Does anyone know how to calculate the torque that a knurled press fit connection can have?

Regards,

Peter

 

I would think of a straight knurl as a bunch of small "gear teeth" engaged with a matching shape in the bore.

Make some kind of guesstimate of the depth of engagement and the thickness of the "tooth"

Calculate compressive stresses on the flanks of the teeth and shear stresses across the thickness of the teeth.

Check both shaft and hub for stresses, since they are likely made from different materials with different tensile strengths.

Apply a LARGE factor of safety.

Build a prototype and measure actual performance.

Iterate design as necessary.

 

Here Is a link to an online calculator

The link below will allow you torque calculations

http://www.meadinfo.org/2009/07/press-fit-pressure-calculator-optimize.html

I think this was derived from a book called Schams outline of machine design 1961 you can search for this as well. There is a plethora of information in this book

Cheers

 

Hi peter,

why knurl the part if you want torque transmission ? much simpler to have a plane surface and an intemperance fit.

tony

[edit] the link from earlier thread is for a plain shaft press fit, not knurled. how it would change, not sure but it would not be as good as you wouldn't have the same surface contact [/edit]