Axial thrust bearing with radial movement

[alansimpson]

I submitted this post in bearings, however there seems to be more traffic here.

I am doing tests with spinning objects and I need an axial thrust bearing that allows some radial movement 2-3 mm.
Axial loading 10 Kg, 20 Lbs. Speed 200-500 RPM

At the moment I use a steel or ceramic ball 2-3 mm fixed to the to end of spindle. The spindle spins with ball coming into point contact with hardened polished steel surface of micrometer anvil 1/4 " dia. This is a bit of made up arrangement but it works quite well. I would prefer something off the shelf. Also I have no idea of how much wear is going on and what would be the best combination of bearing materials or ball radius

Jewel bearings are too small and "cup and cone" arrangements wouldn't allow radial movement. Axial thrust ball or roller races would result in roller noise.

I need radial movement as spindle finds it's own center.

I need low friction, low noise.

Environment is normal room conditions reasonable clean. Lubricants can be used.

Any input would be welcome.

Thanks

 

[benta]

It's not a problem to buy axial ball bearings with flat raceways, this would allow radial play.
See for instance INA series EW, FT and FTO.

http://medias.ina.de/medias/de!hp.ec/1_R*0*2_R*25_R*26_R;aI0JAsioFI35?lang=en&x=5&y=10

Benta.

 

[j8715]

I'm not totally sure if I am following your description, but I think self-aligning ball bearings might be what you are looking for.

They are certainly low friction, noise I'm not sure about.

http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=1_2_1

 

[BobM3]

Self aligning bearings can rotate the inner race a bit for angular misalignment. I believe the OP is looking for radial movement.

 

[SincoTC]

I assume that what you want, is to avoid the rotating "point contact" between the ball and the anvil but retain the ability of the spindle end to find its own position as it rotates. I'm concerned that the spindle is very spindly (it goes up unsupported out of sight so it may be even worse) and will tend to "walk about" if the ball is not on the axis of rotation, or if the anvil is not truly square to this axis.

I see two possible solutions: Obtain a Helical coupling, (we use these):

http://www.heli-cal.com/cm/Home.html

with a bore and clamp screw to fit onto the spindle, open out the hole and thread the other (bottom) end of the coupling to accept the anvil's adjusting screw and then mount the couplings bottom end's OD (machine a shoulder if necessary) onto a grooved Ball Thrust Bearing sitting in the recess of the base plate. The coupling will drive the anvil assembly at spindle speed and if the coupling is of a suitable length, it will allow radial movement without over-controlling the shaft position, the helical construction of the coupling effectivly make it a weak compression spring so that there will be no axial conflict problems.

the other solution, altough not really thought out in detail, would be to put an enlarged head onto the spindle and support the face on an air-cushion by bleeding compessed air through a "Puck" mounted in the base plate.
The face of this enlarged end would need to support the load but allow the end to remain parallel to the face of the puck (retain the ball to take end load and use a flexure mounting to drive and allow swivel)




Trevor Clarke. (R & D) Scientific Instruments.Somerset. UK

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