Tolerance Grades

It is possible but not with the information you gave since it is not complete: piston diameter kind of seals, width of the part you press or depress and so on. Pressure is related via the cylinder to the force and the force is related to the geometry and fit as well as with the material via its intrinsic stiffness called also Young modulus. An important factor not to forget is the surfaces roughness as well of shaft as of bore.

For small dimensions the roughness can if too big totally compromise the press fit.

Sqanesh,

Just as Nic Name says, not with the information given. In many cases 125 bar is not that un-common when dealing with couplings by use of hydraulic tools.

In many cases hydraulic pumps are used to "float" off a coupling that has been fitted to a tapered shaft, this requires both high pressure and a little luck. This is presuming the man before you did not overheat the coupling when installing it....

Straight shafts.... There are likely some sort of a standard chart available for different size shafts depending upon the type of fit the equipment requires. I do not have it, but I definitely will wait to see if someone else does. There are many variables that will influence the type of fit. Too loose and premature failure of shaft and/or coupling, too tight and you have a lot of fun getting them off as you have experienced already...

In my humble opinion, (as I was trained by the old school guys), its more knowledge of the system and good practical sense when making your assembly.

Tim

Sqanesh,

On another note, you neglected to mention the specifics in regards to your hydraulic cylinder being used. For this reason no one knows the actual force required to remove your coupling...

Its safe to assume if you were using the proper pulling set-up, then you probably had a hollow cylinder but without the actual size the Cylinder Effective Area x Pressure can not be calculated.

Lets say for simplicity sake (using solid rod cylinder);

2" bore x 1" rod @ 1750 psi= 5,498 lbs force extending and 4,123 lbs force retracting where as a 6" bore x 2.5" rod @ same psi would be 49,480 lbs force extending and 40,890 lbs force retracting. But I guess you are already familiar with the simple fundamentals?

Very helpful to have more specifics in order for anyone to offer you a usable reply.

Tim

Sganesh,

The information you had given is not sufficient to suggest you the type of fit you require. Normally this type of pressure ie required to press the couplings with key-key ways. How ever reall hydaulic fit couplings are taper bore interfrence couplings. Your case may fall under push fit.

This has a lot to do with materials and actual dimensional measurements. Temperature of the mating parts when machined(they probably weren't all machined in the same set-up or even the same factory in some cases).

Assembly temperature is also a factor. Each mating part would have to be measured at the time of assembly, or be closely controlled for any accurate estimation of assembly pressure.

Machinery's Handbook (Not an endorsement)has these clearance numbers, I believe.