NTN Develops Next-Generation Deep-Groove Ball Bearing For High-Speed Servomotor Applications

NTN Corporation is pleased to introduce the "Next-Generation High-Speed Servomotor Deep-Groove Ball Bearing," a product perfected to primarily target application in machine tool main shaft use servomotors, featuring high-speed capability (dmn value *1= 950,000). The new bearing will be displayed at the Japan International Machine Tool Fair, scheduled to open to the public on November 1.

Recently, a number of significant advances have been made in the high-speed operation, efficiency and accuracy of machine tools, requiring higher speed, greater rigidity, longer service life and other qualities of the associated main shaft servomotors. In order to keep pace with the improvements in the performance of these servomotors, higher speed operation is also being demanded of bearings.

Sealed type deep-groove ball bearings are bearings that are enclosed in grease and sealed on both sides, a structure which offers easy handling at low cost. The dmn values of these bearings have been limited to 800,000 until now, so higher speed requirements have led to the use of angular contact ball bearings - components that are high in price and require separate lubrication systems.

In response to these market demands, NTN has developed the "Next-Generation High-Speed Servomotor Deep-Groove Ball Bearing" - a product engineered to excel at high speed (dmn value = 950,000) and long service life. This ball bearing features a newly configured resin cage that functions to curb deformation at high-speeds, and is combined with a grease reservoir designed into the pocket sections to enhance lubrication. These features provide high-speed operation of 950,000 dmn, a level that has proven difficult to achieve with conventional sealed-type deep-groove ball bearings. Moreover, the mixture ratio of the base oil has been adjusted and combined with the conventional motor grease base to provide encapsulation in a new heat resistant grease (ME-1) resulting in significant improvements in bearing service life.

*1: "dmn value" refers to D (ball PCDmm) × N (rotational speed in min-1).


(1) High-Speed Improvements
With a newly configured resin cage to reduce deformation at high speeds, grease reservoir designed into the pocket sections, high-speed dmn value of 950,000 is achieved in an sealed-type deep-groove ball bearing (approx. 20% improvement over previous versions).
(2) Longer Service Life
With adoption of newly developed base oil, improved heat resistant grease and a newly configured resin cage, service life at high-speed operation (dmn value= 850,000) is more than tripled, compared to the life of a conventional bearing dmn value < 700,000.

<Target Model Types>

Sealed-type, deep-groove ball bearings with inner diameters ofΦ35mm and larger (62, 63 Series).

Next-generation deep-groove ball bearing for high-speed servomotor applications
Next-generation deep-groove ball bearing for high-speed servomotor applications