×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

calculating rotational torque limit based on press fit
3

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

3
Hi Rustang

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

Nice work, I will save this for future reference.

Bill Corrigan

RE: calculating rotational torque limit based on press fit

(OP)
Thanks for the input Desertfox.  I do have a question, however.  I'm assuming that Dc is the inner diameter of the hub, and Di is the diameter of the shaft?

Thanks again,
Rustang

RE: calculating rotational torque limit based on press fit

(OP)
One more question!  What should I use for a friction coefficient?  (steel on steel)

Rustang

RE: calculating rotational torque limit based on press fit

Hi Rustang

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

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources