Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Factorzing Condition in Epicyclics

Factorzing Condition in Epicyclics

Factorzing Condition in Epicyclics

Dear all,

is somebody able to explain the factorizing condition?

I think it is mentioned in ANSI/AGMA 6123 and has something to do with the interactions of sun-planet and planet-annulus mesh.

Thanks in advance

RE: Factorzing Condition in Epicyclics

The sun-planet mesh is factorising if the number of teeth on the sun is divisible by the number of planets.
The planet-annulus mesh is factorising if the number of teeth on the annulus is divisible by the number of planets.

In a factorising combination, the fluctuations in the gear mesh forces are all in phase giving high torsional force fluctuation but low lateral force fluctuation.


Dr Michael F Platten

RE: Factorzing Condition in Epicyclics


The AGMA documentation and MikeyP's summary pretty much describe the basic situation.  However, while the basic differences that exist between factorizing and non-factorizing epicyclics may appear to be fairly straightforward in theory, in practice the situation can often be much more complex.

Depending upon the number of planets, load sharing among the meshes, the accuracy of the gears and their mounting structures, the pitch line velocity of the gear meshes, the relative meshing/passing/structural frequencies of the gears/bearings/structures, etc., either a factorizing or non-factorizing configuration can be the better choice.

Unless you have substantial engineering resources at your disposal to conduct a detailed analytical trade study to determine which approach is best for your application (factorizing/non-factorizing), then the safest approach would be to select gear tooth counts/geometry combinations for your epicyclic that give good load sharing, ease of manufacture, and have compatible meshing frequencies.

Good luck.

RE: Factorzing Condition in Epicyclics

Hi tbuelna, Can you explain what you mean by "having compatible meshing frequencies"?



Dr Michael F Platten

RE: Factorzing Condition in Epicyclics

Just to refine my statement about force fluctuations... This only applies if the planets are evenly spaced.



Dr Michael F Platten

RE: Factorzing Condition in Epicyclics


Sorry if I was confusing.  And I hope you'll correct me if I'm wrong.

I meant "compatible" as in not tending to couple with other modes occurring in the drivetrain.  For example, if your epicyclic was the output stage for a propellor speed reduction gearbox, you probably would not want to have a fundamental mesh frequency that was a multiple of the propellor blade passing frequency.

I believe there is a table in AGMA 6123-B06 that gives fundamental meshing frequencies for various epicyclic configurations & tooth counts.


RE: Factorzing Condition in Epicyclics

Thanks a lot!


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper - Strategies to Secure Connected Cars with Firewalls
White-hat hackers have demonstrated gaining remote access to dashboard functions and transmissions of connected vehicles. That makes a firewall a vital component of a multilayered approach to vehicle security as well as overall vehicle safety and reliability. Learn strategies to secure with firewalls. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - What is Generative Design and Why Do You Need It?
Engineers are being asked to produce more sophisticated designs under a perfect storm of complexity, cost, and change management pressures. Generative design empowers automotive design teams to navigate this storm by employing automation, data re-use and synchronization, and framing design in the context of a full vehicle platform. Download Now
eBook - Simulation-Driven Design with SOLIDWORKS
Simulation-driven design can reduce the time and cost of product development. In this engineering.com eBook, we’ll explore how SOLIDWORKS users can access simulation-driven design through the SOLIDWORKS Simulation suite of analysis tools. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close