Swerve Drive Concept

[magnets]

Here is a swerve drive concept that I've been working on. Any suggestions/feedback is welcome. Not shown is a steering encoder and a schedule 80 PVC pipe that goes around the swerve module. The module has a disc connected to the side plates that has a delrin ring to provide another bearing for the module's rotation.

[EricH]

Question: Is this meant to also be the power unit for the entire drive? Or is one of those motors a Mini-CIM? (Or, is this for a 3-wheeled swerve?)

[magnets]

It can be a three wheel swerve, or it can be a four wheel swerve with a minicim.

[Gregor]

Originally Posted by magnets

it can be a four wheel swerve with a minicim.

8 motor drive, I love it.

What is the steering motor?

[CENTURION]

Design looks pretty good. I dig the 8 motor design.

The top orange plate on the module seems overly complicated, from a machining standpoint.

Instead of having those little flanges hanging down, why not just bolt downwards through the orange plate into the two side plates?

What are you using to rotate the module?

And how are you tensioning the chain? It's hard to see what's going on back there.

I sort of consider 1640 to be the gold standard of swerve (Well, tied with 1717 maybe ), and they've really taken the time to iterate, improve their design, and cut out unnecessary things. They also released everything you could want to know online. I'm not saying ditch your design and go with theirs, but they've already solved a lot of the problems for you, so you can learn from their mistakes so to speak

[DampRobot]

Originally Posted by CENTURION

What are you using to rotate the module?

If you look at the first photo, you can see a second chain run going up to a motor hidden behind the top plate and the two CIMs. From the little I can see, I'd hazard a guess that it's a 550 with a BaneBots planetary.

[magnets]

Originally Posted by CENTURION

The top orange plate on the module seems overly complicated, from a machining standpoint.

Instead of having those little flanges hanging down, why not just bolt downwards through the orange plate into the two side plates?

You're right, to make the orange plate would waste a lot of material, so I think the little tabs could be replaced with a steel bracket, and then I could put a could more bolts straight down through the orange plate and into the blue side plate, like you described.

To keep the chains tight, we plan on putting spacers underneath one side of the lower gearbox plate until the chain is tight. We've done this in the past, and we only had to adjust the shims twice during the season to keep up with the stretching chain. The chain for the swerve module has a calculated center to center distance, and its small enough that it doesn't need tensioning.

[Nate Laverdure]

Originally Posted by magnets

You're right, to make the orange plate would waste a lot of material, so I think the little tabs could be replaced with a steel bracket, and then I could put a could more bolts straight down through the orange plate and into the blue side plate, like you described.

You could use this type of joint.

[magnets]

I could, but then I would have to move the side plates in a little bit, or make the tabs thinner than the side plates. Also, I don't really know how those right angles could be machined easily.

[nathan_hui]

You won't be able to machine the female slots the way they are in the picture (at least not with conventional subtractive manufacturing). What you could do though is do a pair of slots oriented orthogonal to each other (one provides constraint in the Z axis, the other provides constraint in the Y axis, and the screw/surface provide constraint in the X axis). As for the male bosses, you'd clamp the piece in the vice so that the bosses would be sticking straight up, and mill across the top. Not very nice if you've got a long piece (or you'll want to use a horizontal mill). That tab design is generally reserved for plastics cut on a laser cutter.

[CENTURION]

Originally Posted by nathan_hui

You won't be able to machine the female slots the way they are in the picture (at least not with conventional subtractive manufacturing). What you could do though is do a pair of slots oriented orthogonal to each other (one provides constraint in the Z axis, the other provides constraint in the Y axis, and the screw/surface provide constraint in the X axis). As for the male bosses, you'd clamp the piece in the vice so that the bosses would be sticking straight up, and mill across the top. Not very nice if you've got a long piece (or you'll want to use a horizontal mill). That tab design is generally reserved for plastics cut on a laser cutter.

I assume you're replying to this post:

Originally Posted by Nate Laverdure

You could use this type of joint.

You're right, those sorts of joins are generally used in laser cut parts. However it can be done with normal machining, the design just needs to be modified a little. Your cutter will leave a radius in the corners of the female slots, so just add a matching radius to each corner of the male boss.

As long as there are still flats on each side of the boss and hole, there won't be a change in effectiveness. In fact, having the radii in the corners will increase the strength of both parts. (Sharp corners provide a convenient fracture point for the material)