NSK develops LCube II Tapered Roller Bearings for EV Transmissions

NSK Ltd. has developed a new tapered roller bearing “NSK LCube II” for use in electric vehicle (EV) transmission systems.

NSK Ltd. has developed a new tapered roller bearing “NSK LCube II” for use in electric vehicle (EV) transmission systems.

A special process is applied to the surface of each roller, significantly increasing durability and seizure resistance under severely low (thin) lubrication conditions. Utilising less lubricant and lower viscosity lubricant contributes to higher fuel economy (lower fuel/electricity consumption). NSK is targeting JPY4 billion ($36.8 million) in sales by 2030.

Amongst increasing environmental concerns, consumers and businesses around the world are demanding better fuel economy from motor vehicles, leading to the rapid development of EV.

To improve fuel economy, there has been a shift to using less lubricant and/or lower viscosity lubricant in transmission systems. As a result, tapered roller bearings in transmissions are being subject to increasingly severe lubrication conditions, increasing the risk of lubrication oil film depletion (lean lubrication conditions), surface damage, and bearing seizure.

Higher efficiency transmission systems are seen as key to improving fuel economy, so NSK set out to develop a high reliability bearing capable of overcoming these hurdles.

The rollers are processed to create pore-like micro indents in the surface of the steel (rolling contact surface and roller head). This microstructure helps retain an oil film that is well suited for tapered roller bearing applications. Improved oil film retention significantly inhibits surface damage, achieving more than eight times higher durability and equal or greater seizure resistance compared to conventional products.

Improved lubricant oil accumulation and retention (easier to form oil film) in the roller surface contributes to 10% lower friction at low speeds compared to conventional products.

NSK LCube II contributes to improving efficiency and reliability in EVs.