Thread: tappered rollor bearings.

could any here please tell me what they think would be roughly the right toque for 2 opposing tapered roller bearing of a large size. running on a shaft of 150mm. the out side ring would be at least 200mm.
these bearings run on a heavy machine and are wheel bearings. they are lubricated with grease. the manufacturer says 1000nm toque on the nut that tightens on to the bearing.
to me this seem far to high.
so if any body works on large Mobile equipment i would be interested to hear how much pre load they use.
aaron

Hi Aaron,

You work with some interesting stuff, 1000nm would be roughly 100kg on a 1m bar, given that it's a 150mm diameter shaft, I would guess that might well be correct, but since it sounds like a critical application, (probably expensive, I'm guessing) it might be worth while to get a clarification from the bearing supplier, you don't want to be holding the baby if it fails.

What's it on?

Regards
Ray

hi ray thanks for the reply. its on a valmate straddle carrier

[ame=http://www.youtube.com/watch?v=MJAwpvgyrhc]Cargotec's Kalmar cargo and load handling solutions: automatic stacking cranes - YouTube[/ame]

you know the bearings are expensive. we don't see, to get any more than 8000 hrs our of them. besides that between the rollers and outer race these bearing are dry when we pull the hubs off.
most wheel bearing applications ive come across don't need to tightened so much.
you know ill continue to do as the manufacture says. it just seem like they have it mixed up.

After torqueing/tightening,do you ever check clearance with a feeler,I used to check with a .001" feeler if it fits its to loose,we never actually set them to a specfic torque,just flogged the nuts with a spanner and 14 pounder.
These bearings veried in size from 3" ID to 10" ID and were used in liquid ring vacumn pumps up to 15000cfm.

Falcon hub nuts get tightened very hard. I forget the figure, but roughly 'till you fart'. That's because there's a spacer between the cones, and that's what sets the preload, not the nut torque. Maybe your machine is s similar setup?

Wow you guys have nice toys
They have to be tight enough that when loaded it doesn't lose preload, one would think the manufacturer would have that under control but maybe there is a misprint? To loose is only a little better than to tight. Have you had the bearings looked at to see why they are failing? lubrication sounds like an issue.

Stuart

Originally Posted by azzrock

could any here please tell me what they think would be roughly the right toque for 2 opposing tapered roller bearing of a large size. running on a shaft of 150mm. the out side ring would be at least 200mm.
these bearings run on a heavy machine and are wheel bearings. they are lubricated with grease. the manufacturer says 1000nm toque on the nut that tightens on to the bearing.
to me this seem far to high.
so if any body works on large Mobile equipment i would be interested to hear how much pre load they use.
aaron

It would depend on the pitch of the thread as to how much force you are putting on the bearing...

1000Nm does not seem excessively high... Have a Cat D7G repair manual here and you tension the final drive bearing nut to 3000Nm and that is not a typo...

If the bearings are dry when you are pulling them apart are they getting lubricated on a regular basis...

Other problem could be contamination or even the bearings are too small/wrong type for the application...

pipe clay do you mean between the bearing cone and roller. im pretty shore the would be no clearance. ill have a look next time.
bryne the bearings are separated by the hub ot a spacer there is probably 150mm between bearings.

stu they are impressive toys. Until you have to climb the ladder 20 times a day to adjust a seat. reset breaker check A/C ect. the bearings rarely have a major failure just are worn or the ring spins in the hub at inspection.

thats interesting rc. i was wondering about other heavy equipment bearing pre loads. it is a fine thread on the axil

Yes that would be taken between the roller and the outer race.these bearings are running in 38 degree ambient and 65 degree working.

Of course 8000 hours is not that bad for life expectancy....

some times 4000 sometimes 8000. i thought they if lubricated correctly should last longer say at least 5 years. bearing in a car can quite easily last the life of the car. but this is why i made the post to see what all you guys think. the bearing toque setting used to be way less. the manufacture revised there instructions.

Who's the manufacturer?

Nev

Originally Posted by azzrock

the bearing toque setting used to be way less. the manufacture revised there instructions.

When you say "Manufacturer" do you mean the manufacturer of the bearing, or the manufacturer of the machine it is fitted to?

Have you ruled out all other possibilities like bearing contamination, incorrect lubrication..

If some are lasting 8000 hours and some 4000 hours, I would be looking at other reasons for failure as well....

It is a bit like when on the various forums people buy a used lathe and get a crap finish.... Immediately they think spindle bearings and disregard any other possibility..

Hi azzrock,
This is the sort of thing I was talking about.
http://www.kamandirect.com/resources...eandcauses.pdf

It should give you some idea as to why the bearing is failing. Are your records good enough to show if the bearing are lasting longer with the manufacture revised bearing torque?

"ring spins in the hub at inspection" That would be bad.
Page 21 of the PDF.
The last sentence is pretty interesting.
"Smearing of external surfaces

Smearing may occur on the external
surfaces of heavily loaded bearings.
Here, the smearing is the result of
movement of the bearing ring relative
to its shaft or housing. Smearing of the
inner ring bore, outer ring outside surface
and ring faces can only be avoided
if the fits are tight enough to prevent
movement of the ring concerned
in relation to its seating. Increasing the
axial compression does not result in

any improvement."

Stuart

hi again every one. the manufacturer i was talking about is valmet/kelmar.

thanks for the link Stuart its a beauty.the bearing we use seem good quality. and the grease i believe is top shelf. 4000 and 8000 is the frequency of the service where they are checked re greased ect,,
the main reason to ask and this post is to satisfy my curiosity. no one there is going to notice if i save the company a few bearings. there happy as long as the hub goes on and the machine goes back to work.
the bearing cone spin can cause trouble thou. as it wears the hub out. occasionally the inner bearing race part might spin on the axle. causing wear to the axle. this is a major repair. done off site.