NSK Develops Low Friction Hub Unit Bearings for EV

NSK's advanced grease technology reduces friction to increase EV range

NSK Ltd. has developed new low friction Hub Unit Bearings*1 (HUBs) ideal for electric vehicles, hybrids, and new energy vehicles. The new bearings maintain the high reliability of conventional products despite offering lower friction. The lower friction of the new HUBs improves fuel economy (reduces energy consumption), contributing to longer travel range in EV and other vehicles. NSK is targeting 30 billion yen in sales by 2026.

*1: Hub Unit Bearings (HUBs) are unit components that integrate bearing and attachment structure. HUBs connect the wheels and vehicle body, and enable the wheels to turn freely and smoothly.

Development Background

Protecting the environment and reducing CO2 emissions is vital to the continued prosperity of global society. To enhance sustainability, the automotive industry is accelerating the development and production of electric vehicles, hybrids, and other new energy vehicles. However, the limited range of these vehicles remains a significant barrier to adoption.

Reducing friction is an effective method of increasing maximum vehicle range on a single charge, especially in HUBs, which support the vehicle body and are a component vital to the smooth rotation of the wheels. Accordingly, NSK directed development efforts to focus on reducing friction in HUBs with the aim of contributing to increased vehicle range.

Grease Features

Reducing friction while maintaining high reliability

NSK implemented improvements to the base oil and thickener components of the lubricating grease used in HUBs, achieving a 30% reduction in friction without undermining the reliability compared to conventional products.

Improvements include reducing the base oil viscosity to reduce friction caused by resistance arising from balls rolling inside the bearing. A different type of thickener was adopted, further reducing resistance. This also made the grease harder, which facilitates the grease shifting to a more optimal position within the bearing, thereby reducing stirring resistance when the balls are rolling.

Benefits

HUBs packed with the developed grease contribute to improving fuel economy, vehicle range, and reducing CO2 emissions. The HUBs can be employed in any kind of vehicle, and are ideal for EV, hybrids, and new energy vehicles.

Adopting the new HUBs can increase EV range by 0.6%, which is equivalent to reducing battery weight by 1.4 kg.

These HUBs are expected to contribute to reducing around 345 thousand tons of CO2 emissions by 2026.

* Based on NSK Ltd. calculations