What is a smart bearing?

Jon Lawson

According to the TUC, the average rail commute in the UK takes an average of 2 hours and 11 minutes every day. Also add to the equation that last year, more than one third of trains failed to arrive at stations due to technical faults, and you’re left with one very miserable commuter. Chris Johnson, managing director of industrial bearing supplier SMB Bearings, considers the future adoption of smart bearings and their impact on Industry 4.0 and the UK.

Bearing designs have stayed fairly consistent for decades. There have been new developments in the form of bearing materials like ceramic, hybrid and plastic; and new lubrication options are now available in the newly-discovered material, graphene. But, a new development could surpass even these: a collaboration between bearings and the Industrial Internet of Things (IIoT) that could provide value both across production processes and entire operations.   

Digitalisation is making a major change in how maintenance can be executed. Specifically, with the adoption of IIoT-based smart bearings that can self-diagnose impending faults and failures using sensors integrated into the bearings themselves. These sensor bearings are different from traditional solutions, which usually involve a standalone sensor mounted near the bearing. Instead, the sensor is integrated to measure bearing speed and direction, which is then relayed to a control system.

Sensor bearings work through a magnetic pulse generator ring. Alternating poles are mounted to the inner rotating ring, while the outer ring carries the sensor housing. As the inner ring rotates, the generator ring passes over the stationary magnetic sensor and detects the change in magnetic polarity. This generates an electrical signal that is then processed and converted into direction of rotation and rotational speed data. 

Recorded data can then be transferred via a gateway to the cloud, where engineers will be able to access the information in real-time. Take, for example, smart bearings used in the railway industry. Measuring radial shift displacement allows the radial force on the sensor bearing to be calculated. This is mixed with innovative software, to give accurate calculations of the displacement and torque of other bearings and elements. 

This means that information on overloading can be easily recorded and used to limit torques, or even switch off the drive if needed. By monitoring these critical assets, there’s a higher chance of avoiding unplanned stops for enhanced overall rail operations.

Smart bearings also address a host of industrial applications, including the monitoring of thermocouple (speed and temperature) and accelerometer (vibration) levels. 

But, does this make them smart? It all depends on the key parameters that are to be monitored. After all, anything can be sensed — the hard part is knowing what to sense and what the output signals mean. 

With smart bearings, engineers can adopt a proactive approach to maintenance by monitoring machine processes such as pressure, force and vibration — each of which provide critical data for predictive maintenance. Real-time updates on the condition of bearings and other components allow for advanced diagnostics to be performed. Early warnings about any deterioration in bearing condition can also be accessed.

Adopting a proactive maintenance approach has many benefits. When a piece of equipment or a system malfunctions, the entire process comes to a standstill while the problem is fixed. By accessing advanced data on the operating status of a machine, it’s possible to drastically reduce downtime and prevent factors that cause breakdowns. Avoiding system or machine breaks also minimises the need for repairs during operating hours.

A proactive approach to maintenance also benefits the durability of a component or machine, specifically, by solving the root causes of a problem, rather than merely dealing with the signs of a pending error. The longer the machine or component lasts, the longer the replacement costs can be deferred.

What component could be better-equipped to gather this critical data than a smart bearing? Bearings are typically located in the heart of all rotating applications; with rotational speeds, forces and vibrations all impacting on them in some way. 

As industries continue to grow and develop, additional smart bearing sensor data is needed to more closely monitor proper bearing functions and optimise operations. Advancements in bearing technology, including data sharing and maintenance tracking, will continue to be researched and developed across more applications. 

In the railway industry, adding smart bearings will provide operators with real-time, on-board information on bearing health, and allow the detection of early bearing damage. Because train bearings are key elements in the integrity of railway wheel sets, the integration of condition monitoring will significantly impact railway operating costs, and train safety.

Hopefully, in the future, with the integration of smart bearings, the rail commuters of the world will finally arrive at work on time.