Efficient long life bearings for electric motorsIn addition to the low torque and low noise demands placed upon rolling bearings used in electric motors, there is now the added requirement for longer service life to conserve energy and resources. As a major global supplier to electric motor manufacturers, NSK is meeting these requirements with a programme that delivers innovations in materials, production techniques and lubrication technologies. The programme has achieved a 30% improvement in efficiency for NSK's standard deep groove ball bearings, and an even larger 47% saving for domestic appliance bearings: both compared to conventional ball bearings of the same size.
NSK has collaborated with leading steel makers to improve the steel making process, reducing impurities substantially and achieving a decrease in AI2O3 alumina oxides. The resulting long-life Z Steel is now the standard material for NSK's ball bearings. Bearings manufactured from Z steel have a significantly extended service life when compared to conventional vacuum degassed steel: up to 1.8 times longer. In addition, Z steel also benefits from more uniform response to heat treatment, a process that ensures good hardness and excellent wear resistance.
Building upon the life and wear improvements achieved through new materials technology, NSK developed its surface optimisation process - a key factor in achieving increased efficiency. However, surface optimisation goes further by reducing the energy-consuming friction that impairs efficiency and ultimately leads to wear. A good surface geometry aids optimum oil film formation, while the machining processes ensure good compressive stress levels and high resistance to abrasion and excessive wear. The raceways of NSK's ball bearings are specially honed to reduce operating friction and to reduce noise. In addition, the better lubricant distribution that results from this operation also ensures longer operating life.
Complementing the role of surface optimisation, improved bearing design, provided by a unique combination of cage and bearing balls, also contributes greatly to improved efficiency.
The pressed steel cages used on NSK's ball bearings have close coined pockets and tightly controlled clearances to reduce friction and ensure even distribution of lubricant. The balls optimise this combination with their almost 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 also helps the bearings deliver maximum service life.
In addition to materials technology and surface optimisation, NSK has also achieved incremental improvement in the efficiency of its ball bearings with improved low torque seals and lubricants.
Other News from NSK Europe
Latest news about Rotary bearings