[IDEA] Planetary reduction

[FoxOne]

I'm working on an autocannon now, and needed some serious gearing up. This is to spin rollers at high RPM.

I wasn't satisfied with some combined z36:z12 pairs, due to awkward geometry. Funny I've ended up with those 42099's planetary hubs.

The ratio is app. 1:29 (yellow to red). Something like a worm gear with z24; but you can't reverse a worm gear, right?

Talking of torque, there's almost none at the output, sure. PF L motor can spin it with Buwizz Ludicrous mode, but hardly with any load. Will test it with two L motors.

 

Edited January 21, 2021 by FoxOne

[nerdsforprez]

With that much juice going into the yellow axle you might also want to use two wedge pulleys instead of one.....Looks like it should be possible.  Things might pop loose with just one..

[FoxOne]

Yep, thanks!

That's just a concept; bracing isn't final as well.

[Jurss]

  On 1/21/2021 at 3:52 PM, nerdsforprez said:

use two wedge pulleys instead of one

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I assume, that axle goes also inside that hub. I think there was axlehole.

[MinusAndy]

This is exactly how I geared up the gau8 in my latest moc. I used 2 pulleys on each one. 
in the end I decided on less speed as it was taking too much torque to spin it up as it was a shared output from a motor. That will fly with two hubs though!

[FoxOne]

  Quote

I assume, that axle goes also inside that hub. I think there was axlehole.

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Unfortunately, no -- hub has only 3 pins, no axle hole at all.

  On 1/21/2021 at 4:04 PM, MinusAndy said:

This is exactly how I geared up the gau8 in my latest moc. I used 2 pulleys on each one. 
in the end I decided on less speed as it was taking too much torque to spin it up as it was a shared output from a motor. That will fly with two hubs though!

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My fist intention was to ask for the link, but please don't ruin my design experience yet )).

I'm not sure I will keep two hubs, too -- but I'm kinda obsessed with linking them in a row at the moment, just want to test it with more power )).

Frankly speaking, gear up ratio of 1:9 has already brought me a decent performance with Nerf bullets.

Edited January 21, 2021 by FoxOne

[ralphie]

I've been using the inside teeth of 64712 for planetary. This is definitely smaller and tidier.

[FoxOne]

  On 1/21/2021 at 4:18 PM, ralphie said:

I've been using the inside teeth of 64712 for planetary. This is definitely smaller and tidier.

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One level reduction I suppose? What is the maximum ratio in that configuration?

As for my choice, I needed something relatively thin but possibly long.

[MinusAndy]

  On 1/21/2021 at 4:06 PM, FoxOne said:

Unfortunately, no -- hub has only 3 pins, no axle hole at all.

My fist intention was to ask for the link, but please don't ruin my design experience yet )).

I'm not sure I will keep two hubs, too -- but I'm kinda obsessed with linking them in a row at the moment, just want to test it with more power )).

Frankly speaking, gear up ratio of 1:9 has already brought me a descent performance with Nerf bullets.

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Mine is just visual and spins, it doesn’t fire and your system looks pretty similar. 

 

[ralphie]

  On 1/21/2021 at 4:27 PM, FoxOne said:

One level reduction I suppose? What is the maximum ratio in that configuration?

As for my choice, I needed something relatively thin but possibly long.

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I was unclear, I meant to say yours is better. One stage of 64712 gets about 4:1 ratio, but the diameter of the part is ~7 studs, plus it is quite hard to mount. The length of one stage is also ~7 studs. I’m mainly using it because it looks cool when operating.

[FoxOne]

Got it! It's hard to beat specifically designed part, but yours definitely has that steampunk'ish looks!

I think there's a room for improvement in my mounting rails as well, it's possible to cut 2 studs width-wise.