In recent years, demand for hybrid vehicles has been rising rapidly, thanks to the low fuel consumption and low emissions realized through a more efficient integration of the engine and electric motor. In order to further improve fuel efficiency, there is a growing need to reduce torque loss in the bearings used in the transmissions (drive-trains) of new generation hybrid cars. NSK has met this need with its new low-torque bearings, which dramatically reduce frictional loss. The new product will be featured first in Toyota’s latest Prius.
NSK has found a way to cut torque by 50–65%, compared with existing products, thanks to the following developments:
1. Optimisation of internal design
The number of balls has been dramatically reduced, and ball diameters, race dimensions, and clearances have been optimised utilising analysis technology, which has allowed rolling friction losses to be minimised.
2. Introduction of low-torque cages
Losses have been reduced dramatically by agitating lubrication oils during operation via the introduction of specially shaped cages made of resin.