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BEARING INTELLIGENCE: the clever way to extend machine life?

Bearings that can diagnose and report on their own surroundings offer huge potential benefits to engineering applications – from trains to wind turbines. Donald Howieson, business manager, Service Platform at SKF, explains


hen a warning light flashes on your car dashboard, it usually

means that something – perhaps the fuel pump or an electronic component – has failed, and replacing the part usually fixes the problem. But what if component problems could routinely be diagnosed before they needed replacement? This is a scenario that is becoming far more prevalent in industry – where machinery can cost millions rather than thousands – and every minute of downtime equates to a lost fortune. By fitting an array of sensors to the

machine, engineers can measure conditions such as excessive bearing vibration, reducing the total cost of asset ownership and extending machine operating life, while maximising machine uptime and minimising downtime. However, while this can help to avoid catastrophic failures, vibration signals are normally produced when fragments of steel begin to spall from the raceway surface of the rings or rolling elements – at which point the bearing has already suffered damage that affects performance and lifetime. A new approach puts diagnostics at the

heart of the machine by transforming the bearing into its own sensor. Intelligent bearings are equipped with a self-powered, wireless sensor that can transmit process data to a central point, identifying potential problems very early. This takes it beyond the capabilities of traditional condition monitoring. Of additional benefit, the bearings could be used in previously inaccessible places such as rotating gearboxes. Here, leading wires in (to supply power) and out (to deliver data) would be impossible, but intelligent bearings could cope with ease. The ability to use these at the heart of a machine, where sensors are normally impossible to embed, would provide much more detail of the operating environment, and could even make it possible to uprate a machine, extending its life or power rating beyond

its initial specification.

INTELLIGENT BEARINGS SKF has commercialised an intelligent bearing, in the shape of its SKF Insight technology. This is capable of measuring the critical parameters that lead to early bearing failure, such as lubricant contamination or excessive temperature. As a result, it can anticipate and prevent damage to bearings – and to the machine itself. Insight was developed because it was recognised that bearings rarely fail in service under normal operating conditions. Instead, the usual cause of failure is misuse: insufficient lubrication, for example, or running the bearing under conditions outside those originally specified. The concept has been designed

SKF has

commercialised an intelligent bearing, in the shape of its SKF Insight technology

the rail industry. These safety-critical components are normally changed at set intervals, regardless of their condition. Intelligent bearings would provide more accurate data, allowing change-out intervals to be determined based on actual – rather than predicted – operating conditions. Wind turbines, however, could benefit

most from this kind of technology. In some offshore applications, the cost of changing a wind turbine main bearing is so high that it undermines the business case for building the turbine in the first place. So it makes sense to record lubrication conditions in service, and take action to avoid damaging conditions. Smart bearings are being explored for wind turbines that can monitor bearing speed, vibration, temperature and lubrication levels.

They will allow dynamic bearing information to be

measured in the true operating “Insight

was developed because it was

recognised that bearings rarely fail in service under normal operation conditions. Instead, the usual cause of failure is misuse”

SKF Enter 204

state and wirelessly communicated to remote monitoring centres or local maintenance crews. Furthermore, because technology such as SKF Insight can be retro-fitted, it could enhance the efficiency of both new and existing turbines. For now, intelligent bearings are squarely aimed at these high end applications. In the future, however, they may find their way further downstream, and into the prime example of consumer engineering: the car. Now that really would revolutionise the maintenance process.

for challenging applications. In steel manufacturing, for example, SKF has fitted smart bearings into a continuous caster – an environment far too hostile for cables and external sensors – to monitor key process parameters, thanks to embedded self-powered wireless sensors. Further ahead, there may be

applications for wheel end bearings in / DESIGNSOLUTIONS DESIGN SOLUTIONS | FEBRUARY 2015 11

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