Simple Motion Study/Animation problem 2

[razzendahcuben]

I assume that this is a very basic question, but, sadly, I have yet to dig up anything on the net that helps.

Basically, I have two gears meshed together in an assembly. To maintain their locations relative to one another, they a connecting rod attaches to both of their centers. Now I want to move one gear such that the other gear moves, as it would in real life. Instead the teeth of the first gear simply move THROUGH the teeth of the second gear, as though nothing is there. So is there a way to make SW realize that my parts are "solid"? The same thing occurs when I use a motor to drive one gear. Thanks.

 

[JMirisola]

Use physical simulation.

Jeff Mirisola, CSWP, Certified DriveWorks AE

http://designsmarter.typepad.com/jeffs_blog

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[razzendahcuben]

OK, using 3D contact the teeth no longer move through one another. But the actual simulation makes no sense---the teeth on one gear are jittering back and forth---"bouncing" against the teeth on the other gear if you will. Undercutting isn't an issue so I am at a loss as to what is going on.

My model is nearly identical to this:

http://www.youtube.com/watch?v=xUK_PDopiiA

His is moving fine, though. And he probably is using the same mates as me---a coincident and concentric mate between each gear and the rod.

 

[GregLocock]

The usual way is to use a rotational constraint between the two shafts, with the correct gear ratio. Using a contact constraint between the gear teeth is not really feasible for more than one tooth at a time.

Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[razzendahcuben]

Beautiful.

 

[pdybeck]

razzendahcuben,

Perhaps you saw "chattering" on your first example was because of the frame rate of the animation relative to the speed of rotation. For example, if you had a speed of 1 revolution per second and a frame rate of 1 frame per second, the gears would appear to be stationary because the animation frame to frame would capture the gears in exactly the same orientation each time. Make your frame rate something different than the rotations speed, somehting much smaller in time and not divisible by... Physical simulation definitely works for this scenario, but as Greg mentioned you can use the gear mate with the correct gear ration between the two...

 

[razzendahcuben]

Good idea, that helped.