CARB® toroidal roller bearings – a revolutionary ... - Acorn Bearings

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The winning combination Page ............. 12 Page ............. 37
The winning combination
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Self-alignment ...
Self-aligning bearings are the hallmark
of SKF – not surprising since SKF was
founded in 1907, based on the invention
of the self-aligning ball bearing by Sven
Wingquist. But the development did
not stop there, other SKF inventions
followed: the spherical roller bearing in
1919 and the spherical roller thrust
bearing in 1939.
Self-alignment is called for
• when misalignment exists as a
result of manufacturing or mounting
errors
• when shaft deflections occur under
load
and these have to be compensated for
in the bearing arrangement without
negative effects on performance or
any reduction in bearing service life.
... and axial
displacement ...
SKF was also heavily involved in the
development of bearings having rings
that can be axially displaced with
respect to each other. In 1908, for
example, the cylindrical roller bearing
in its modern version was largely
developed by Dr.-Ing. Josef Kirner of
the Norma Compagnie in Stuttgart-Bad
Cannstatt, which became a subsidiary
of AB SKF.
Cylindrical roller bearings are applied
when
• heavy radial loads and relatively
high speeds prevail and
• thermal changes in shaft length
must be accommodated in the bearing
with as little friction as possible –
provided, of course, that there is no
significant misalignment.
... combined for success
Previously, it was always necessary to
compromise. Because misalignment or
shaft bending makes the use of selfaligning
bearings essential – and,
depending on load and speed, the
choice lay between self-aligning ball
bearings and spherical roller bearings.
However, in contrast to cylindrical
roller bearings, those bearings cannot
accommodate important axial displacements
within the bearing.
Therefore, it was necessary for one
of the bearings to move axially on its
seating in the housing. Such movement
is always accompanied by considerable
friction, which produces internal axial
forces in the bearing arrangement.
The result is a shortened bearing service
life and relatively high costs for maintenance
and repairs.
Today, this is a thing of the past.
Because Magnus Kellström, a product
designer at SKF, had a brilliant idea;
he invented the toroidal roller bearing.
This bearing not only can compensate
for misalignment without friction, but
also for changes in shaft length within
the bearing. Thus a completely new
type of bearing for non-locating
arrangements has become available
to the engineering world.
It is no longer necessary to compromise,
and there are added benefits
too – much longer service life for the
complete bearing arrangement and
minimized maintenance and repair
costs.
Self-alignment …
… and axial
displacement …
… combined in
a toroidal roller
bearing
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