Knurl shrink fit analysis

[UCengno1]

Any guides for caluclating the pressure force that exists when you shrink fit a carrier to a knurled shaft. Assuming the shaft as a solid member seems extremely conservative. You should get into plastic range on the knurls peaks pretty quickly with a appreciable fit.

 

[UCengno1]

I am talking about a straight knurl not a diamond pattern.

 

[plasgears]

Knurls do not yield to shaft interference analysis because of the local deformation inherent in the interface.

Straight knurl interference equivalent to up to the upset height of the knurl is recommended. Knurl dimensions are detailed in Marks Hdbk and in knurl mfr catalogs.

Diamond knurls work well for metal-plastic interference like you would employ for a plastic gear. It constrains the gear in all directions.

The best "knurl" I saw was generated like a spline. The PM gear had semicircle lobes on the ID, and it was heat treated. The mating un-heat-treated shaft had a collar that was cut by the gear spline, and it developed a tight intimate fit in the form of a spline. The semicircle form was employed because it was strong in shear acting as a cutting tool.