Low Cost Planetary Gearbox Source...

[Kevin Sevcik]

About the pinions splitting. I think it's only a problem with the 5:1 pinion since it's so small. I split the first one pressing it on the shaft and didn't even notice till the tranny wouldn't work under load. My solution was to grab a new pinion and a .1247 reamer I had from the NBD mod we did last year. I ran it through with a hand drill and it pressed on fine after that. If you can actually chuck up the pinion in a lathe, I'd use a .1250 reamer, as that's what I ended up using on the FP last year when I could chuck the dewalt pinion.

Second comment. Has anyone else gotten one of the trannies with a crooked keyseat on the shaft? We've got one that takes a distinct jog to the side halfway down the keyseat.

[Andy A.]

Originally Posted by jonboy

Just got our Banebot transmissions and noticed that the air duct of the motor near the output shaft is blocked by the Banebot transmission. The FP plastic transmission has some holes to i assume let cooling air flow. The question is at what loads and duration at room temperature is this detrimental?

No data that I am aware of for exactly the effect this will have on the lifespan of the motor. Obviously, it will limit airflow, as a good deal of air does flow out of those front vents.

My suggestion may come to late, but if you can permit some standoff between the front of the motor can and the transmission, obviously airflow would be better. By using longer screws and some very small spacers it would be easy enough to move the motor back. This would require that the pinion be hung out at the end of an unmodified motor output shaft, and you'd probably want to support the end of the motor can to keep strain off of the very small and very weakly threaded attachment screws.

As for 885, we are just hopping that the motor will make it through. In the end, the way FP motors die pretty much negates air flowing through the front vents. If a FP motor dies, its because it stalls and there is no fan moving air period, and all the venting and heat sinks in the world won't help you. A slow, gradual death from heat build up is probably a lot more rare.

Give the motors time to cool between matches, and invest in some canned coolant.

-Andy A.

[Ken Streeter]

Originally Posted by Joe Johnson

While looking for some gearboxes for Robotic Amusements on ebay, I came accross the company BaneBots.

On behalf of Team 1519, I'd like to thank Joe, Richard, and all of the other contributors to this thread.

Our team ended up using three BaneBots gearboxes on our 2006 Robot. Without these gearboxes, we wouldn't have been able to come up with a workable design for our shooter turret. We used a 5:1 BaneBots gearbox on each of two FisherPrice motors in order to drive the shooter wheels. We also used a 25:1 BaneBots gearbox on the Mabuchi motor in order to drive our shooter's "feed roller." The use of these gearboxes enabled us to come up with a relatively small, lightweight turret which was able to track the light effectively.

Our experience with the BaneBots gearboxes was very positive. Our only major problem was that we needed to machine the pinion gears that came with the gearboxes in order to increase the ID sufficiently to get the gears onto the shafts of the Fisher Price and Mabuchi motors. It took us quite a few broken pinion gears to get it right before we got one to work! However, once we learned that piece of knowledge, the BaneBots gearboxes served us very well.

Thanks to all who contributed to this thread -- without this awesome information sharing, we would have had a much more difficult time building a competitive robot in 2006.