NSK Extends Basic Rating Life *1 (Estimated Life) of Rolling Bearings

Practical application of highly accurate bearing life prediction method applying ultrasonic testing*2 improves the basic dynamic load ratings*3of NSK’s rolling bearings 

●Improved basic dynamic load ratings,*3 which are used for estimating the life of rolling bearings, by applying the "Highly Accurate Bearing Life Prediction Method Applying Ultrasonic Testing (World's First)"*2 announced in March 2023

●Up to twice the estimated life due to improved basic dynamic load ratings*3

●Contributes to downsizing and weight reduction of customers' machines by enabling smaller bearing sizes to do the same job

● Reducing bearing torque by replacing bearings with smaller products helps to reduce the energy consumption during the use of the product, thereby reducing CO2 emissions, and helping to build a carbon-neutral world

  NSK Ltd. announced today that it has revised its basic dynamic load ratings,*3 a parameter used to calculate the estimated life of rolling bearings.

 This revision, which extends the basic rating life*1 (estimated life) of the main types of NSK rolling bearings, applies the

“Highly Accurate Bearing Life Prediction Method Applying Ultrasonic Testing (World's First)”*2 announced in March 2023.

Bearings with improved life estimates include deep groove ball bearings, angular contact ball bearings, self-aligning ball bearings, cylindrical roller bearings,

and tapered roller bearings.

The “Highly Accurate Bearing Life Prediction Method Applying Ultrasonic Testing (World's First)”*2 has made it possible to calculate the long-life performance of NSK bearings with higher accuracy than before. NSK has now applied this calculation method to NSK bearings, improving basic dynamic load ratings,*3 which are used for calculating the estimated bearing life. With this revision for example, the estimated life of radial roller bearings is up to twice as high as before.

　The revised basic dynamic load ratings*3 are reflected in the engineering tools (NSK Online Catalog, Technical Calculations, and 2D/3D CAD Data) on the NSK website as of today. The revised figures for basic dynamic load ratings*3 can be verified in the NSK Online Catalog and 2D/3D CAD Data. Bearing life and other calculations utilizing the revised basic dynamic load ratings*3 can be performed on the Technical Calculations section of the website. (Please refer to the press release, “NSK Offers Improved Engineering Tools on Website: Delivering ease-of-use, helping to improve customers engineering work efficiency,” issued today, July 1.)

*1 Basic rating life : The total number of revolutions at which 90% of bearings can roll without flaking due to rolling contact fatigue when a group of identical bearings revolve individually under the same conditions.

*2 Highly accurate bearing life prediction method applying ultrasonic testing: A technique for accurately predicting the life of a rolling bearing based on the size and amount (statistical data) of non-metallic inclusions in the steel （Patent pending）

*3 Basic dynamic load rating: The load capacity of a rolling bearing that allows the inner ring to rotate one million times with the outer ring stationary without changing direction or size.

Effect of this revision

　With this improvement of basic dynamic load ratings,*3 customers will be able to take even better advantage of the long-life performance of NSK bearings in their machine design. This will have the following effects.

　1.Contributes to downsizing and weight reduction of machines.

　　As the basic dynamic load ratings of bearings*3 improves, they can be used in higher load conditions, enabling smaller bearings to do the same job.

　Example: Machines that used the tapered roller bearing HR32306J can now use the smaller-sized HR33206J. This change results in a smaller size (bearing outside diameter: approx. 14%, bearing assembled width: approx. 13%) and lighter weight (bearing weight: approx. 38%).

2. Helps to build a carbon-neutral world

1) Existing product mix will shift toward smaller bearings, which require fewer resources to manufacture.

2) Improved basic dynamic load ratings*3 allow the use of smaller bearings, yielding lower bearing torque resulting lower power consumption and lower CO2 emissions during bearing use.

  Example: Tapered roller bearing HR32306J can be replaced by the smaller HR33206J. Replacing the bearings is estimated to reduce bearing torque and power consumption by approximately 18% and generate an annual power savings*4 during product use of approximately 48 kWh. This converts to a reduction of approximately 22 kg in CO2 emissions*4.