Planetary 2:1 Gear Design questions 1

[RedCoat999]

I have been tasked with designing a 10000 rpm to 5000 rpm planetary reducer. Output load is about 9 HP. It has to fit inside a 4 inch diameter. Are there any particular pressure angles, diametral pitches to use/avoid?
Will this need any lube for short <1 hour running times?
How is the efficiency determined?
Thank you.

 

[RedCoat999]

Just as a further note, I am confused about the calculations to use. Each book I have has different calculations, and some just list tables of gear data which is no use to me because the sizes are too large. I know how to design 30° external gears, but the internal gears and trying to fit inside a small package is bugging me. The size has gone down from 4 inch to 3.25" now!

 

[Matt51]

A 2:1 reduction ratio cannot be achieved with a rotating carrier (planetary) epicyclic. You can achieve a 2:1 ratio with a fixed carrier, ring gear output epicyclic (star). Typical pressusre angles are 20 or 25 degrees. If you post an email adress, I will send you a proposed schematic design.

 

[RedCoat999]

Thank you Matt. favelinks@hotmail.com