With the Model LTR rotary ball spline, the spline shaft has three crests on the circumference, and along both sides of each crest, two rows of balls (six rows in total) are arranged to hold the crest so that a reasonable preload is applied.
Angular-contact ball raceways are machined on the outer surface of the spline nut to constitute support bearings, allowing the whole body to be compactly and lightly designed.
The rows of balls are held in a special resin cage so that they stay aligned and recirculate. With this design, balls will not fall even if the spline shaft is removed.
In addition, a dedicated seal for preventing the inflow of foreign material into the support bearings is available.