Products and Technology

Hydrodynamic BEARPHITE

In recent years, with the performance improvement of OA ยท AV equipment, the bearing have been required to have high rotation accuracy and quietness. But there are increasing number of areas where this required characteristics can not be satisfied by the rolling bearing, which is mainly used, replacement to the fluid dynamic bearing has been paid attention.
NTN has developed hydrodynamic bearing using technology of the sintered bearing. We adopt sintered oil-impregnated bearings as material, and take mass production of the Hydrodynamic BEARPHITE with herringbone type dynamic pressure grooves in the inner surface.
Examples of use : Spindle motor for HDD, Polygon scanner motor, Cooling fan motor.



  • High rotational accuracy Because the shaft is held in the oil film over the entire circumference in the dynamic pressure effect, high rotational accuracy can be obtained.
  • Excellent quietness Supporting the shaft in the oil film does not cause noise by metal-to-metal contact, it has low noise.
  • High reliability Because lubricant is present in the interior of the bearing, it has long life due to large oil retaining amount.

Result of performance test

Fig.1 Measurement result of NRRO and Current

Fig.2 Measurement result of oil film formation rate