Dismantling of Fluid Coupling

If by "jacking bolt" you mean a bolt threaded into the hub to push it off, you might try removing the bolt and fitting a high pressure grease gun. Be careful!

yes by jacking bolt i mean bolt threaded into the hub... i have tried to remove it by using plate type puller fabricated in our workshop using 100ton hydraulic jack.. but no use, the rod inserted in the hub to push bends... the rod i am using is of 25mm and its length is around 500mm...

if i use high pressure grease gun, how will i seal it from coming out of front... the side from which i insert the bolt...

A grease gun cannot be used in this case.

A slide hammer might work, but you may damage the bearings. If you are going to replace the bearings anyway, damage may not be an issue.

used a sledge hammer 20 lb, i inserted a plate between coupling and motor and tried to hammer it off. not a dent on coupling... still its stuck.. i have to change to bearings so no issue of the bearings.

I am talking about a SLIDE hammer, threaded into the jack screw hole. There are thread adapters available to adapt the tread of the hammer shaft to other threads for a direct pull,. Or you can fabricate.

You will need one much larger than this. WARNING! Do not place hand on rear of the slide weight when operating!

I would try a penetrating agent such as Kroil, plus heat, to loosen the coupling hub from the motor shaft. A screw-type puller seems too light for this example, but there should be a way to arrange a hydraulic cylinder in compression.

If destroying the hub is acceptable, you could cut through it with an air-arc gouger.

Apply penetrating oil and heat to the larger part. Once it is warm, drive it off the smaller part.

If the two are rusted together, repeated warming/sudden cooling of the larger part might be sufficient to free the two off each other.

Please check whether the shaft is protruding out of the hub by a mm or more. If so, is the protruding portion of the shaft have rusted badly? If yes, it would be very difficult to remove, how ever you try. If this be the case, with enough care and protection, run the motor and file the rusted portion, until you reduce the diameter considerably and try. This can be tried even without running the motor, but by cranking the rotor from the rear end fan after removing the fan cover and simultaneously filing/emerying. Avail a turner/machinist's assistance who are used to these kind of job on their lathe.

i have inserted wd40 from the front and left it over night hope it works. the coupling we have is similar to the one in this image

the inner part is slide over the motor shaft with key and the v belts on the out part are connected using belts to the gearbox. the outer part is supported on the inner by means of bearing. it is not possible to heat it as it will only heat the outer part of the coupling where as the inner part is stuck on the motor shaft.

If you plan on replacing the bearings, use two rose buds to heat the coupling quickly along with the pullers this should help. I'm a millwright and we use this method all the time.

Where might this "jacking bolt" be located? your mention of it as being used to force the hub led me to believe it was on the end of a through shaft. If it is like the fluid coupling shown, the shaft bore is blind.

Make sure to drain the fluid before applying heat!

I agree if the jacking bolt is located in side the coupling it is a blind bore, Which leads me to question how the OP used a hydraulic puller if it was pushing on a blind bore the end result would be as the OP described disaster.? If the converter is keyed to the shaft what is the original method of locking it on to the shaft to stop it sliding off? grub screws? shear pin? there must be something, if so there must be an exposed hub boss there [ has the locking screws/pin or whatever been removed]? Would the OP give a better description of the mounting?

If this is a taper-lock hub, heat and kroil, as you suggested, should get it to move.

Wish you could have given a sectional view of this coupling.

On seeing the image, I made google image search as to figure-out some sectional view of this design. Of couple images, one looked appropriate is like this:

There has to be a detachable disc on the' non-drive end side' of the coupling as in this picture.

The THREAD – A is for fixing up and the THREAD – B is for pulling/withdrawing purpose. THREAD – B would be of higher sized than THREAD – A.

If you work on THREAD – A, you could be pulling only the shaft and we go nowhere.

Figure-out the size of THREAD – B and use a jack bolt of this size and tight against the shaft, it has to jack up.

He has broken a 30mm rod in it, where would a 30mm rod fit in your drawing?. unless that is a 30mm bolt hole in the drawing. From the design you show it looks possible to dissasemble the fluid coupling from the shaft this would then expose the mounting hub which could have some heat applied to help release it, assuming the Op can get the broken push rod out. At the very worst it could be sacrificed by grinding it off and fit a new one if available if not then it will be the hard way.

the design you have posted is quite similar to one installed.. but the threads B are almost with threads A. i have verified twice that i am using the right threads to pull out the coupling...

Thread A and Thread B are meant for different purpose and has to be of different sizes.

Without the proper drawing we are unable to visualize the proper scenario. All are like blindfolded men touching an elephant and suggesting that elephant should resemble a 'pillar, hose, rope etc'.

How about scanning and attaching a sectional view so that our discussion would be more relevant? You have indicated that you have the manual...

I agree.

So far, his contradictions to suggestions are not inline with what he describes.

Is this perhaps the reason elephants avoid blindfolded men?

Further to the principle of operation, the following illustration could help:

Since nothing is visible externally, by mistake, if you are working on the shaft (thread-A), you could be never move any thing.

Normally those are tapered and the harder you pull the tighter they get. I'm from the bigger hammer school but the jack screws move the taper out. I've had luck with dry ice(CO2) and shrink the shaft somewhat. Shock and penetrating oil helps most of the tapers are brass and not prone to rust.

Good luck,

Matoaka

the picture shows the back side of the coupling.. the wd40 did not work... i broke a 30mm rod in it while using a fabricated puller to remove it.. now machinist is working on removing the rod..

You should see a brass taper lock between the shaft and the hub. You should see two or three threaded holes, if so, insert bolts in the holes and torque them equally until the taperlock pop out. If no taper lock, shock or cooling the shaft may work. On large hubs heat sometimes swells the hub and actually tightens on the shaft>> when it cools completly sometimes it breaks the rust, if there is the slightest difference in the metal in the shaft and hub over time they actually weld themselves together. In that case, brute strength the bigger hammer

I can advise you to follow the procedure below which we tried successfully to remove shrink-fit coupling from a 5100 kW motor shaft:

Step-1: Arrange a 100 ton hyd jack with a lift more than coupling contact width with the shaft and puling arrangement with sufficiently thick plate and bolts. Install it and put jack in poition. Take a wooden box (specially made) lined with thermocol, just to cover the coupling portion to be taken out.

Step-2: Fill the box with dry ice (solid CO2) and keep it overnight (at least for 12 hours). Evaporated (sorry- sublimated) dry ice to be replanished at regular intervals during this time.

Step-3: Now, remove the dry ice and wooden box comletely, as early as possible. Immediately start heating the outer of the coupling with the help of two heavy duty gas torches evenly all round. Apply pressure in hyd jack symultaniously. COUPLING WILL COME OUT.