Single-row deep-groove ball bearings from NKE

New bearings designed for conveyor belt support and tensioning rollers operating in adverse operating conditions

ROLLER bearings are among the most important components of support and tensioning rollers in conveyor belts. To enable conveyor belt rollers to operate in extreme conditions, NKE Austria GmbH have developed single-row, deep groove ball bearings which have optimized performance capabilities and longer service life compared with standard bearings, thereby reducing downtime for the entire conveyor system.

The primary purposes of the support and tensioning rollers in a conveyor belt are to shape the belt, serve as a support element for the material that is to be transported, and reduce resistance to movement. When the material is transported with minimal friction, the overall energy required for transportation is reduced, thereby also reducing operating costs.

In a quarry or opencast mining environment, conveyor belt rollers can be exposed to harsh operating conditions and environments: heavy loads, vibration and shaft deflection stresses, high rotating speeds, increasing load from external contamination, and demanding weather conditions such as high humidity, rain or snow.

In such environments, impurities can infiltrate the bearing point and can lead to premature equipment failure. This not only shortens the service life of the bearing, but also has negative consequences for the performance and reliability of the other components of the conveyor system.

After extensive analyses, NKE have developed single-row deep groove ball bearings especially for conveyor belt rollers that operate in harsh conditions. With a completely re-engineered design, the company say it has succeeded in making targeted improvements that optimize performance capability and service life compared with standard bearings.

These bearings have a special cage construction of low-friction synthetic material, improved raceway geometry, adjusted radial internal clearance, special low-friction seals and a selected lubricant for use in a broad operating temperature range.

According to NKE, the new design is able to sustain operating demands to which conveyor rollers are exposed even where conventional bearings fail.

When contaminants infiltrate the interior of the bearing, standard bearings often suffer from a sudden, uncontrolled rise in temperature that impairs the positive lubricant properties, destroys the steel cages and, ultimately, causes the bearing to seize up. When bearings seize, they, in turn, block the rollers, the conveyor belt is damaged and the risk of fire increases significantly.

Despite relatively high contamination levels, NKE roller bearings for conveyor belt rollers are said to maintain their function even under heavy loads and without increased frictional torque.

The new bearing concept, designed especially to withstand the requirements of conveyor belt rollers, offer a range of advantages, including reduced the risk of fire, prolonged service life of the roller bearings in the harshest conditions, reduced energy consumption, increased conveyor system reliability and lower overall operating costs.

‘We have tremendous expertise in mining applications,’ said NKE applications engineer Michael Rößl. ‘This is an extremely complex engineering achievement in response to the wish expressed by many customers for improving the functional capability of conveyor belts. Our new roller bearing system will help to substantially lower outage times in material transportation.’

The new bearing design ensures frictionless rolling processes, thus helping to minimize friction throughout the entire system, and makes it possible to run the transport system more cost-efficiently and more reliably.

‘In order to achieve the best-possible results, measures to prevent particulate contaminants from penetrating the bearing and the bearing interior as completely as possible must begin with the plant developer or the plant operator installing external sealing systems,’ added Mr Rößl.