To be clear, “smart” bearings—i.e.,
bearings and sensors integrated into
a component to monitor bearing
performance—are not new. They’ve
been around for decades, dating back to
military applications circa World War
II. Since then, they have played a vital
role, according to the Bearing Specialists
Association (BSA), in the automotive,
motion control, robotic control, paper
and printing, web processing, wood
processing, chemical, textile, agricultural
and food processing industries. (Ed.’s
Note: Please see accompanying BSA sidebar
on smart bearings.)

Victoria Wikstr?m, manager of
SKF’s industry applications segment group, provides some additional historical
perspective.

“(Smart bearings were developed) for
applications where personal damage and
safety are key, and the consequences of a
bearing failure can lead to serious injury
and even fatality, as opposed to ‘merely’
fi nancial issues. Therefore, bearings in
jet engines were fi rst to be monitored
by sensors (in fl ight), and by inspections
and oil analyses on the ground. The
automotive industry’s adaptation of antilock
brake systems (ABS) is probably the
fi rst large-volume sensorized bearings
(position sensoring). Railway locomotives
and cars have been using temperature
warning sensors for some 20 years, even
if these were not mounted as an integral
part of the bearing but as an add-on
through the housing.

“For industrial applications, use of
sensorized bearings has not been as
widely adopted as the opportunities and
available benefi ts that are out there. But
with higher demands on uptime and
reducing maintenance costs, it is defi nitely
increasing—load sensing (using strain
gages) for paper machines, vibrationand
temperature-condition monitoring
for many industries, oil quality sensors
for gearboxes. Today, for car applications,
SKF has working prototypes of load
sensing via sensor technology integrated
into the wheel bearings.”

Darin Davenport, product business manager for Dodge Roller Bearings,
adds that in addition to the military
applications, “Sensor technology was also
likely improved through R&D dedicated
to aerospace. We don’t have proof of this
though. Dodge only started offering smart
products in 1995, when we leveraged
Rockwell (Automation’s) experience.” He
adds, “Sensor and monitoring capabilities
are the primary value added features,
but the bearing housings are modifi ed
to provide accurate sensor reading and
proper sensor mounting.”

Given that bearings are often one
of the most important components in a
machine, system, etc.—and are often one
of the fi rst to fail—having a reasonable
expectation of their longevity is essential
to maintaining peak performance cost.
Smart bearings do just that in sensing
vibration, temperature, speed, load and
debris levels, to name just a few. Taken a
step farther, they also are commonly used
in industrial applications, in that the
sensed data is extrapolated into condition
monitoring systems for the monitoring
of the aforementioned vibration and
temperature issues. (Ed.’s Note: For more
on condition monitoring, please refer to our
feature story on page 20.)

According to the BSA, smart
bearings have long played a big role in the
automotive industry—in hub units, for
example. That anti-lock braking system
and traction control in your automobile are made possible by smart bearings.