topic Re: Rotating a gear around a fixed Sun gear in Inventor Forum

Rotating a gear around a fixed Sun gear

FritchJ21 — Wed, 26 Mar 2025 18:38:01 GMT

Hello,

We are trying to simulate a system that requires us to have a spur gear spin and rotate around a stationary, fixed bull gear (the sun gear). This gear has a shaft with a Bevel gear on the other end, mating to a bevel gear keyed to a shaft. This shaft is the driven component. We have been able to use dynamic simulation to achieve the rotation of all gears with one another using a torque force on the shaft. However, we are having trouble getting the spur gear to climb around our stationary bull gear as it rotates. Could anyone give any pointers or tips to try and solve this problem? I have scoured the internet for hours and have come up empty handed (shocking).

Re: Rotating a gear around a fixed Sun gear

JDMather — Wed, 26 Mar 2025 23:36:07 GMT

@FritchJ21

Can you Attach your assembly here?

Re: Rotating a gear around a fixed Sun gear

johnsonshiue — Tue, 01 Apr 2025 01:27:02 GMT

Hi! Without seeing the actual files, I can only speculate. I suspect there is lack of a ground component or there are too many degrees of freedom. Please share the files to facilitate the discussion.

Many thanks!

Re: Rotating a gear around a fixed Sun gear

FritchJ21 — Tue, 01 Apr 2025 11:47:32 GMT

Let me know if this format is not acceptable for file transfer, thanks! The .iam is FP 227-202

Re: Rotating a gear around a fixed Sun gear

johnsonshiue — Wed, 02 Apr 2025 21:59:34 GMT

Hi! The attached file is incomplete. The Content Center parts are missing. Please use Pack&Go to collect all the reference files. Zip them up and attach it here.

Many thanks!

Re: Rotating a gear around a fixed Sun gear

FritchJ21 — Thu, 03 Apr 2025 12:25:50 GMT

Apologies for the confusion, I am newer to Inventor! Thanks for the tip, I have attached the new zipped folder here. Let me know if I have left anything else out, Thanks!

Re: Rotating a gear around a fixed Sun gear

johnsonshiue — Thu, 03 Apr 2025 20:08:29 GMT

Hi! Many thanks for sharing the files! I took a quick look at the assembly. I think there are two major issues. The Angular constraint to the planet gear does not make sense. It should be suppressed. The Motion constraint between the planet gear and the main gear seem to apply to the wrong target. As a result, there is no motion.

I also add another Motion constraint between the planet gear and the vertical gear. The motion seems more reasonable now. Please take a look at the attached file.

Thanks again!