Its not a planetary............ so what is it?

[DeathBlade]

Well its been a while! A few months back I found what I thought was going to be a cheap 33:1 planetary gearbox at harbor freight but now that I've found it(it was in my camping gear somehow) and taken it apart I don't know what kind of gear box it could be.

First you turn the input 33 times the output turns once, it looks like a planetary when you open it but its not.
You can see two sets of gear on the outer edge when you rotate the input shaft the top gear "walks" around in the housing and the bottom gear takes one step I think there cam in between the two gears. I'm not explaining it well but what kind of gear box is this?

http://www.harborfreight.com/torque-multiplier-lugnut-remover-93645.html

 

[12p3phPMDC]

I think it's called an eccentric cycloidal reduction

 

[DeathBlade]

Thanks! I have a place to start googling
From closer inspection I dont think it would be able to take the RPM I want to put through it
Now to find a real 30:1 planetary.........

 

[Miles]

Now to find a real 30:1 planetary.........

It will need to be a 3 or 4 stage planetary, to get that much reduction.........

http://www.matexgears.com/

 

[spinningmagnets]

I believe it is a planetary, the six pins in the pic with your thumbs suggest there are 6 planets inside the two sister-ed gears. I believe those two side-by side gears are hollow in the space where they face each other.

Of course, I'm not certain....

 

[jag]

Thanks! I have a place to start googling
From closer inspection I dont think it would be able to take the RPM I want to put through it
Now to find a real 30:1 planetary.........

A similar idea for high reduction gearing, but with better high rpm capabilities are harmonic drives. They are used in robotics, eg. the Mitsubishi heavy industries PA 10 robot arm.

http://en.wikipedia.org/wiki/Harmonic_drive

 

[rkosiorek]

eliptical teeth. the a pair of inner "gears" 180 degrees out of phase. 1 fewer lobes on the "gears" than on the "ring" even number of teeth on the ring. odd number on the gears. 34 lobes on the ring. yep all the classic signs of a 33:1 cycloidial reduction unit.

it is a CYCLODIAL.

rick

 

[spinningmagnets]

Thanks, rick!