Planetary Gear Question
Planetary Gear Question
(OP)
Sorry if this seams really simple, but it is my first time working on a project involving planetary gearing. I have a sun gear with a diametrical pitch of 20 teeth/in and 16 total teeth, planetary gears with the same pitch and 12 teeth each, and the annulus with 40 teeth and the same pitch.
As you can see in the attached image, I cannot get the gears to line up so that they all mesh with the annulus. Is there something that I am missing? I plan on having the sun and planetary gears stationary so that the outer housing rotates in the opposite direction relative to the center shaft.
Sorry if this is something really simple. It may just be something that is going right over my head.
http://tinypic.com/r/14abmg5/5
As you can see in the attached image, I cannot get the gears to line up so that they all mesh with the annulus. Is there something that I am missing? I plan on having the sun and planetary gears stationary so that the outer housing rotates in the opposite direction relative to the center shaft.
Sorry if this is something really simple. It may just be something that is going right over my head.
http://tinypic.com/r/14abmg5/5





RE: Planetary Gear Question
John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:
To an Engineer, the glass is twice as big as it needs to be.
RE: Planetary Gear Question
RE: Planetary Gear Question
Timelord
RE: Planetary Gear Question
The annular gear seems different. That will affect the PCD and therefore the number of teeth, which appears to be the problem.
RE: Planetary Gear Question
the planetaries look simple, but there are some restrictions when designing them.
One of those restrictions is how many EQUALLY spaced planets (sometimes called pinions) can be allocated in the assembly.
For simple planetary (your case) you can calculate how many pinions can be put there:
(No_of_teeth_sun + No_of_teeth_annulus) / Number_of_pinions has to be integer.
In your case there can only be be 4 equally spaced pinions. (16 + 40) / 4 = 9
If you select an assembly with 16 teeth sun, 44 teeth annulus, 14 teeth pinion
you can locate 3, or 4 or 6 equally spaced pinions. Try your math...
gearguru
RE: Planetary Gear Question
(that's another restriction - enough space for the pinions).
gearguru
RE: Planetary Gear Question
Good luck to you.
Terry
RE: Planetary Gear Question
Happy New Year to all
gearguru
RE: Planetary Gear Question
RE: Planetary Gear Question
the formula I mentioned is mathematically derived, it has to work. The no's of teeth on sun and annulus each do not have to be divisible by no. of planets. Just their sum has to be.
RE: Planetary Gear Question
RE: Planetary Gear Question
PF 2014