NTN-SNR is supplying specially-designed bearings for the Kogakuin University car participating in the “World Solar Challenge” international solar-powered car race to be held in Australia in October this year.
NTN-SNR has increased its interaction with the Kogakuin University’s Faculty of Engineering, Department of Mechanical Engineering through the Tribology Workshop, and has developed bearings for motors and axles as part of support for student “monozukuri” activities for Kogakuin University, which will be participating in the challenge for the first time.
The “World Solar Challenge” is one of the largest solar-powered car races in the world, where participants race against the clock over 3,021 km through the desert between Darwin and Adelaide in Australia, using the sun as the only source of power. With a 20-year history dating from its beginnings in 1987, the race attracts participants from around the world, including many universities and corporations. Kogakuin University is aiming to win its first podium finish in the race.
Solar-powered cars are electric vehicles that convert energy from the sun to electrical energy in order to drive electrical motors and turn the tyres. A structural design with minimal electric loss is required to drive long distances using electrical energy obtained only from the solar cells.
The deep groove ball bearing developed by NTN-SNR for the challenge offers JIS 5 class, which is two grades higher than the general JIS 0 class, to help improve turning precision. Steel balls have been changed to ceramic balls and the curvature of the rolling contact surface has been optimised in order to reduce the contact area and achieve a lower torque, while a low-viscosity grease with minimal agitation resistance has been used.
These help to reduce rotational torque by 50% compared to conventional products. The steel shield has been changed to a non-contact rubber seal to improve resistance against penetration of foreign matter in preparation for driving through desert areas.
In addition to drive wheel motors, NTN bearings are used in driven wheel axle shafts to reduce rotational torque. This helps to deliver a high speed with minimal consumption of electrical energy, and also contributes to longer distance driving.