NSK Ltd. (NSK; Headquarters: Tokyo, Japan; President and CEO: Norio Otsuka) announced that it has developed grease-lubricated*1 ball bearings that enable a world-class, high-speed rotation of one million dmN*2-1.8 times the conventional speed—for electric vehicles (EVs) and hybrid vehicles (HEVs). NSK will promote sales of the new high-performance product to help extend the running distance, and contribute to better electricity/fuel consumption in EVs and HEVs. NSK is targeting annual net sales of ¥800 million in 2017 for this product and other EVs and HEVs products.
*1: Grease: A semisolid lubricant in which a thickener, a substance that turns lubricating oil into a semisolid, is dispersed in a lubricating oil (base oil)
*2: dmN = (pitch diameter of rolling element in mm) × (speed of rotation in rpm)
In recent years, automobile manufacturers’ need for high-speed rotation has been increasing in order to ensure power output. The need exists to simultaneously downsize and lighten drive motors and power generators to extend the running distance and improve the electricity/fuel consumption in EVs and HEVs. Bearings that support motors include oil-lubricated bearings and grease-lubricated bearings, both of which need to provide high-speed performance. Grease-lubricated bearings have the advantage that they enable a more simplified surrounding structure than that of oil-lubricated bearings. On the other hand, they present a difficult challenge in terms of achieving the necessary high-speeds.
This product makes use of the proprietary NSK technologies outlined below to achieve a world-class, one million dmN.
1.The use of a highly rigid and lightweight cage with an improved shape made from a new resin material optimizes ball movement and enables high-speed rotation.
2.Optimization of the grease composition achieves improved bearing longevity under high-speed rotation.
•Suppression of heat generated during high-speed rotation by adoption of a low-viscosity base oil with good heat resistance.
•Furthermore, low tourque (low heat generation) has been enabled by selecting a thickener with outstanding fluidity
This product will contribute to the downsizing and greater efficiency of EV and HEV systems by achieving high-speed motor rotation (one million dmN).