Chief Delphi - Banebots Doubt

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Re: Banebots Doubt

Quote:

Originally Posted by Al Skierkiewicz (Post 578665)

Jim,
I could have sworn there was a fan. I will try to check tonight, we are not using the Banebot motors. The Fisher Price motors are a similar design and have an internal fan.

There is no fan in the banebots motor. If the holes in the front
of the motor where the output shaft are open the spinning
armature does cause some air flow through the motor. Nothing like you
get from the little white fan from the FP motor, however.

If your FP motors are not used elsewhere, you can easily put these
on the banebots gear box. You can use the longer motor shaft to
allow a 1/8 inch thick spacer between the motor and the gearbox that
allows air flow into the cooling holes that air is drawn into. The FP
motors are much more robust, so you should use them on your banebots
gear boxes if they are not used elsewhere.

Eugene

Re: Banebots Doubt

Well, I guess the last week of build is showing. It's a good thing I don't have to inspect this weekend.

Re: Banebots Doubt

Quote:

Originally Posted by eugenebrooks (Post 578907)

You can use the longer motor shaft to
allow a 1/8 inch thick spacer between the motor and the gearbox that
allows air flow into the cooling holes that air is drawn into. The FP
motors are much more robust, so you should use them on your banebots
gear boxes if they are not used elsewhere.

Thanks for the tip! looks like a great idea. I brought an FP motor home, maybe I'll tinker on the lathe in the morning.

Re: Banebots Doubt

I did get a chance to look at the FP motor, removed the gear, and the shaft is knurled...which looks like a potential problem when using the BB 36mm 125:1 trans, which has a very small pinion gear, that might break when pressing over the knurled shaft. Also the spacer needs to be about .325" thick, as best I can tell.

Anyways....I have taken apart a KOP 64:1 gearbox, and discovered that it uses 3 gear planets for the first and second stages, and a 4 gear planet for the third stage. Not much interchangeability there. And then I took apart a 125:1 gearbox and discovered that it has 4 gear planets in all stages, but the sun gear (pinion) in the second two stages is pressed into the planet carrier of the previous stage, while the final stage has the typical DD joint to the output shaft. Not much interchangeability there, and it also seems to prevent mixing stages to get custom gear ratios, which I had hoped we could do.

Also the team ran the robot today some more, and the 125:1 gearbox was showing noticeable backlash.....like maybe the output carrier plate is getting bowtied.....

Maybe we'll go back to the Globe plan B.

Re: Banebots Doubt

Quote:

Originally Posted by squirrel (Post 580021)

We can testify to the fact that if you try to press the BaneBots pinion gear for a 5:1 stage directly onto the FP motor shaft, the pinion gear will crack. We broke about 4 last year before we finally learned how much we needed to turn down the FP motor shaft. Alas, I don't have the specs that the machinist finally determined (empirically) to have the pinion pressed safely onto the FP motor shaft.

Best Regards,

--ken

Re: Banebots Doubt

Huh, I guess my intuition was right that time :)

the non-knurled part of the FP shaft is the same diameter as the BB motor, 0.125", while the knurled part of the FP shaft is about .004" larger.

My guess is that if you turn the knurl down to .125-.126" it would be fine.