2-d rack & pinion

[Mloew]

I am trying to help one of the engineers in my office with a mechanism problem in Wildfire 2 (M140). The design calls for a sprocket to roll over a track (chain) that is curved in the plane of the sprocket. I thought it should be simulated with a cam and no lift-off to capture the correct rolling (gear ratio) relationship. We tried several iterations of flipping the axis, using an extra point on surface or aligning on planes to get the rolling axis aligned, etc. to get it to work. Unfortunately, there seem to be two independent degrees of freedom in the system. We used a slot (center point on an offset curve) to get the bulk assembly motion, but it will not capture the rolling of the sprocket on the track. I have come very close by using a measure to capture a relationship between the traversing in one dimension the distance covered and outputting it to a spreadsheet and then trying to relate the distance covered to the rotational rate. This is a way to come close, but not exactly right. I am still refining the methods, but would like to have a purely kinematic solution if possible.

Any clues?

Thanks in advance!<?:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" />

 

[slashct]

Is it possible you post an image? I am lost in what you are trying to do.... From the sounds you need to enable liftoff if you want it to roll over the chain, as well you will need to have a pin joint to allow the rotationof the wheel.