# Planetary spur gear problem!

1. Nov 27, 2011

### andycampbell1

1. The problem statement, all variables and given/known data
Hi

I am doing this gear problem, I have attached the question and how I've started this off I am having problems working it all out as the question said I should try and have the casing rotating at a speed of 15-25 rpm.

I have, these gear sizes which were obtained from a manufacturers catalogue.

TB = 36
TC = 24
TD = 40
TE = 80
NX = 100 rpm
NY = 350 rpm

3. The attempt at a solution

To work out the number of teeth on casing F, from the geometry of the figure
dF/2 = dE/2+dB
so dF= dE + 2dB
dF= 80+ 2(40) = 160 teeth.

Using my my table of motion which I have attached for the speed of gear F, there is a mistake on it as the 2 TC's cancel out to end up y-x*(TB/TF) I have used the input speed for x and the output speed for y so my equation works out as 350-100 * (36/160) = 327.5 rpm this is obviously very wrong. Where have I went wrong? Have I started at the wrong point?

File size:
42.1 KB
Views:
60
File size:
30.9 KB
Views:
62