NSK has unveiled its new LCube II series of tapered roller bearings for use in electric vehicle (EV) transmission systems. LCube II bearings are specifically designed to improve efficiency by contributing to better fuel economy (lower power consumption), and enhance reliability through higher levels of durability and seizure resistance.
To improve efficiency and fuel economy in EVs, the industry has seen a shift to using less lubricant and/or lower viscosity lubricant in transmission systems. As a result, tapered roller bearings in EV transmissions are being subjected to increasingly severe lubrication conditions, heightening the risk of depleting the lubrication oil film, which in turn promotes surface damage and potential bearing seizure.
Higher efficiency transmission systems are seen as key to improving EV fuel economy, so NSK set out to develop a highly reliable tapered roller bearing capable of overcoming these hurdles. The result is the new LCube II.
Of particular note, LCube II bearings feature pore-like micro-indents in the rolling contact surface and roller head. This microstructure helps retain an oil film, which significantly inhibits surface damage. The upshot is that LCube II tapered roller bearings achieve more than eight times higher durability and equal or greater seizure resistance compared with conventional alternatives, even under severely low (thin) oil film conditions.
An additional benefit is that improved lubricant oil accumulation and retention on the roller surface contributes to 10% less friction at low speeds in comparison with conventional bearings. Reduced friction is a further factor that imparts a positive effect on overall efficiency in EV transmissions.