one way bearing mounting

[mud2005]

Hi all, I'm considering using a one way bearing, but I've never used one before so I thought I'd throw some ideas out and see what you guys think.
I want to mount on a 1/2" hardened shaft so I'm looking at this bearing.
So mostly what I'm wondering is how it stays in place on the shaft? It seems like it would slide from side to side as it's rolling.
This could be prevented by mounting 2 collars on either side of the bearing, but that would create friction it seems.
Could side friction be prevented with a couple of these thrust bearings in between the collars?

If that sounds like a good mounting strategy the only other thing I'm wondering is the efficiency. I want to use a one way instead of using a freewheel because I'm assuming it will be more efficient when freewheeling due to lack of ratchet/pawls. Is that a correct assumtion? Do the one way bearings make any noise when freewheeling?
Thanks for reading

 

[Miles]

mud,

The one-way clutch bearing will align itself on the shaft. You don't necessarily have to constrain it axially.

There are lots of variables but the drag from a freewheel or a one-way clutch bearing of similar size aren't that different. If you are back-driving a reduction stage that will add drag, though..

 

[amberwolf]

If you look carefull at that needle bearing, you'll see that it has two "shelves" at either end, with separate bearings. Assuming your shaft is smooth and of the same diameter along it's length, you could press fit a thin sleeve onto it at the inner end of where that bearing needs to ride, which would then slip over that sleeve once inserted to the shaft. Press fit a second sleeve into the shelf on the bearing on the shaft, and it will lock it into place.

 

[mud2005]

The one-way clutch bearing will align itself on the shaft. You don't necessarily have to constrain it axially.

cool 8)

There are lots of variables but the drag from a freewheel or a one-way clutch bearing of similar size aren't that different. If you are back-driving a reduction stage that will add drag, though..

I was thinking of doing exactly that, but keeping the reduction around 3:1. hopefully that won't add too much drag. I want this bike to coast well so drag would be a bummer.

If you look carefull at that needle bearing, you'll see that it has two "shelves" at either end, with separate bearings. Assuming your shaft is smooth and of the same diameter along it's length, you could press fit a thin sleeve onto it at the inner end of where that bearing needs to ride, which would then slip over that sleeve once inserted to the shaft. Press fit a second sleeve into the shelf on the bearing on the shaft, and it will lock it into place.

hmmm, are you saying the bearings at the ends are slightly larger than the middle? I was under the assumption it was all .5" ID. how thin of are sleeve are you talkin?

 

[amberwolf]

I don't know how big the difference in I.D. is on the end sections vs the middle, only that I can clearly see there is a difference. If that primary I.D. is only 0.5", the difference may be like 1/64" or something. You would have to ask the company.

Regarding the drag, if you can put the one-way bearing on the other end of things, it'd mean none of the driveline is backdriven by the wheel in coasting. But if you do, it has to take more torque in the locked direction that it would on the upstream end of the reduction.

 

[Miles]

It's designed to work on 1/2" shaft - no need for additional sleeves.

 

[j3tch1u]

So mostly what I'm wondering is how it stays in place on the shaft? It seems like it would slide from side to side as it's rolling.
This could be prevented by mounting 2 collars on either side of the bearing, but that would create friction it seems.
Could side friction be prevented with a couple of these thrust bearings in between the collars?

i think you probably want to turn a groove in the shaft and slip a retaining ring (ie circlip) onto it. circlips are generally preferred over locking collars.

 

[dontsendbubbamail]

i think you probably want to turn a groove in the shaft and slip a retaining ring (ie circlip) onto it. circlips are generally preferred over locking collars.

I pressed one of these into a gear on my push trailer. To keep it from possibly coming off should the chain break, I tapped the end of the shaft and screwed a washer to the end.

Another thing to think about is how much torque you are putting to the clutch. I am no expert at the calculations for touque and it has been a while since I did them, but this clutch would have been marginal if used on the second stage of a two stage reduction system that drives a 26" wheel. One of our mechanical masters might be able to explain this better or let us know if I am off base.

Bubba

 

[Miles]

More info, here:
http://www.pacificbearingsales.com/pdf/rollerclutch.pdf

VXB should really give the torque rating..........

Is this on a motor shaft, mud?

They can be more trouble to mount, but I much prefer the sprag type clutch bearing to the drawn cup roller type.
http://www.vxb.com/page/bearings/PROD/Kit8178

 

[j3tch1u]

Another thing to think about is how much torque you are putting to the clutch. I am no expert at the calculations for touque and it has been a while since I did them, but this clutch would have been marginal if used on the second stage of a two stage reduction system that drives a 26" wheel. One of our mechanical masters might be able to explain this better or let us know if I am off base.
Bubba

good point. that bearing vxb sells is made by nsk shanghai. torque rating is only 8.34 Nm. i've blown up an FCB-12 (13 Nm). at the very least, go with RCB-121616 (3/4" shaft, 22 Nm) and make a hardened steel collar locked to the shaft with two pairs of opposing cup-type set screws offset away from the needle bearings (the holes interfere with proper bearing contact). oh and don't forget the loc-tite.

RCB-162117 (1" shaft, 33 Nm) would be the best choice.

ben

 

[mud2005]

Is this on a motor shaft, mud?

no, on the shaft of a single stage reduction unit.

They can be more trouble to mount, but I much prefer the sprag type clutch bearing to the drawn cup roller type.

those look good, but would require a different design to use with a small sprocket due to their larger diameter.

also how would you prevent it from turning on the shaft w/o a keyway? would some kind of epoxy be enough?

 

[liveforphysics]

More info, here:
http://www.pacificbearingsales.com/pdf/rollerclutch.pdf

VXB should really give the torque rating..........

The torque rating is totally dependent on shaft hardness, and the lube used. It would be really tough to list a rating that had much meaning.

 

[mud2005]

I got the shaft in the mail today, it's hardened and claims to be 60-65C http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=7155279&PMT4NO=0

 

[liveforphysics]

I got the shaft in the mail today, it's hardened and claims to be 60-65C http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=7155279&PMT4NO=0

I don't know how to calculate the differences, sorry! I bet BigMoose can though You gotta look at the sprague clutch at it's base level. It's a little rounded metal edge that gets pressed against a surface, and the friction between the two is the only force letting it transfer any torque. It must be lubricated to not wear while spinning in the unloaded direction, and yet the lubrication has a direct effect on the friction when it locks to transfer torque. A bit of high pressure lube, like moly grease, means instant slippage and destruction. The choice of lube must be something that can push out of the way and try to leave as minimal of a film between the surfaces as possible.

IMO, 1-way bearings have been a continous disappointment for me. Even Honda can't make them last in there auto-trannys (it works of course, but fails in time, or quickly when abused.) I've serviced cranes that used 5" diameter sprague clutches on the main hoist spool, and they fail just like all the other ones fail. Trying to grip a lubed smooth polished rounded hard surface with another smooth polished rounded hard surfaces is possible (due to crazy torque to force leverage happening on the little oval roller), but it's always been sorta a temporary unreliable band-aid type solution in my experience.

 

[Miles]

those look good, but would require a different design to use with a small sprocket due to their larger diameter.

also how would you prevent it from turning on the shaft w/o a keyway? would some kind of epoxy be enough?

You could use Loctite 603 to bond it to the shaft.

 

[Miles]

More info, here:
http://www.pacificbearingsales.com/pdf/rollerclutch.pdf

VXB should really give the torque rating..........

The torque rating is totally dependent on shaft hardness, and the lube used. It would be really tough to list a rating that had much meaning.

And containment....... Nevertheless, there are torque ratings for them.....

 

[mud2005]

thanks Luke, good to have some perspective. You have some valid points there. Might have to use a freewheel after all.

You could use Loctite 603 to bond it to the shaft.

sweet, thats good to know.

Miles, did your Moulton build use a one way bearing? if so hows it holding up?

IMHO the ultimate solution would be a custom freewheel inside a chainwheel adapter that bolts to a disc brake mount.

 

[Miles]

Miles, did your Moulton build use a one way bearing? if so hows it holding up?

Yes. It's fine.

 

[liveforphysics]

Miles, did your Moulton build use a one way bearing? if so hows it holding up?

Yes. It's fine.

If you've got a long-term winner on your sprague Miles, you should share the model/brand, the loading it's under (and estimate of shock loading), what care you give it, and what shaft materials and lube it's using. Maybe you've found a combo for long-term success.

For a sprague/shaft set, you might want to check an auto-tranny rebuild shop. Most of them each have 2 sprague clutches at diameters around 1-1.5". You could get hosed shafts and used sprague clutches for free, as they just go in a scrap metal recycle box otherwise. Again though, this is a part that has a history of plauging me with failures and disappointments, so I would definately recomend something with some mechanical locking function over friction function. Just my $0.02 But if it works for Miles, you might wana copy his setup.

 

[Miles]

Hi Luke,

I used a CSK35 on the rear wheel pulley. Nominal rating is 140 Nm (50% of peak rating).

It's an independent unit - it doesn't use the shaft as part of the clutch mech. I'm not that keen on the type that do.

 

[j3tch1u]

Hi Luke,

I used a CSK35 on the rear wheel pulley. Nominal rating is 140 Nm (50% of peak rating).

It's an independent unit - it doesn't use the shaft as part of the clutch mech. I'm not that keen on the type that do.

thanks for the part # miles. i am going to try that as well--looks more robust than a drawn cup. it's also thin enough to cut out a keyway with a t-slot end mill (from both sides) and stack a couple of them together.

 

[Miles]

it's also thin enough to cut out a keyway with a t-slot end mill (from both sides) and stack a couple of them together.

You can get them with internal and external keyways (not from VXB).

 

[j3tch1u]

it's also thin enough to cut out a keyway with a t-slot end mill (from both sides) and stack a couple of them together.

You can get them with internal and external keyways (not from VXB).

i didn't know that--awesome! . now i should be able to shave 6mm off the width of my drive.

 

[mud2005]

i didn't know that--awesome! . now i should be able to shave 6mm off the width of my drive.

please post a link if you find a supplier for the keyed units I couldn't find any. Thanks

 

[Miles]

http://www.bearingexperts.com/ONE_WAY_CLUTCH_BEARINGS_CSK_Series.htm
No idea of the quality/manufacturer............