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Trying2Learn

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- What is the relation between torque to teeth in an epicyclic gearing system?

Hello,

I am confused about something. I will take the time to work it out, but right now, I am using it to remember. And I am now confused.

Go here:

https://www.smlease.com/entries/mechanism/gear-train-gear-ratio-torque-and-speed-calculation/

Scroll down to the section on:

In a loss-less system, I get that that ratio of output to input torque is inverse to the output to input number of gear teeth:

To/Ti = Ni/No

Now go hear for a planetary gear system:

https://en.wikipedia.org/wiki/Epicyclic_gearing

Scroll down about one third to:

(Granted, there are three gears here and in an planetary style, not simple).

But why (say, for the first one), is this ratio reversed.

Tr/Ts = Nr/Ns

Am I missing something, or is there an error in one of these`? I get the simple gear system (and I am confident of working it out), but for the planetary one, is there an inverse relation because the teeth are INSIDE on the ring gear? Can someone point me to where (assuming the wiki page is correct) it is worked out?

I am confused about something. I will take the time to work it out, but right now, I am using it to remember. And I am now confused.

Go here:

https://www.smlease.com/entries/mechanism/gear-train-gear-ratio-torque-and-speed-calculation/

Scroll down to the section on:

**Gear Ratio and Torque**In a loss-less system, I get that that ratio of output to input torque is inverse to the output to input number of gear teeth:

To/Ti = Ni/No

Now go hear for a planetary gear system:

https://en.wikipedia.org/wiki/Epicyclic_gearing

Scroll down about one third to:

**Torque Ratios of Standard Epicyclic Gearing**(Granted, there are three gears here and in an planetary style, not simple).

But why (say, for the first one), is this ratio reversed.

Tr/Ts = Nr/Ns

Am I missing something, or is there an error in one of these`? I get the simple gear system (and I am confident of working it out), but for the planetary one, is there an inverse relation because the teeth are INSIDE on the ring gear? Can someone point me to where (assuming the wiki page is correct) it is worked out?