Torque to be applied 3

[Guardiano]

Dear Forum Members,
I don't know if this is the right forum but I'm sure the gurus present would shed some light. We have a gearbox arrangement and the motor/gearbox assembly drives a shaft which itself drives a conveyor. The gearbox was removed for maintenance and now it has just been put into position. We are looking for the right procedure and the correct torque to tighten the shrink disc bolts on the gearbox. See the attached picture. We contacted the OEM but without much success. The gearbox is rated @ 3200 k Nm.

Thank you.
Guardiano

 

[Compositepro]

With tapered fits if one bolt is tightened too much (in terms of distance, not torque) before the other bolts are tightened, the fit will be off-center and it will never be right until you start over. So incremental tightening is essential.

 

[mfgenggear]

re-disassemble and inspect both tapers and inspect for damage. if there is any damage to the taper it will not assemble properly.

 

[dvd]

1. Is the 730mm shaft toleranced to manufacturer's recommendations? The shaft tolerance must agree with the hub tolerance in the manner that the manufacturer specified/designed into their product.

2. Was the lubrication on fasteners applied/performed as indicated in the manufacturer's literature? There are subtleties involved -

https://www.ringfeder.com/globalass...discs-2-part-rfn-4161-rfn-4181_en_08-2019.pdf

3. Is there a local representative for the shrink disc manufacturer who could come witness the installation? 730mm is a big shaft to replace due to improper shrink disc installation.

 

[JS_]

A 30mm gap?

I've run into something similar, you might need to look for an adapter sleeve or European term collet as we discovered when management went looking for a replacement for a damaged part.

Re-Measure everything, make sure it right.

I know its a long process, use the 1/4 turn draw up and torque wrench increased after reliable readings....


(Edited for typo)

 

[Guardiano]

Hi All,
Some feedback. We took our time(10 days) and tightened the bolts incrementally. At 3420 Nm, there is now a 3 mm gap between the inner and outer rings and no more tightening is possible at this torque. The original shaft tolerances were (730-0.024)mm and (730 -0.072)mm. The new shaft was manufactured to (730+0.017)mm tolerance. Two questions, 1. Is it safe to operate with the 3 mm gap? 2. We don't know if the new shaft tolerance agree with the hub tolerance, could this minor difference matter?
Best
Guardiano

 

[dvd]

The new shaft is larger than the old shaft, by as much as 0.089mm - why weren't tolerances followed?

Without a sketch of the shaft and shrink disc, and more specific information about the shrink disc, any response is speculation.

Where is the gap you discuss - include this in the sketch you send to shrink disc manufacturer.

I would speculate that the inner ring is encountering the (too large) shaft before it expands outward into the hub.

A discussion of your application with the shrink disc manufacturer seem appropriate.

 

[Strong]

I would speculate that no gap is acceptable for full torque rating and for maintaining shaft alignment and for low vibrations.

Walt

 

[MacGyverS2000]

I remember the project thomaspd is posting from earlier this year... I think we beat that (perpetual motion) dead horse and booted the project (and him).

Dan - Owner

http://www.Hi-TecDesigns.com