[Basic Dynamic Load Rating] is a bearing term that represents an applicable constant load (in direction and magnitude) where a bearing will achieve 10 6 (1,000,000) rotations of Rated Life.

The Rated Life of a bearing is defined as: Total number of rotations reached by 90% of a specimen group of bearings, without sustaining any material damages due to rolling stress.  This in a Ball Screw perspective, will mean: An axial load applied to a group of same ball screws where 90% of them will reach 1,000,000 rotations without suffering any Flaking.

For instance, our catalog shows that a ball screw, 10mm shaft diameter with a single ball nut with 1-ball-row x 1.5 turns, has a Dynamic Load Rating of 440daN.  This means that when we apply 440daN of axial load on 100 specimens of this type, 90 specimens or more will reach 1,000,000 rotations without any damages.  (One million rotations will equate to 500 hours if the ball screw is operated at 33.3 rpm)

In other words, the Basic Dynamic Load Rating provides a basis of Life Calculations based on the size and type of ball screws.  This rating will be the same for different ball nut types such as Single Nut, Integral Nut and Double Nut, as long as the shaft diameter, lead, number of recirculating circuits, and ball diameter are the same.