Oil Sling RIng

[smurf40]

Dear Group,

I need some help regarding sling ring design. I'm looking for some theory for the correct dimensioning of the geometric form of a sling ring in relation to protecting oil seals on the motor input shaft to a industrial gearbox.

Does the sling really help in reducing the oil pressure on the seal lips thus reducing oil forced past the seal once worn ?

Thanks

 

[electricpete]

Does the sling really help in reducing the oil pressure on the seal lips thus reducing oil forced past the seal once worn ?

Yes, if compared to the alternative of raising the oil to 1/4 - 1/2 height of the lowest rolling element.

Oil level should be in the neighborhood of 1/4" to 3/8" above the inside of bottom of the oil ring. I think I heard somewhere oil ring diameter is typically 1.5 - 2 times diameter of shaft. But I am no machine designer. I'll bet there might be a lot more to it than that.



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[smurf40]

Thanks for your reply electricpete

Just to clarify, this particular sling ring has been added to the shaft only to protect the seals on the input shaft from the electric motor, that is sling oil away from the seals, not to throw oil up on rotating gears.

I have seen applications where sling rings are used so that oil levels in gearboxes can be reduced due to the sling ring throwing oil up onto the rotating parts of the gearbox but not as a preventative measure for oil seals as this is.

 

[electricpete]

ok, I misunderstood. I have never heard of that.

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[diskullman]

This sounds similar to a Forsheda V ring.

http://www.skf.com/portal/skf/home/products?newlink=4_3_1&lang=en&maincatalogue=1

Russell Giuliano

 

[sreid]

There is a picture of a shaft slip on rubber slinger ring in the Fagor Rolling Bearing book but I have no idea where to purchase them.

 

[Tmoose]

I'm not clear which component you are protecting from oil.
Generally Rotating Lip seals expected to last are not directly subjected to pressure, lest they wear quickly.

The SKF website has some seal info. It's hard to navigate, in my opinion.
Here's a site with some condensed SKF info.

http://www.ckit.co.za/secure/conveyor/troughed/pulleys/pulleys_plummer_blocks_seals.html

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http://www.gemotors.com.br/products/motors/imagens/bearing_2.jpg

This labyrinth appears to have a rotating slinger on the shaft to block a "line-of-sight" gap from outside contaminants, and also centrifuge liquid away from the gap.
Notice the shape would direct blocked liquid down and back out to the environment. Some diameters must be tapered or conical to provide dynamic and static sealing.

The blocked liquid must be managed and directed.
This design has a drain port out the bottom.

http://industrialpackingseal.thomasnet.com/ImgMedium/seal.gif

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Static sealing management can benefit from (or require) details that force liquid to run or drip in a safe location. The formed aluminum drip edge used on roofs is used specifically to block water from sneaking back toward the wall, even when wind driven. Similar details appear on window sills.

http://www.copper.org/applications/architecture/arch_dhb/flashings_copings/images/11a.gif

I routed a drip groove under our kitchen counter top to keep spills from creeping back to the cabinets. (When un-named family members leave drawers partly open, the drip groove is defeated, and the forks, spoons, and english muffins suffer the consequences)

p://

http://www.yemmhart.com/images/materialdata/dripgroove.jpg

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