of the ratios in the module. This is to make calculations for the gearboxes (maybe 2 speed?) which are elsewhere on the robot.

[Stephen Kowski]

Originally Posted by 114ManualLabor

The plates used are 1/4", and it can't be any thinner, as it's held together with bolts. As for sideload issues, Inventor 11's stress analysis tells me that it can take about 900 pounds of sideload as a whole, which just might be enough for a FIRST bot.

I would recommend you re-evaluate you 1/4" plate idea....1/8" bent sheet metal is more than capable.....

[DB_UPS]

Originally Posted by Stephen Kowski

I would recommend you re-evaluate you 1/4" plate idea....1/8" bent sheet metal is more than capable.....

The bent sheet metal looks easy to make and harder to screw up. Joe, you should look in to make a version this way too. So if swerve drive is a optional next year we have two ways to make it. But i do like the milling way too.

[Cory]

Originally Posted by DB_UPS

The bent sheet metal looks easy to make and harder to screw up. Joe, you should look in to make a version this way too. So if swerve drive is a optional next year we have two ways to make it. But i do like the milling way too.

Sheetmetal is only easier if you have the resources to precisely punch and bend it. Otherwise it's a disaster waiting to happen.

[Stephen Kowski]

Originally Posted by Cory

the resources to precisely punch

You don't have to use a punch....you could get it done by a waterjet or laser just as easy....

[Greg Needel]

Originally Posted by Stephen Kowski

You don't have to use a punch....you could get it done by a waterjet or laser just as easy....

something tells me that teams are more likely to have a punch then a waterjet...

[DB_UPS]

Originally Posted by Cory

Sheetmetal is only easier if you have the resources to precisely punch and bend it. Otherwise it's a disaster waiting to happen.

Good point. But 1/8 sheet metal bends really nice in a vise. You can also mill holes in it, thats if you now to do it right. So you do need a punch.

[Cory]

Originally Posted by DB_UPS

Good point. But 1/8 sheet metal bends really nice in a vise. You can also mill holes in it, thats if you now to do it right. So you do need a punch.

There's absolutely no way you can fabricate a swerve module out of sheetmetal by bending it in a vise--it needs to be very precise, far more than you can ever be by using such a method.