Seal design
Seal design
(OP)
Hello folks,
I'm designing a new spindle and I'd like to have a great seal design. I got some information with skf but i'd like to have something more relevant. Does someone have an idea where I can find more information?
Thanks for any help
I'm designing a new spindle and I'd like to have a great seal design. I got some information with skf but i'd like to have something more relevant. Does someone have an idea where I can find more information?
Thanks for any help





RE: Seal design
RE: Seal design
Most bearing distributors also sell seals. I would start there. They can at least give you some company names to further your research.
RE: Seal design
May only be available on SETCO spindles or under licence.
RE: Seal design
EnglishMuffin, I looked for those setco seals. They seem to work really good. I'll let you know if they sell it apart.
RE: Seal design
See - ht
RE: Seal design
I called setco en unfortunately, they don't sell the seals apart.
And what about the axial clearance on labyrinth seals? I designed some axial labyrinth seals and the axial gap between the seals should be, according to skf recommandation, 3mm. Why this gap is so big? Is it because of the thermal expansion or to have a room for the grease? I wonder if I have to be so precise?
RE: Seal design
My recommendation is not to have labyrinths or other metallic non-contact seals embedded in big housings. In the event of a touchdown the heat generation forces the seal to expand inward, quickly turning into a brake gripping or even welding to the shaft. Using various bearing bronzes for the lab material does not help. Bronzes' high thermal expansion just makes it grip harder faster.
RE: Seal design
RE: Seal design
Many companies sell unitized seals, just press on shaft & bore and don't need to worry about setting the clearances.
RE: Seal design
Sometimes it makes sense to machine part of the labyrinth right in the bearing side of the spindle flange. Decreasing bearing width then stuffs the labyrinths deeper axially. There will be a radius or chamfer at the "bottom" of the laby groove. The mating laby lip would need a generous chamfer to ensure no rubbing. The chambers resulting from axial clearance can be used as collection areas for pressure relief and leakage, especially when combined with grooves, drip edges, and drainage troughs or weep holes.
Axial labyrinth clearance is my friend.
RE: Seal design
RE: Seal design
RE: Seal design
Give them a call.
http://www.inpro-seal.com/apps/machine.phtml
RE: Seal design
RE: Seal design
Like everyone else we had some failures, mainly from the use of "hardcore unemployable mechanics" making field adjustments. As you probably know the Isolators requires a little finesse.
I can’t recall any on the spindle side though I know there had to be a few due to bearing failures.
RE: Seal design
RE: Seal design
Mid 90s FORD Europe (Lima?) received a batch of new spindles for an engine component machining tranfer line. FORD, against the spindle manufacturer's vigorous protestations, had specified the then-current spindle version of INxxO seals. Shortly after the line was commisoned spindles started failing. Each time the spindle manufacturer claimed coolant contamination had been the cause. After many coolant contamination bearing failures, and receiving the report from the spindle manufacturer's in-house testing, FORD payed the spindle manufacturer to substiture their own proprietary labyrinth with AIR purge (which is what the spindles would have been built with). The spindle failures stopped.
The coolant environment on machining transfer lines of the time was EXTREME. Coolant sprayed everywhere inside an enclosure where the workpieces, tooling, (and spindle noses) lived.
As of about 3 years ago I believe at least one of the INPRO designs for spindles included, (if not relied on) a certain amount of AIR purge, probably along with their belov-ed vapor blocking flying o-ring.
Please don't get me wrong. I am sure bearing isolators have their place.
I checked out the INPRO performance gurantee. http://www.inpro-seal.com/guarantee.phtml.
It is signed by Mr David Orlwoski, the inventor and patenter of bearing isolators.
"If you are not satisfied that it is working to your satisfaction, Inpro will either modify the Isolator to your satisfaction or refund your purchase price. "
They promise, by golly, to keep re-designing that isolator until it actually works, or maybe you will just get the isolator price back.
Each Machine tool Spindle rebuild cost several 1000s of $ (American bucks). Machine tool spindles are typically sold with a 1 year warrantee. Defective bearing, ineffective seal, poor workmanship or flawed materials, the spindle maker gets to eat it all, for a year.
Several years ago an acquaintance who builds race engines professionally had a valve spring retainer fail, and a valve wandered into areas it did not belong. Many expensive parts were destroyed. The manufacturer of the cam/lifter/valve/ spring/retainer system paid to fix the engine. I don't think many companies did that then, and fewer would today.
As of about 3 years ago The SETCO seal included a fully developed (by design and verified with tests) AIR purge with carefully managed AIR delivery.
Air, air, air.
If I suspect something is going to try to get into my spindle bearings I'd include some air purge.
RE: Seal design
Also, I read something interesting on seals. It says that spiral seal design should be avoided when the spindle is designed to rotate in both directions. Can someone tell me what is a spiral seal design? Is it a labyrinth seal?
RE: Seal design
RE: Seal design
Title : Konstruktionsrichtlinien fur beruhrungsfreie Spinddelabdichtungen im Werkzeugmaschinenbau - Teil 2
or "Construction Guidelines for Non-contacting Seals of Spindles in the Machine Tool Industry". Part 2
It was created by order of the association of German Machine Tool Manufacturers.
University of Stuttgart - Department of Sealing Technology
Authors : Leader : Prof Dr. Eng. H.K Mueller
Project Leader : Dr. Eng. W. Haas
Expert : Dipl. Eng E. Fritz
RE: Seal design
Either way, there is one direction of operating rotation.
RE: Seal design
The pumping effect of a seal is pretty interesting. I have some machines with vertical spindles with radial seals. The seal diameter grows from the inside of the spindle to the outside. So on a vertical spindle, for the top side, the pumping effect fights the gravity which is great. But for the bottom, the pumping effect flows with the gravity and I'm afraid that it could pump out both the seal and the bearing grease.
RE: Seal design
Keeping the bad guys out is tough.
There are a few machine tool exmples here.
http://
RE: Seal design
RE: Seal design
Getting the right grease, in the right (small) quantity, uncontaminated and evenly distributed into precision bearings thru a fitting or (?)in a "high speed" spindle would be a miracle.
One of hybrid ceramic bearings legitimate claims to fame is markedly improved "grease life." HC bearings, lubed at the factory with one of the super synthetic spindle greases, with non-contact "seals" (shields, to my way of thinking) are a pretty impressive product. It takes aggressive sealing, excellent manufacturing and craftsmanship to let them perform to their fullest.
RE: Seal design
RE: Seal design
RE: Seal design
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Which Inpro are you speaking of?
The front door link to machine tools took me to the VBX series.
More digging revealed Air Mizer, which is here. http://www
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The Air mizer appears to have airpurge (with a drain) on the work side, and the flying o-ring on the bearing side.