Motion Skeleton Integration

[DaltonF.]

Lets assume that this example has one putting a bearing onto an output shaft, driven by an input shaft through a set of gears. The large scale motion skeleton is set up, and works to allow the output shaft to rotate after defining gear connections.

I want to simulate the motion of the bearing carrier, but is it possible to crate a motion skeleton within the bearing assembly then assembly it onto the larger Gear reducer assembly, or will I have to assembly it piece by piece? I want to allow myself to auto populate the BOM by the features contained inside the model, and to do this the bearing has to be assembled before it is put on.

The only way I've done it before is to assembly the carrier onto the shaft separately from the inner and outer race, which causes it to show up in the model tree as two separate parts (in reality the bearing is pressed on as a single feature). Any ideas how to do this?

Currently, I am defining the bearing as a Gear Pair through a Motion skeleton, and the gear pair definition occurs inside the bearing assembly. Do I just need to change where the gear pair definition occurs, or is there some other proble.

Any advice is great help.

Thanks

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[DaltonF.]

If anyone is reading this, there is a way to do this. I was able to figure it out. There are actually a couple of different methods, which all are useful for certain applications. Let me know if you need help

[TomD.inPDX · Accepted solution]

Your considerations in the original post are correct. its a real mindbender to get this all to function and it takes only a small error in judgement to lock the whole system up.

[DaltonF.]

Basically, I had to assembly everything using plane and axis connections, using extra connections after the part was fully constrained (setting different planes rigidly to the motion skeleton parts). Then, the assmebly as a whole was attached in the same manor to the correct planes in the high level skeleton, and boom. It works, and well might I add.

I altered a bit and used your mechanism link check for the ball bearings as well. It was all done primarily through motion skeletons, though, so that it is more adept to fitting into a top down design methodology (mechanism links positively will not operate top down, so there is some user alterations, but not nearly to the level that I imagined there would be).

On a separate note, do you know of any references on tandem part creation? For example, creating the helical sweep of a worm drive and the gear to go with it.

[TomD.inPDX]

There are a lot of great resources for gears but the work is significant.

The work drive is the same as a rack (generically) with 20 degree straight teeth. And the driven gear can be a typical spur/pinion. However, two things to be aware of; 1) PTC's revolve or sweep cuts are planar rather than the shape a cutter wheel takes on. The two are -not- alike. and 2) There are serious variations in worm drives based on many factors. What is sufficient and acceptable in your application can make a very simple task much more complicated.

Here's a good place to start: http://www.qtcgears.com/Q420%20PDF%20Files/Tech.pdf