Development of “Grease Lubrication Type High Speed Deep Groove Ball Bearing” for EV/HEV

[Double the rotational speed compared to conventional products and the industry’s highest level high-speed rotation to replace current bearings]

ntn-09032015-cnt1

“Grease Lubrication Type High Speed Deep Groove Ball Bearing” for EV/HEV (left), newly developed retainer (center) and conventional retainer (right)

NTN Corporation (hereafter, NTN) has developed the “Grease Lubrication Type High Speed Deep Groove Ball Bearing” with double the rotational speed compared to conventional products and the industry’s highest level high-speed rotation for use in motors mounted in electric vehicles (EV) and hybrid vehicles (HEV).

There is an increasing need for higher rotational speed for EV/HEV drive motors to achieve a more compact size and lighter weight. The bearings that are used also need to be capable of high-speed rotation, however conventional grease lubrication type deep groove ball bearings suffered from higher temperatures caused by distortion to the retainer due to centrifugal forces when operating at high rotational speeds, and a lack in lubrication due to the grease scattering.

The newly developed “Grease Lubrication Type High Speed Deep Groove Ball Bearing” for EV/HEV features a reviewed material ratio with the use of a new plastic retainer, while the retainer shape and material ratio have been modified to minimize its level of distortion due to centrifugal forces when operating at high rotational speeds. A smooth grease supply along the raceway surface also helps to increase sliding between the retainer and steel balls.

ntn-09032015-sl

Applicable parts (example) of motor for EV

The filled grease has also been optimized with a combination of consistency (thickening agents) that can resist centrifugal forces at high rotational speeds, and viscosity (base oil) that can supply lubrication constituents to the raceway surface at high speeds, resolving the lack of lubrication when operating at high rotational speeds.

NTN will propose and develop markets for the “Grease Lubrication Type High Speed Deep Groove Ball Bearing” globally as a product that can contribute to more compact and lighter weight EV and HEV.

Features

  1. Double the limiting rotational speed (compared to NTN conventional products), industry’s highest level high-speed performance: dmn* value = 1.08 million
    • *: Index that represents bearing rotational performance, bearing pitch circle diameter (mm) × rotational speed (min-1)
    • Optimized retainer material and shape
    • Optimized grease
  2. Same assembly dimensions as standard type bearing (can be used for replacement)

Applications

Applications such as drive motors for EV/HEV

Contact for inquiries:

NTN (link: http://www.ntn.co.jp/english/news/new_products/news201500013.html)

B&P2024 B&P2024