NSK develops long-life, large-size, roller bearing for large gearboxes

Supplier: NSK Australia
23 March, 2015

Improved reliability for large gearboxes used in wind power generators and other industrial machines

Tokyo, Japan, May 27, 2014 - NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Norio Otsuka) today announced that it has developed a long-life, large-size roller bearing for large gearboxes.

The key to the development was a combination of special heat treatment technology and material developed by NSK that provides excellent flaking resistance, including that of white structure flaking.

NSK is targeting one billion yen in global annual sales by 2017 for this product, which is designed for large gearboxes used in heavy load conditions, such as wind power generators.

Development Background

Roller bearings that can support heavy loads are used in gearboxes* which are used in large industrial machines such as wind power generators, mining and construction equipment, and steelmaking equipment.

In recent years, wind power generators have increased in size in order to generate more power. Also, mining and construction equipment and steelmaking equipment are used in very harsh conditions. Therefore, bearings used in the large gearboxes used for such applications must be highly reliable.

In response to these needs, NSK has developed large sized roller bearings that provide a high level of reliability through a combination of special heat treatment technology and material developed by NSK.

*Gearbox: A device made of many gears that is located between the input and output shafts and that is used to change the input RPM to the desired output RPM.


Specialised material developed by NSK (optimised chemical compositions) and special heat treatment technology

 NSK was able satisfy the demand for greater performance in roller bearings for large gearboxes by combining special heat treatment technology and material developed by NSK. In particular, NSK has been able to decrease early damage by white structure flaking that leads to seven times service life longer than conventional bearing.

Product Benefits

The newly developed bearing is better than the conventional bearing as outlined below, for improved gearbox reliability in harsh usage environments.

White structure flaking life - seven times

Surface originated flaking life - three times

Subsurface originated flaking life - twice

Fracture toughness - twice

Dimensional change rate - 1/50th