TechArchive

Original article date: March 2000

A totally new generation of spherical roller bearing developed by SKF, the world’s leading bearing manufacturer, will accommodate up to 25% higher torque loadings, and provide a 300% increase in service life compared with the equivalent size of standard spherical roller bearing.

The new bearing, designated ‘Explorer’ also provides the opportunity for designers to gain increases in product performance by adopting ‘size-down’ or ‘power-up’ principles due to the higher load ratings. Designers can also take advantage of individual factors such as higher speeds, cooler running, lower vibration and a stiffer final design due to the lower cross-section of a downsized bearing.

The new range of bearings will be manufactured at the SKF plant in Luton as well as Sweden and the Far East. SKF has invested heavily in the development of the new bearing since 1995, in order to improve its position as market leader and inventor of the spherical roller bearing design. SKF’s dominant position in the market is already qualified by achieving sales double those of any other manufacturer for this type of bearing.

During the development programme for Explorer, the resources of SKF’s Engineering and Research Centre (ERC) in Holland were combined with the specialised competencies in bearing design, metallurgy, tribology, lubrication along with the application of precision manufacturing and measurement within the Group.

Henning Wittmeyer, Head of Technology Development at SKF claims that: “The Explorer Series of bearings represents a significant leap in bearing development setting a new ‘world standard’ for endurance and performance. The bearing is so good we even had to modify certain factors in the formul3/4 to calculate life expectancy.” He predicts the new bearing will significantly influence design and maintenance engineers and subsequently widen SKF’s penetration of world markets due to the resulting improvement of cost to performance ratio.

Explorer bearings are dimensionally interchangeable with conventional ISO spherical roller bearings and can be used to upgrade existing designs. By changing to Explorer in a gearbox, for instance, torque can be increased by up to 25%, depending on operating conditions, while new gearbox designs can benefit from the lower bearing cross-section and higher performance to allow larger, more rigid shaft sizes to be incorporated. The result is a stiffer design, or as an alternative, down-sizing of the whole unit can be achieved to reduce friction, lubrication, weight and cost while obtaining equal performance or higher speeds without external cooling.

By studying the inter-relationship between each component within the bearing, SKF’s team of scientists, development, application and production engineers were able to maximise the effectiveness of lubrication and minimise the effects of friction, wear and contamination on the bearing design. However, SKF’s heavy-duty steel cages, the floating guide ring and self-guiding rollers are all well-proven and retained in Explorer to ensure improvements in performance are synonymous with improvements in reliability. Each component was examined by the team which even involved re-engineering right down to the micro or molecular level to reduce stress concentrations. The crystalline micro-structure of the steel used was investigated and changed to an extremely low oxygen content in order to provide a clean homogenous structure and the geometry optimised for the rollers, cage and raceways as part of the extended development process. This, coupled with the development of new processes of manufacture enabled SKF to ensure the ultra-high precision and quality levels required to manufacture the SKF Explorer spherical roller bearing.

For further information contact

• SKF (UK) Limited
  Tel: 01582 496436
  Web:www.skf.co.uk

< p class="received">March 2000