THK Ball Splines
The Ball Spline is an innovative linear motion system, in which balls accommodated in the spline nut transmit torque while linearly moving on precision-ground raceways on a spline shaft.
One significant difference between this design and a conventional design of this kind is that a single spline nut can exert a preload. As a result of this ability, THK Ball Splines are well suited for use under severe service conditions involving vibration and the application of impact loads, and in locations that require highly precise positioning and high-speed operation.
When used in place of a linear bush, the Ball Spline can be provided with a compact design, as it has a load rating more than ten times greater than that of a linear bush with the same shaft diameter. Capable of withstanding overhanging loads and moments, THK Ball Splines provides a high degree of safety and an extended service life.
Ball Spline types LT and LF have four or six trains of load-bearing balls to hold two or three crests on the spline shaft from both sides, so that an appropriate preload is unforcedly applied. The balls are held in place by the retainer, which is made of special synthetic resin, and is built into the interior of the spline nut. The retainer causes the balls to circulate in line and prevents them from falling off if the spline shaft is removed.