|Introduction NIS bearing units
A typical ball bearing unit consists of a double sealed, single row
bearing and one of the various housings of cast iron or pressed steel.
Bearing Unit Structure
The outer ring of the self-contained ball bearing is ground to a
sphere and the bore of the housing is machined to a matching radius.
This permits self-alignment between the two members. Above figure is a
view of a pillow block which is the most popular type of insert ball
bearing unit with set screw locking. Bearing units have various types of
sealing options and can operate satisfactorily under hard working
conditions, especially for machines operating in dusty or muddy
surroundings. They are thus, widely used in agricultural, construction,
foodstuff and conveying machinery.
NIS Bearing unit features
Three types of sealing methods are available for use in various
RS+Slinger : A pressed metal shield is fixed to the
inner ring of the bearing unit and a rubber seal is attached onto the
outer ring. The pressed metal shield acts as a "slinger"
ejecting contaminants upon contact. The rubber seal forms standard
sealing torque. Working in combination with the rubber seal it forms an
effective barrier against entrance of foreign matter such as dust, mud,
vapour and prevention of grease leakage to keep the bearing in good
Triple lip seal : A metal
shield with long triple rubber lips provide high sealing torque and
forms good sealing against wet environments. It is especially suitable
for agricultural machinery operating at poor environmental conditions.
RST type : Covers the
functions of both shield and seal. The rubber lip and inner ring form a
standard torque contact sealing. It will provide an effective barrier
All NIS bearing unit housings are made from solid "one-piece
construction" cast iron to provide maximum rigidity against
deformation at mounting and wear resistance at any operating conditions.
Shaft locking mechanisms
NIS bearing units can be locked onto the machine shaft by three methods.
Locking by set screws, eccentric collar and adapter sleeve methods are
available. All methods employed ensure easy and secure locking of the
bearing to the shaft. Most popular method is by set screw locking.
|Special heat treatment on bearing inner
The inner ring of the self-contained bearing is hardened on the
raceways and surroundings. For NIS bearings the set screw hole area is
also hardened and tempered, imparting high hardness and impact
resistance. This additional heat treatment ensures full bearing
performance and prevents the set screws from loosening during operation
as the set screw can be tightened enough without causing the screw
threads on the set screw hole to shear off.
NIS bearings come equipped with a unique locking pin (or ball) which
prevents the bearing outer ring from rotating without interference to
the self-alignment of the bearing. This improvement is capable of
extending bearing life.
Skilled precision workmanship on the self-contained bearing and the
housing provides complete interchangeability between bearing and
housing, thus allowing quick and simple replacements when required.
All NIS bearings come pre-lubricated with sufficient quantity of high
quality grease, individual seal and packed. These bearings are ready for