NSK widens range of electrical erosion resistant bearings


Following the completion of performance evaluations, NSK can now offer a broader
range of anti-electrical-erosion technologies for eAxle bearings used on electric
vehicles (EVs). Among the new options are over-moulded bearings and conductive
brushes, elevating NSK’s ability to meet diverse demands from automotive OEMs as
they look to combat electrical erosion and, in turn, improve reliability and extend EV
With growing awareness of the world’s urgent climate-change agenda, society and industry
are accelerating their journey towards carbon neutrality. The rising demand for EVs means
there is a real opportunity to enhance the sustainability of the transport sector, but the
success of this endeavour depends heavily on the underlying technologies. For instance, a
key issue in ensuring the long operational life of EVs is preventing the electrical erosion of
critical eAxle components such as bearings.
Preventing electrical erosion is becoming increasingly difficult due to the higher output of
electric motors and higher drive voltages. Here, technologies like insulating ceramic-ball
bearings (hybrid bearings) are most effective way of providing electrical insulation, but are
not always the optimal solution for high-volume applications such as EVs.
A good alternative is the adoption of plastic over-moulded bearings, which deliver the
electrical insulation required for eAxles but at a lower cost than ceramic-ball bearings.
Notably, NSK configures its over-moulded bearings to suit the application and any specific
requirements. The materials and manufacturing processes would be quite different for an
eAxle and those of a railway application, for example.
Another option to resist electrical erosion is the use of conductive brushes. However, trends
in eAxle motors are moving towards the use of highly efficient oil-cooled systems, for which
conventional conductive brushes are not suitable, especially in combination with high
speeds. NSK’s new brushes differ in that they offer sufficient conductivity for a wide range
of eAxle applications, even those involving cooling oil lubricated environments. As a further
benefit, it is possible to incorporate the conductive brush directly into the shaft to save
NSK has already completed basic durability evaluations and can now provide customers
with proposals for its latest anti-electrical-erosion technologies, including evaluation data,
for practical applications.
In summary, the company’s anti-electrical-erosion options cover both insulating and
conductive methods to meet a diverse range of design requirements that balance

PR Ref. A022023-N | 1/3

application and volume criteria. These technologies improve reliability and include
measures that support the reduction of overall eAxle unit size. They also contribute to lower electricity consumption and longer vehicle range on a single charge.
Press pictures
1) Example of an NSK plastic over-moulded bearing. Photo: NSK

2) NSK’s anti-electrical-erosion technologies contribute to longer EV range on a single
charge. Photo: Herr Loeffler/Shutterstock

About NSK Europe
NSK Europe Ltd. is the European organisation of the Tokyo-based bearing manufacturer NSK, which was founded in Japan in 1916 and today employs nearly 29,882 people in its worldwide operations. The products and solutions provided by the industrial and automotive supplier can be found wherever things move. In addition to nearly all types of rolling bearings, the company’s portfolio includes housed bearings, linear technology,
wheel bearing units, transmission and engine bearings and steering systems. The company is oriented to perfection in all of its business activities. Its aim is quality leadership in its industry, which it strives for through a continuous process of improvement, excellent product development, optimised production processes and customer-oriented service processes. In fiscal year 2022, the more than 4,030 employees of NSK Europe Ltd.
generated sales of over € 893 million.