I brought this to GTAC, but they did not have an answer and are currently investigating the capability of NX 10 (or 11) to handle this particular problem (attached for screenshot).
The orange pinion gear is between two racks - (green is moving, grey is fixed)
The vertical slider joint is the driver and we are expecting the output to be a smooth rolling pinion velocity (translational and rotational velocity).
With 3D Contact of both pinion interfaces and friction = 1, the solver will produce the correct motion but due to friction, the velocity curves are very noisy. Even with solver parameter adjustments, it cannot create what we are looking for.
I'm thinking NX Motion should be able to handle such a problem WITHOUT the need to invoke friction, but the rack/pinion command struggles to handle more than 1 rack.
If anyone has suggestions, I would be most appreciative. Thanks!
Here is my idea (not sure if it works).
>> but the rack/pinion command struggles to handle more than 1 rack
What about using two pinions? One is connected to the fixed rack, the other one to the moving rack. The pinions are on the same axis. You connect the pinnions with a rev joint. To convert the rev joint into a "rigid" connection you have to give it a constant driver with 0 velocity and 0 acceleration.