NILOS-Rings

Optimizing ring
performance
Lubrication
Prior to mounting for first-time use, the
S-shaped sealing grooves of NILOS-Rings
should be filled with grease to prevent
subsequent damage to the ring’s sealing
tongue.
In preparing double externally sealing
NILOS-Rings (AK), featuring two sealing
edges, the space between the edges
must likewise be filled with grease before
mounting. (The type of grease used to lubricate
tapered roller bearings will suffice.)
If a bearing will be exposed to excessive
amounts of water, the grease chamber
would best be filled with a water-repellent
sealing grease.
After grease is applied, NILOS-Rings
require no further maintenance.
Sealing
As part of the installation process,
the sealing edge of a NILOS-Ring is rotated
under light pressure against either the
inner or outer ring of the bearing. (This is
known as run-in or groove-forming.) This
rotation creates a shallow groove (or miniature
labyrinth) in the hardened bearing
ring, which inhibits loss of bearing grease
and prevents penetration of debris.
If a design permits, inner-sealing NILOS-
Ring types offer particular advantages:
Their sealing edges are relatively smaller
(for optimum fit) and the position of sealing
edges with regard to centrifugal force of
lubricant will prove highly favorable.
Concentric location
In order for the miniature labyrinth groove
to form during run-in, the sealing edge of
the NILOS-Ring must run precisely concentric.
With externally sealing rings (AV types),
users should fit the bore of the ring closely
to the shaft; with internally sealing rings
(JV types), users should locate the outside
edge of the ring centrally within the bearing
casing hole. In either case, the locating diameter
should not be proximate to keyways
or grooves and the inner and outer edges
of a ring’s inside recess should not be on
(or in) threads, thread runouts, pushed-up
sections, or hollow sections.
Space requirement (h 1 )
An often-cited benefit of NILOS-Rings
is that they require minimal space to install,
whose parameters can be calculated quickly
and easily.
Referring to dimension tables, installation
height (h) represents the overall height
without affecting sealing action and h + 1
mm represents the space required to mount
the ring. Adhering to this formula can eliminate
the possibility of ring distortion upon
installation.
Slip-proof clamping
Ring design and installation procedure
offer certain safeguards to prevent rings
from turning in service. The shaft collar of
externally sealing types (AV) is designed to
fit snugly against a bearing to promote slipproof
clamping. For internally sealing types
(JV) users can rely on installation clamping
elements.
Space requirements
h
D
c
i
h 1
Run-in groove after 24 hours
s
Application notes
NILOS-Rings can seal self-aligning or
spherical (barrel-type) roller bearings only
when the bearings are utilized for their high
load-carrying capacities and never when
misalignment may be a factor.
In applications utilizing cylindrical bearings
without rims (or flanges) LSTO-type sealing
elements are recommended, since they can
accommodate axial shifts to a maximum
of 0.3 mm. (LSTO types are profiled in a
separate section of this catalog.)
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