Spur gears - proper meshing

Mods FEM
1

Hi,

I want to prepare a 2D finite element analysis of a spur gear set. I followed this tutorial but with different parameters: https://www.youtube.com/watch?v=IhcLSx2ppUY

My settings are:

  1. gear 1:
  • number of teeth: 26
  • module: 2,5 mm
  1. gear 2:
  • number of teeth: 13
  • module: 2,5 mm

I separated the gears using a distance calculated with this formula mentioned in the video:
distance=(module*(teeth_number_gear_1*teeth_number_gear_2))/2

Then I wanted to rotate the smaller gear properly using this formula for the angle: (360/teeth_number_gear_2)/2

but somehow the gears were already in a seemingly correct position.

Here’s what the meshing looks like:

gears.JPG
I also attached the file below. My question is whether the meshing is correct (I’m not a gearing expert). For the purpose of FEA, I would like the surfaces (or actually edges since I will convert this to a 2D model) to be in contact initially (this will eliminate the problems with convergence). But it’s also important for me to make sure that the meshing is correct from the engineering point of view.

Gears for analysis.FCStd (599 KB)

2

Hello NewJoker, hello to the Community!
Here you will find many useful things https://forum.freecadweb.org/viewtopic.php?f=3&t=65010
attention the spacing formula is wrong, the correct one: distance = (module * (teeth_number_gear_1 + teeth_number_gear_2)) / 2

3

Thank you for the reply. So the meshing in my case should be fine ?


Right, I used the correct formula in the model but rewrote it here with a mistake.

4

Hi J4mes, greetings to the Community!

I understood that you had typed wrong but it was right to pay attention to the error so as not to mislead the reader.
Yes, the theoretical wheelbase calculation should be right.

5

Moved from Help forum.

6

Actually, I forgot to add that FEA will be done in other software since FreeCAD doesn’t support 2D (plane stress in this case) elements at the moment. So I was only asking about the proper meshing (teeth contact, not finite element mesh) to make sure that the geometry for FEA will be prepared correctly. Thus, I’m not sure if this topic fits in the FEM subforum but it’s up to you.