Ball spline structure

The preloading of ball splines has a significant impact on accuracy, load resistance, and rigidity, so it is necessary to select the appropriate clearance according to the intended use. Now, the gap values of each model have been standardized, so they can be appropriately selected according to the usage conditions.
Rotation direction clearance
In the ball spline, the total circumferential clearance is taken as the rotational clearance and standardized.
Preloading and rigidity
Preloading is the process of applying a load to the ball bearings in advance, with the aim of eliminating clearance in the direction of rotation and improving rigidity. When preloading is applied, the ball spline can eliminate the rotational clearance and increase rigidity according to the strength of preloading.
Selection of usage conditions and preloading
The rotational clearance of the ball spline has a significant impact on the accuracy or rigidity of the spline outer cylinder. Therefore, it is also important to limit the appropriate gap according to the purpose. Generally speaking, products with preloading are used. When performing repeated rotational or reciprocating linear movements, there will be significant vibration and impact. So applying preloading will significantly improve the lifespan and accuracy.
In Table 2.4.1, the reference for selecting the clearance in the direction of rotation based on the usage conditions of the ball spline is shown.