Fisher Price Gearbox?

[excel2474]

I saw a few threads on this, but none really answerd my question. First, is it allowed to modify these, and second, how do I do it? Could you give me a link to specific instructions? Thanks alot.

[kevin.li.rit]

I believe you are allowed to modify the gearbox since it is not considered integral. We can't really answer your question on how to modify it since you have not described what you wish to achieve.

Please elaborate.

[excel2474]

Sorry, I should have specified. I want to increase the output speed. I'm not quite sure how much though, so if there are several ways of doing it, then you can just show me what you know. Thanks.

[kevin.li.rit]

If it's not by much I would use a sprocket to step up the speed. I can't think of a good way to modify those gearboxes for that purpose. You can open up the gearbox if you want to take a look inside.

I would also try http://banebots.com/pc/P60K-nnnn/P60K-44-0004 or picking another one from andymark.

[EricH]

Yeah... you can modify the FP gearbox, as it isn't integral.

However, it might not be worth it. The FP goes 15000 RPM free speed (give or take a few hundred or so), and I'm trying to remember what that gearbox takes it down to. If it's close to the gearbox number, use a sprocket or two; otherwise, use a different gearbox.

[MCahoon]

I think the F-P gearbox is 124:1. Pretty slow. Works for arms (like 330 has done with it). As was pointed out, there are a couple of other options for using the F-P motor, and which mount more easily. The kidney bean shape of the F-P gearbox takes some creative mounting work, and you still have to make something to couple onto a shaft (usually).

[Teched3]

The Fisher Price motors will mount on planetary transmissions available from Banebots.com in various output speeds. We have also used the plastic gears mounted between plates to create a transmission, and have abandoned the plastic housings. To speed it up, we have eliminated one or two spur gear stages. They will hold up well if you don't put them into an application that will stall the motors. You will need a milling machine to bore the plates to mount the gear shafts the proper distances apart.

[JCharlton]

Our team did that in two places on the 2006 Championship bot. It's sitting here beside me, and all I know is they hacked off the output gear and the body around it, and jacked a shaft into what looks to be the next-to-output gear. I asked one of the 2006 team members about it (before my time) and he said it was a pain, but it's still working. Good to have some spares to practice with, but don't be afraid to open one up and take a look.

Mounting the gear box ordinarily can be quite simple. Run a shaft through the hole (supports the weight) and any bar with a screw or two through the plastic to take the torque.

Good luck!

[EricH]

Originally Posted by MCahoon

I think the F-P gearbox is 124:1. Pretty slow. Works for arms (like 330 has done with it). As was pointed out, there are a couple of other options for using the F-P motor, and which mount more easily. The kidney bean shape of the F-P gearbox takes some creative mounting work, and you still have to make something to couple onto a shaft (usually).

330 uses two further reductions for arms.

15000/124= 120 RPM output speed, roughly. What speed are you looking for (roughly)?

[excel2474]

about 600 rpm.

[kevin.li.rit]

I would probably go with a couple 25 pitch sprockets to increase the speed. My second option would be to get another gearbox.