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NX Motion - Double Rack, Single Pinion Capability

[ Edited ]

Hi all. 

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!


-Jeff

8 REPLIES

Re: NX Motion - Double Rack, Single Pinion Capability

Hi Jeff,

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.

 

 

 

 

Re: NX Motion - Double Rack, Single Pinion Capability

I'll give it a try next week and report back. Thanks!

Re: NX Motion - Double Rack, Single Pinion Capability

No Luck! Thank you anyway. Still open to any more ideas.

Re: NX Motion - Double Rack, Single Pinion Capability

I played with my nx-motion-modul. You can find the result in the video. If it is ok let me know. Than I try to explain how I did it (and I think I need a lot of paper...)

 

Re: NX Motion - Double Rack, Single Pinion Capability

I had some problems uploading my video.

I hope it works now...

Re: NX Motion - Double Rack, Single Pinion Capability

I don't think the video is working - but perhaps a screenshot of your NX motion Joint list and perhaps a cloud link of your video so that I may view it? 

Re: NX Motion - Double Rack, Single Pinion Capability

[ Edited ]

Ok, now i know witch video codecs work. Here it is (i hope)....

 

(view in My Videos)

Re: NX Motion - Double Rack, Single Pinion Capability

Hello - saw the video. Looks ok (although the right side link is the driver and has a velocity UP (not down as shown). 

If you get a chance, I am curious as to what link settings were used. Thanks