Rack and Pinion issue

[danny13]

Hello everyone,

 

Iam developing a rack and pinion model using Solidworks/Cosmos 2007 and I have not been able to figure out how to plot or get the forces acting at the contact point of the teeths (once i run the simulation with Cosmos Motion 07). I went through some of the threads about Rack and pinion and noticed that I had not used the advanced mating option called "rack and pinion or gear", but my model seem to be working fine and behaving as it is supposed to be with the regular mates and with a "3D contact in between pinion and the rack.

 

I would like to know if I have to make a rack and pinion matting between the gears to get the contact forces or is there a way around this with my existing model.

 

Thanks in advance

[shift1313]

When you are running your simulation are you doing a Basic motion simulation or Motion(or advanced) Analysis? the Basic simulation I do not believe will allow reaction forces but the advanced one will. I dont have SW in front of me so I cant play with it at the moment

[danny13]

Thanks for responding Shift....I am really sorry but iam not sure what the difference is between a basic and advanced motion simulation. How do I find it?

 

Are you talking about Solidworks or COSMOS motion?.I am Sorry for my ignorance but I never seem to have seen any such option.

[shift1313]

no worries danny. Check the second page of this post

 

http://www.cadtutor.net/forum/showthread.php?t=31599&page=2

 

i have a screen shot in there showing where animation, basic motion and advanced motion are. I believe I posted those shots when i was using SW08(still used cosmos). I only have 09 now which has changed their simulation engine but the features are mostly the same. I should be back at work tomorrow and have SW in front of me to play with.

[danny13]

Looking at the snap shots, I am sure that that feature is not available in the SW/COSMOS 2007, It should be version 08 or above. I tried looking at all the available options and it just doesn't seem to have such a option. May be I will have to upgrade it to 09

 

[shift1313]

When you start your cosmos simulation, does it ask(or automatically) suppress some of your mates? I know if you created a mechanical mate in the assembly it will need to be suppressed. Mechanical mates in assembly mode are only mathematical approximations of movement. In Cosmos its based solely off solid object contact.

[danny13]

yes I have noticed that, some times it suppresses mates automatically but never asks, especially the ones such as parallel mates and distance mates for moving parts gets suppressed when the motion specified on that part fails to satisfy the mate condition.

[shift1313]

is it possible for you to upload your model or send it to me?

[shift1313]

i setup a rack/pin and created a force plot for the reaction between the gears. is this what you are trying to do?

[danny13]

I was able to get it going Shift, all I had to do was drag the pinion into the Reaction forces under the "results" after the simulation was done. and that gave out all the contact force and other forces connected to the pinion. The guys in Europe who work for the Cosmos tech support sent me this idea and it seems to work fine....and yes, I am sure you could have come up with the same idea.

 

Thanks again. Will keep in touch if something else pops up down the lane