pic: AndyMark has the Nano; we have the Shuffle!

[rob_c]

[cdm-description=photo]34521[/cdm-description]

[craigboez]

I was thinking about a Toughbox Shuffle as well, for the purpose of direct driving a 6" Mecanum wheel. Looks like you may be doing something similar? If so I'd be interested in what gear ratio you're expecting to use.

[mathman05]

I'm sure this will be the same gear ratio as the AM Toughboxes. It looks like they're using the same gears, they're just using a different housing.

[Chris is me]

Neat gearbox. What I like about the Nano is that it's narrow and very strong. Like, Battlebots strong. This gearbox seems to be a bit wider in exchange for a narrower box, though one of the gears protudes. It's probably optimized for its intended use, so i'm going to guess mecanum drive.

[Fe_Will]

Why not use a Banebots P80 gear box (http://banebots.com/c/P80K-nnnn-0005)? It would be smaller, more compact, and more efficient.

[Chris is me]

Why not use a Banebots P80 gear box (http://banebots.com/c/P80K-nnnn-0005)? It would be smaller, more compact, and more efficient.

First thing that comes to mind is a cantilevered wheel, but if you're doing that then the Nano would be perfectly adequate and strong.

[craigboez]

Why not use a Banebots P80 gear box (http://banebots.com/c/P80K-nnnn-0005)? It would be smaller, more compact, and more efficient.

We're just trying to avoid the $450 investment in Banebot transmissions. They'd definitely do the trick, but since we don't have any and we do have several Toughboxes we're looking for a more economical solution that uses parts we already have.

Also, aren't planetary gears less efficient than spur gears? I couldn't find anything too official, but this (http://www.societyofrobots.com/mechanics_gears.shtml#gearefficiency)
website seems to agree.

[craigboez]

I'm sure this will be the same gear ratio as the AM Toughboxes. It looks like they're using the same gears, they're just using a different housing.

I didn't (couldn't) count the teeth, but it could also easily be one of the optional gearing configurations that AndyMark offers. I was specifically looking into using their 8.45:1 setup. From what I've read that would be a good ratio for a relatively fast bot running on 6" mecanums.

[Fe_Will]

Also, aren't planetary gears less efficient than spur gears? I couldn't find anything too official, but this (http://www.societyofrobots.com/mechanics_gears.shtml#gearefficiency)
website seems to agree.

Advantages of planetary gears over parallel axis gears include high power density, large reduction in a small volume, multiple kinematic combinations, pure torsional reactions, and coaxial shafting. Disadvantages include high bearing loads, inaccessibility, and design complexity. The planetary gearbox arrangement is an engineering design that offers many advantages over traditional gearbox arrangements. One advantage is its unique combination of both compactness and outstanding power transmission efficiencies. A typical efficiency loss in a planetary gearbox arrangement is only 3% per stage. This type of efficiency ensures that a high proportion of the energy being input into the gearbox is multiplied and transmitted into torque, rather than being wasted on mechanical losses inside the gearbox.

Another advantage of the planetary gearbox arrangement is load distribution. Because the load being transmitted is shared between multiple planets, torque capability is greatly increased. The more planets in the system, the greater load ability and the higher the torque density.

The planetary gearbox arrangement also creates greater stability (it's a balanced system) and increased rotational stiffness.

FYI

[JesseK]

What I like about the Nano is that you can support the weight of the drive train through it since it's an enclosed box extrusion. This allows for very compact direct-drive designs which are particularly useful for omni and mecanum drive trains. This one looks perfect for an arm though.

[Mr. Ivey]

The Shuffle is an AndyMark ToughBox, but configured differently. This year we are in somewhat of a budget crunch, and Rob was looking for a way to save some money. After going through our shelves of parts and finding a bin full of random gears, and a bin of AM ToughBox cases, we realized we had about 6 ToughBoxes. Not being able to use the full size TB this year we were going for the Nano, but that was an expensive investment this year. So we took some 3/8 lexan, found all the bearings and bits to the original ToughBox systems, and a few hours later we had the Shuffle! Amazingly the prototype we build was all by hand, and it works unsettlingly well for a hand built gear box. Hopefully Rob and the rest of the team will be posting more soon.

Ivey