Hexagon Shaft-Hub-Connection 1

[engineer_ag_t]

Hello all,

I want to compare several shaft-hub-connections regarding transmissible torque. The failure criterion should be the max. allowable surface pressure.
For lots of shaft-hub-connections you can find appropriate formulas, for example for spline shaft connections:
T=h*L*p,max*r*phi*z
with T=torque, h=spline height, L=hub length, p,max=max. allowable surface pressure, r=mean radius, phi=contact area ratio, z=number of splines

Is there a similar formula for hexagon connections? Any reliable source concerning this topic would be great, too!

 

[Sparweb]

I think the equation you've posted for splined shafts can be adapted to a hexagon if you just make a FBD of the spline cross section and the dimensions in the equation, then relate the corresponding dimensions for the hex shaft. Just bear in mind that the surfaces in contact are not normal to the net contact forces, so your equation will have an extra trig term, like " T=(...)*sin(30) " or something similar.

STF

 

[tbuelna]

You are asking a question that can get very complicated. The contact stress levels in your hex profile shaft/hub coupling can vary greatly based on factors like precision/alignment of the mating parts under loaded conditions. If no relative motion is required at the connection, it is usually best to have an interference fit between the mating parts.