NB Corporation of America's rotary ball spline
The NB rotary ball spline can be used for both rotational motion and linear motion. Popular applications include SCARA robots, the vertical shaft of assembly equipment, automatic tool changers, and loaders, etc.
NB’s rotary ball spline has a nut that rolls on the ball spline shaft making it capable of both linear and rotary motion and provides sub-millimeter accuracy every time.
Splines feature arch-shaped grooves on both the shaft and inner portion of the cylinder. These grooves approximate the diameter of the ball bearings, allowing them to carry a high load in a linear motion.
A ball spline’s forte is the transfer of torque. In addition, it can even be customized so cabling can run the length of the robotic arm by using a hollow shaft ball spline.
Ball splines with cross rollers as opposed to balls in the rotary motion increase load rating without increasing size.