calculating rotational torque limit based on press fit
calculating rotational torque limit based on press fit
(OP)
I'm looking for information on calculating how much rotational torque and axial force a pressed fit steel hub on a solid steel shaft can withstand before slipping.





RE: calculating rotational torque limit based on press fit
Here are the formula you need:-
Torque that can be transmitted by an interference fit
without slipping:-
T= f*Pc*3.142*d^2*L/(2)
where f=friction coefficient
Pc=contact pressure between the two members
d=nominal shaft dia
L=length of external member.
to calculate Pc for a given interference use the formula:-
Pc=x/[Dc*[((Dc^2+Di^2)/(Ei(Dc^2-Di^2))+....................
((Do^2+Dc^2)/(Eo*(Do^2-Dc^2))-((Ui/Ei)+
Ui/Eo))]
where x = total interference
Dc=dia of the contact surface
Di = dia of inner member
Do= outside dia of outer member
Uo=poissons ratio for outer member
Ui=poissons ratio for inner member
Eo=modulus of elasticity for outer member
Ei=modulus of elasticity for inner member
This formula for Pc will simplify if the materials are the same.
Hope this helps
regards desertfox
RE: calculating rotational torque limit based on press fit
Bill Corrigan
RE: calculating rotational torque limit based on press fit
Thanks again,
Rustang
RE: calculating rotational torque limit based on press fit
Rustang
RE: calculating rotational torque limit based on press fit
to answer your last questions:-
Di = the inner dia of the
inner component ie:- a
tube, this is zero for
a solid shaft.
Dc = outside dia of the
inner member (o.d. of
shaft)
Finally for steel on steel (dry) the friction coefficient
around 0.25 but can vary below this depends on surface
finish , if you want to give a margin of safety use a friction factor around 0.15.
good luck
desertfox