When a Bearing is Really a Hinge

Across a huge range of industries, continued production hinges on the performance and reliability of bearings. In sectors with aggressive operating environments, there’s a constant battle to keep bearings working in the face of high contamination levels, speed and temperature extremes, shock loads and vibration. NSK has a range of bearing solutions which keep equipment operating even in the most challenging conditions – reducing the risk, frequency and cost of downtime. 

If you were asked to name good examples of aggressive operating environments, you’d probably mention quarrying, mining and construction. It’s not only the conditions – where dust and dirt are intrinsic parts of the job – but also the often remote locations, that can make getting replacement parts a slow process and can lead to lengthy production downtime.

Yet the sector depends on bearings for equipment ranging from draglines to shovels, trucks and onveyors, and for operations from digging access tunnels to removing ore or mineral deposits, and crushing, grinding and screening the resulting material. In the unforgiving conditions, machinery and bearings are pushed to the limit, and 80% of premature bearing failure results from high contamination levels combined with poor lubrication. 

For one large quarrying company, the handling of 60% of their plant’s production depended on a single conveyor – which needed replacement head pulley bearings every 18 months. Bearing analysis by NSK revealed the root cause as water and grit ingress, and NSK High Tough steel (HTF) technology was trialled as an alternative bearing solution.

The heat is on

The steelmaking sector is another which provides unique challenges for bearings. Along with particle contamination, water, heavy and shock loads, vibration, extreme operating speed ranges, and rapid
acceleration and deceleration, a significant factor is the extreme temperatures, which were causing twice-yearly bearing failures on one international steel manufacturer’s rotary coal valve. 

The bearing failure also had knock-on effects in terms of lost production, downtime costs and damage to associated components. NSK conducted a bearing review which revealed the current bearing was inadequate for the high temperatures involved, and recommended a customised Self-Lube HLT bearing insert within a Self-Lube cast iron FC housing, plus a special heat-isolating spacer. Changes to lubrication amounts and frequencies were also recommended, and NSK engineers oversaw fitting of the new bearings for a trial. 

After more than 12 months the bearings still hadn’t failed, which meant a cost saving for the customer of over £127,000. 

A vital ingredient

In the food industry as in many other sectors, a single bearing can play a key role in a processing line – and a single bearing failure can shut down an entire process. But in addition to the need for high reliability, low- or no-maintenance and high speed operation, bearings in food processing environments are also required to comply with strict hygiene requirements.

There may also be frequent washdowns, hugely fluctuating temperatures, or constant high emperatures (up to 260°C for baking or roasting). 

At the opposite extreme of cleanliness and hygiene, some bearings in the sector may operate in extremely dirty conditions, and in the presence of contaminated water – for example on vegetable
conveyors, milling machines, and fruit or vegetable washing. NSK have a range of bearings to suit all these environments, so when a large producer of cooked fish products was experiencing bearing
failures every eight weeks, naturally they called NSK for advice. 

The problem proved to be water and hard contaminants entering the bearing on the customer’s Scraped Surface Heat Exchangers, causing failures which resulted in high maintenance costs, lengthy machine downtime, and a waste of around 60 man-hours a year. 

A trial with NSK Molded-Oil Deep Groove Ball Bearings resulted in an extension of bearing life to more than three years – saving the customer over £84,000 a year in production costs. 

As in many other industries, when productivity hinges on a single bearing, a reliable bearing choice from a reputable manufacturer such as NSK can open the door to significant savings on lost production, downtime and maintenance costs.