Load capacity increased by  approximately 25% over the conventional model by optimizing roller crowning shape1

● Higher load capacity delivers longer bearing life and lighter weight ideal for larger wind turbines, contributing to the spread of offshore wind power

　NSK Ltd. has developed Next-Generation High-Load-Capacity Tapered Roller Bearings for Wind Turbines, ideal for reducing the construction and maintenance costs for wind turbines while supporting larger turbines and the spread of offshore wind power.

　This product has been selected for use in the gearboxes of 15MW class offshore wind turbines by a leading European wind turbine manufacturer, with mass production and delivery to start in fiscal 2024. Delivery to the Chinese market is also planned to start in fiscal 2024. NSK aims to achieve annual sales of 4 billion yen by fiscal 2026 for this product.

1 A slight arc shape created in a bearings’ rollers to avoid stress concentration at the roller ends

1.    Background

　In recent years, the push for decarbonization has been driving expansion of the wind power market. In particular, there is growing demand to improve the power generation efficiency of wind turbines, accelerating development of larger wind turbines and offshore wind turbines.

　There is also increasing demand to reduce the construction, transportation, and maintenance costs of power generation systems, with longer life and lighter weight expected from the bearings used in wind turbines.

2.    Features

(1) Improved Reliability and Longer Life through More Load Capacity

　The roller crowning shape has been optimized by leveraging NSK’s numerical simulation and manufacturing engineering technologies, resulting in a load capacity approximately 25% higher than the conventional model. This higher load capacity translates to more than double the longevity than before.

　The optimized roller crowning shape reduces and equalizes the contact surface pressure between the rollers and the inner and outer rings. This prevents excessive surface pressure at the roller ends even under high loads.

(2) Weight Reduction

　The higher load capacity also enables a weight reduction of approximately 30% compared to the conventional product.

　With the conventional product, excessive contact pressure would occur at the roller ends, so the bearings were made larger to handle the high load. In contrast, with the newly developed product, pressure is uniform, so no upsizing is needed, allowing for a reduction in weight of more than 30% for the same usage conditions.

3. Technology

　NSK’s core technologies leveraged to optimize the roller crowning shape

(1) Numerical Simulation

　Achieved optimal crowning shape design to meet the demanding conditions for wind turbine bearings

(2) Manufacturing Engineering

　Developed a new high-productivity processing technique to achieve the product’s intricate crowning shape