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NSK’s bearing improvement programme has achieved a 30 per cent improvement in efficiency for its greased sealed-for-life deep-groove ball bearings, compared with conventional ball bearings.

This saving is helping to reduce energy use in high-consumption equipment such as electric motors, air conditioners and domestic appliances.

The 30 per cent improvement in efficiency is the result of a synergy of materials, design, lubrication and sealing technology.

Through its developments in the materials technology for ball bearings, NSK has shown that improvements in steel cleanliness, principally in reducing the number of non-metallic inclusions in a steel, strongly correlates with an improved fatigue limit of bearing steel.

NSK has acted upon these results, improving the steel-making process and operating conditions to reduce impurities, thereby achieving a decrease in oxide non-metallic inclusions.

The resulting long-life steel is Z Steel, which is now the standard material for NSK’s ball bearings.

According to NSK, bearings manufactured from Z Steel have an extended service life of up to 1.8 times longer when compared with conventional vacuum-degassed steel.

Z Steel also benefits from a more uniform response to heat treatment – a process that ensures good hardness and wear resistance.

The raceways of NSK’s ball bearings are specially honed to reduce operating friction and noise.

In addition, the better lubricant distribution that results from this operation ensures longer operating life.

The pressed-steel cages used on NSK’s ball bearings have close-coined pockets and tightly controlled clearances to reduce friction and ensure the even distribution of lubricant.

The balls are designed to have near-perfect levels of sphericity, minimising friction with their precision surface finish.

They are ground on machines designed and manufactured by NSK specifically for the purpose, hence the consistent super-precision finish that helps the bearings deliver a long service life.

NSK has also improved the efficiency of its ball bearings with improved low-torque seals and lubricants – in particular, greases.

Originally developed for use on induction motor bearings, NSK’s NS7 grease is a Polyolester diester type, which has low-torque characteristics to maximise energy efficiency in the operation of ball bearings used in motors, pumps, air conditioners and compressors.

Grease is retained within bearings by seals and shields, which also play a role in energy conservation, as a seal or shield that is too tight a fit will lead to friction in a bearing and consequent energy loss.

The challenge in the bearing market has been to develop high-speed seals that minimise bearing friction.

This has led NSK to develop its V-type seal.

The V seals effectively without an increase in torque or operating temperature.

It has better sealing capability than a shield and a speed capability comparable to that of a shielded bearing.

The non-contact lip of the V design reduces drag in the bearing, which is an advantage where power loss is critical, as in small electrical motors.

In addition to ball bearings for general applications, NSK has also developed low-torque ball bearings that help to reduce the power consumption of domestic appliances.

These types of bearings have the same outside diameters and width as the global standard 608 ball bearings but have improved internal specifications.

The torque for these bearings is 40-50 per cent lower than that of conventional bearings.


NSK, a global leader in motion and control products, has developed and continuously upgrades four core technologies: tribology, material engineering, analysis technology and mechatronics, to provide the platform for the company’s innovative product developments. This technology platform provides the basis for the design of NSK’s rolling bearings, automotive components and precision parts. In addition, by integrating these advanced technologies, NSK is able to respond quickly and effectively to customer requirements across all key sectors.

NSK is a driver of new technology developments, with a full line-up of products spanning general industrial, automotive and precision parts industries. These include bearings for mechanical and electrical machinery, IT and aftermarket; innovative automotive products such as electric power steering (EPS) automatic transmission components, steering columns and other steering related products; and precision linear motion components such as linear guides, ballscrews, X-Y tables, mechatronic products and Megatorque motors.

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