pic: Dual Fisher Price gearbox

This is a project I’ve been working on. It’s a dual fp gear box, it would be great to get some feed back for improvements so post away.

-roughly 12in by 6.75in
-using AM planetary gearbox
-2 stages
-total gear reduction 176.16:1
-24 pitch gears
-axles all hex except part of output where there is a sprocket
-made from 4 separate pieces of .100in thick aluminum because its what the laser can make good cuts on with this specific material

What pitch gears are you using?

If you are going to be making your own custom gearbox anyway, I would not use the AM planetaries and include the reduction in the gearbox (AM products are great but sometimes you can do it yourself and save weight/money).

You may be able to get the gearbox more compact depending on the size (Pitch diameter) gears you use and how you arrange them.


:slight_smile: We had a similar transmission design to run ball pickup rollers a few years back, and enlarged the F/P mounting holes so we could get an allen wrench in to remove the F/P mounting bolts that hold the motors to the transmission plate. Makes it easy to remove the motors if they need replacement.:slight_smile:

I would recommend the same for the A/M planetary transmissions mounting bolts.

:slight_smile: Additionally, make sure you have ventialation channels machined in the mating surface between the F/P motors and the input plate side of the A/M planetary transmissions. This is the only cooling the F/P motors get.:slight_smile:

<deleted> posted in wrong thread. oops

What is the output speed?

With a 176.16:1 reduction it would be about 89 RPM.


IMO, I think it’s too big, PM or IM me if you want some tips on reducing the size.

No offense, but I can’t really see there being room for it on a robot right now.

just my two cents, vivek

Agreed, IM Vivek, he has some good ideas up his sleeve :yikes:.

With your material costs there, I’d highly recommend looking at the new GEM500 planetaries from Andymark. They’d probably end up cheaper with 4 stages, which would give you a 189:1 ratio (I think).

Out of curiosity, what made you go with that shape?

The size and shape of the gearbox are specific to a project were working on and fits very nicely vertically in the space its required. The reason for going big was that we have many of the large gears kicking around plus i wanted to keep it to minimal stages. So really the gearbox isn’t costing much because its being laser cut along with a much bigger project which is the main focus.

Very cool. It’s good when teams use what they have. Also props that you successfully designed inside space constraints; that’s not always easy to do.

Ah, if you have contraints, I take back my comments. Good that you’re using things you have laying around. You don’t always need the sleekest, fanciest solution so long as it works well.