Progress Always
Hi Roland,
Ford Motor Co used to fix the rear axle halfshafts with a shrink fit bush. It was absolutely reliable and there is no reason why the much cruder conveyor drum could not benefit from shrink fit hubs. I used to remove the shrink fit bushes, like everyone else, with a hacksaw, for stress raising, followed by a few clouts with a hammer and chisel. Replacement with a new bush was a cheap affair and translated into conveyors on site it is even more cost effective.
Ford bushes were heated on the kitchen cooker when the spouse of the time wasn't looking.
With todays tools you could remove and discard the hubs conveniently. It might be awkward to decide if hot working, for fitting, was permissible on some sites, eg Jubail overland, but that is no different to vulcanising give or take a few oC. ■
Rigid Hub Removal
NO special tools. An Enerpac pump and a little stroking will get the pressure high enough to cause oil to expand the hub enough for motion with a little help from a puller tension.
Must have coupling halves separated. ■
Rigid interference fit coupling Hub with no key way
As you have mentioned that At assembly: hub is to be heated to +200°C + axially precise mounted onto shaft end. When cooling down the interference fit becomes operational and fixes the hub to the shaft.
Similarly , during dismantling we are doing the same procedure with heating and jacking with hydraulic jack.
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Hub to Shaft Connection of Rigid Coupling
Dear forum ,
i'd like to request for operational and maintenance experiences from belt conveyor operators & maintenance staff and also professional opinions from mechanical engineers about a specific hub to shaft connection of rigid coupling hubs at drive pulleys.
This type of connection is known to me as shrink fit with oilhydraulic removal and its working principle is as following:
At assembly: hub is to be heated to +200°C + axially precise mounted onto shaft end. When cooling down the interference fit becomes operational and fixes the hub to the shaft.
At disassembly: hub is to be connected to high pressure hydraulic hand pump, when sufficient pressure is applied the hub will be widened and becomes loose, swimmming on the oil film.
The hubs at pulley and gearbox are connected via high strength bolting.
From the above description one might conclude several points:
- in operation the connection represents a rugged design: no bolts, no gaps
- maintenance of rigid coupling in operation = 0, no wear no tear
- if however maintenance is required (change of pulley / replacement): the process could imo be done only under workshop conditions, as special tools are required (high pressure hydraulic pump, induction heater, maximum cleanliness)
What is your experience / opinion?
Thank you in advance and
Best Regards
R. ■