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worm gear analysis

worm gear analysis

worm gear analysis

I have set up a model to analyse the stresses in a worm and wheel used in a new acuator that we are developing.  The worm is constrained radially at both ends by bearings.  The worm meshes with the coresponding wheel.  There are contacts placed between the two parts.  A torque is applied to one end of the worm.

The problem I have encountered is that when I review the results I have found that the worm gear is growing in diameter, i.e. in the direction that it has been radially constrained.  It also begins to overlap the mating wheel gear.

Does anyone have any suggestions as to why this is happening?

RE: worm gear analysis

Contact analysis results in ProM are often the victim of a bad post processor. Often the results are right, but the graphical representation will show overlapping. However, to make sure, refine the mesh at the contact surfaces and run a Multi-Pass Adaptive (MPA) analysis. Then check the results for the worm component only and look at each displacement component separately.

Also check the validity of the constraints.

RE: worm gear analysis

Make sure your model is not underconstrained.  If you only have a constraint in the radial direction, you would also have to constrain rotations (theta) as well as z.  

I had a contact problem where the model was underconstrained but still solved.  The results showed one of the parts "growing" radially as you described. Adding a rotational constraint fixed the problem.

- dave

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