SPUR GEAR INTERFERENCE

[Edu_P]

Hi everyone,

I´m having some problems, just like some other members, and it´s about interference in spur gears. We all use the Design Accelerator (DA) when designing gears. In my case it´s a couple of spur gears that don´t work togetether. Teeth are just different, so the gear is not going to work, that simple! I mean there must be an option to help correct this error, there must be! Softwares like this should not have this problem. I´ve read some comments about editing the shape or sketch of the tooth but why? there´s no need to do it. If i want a couple of gears to work and i introduce all the required parameters to make them work, then why they don´t?

If anyone can really help me and all other members of this community who have this problem, we would be really thankfull.

Thanks...

[JDMather]

Q1. (aYes or No answer) Are you going to manufacture these gears yourself?

Most gears are purchased off-the-shelf.

So similar to using cosmetic threads rather than cut threads - most users prefer simplified gears that give the representation without slowing down assembly.

The Gear Design Acclerator uses the Wellman's Odontograph simplified representation.

Have you found the technique to get true involute tooth forms?

"If i want a couple of gears to work and i introduce all the required parameters to make them work, then why they don´t?

If anyone can really help me...."

Attach all of your required parameters here.  Someone here will make the gears for you.

[Edu_P]

Thanks for your answer, well, i´m not going to manufacture these gears but what if i do want to? I´ve seen some comments about this and it seems to be that there´s always going to be an interference and the only solution available is to edit the tooth shape.

So, final question, is it possible to avoid interference only using the DA? and not exporting and editing the tooth shape.

Thanks.

[JDMather · Accepted solution]

The Backlash settings in the dialog box above sets the desired clearance.

Gears are complex geometry - it might be best left to the manufacturers who do this for a living every day.

If you do want to manufacture your own gears - there are a lot of reference materials avialable.

The kinematics work fine, interference or not.

The pitch circle diameters form a Rolling Cylinder on Cylinder joint.

[Edu_P]

I was curious about this, like a lot of members. I just found some information about Wellman´s involute odontograph method. I see now that Inventor just creates a simple representation but i´ll try to figure out a little bit more about drawing the real tooth profile.

Thank for your help.

[Anonymous]

Hi, I ve started Inventor recently, Id'like to 3D print some gear for some low power transmision stuff (ofcourse can t do more with PLA material). I'm having same problem then eduardop. Im looking for designing gears with DA.

I don t understand then, why the hell do I have a preview avaiable for the gear? Can t I get these shape generated into 2D sketchs?

Thanks.

[JDMather]

Exactly what problem are you having in generating gears?

More information is needed.

[Anonymous]

Thanks for anwsering me. I m trying to make a planetary gear system. When I try to generate planetary gears 3times smaller then the sun, I have this in the DA preview :

So I can see here that the shap of the smaller gears gonna be kinda shaper then the big one to fit perfectly when rotating them together. But that's not what I get as 3D model.

😞 As said, I find out intersections betwine thoses, even before driving the rotation.

You can even see a gap betwine the gears there (setup : mate constrainte betwine center axis equal to center distance seted up in DA).This become a problem when you put on the ring gear as shown :

Am I doing something the wrong way? Or missing something?

[JDMather]

As  noted in the 2nd post - if you want better toothforms you either have to go the extra steps or you have to create your own involute profile sketches.

The gear generator in Inventor or in SolidWorks creates a simplified representation (just like they do cosmetic threads to represent real threads) rather than the computationally expensive real geometry.

Has your instructor covered gear geometry?

You can have Inventor generate your true toothforms with allowance for backlash (I make extra allowance for 3D printing since 3D printing is not a particularly precise process).