Press Fit deformation/deflection

[GenJT]

Here is the problem:
A sleeve OD is press fitted into a housing ID. There must be an expansion at the ID of the sleeve due to the compression.

I am wondering if anyone has a formula or information how to calculate (or estimate) this change (expansion).
Thanks

 

[CESSNA1]

GENJT: See any good Machine Design Book such as Spotts or Mechanical Engineer's handbook such as Marks. They have equations for calculating interference fits.

Regards
Dave

 

[rb1957]

if the sleeve is press fitted into a housing, the housing hole diameter will increase (slightly) and the sleeve will be compressed, not "there must be an expansion at the ID of the sleeve due to the compression."

as for the precise change in diamter, a machinists handbook might tell you (not the sort of thing i'd have thought they'd have), i'd have thought it might be expressed as an initial hole diameter given the pin diameter (presumably something goes inside the sleeve), the clearance desired inside the sleeve (between the sleeve and the pin, possibly assumed to be a sliding fit), the sleeve wall thickness, the amount of interference designed into the installation, and of course the materials (of the housing and the sleeve). timenoshenko (plates and shells) would have the detail equations. generally, the question is how much of the interference is taken up by expanding the hole in the housing (which is much stiffer than the sleeve) and how much is accounted for by compression of the sleeve.

 

[GenJT]

Thank you both.
Since there is a moving object inside the sleeve with small clearance, I like to see the affect of the sleeve's ID wall after the installation.
GenJT.

 

[arto]

Budynas "Advanced Strength & Applied Stress analysis" p142 has press fit analysis too. basically thick-walled cylinder equations.

look in USAS B4.1 "Preferred Limits & Fits for cylindrical parts" for RC fits for your moving part

 

[Tmoose]

The sleeve ID will get smaller, but if both the parts are metal, probably not the full amount of the interference fit. What is the range of the diamters you allow, and how round and straight/circular are they? How much is your "small clearance"? Unless it is 10 X the interference fit, mass produced pieces will need some selective assembly to keep the final clearance in tolerance. If the ID needs to be rounder and straighter than about 0.001 inch the pieces need to be better than that, and even then the ID may have to be finished after assembly.