PDA

View Full Version : Unusual Bearing



lynnl
08-15-2009, 03:03 PM
My son-in-law is a machinist for a local company doing mainly defense and aerospace stuff, mainly prototypes and test models (wind tunnel, etc.), and I occasionally get a little guided tour. There's always gobs of "Gee Whiz" stuff to see there. This morning I went down to get my 11 year old grandson to hang out with me today, and saw what to me was an amazing bearing.

This one was about 2-3" ID and 4-5" OD, and the inner race w/rollers is kind of a gimble within the outer race. i.e. it can rotate completely around within that outer race. I was amazed. Looked like some top notch engineering went into that. Neither of us could figure out exactly how the rollers are held captive. He didn't know how much the bearings cost, but said they're very spendy.

Here's a link:
www.brammer.com.pl/DOWNLOAD/5215_e_srb_explorer.pdf

Well, that didn't work. Try this google link and click on the bottom pdf download:
http://www.google.com/search?hl=en&q=explorer+bearings&aq=0&oq=Explorer+bear&aqi=g1

I don't know, maybe some of you work with such things every day, but I was real impressed.

winchman
08-15-2009, 03:55 PM
It looks like the outer ends of the rollers are recessed into the outer race to retain the rollers and provide a (probably very) little thrust load capability.

I've got a smaller (1 3/8" OD) double-row ball bearing with an inner race (and balls) that swivels like a ball joint:
http://img.photobucket.com/albums/1003/winchman/bearingswivel.jpg

The inside of the outer race is spherical. The inner race has two grooves.

Roger

topct
08-15-2009, 03:58 PM
Self aligning roller bearings. The rollers are held captive by the cage and inner race.

Timleech
08-15-2009, 04:17 PM
Look at

http://bbs.homeshopmachinist.net/showthread.php?t=31183

Last post in the thread. Bearing is about 6" ID, AFAIR.

It's a German gearbox from the 1950's, this style of bearing was, as I understand it, particularly favoured by the Germans and the new bearing came in from Germany (although the one we replaced was Japanese).

Tim

lazlo
08-15-2009, 04:46 PM
The inside of the outer race is spherical. The inner race has two grooves.

"Spherical roller bearing." They come in ball and cylindrical rollers:

http://www.ntnamerica.com/pics/indust14.jpg

Like Roger says, they're used when there's axial misalignment with the shaft. The Monarch 10EE uses them for the leadscrew bearing.

topct
08-15-2009, 06:05 PM
Spherical is the correct name.

First one I ever hand in my hands twisted like in the pictures and I had a little panic attack thinking the crazy thing was going to fall apart.

A.K. Boomer
08-15-2009, 09:13 PM
Never seen the likes of em,
I'll tell you one thing though - as far as the roller ones - I would expect special lubrication due to the scuffing action involved, like a hypoid grease.

wierdscience
08-15-2009, 09:55 PM
The last set I changed where 250mm ID and ran in DTE24(10wt hydraulic oil) which was pumped through a cooler and back to the bearing housing.Those bearings were $2600 ea,less housings.

lynnl
08-15-2009, 10:29 PM
When the inner race w/rollers is tilted out from the outer race it's obvious the rollers are free floating, certainly on the outer end, and about 2/3 of their diameter is standing proud of the race. (that can be seen in the 2nd pix of the pdf link)

What I assumed is that the separator part of the cage, between the two rows of rollers, which is tapered, tapers more than the angle of the rollers, so that as the roller is lifted up its length is > the space between the separator and the end of the nest holding the roller. (that's not very clear verbiage, but it's the best I can think of at the moment)

$2600 a pop huh? ...the application in question will use 8 of those (movable fins), and is an overall assembly whose ultimate purpose is to go "boom". Well, freedom ain't cheap...

I wouldn't have been so surprised at SOME tilting movement, but these can flip completely 180 deg, so the left inner side becomes the right inner. Pretty amazing to me anyway.

macona
08-15-2009, 10:41 PM
"Spherical roller bearing." They come in ball and cylindrical rollers:

http://www.ntnamerica.com/pics/indust14.jpg

Like Roger says, they're used when there's axial misalignment with the shaft. The Monarch 10EE uses them for the leadscrew bearing.

Yep, both lead screw and the feed shaft.

Also my Tsugami grinder uses them to adjust alignment in the worm gears where there used to be a power feed. The bearing was mounted eccentrically in the end cap and twisting the end cap adjust the clearance between the worm and gear.

lakeside53
08-16-2009, 12:35 AM
Yep.. My Polamco lathe uses one (1209) on the outer spindle pulley support. Stupid expensive from a bearing house, but I've seen NOS on ebay for $19.95!

oldtiffie
08-16-2009, 02:48 AM
Spherical inside and out - SKF plummer bearings and blocks:

http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=6_2_31

http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=6_2_32

http://www.google.com.au/search?hl=en&q=skf+plummer+block+bearings&meta=&aq=1&oq=skf+plummer+block