Recomended Cots gear boxes

[staplemonx]

We are trying to select a gear box for the robot. We used the JVN design calc with 4 CIMs (1 per gear box) with 8” wheels. We want to be able to push folks around so a gear ratio between 14:1 and 16:1 looks good.

We are looking at the tough box with the optional 12 tooth gear to get 14.88:1. http://www.andymark.com/ProductDetai...Code=am%2D0145

We are also looking at a banebot P80 with a 16:1 ratio.
http://www.robotshop.com/banebots-p8...earbox-16.html

Are these any good?

Are there any other gear boxes we should be looking at?

Thanks for the help.

[Richard Wallace]

Those are both good gearboxes.

You should consider that side loads due to chain tension, and to the shock of sudden reversals, will be transmitted from your sprocket to internals of the gearbox. The arrangement of bearings inside the Toughbox make it more robust against side loads than the P80. If you go with the P80, you should provide an external bearing block to support the end of its shaft; i.e, your sprocket goes between the gearbox and the external bearing block.

[PAR_WIG1350]

The Tough box is nice. It used to be included in the kit, but this year they switched to the less expensive CIMple box. However, it is heavy and you probably don't want to waste the weight on four of them (not that it hasn't been done).

I have no experience with the P80, but I do know that cantilevered outputs lead to bad stuff with them.

If you don't really need 4 separate gearboxes, I would recommend 2 tough boxes with 2 CIMs each. Otherwise, the P80s would probably be lighter. You can also get the P80 directly from banebots, http://banebots.com/pc/P80K-S4/P80K-44-0005 , The price winds up being the same if you get the same options offered at in the one sold through robot shop, but the shipping might be less. Also, If you do switch to 2 gear boxes, the P80 has a 2 CIM option as well.

[StevenB]

Sure, both of those are good choices. There were a couple major issues with the BaneBots gearboxes four years ago, but BaneBots has worked hard to resolve them.

Don't forget that you can use various sprocket ratios to achieve the gearing you want. For example, the total motor-to-floor ratio for the kitbot last year was 1 motor revolution = 1.34 in (12.75:1 gearbox, 22:15 sprocket ratio, 8" wheel), while this year it's 1 rev = 2.48 in (4.67:1 gearbox, 26:12 sprocket ratio, 8" wheel).

Given that we're now into week three, what you pick doesn't matter as much as how quickly you pick it. As a rookie team, I suggest you get something moving as soon as possible, if you haven't already.

[Lil' Lavery]

Based on the pictures you've provided of your design in other thread, I think you could possibly save yourself a fair bit of weight and cost by using only two gearboxes, each with 2 CIMs installed on them. You can then transfer the power to 2 wheels from each gearbox via chain. In fact, you can even use the CIMple boxes provided in the KoP to do this and, with the right sprockets, have the ratios you want.

If you use a 12-tooth, double sprocket (provided in KoP) on the output shaft of the CIMple box and attach a 36-tooth sprocket to each wheel, you'll get a total ratio of 14.01:1.

[548swimmer]

We used p80 duals last year and had no problems, and I would highly recommend them if you want to use 2 CIMs a side!

[samir13k]

Toughboxs have never failed on us, and weve used them for all 3 of my years so far. Grease them properly and they are great! If you want to use 4 gearboxes, then I say go for the Toughbox nanos, we used 3 of them for last years Kiwi drive system and they were also very good. They are like the toughboxes except only allow one cim, and have a one piece body.

[Eigenvector]

We used 4 Toughboxes last year with meccanums and nobody could push us around. They're good boxes, just be sure to grease the living daylights out of them.