Dynamic Simulation problem in Inventor Professional 11

[John2004]

Hi Everyone,

I'm trying to run a dynamic simulation on a cam & follower mechanism with Inventor Professional 11. The cam does not make a complete revolution but oscillates back and forth. The cam works with a roller follower that oscillates about a swing arm pivot bearing.

Since the cam curve is not a closed loop of 360 degrees and only lasts for a 70 degree or so portion of 360 degrees, Inventor will not create a rolling joint between the cam and roller follower.

After I select "Ri cylinder curve joint" and then select the curve, Inventor says " Impossible to loop from selected reference, click planar face of loop or one edge of it's outline."

If I try to slect an edge of the curve, Inventor says "a curve can only be a spline or loop of lines and/or arcs." The solid model of the cam was created in AutoCAD Mechanical 2007.

I have tried to go to the assembly panel and create a motion constraint between the cam and roller and then convert the constraint to a joint in the dynamic simulation panel, but this did not work either. Inventor just said that it did not understand the joint.

It seems to me there must be some way to create the joint and run the simulation. I would appreciate any suggestions or feedback.

Thanks
John

 

[rollupswx]

Zip and attach the assembly here.

 

[John2004]

Hi Rollupswx,

I'm afraid I'm not allowed to upload the CAD assembly.

I was going to import a full closed cam of 360 degrees and weld it onto the existing partial cam profile, then just turn the visibility off for the closed cam so all you would see in the simulation and any presentation video would be the actual part I'm using which is just a curved portion lasting for about 70 degrees and not the full 360 degrees.

It seemed to work for one profile and not the other. I was able to select one profile, but when I tried selecting another closed profile, I got the messages mentioned in my original post. I'm not sure what's going on.

It seems to me you should be able to simulate any mechanism that you can design within Inventor or AutoCAD. Is there any way to use and "Ri cylinder joint curve" joint on a solid model having a partial curve that does not last 360 degrees ?

Thanks
John

 

[John2004]

I figured it out, I had to create a rotatable joint at the cam follower roller, and then use the "3D contact joint" to actually make the joint. The "Ri cylinder joint curve" did not work, even though from the animation preview it looked like the best fit.

John