Ball spline Using balls installed in the outer sleeve of the splined shaft, the system ensures smooth rolling within precision-ground raceways and efficiently transmits torque. Thanks to a unique contact design, the contact angle is larger (40°). In addition to high sensitivity, this design significantly enhances load-carrying capacity. It is ideally suited for environments with excessive vibration and impact loads, offering high positioning accuracy and high-speed motion performance, thus delivering effective operation even under such demanding conditions. Moreover, even when used as a replacement for linear ball bushings, the rated load of the ball spline is more than ten times that of a coaxial-diameter linear bushing. As a result, the design can be remarkably compact, allowing for safe use even under cantilevered loads and moments, while also demonstrating exceptional durability.

　　Advantages of ball splines:

　　1. High load-carrying capacity. The raceways of the balls are precision-ground and feature a Gothic 40-degree contact angle. Due to the large contact angle, these bearings offer substantial load-carrying capacity in both the radial and torque directions.

　　2. Zero clearance in the rotation direction. The splined shaft is fitted with 2 to 4 rows of balls having a contact angle of 40° that engage with the outer sleeve of the spline. By adjusting the preload method, the clearance in the rotation direction can be reduced to zero.

　　3. High sensitivity. Thanks to the special design of the steel ball contact point, this mechanism not only boasts high rigidity but also offers greater sensitivity and reduces energy waste.

　　4. High rigidity. Due to the large contact angle and high rigidity, appropriate preload can be applied as needed, thereby achieving higher torque stiffness and moment stiffness.

　　5. Simple assembly. Thanks to the special design, even if the splined outer sleeve becomes detached from the splined shaft, the steel balls will not fall out. Consequently, assembly, maintenance, and inspection are all very easy.

　　The ball spline is a type of rolling-guide spline. By means of the rolling motion of balls within channels connected to the shaft, it can accommodate significantly higher allowable loads compared to linear bushings and can transmit torque simultaneously with linear motion. Ball splines are available in three types: high-torque, medium-torque, and internal-rotation. The appropriate type can be selected based on the intended application. In addition, these splines come with a wide variety of spline master designs, allowing users to choose the most suitable configuration for different installation or operational requirements. On the circumference of the spline shaft of a ball spline, there are three evenly spaced rolling protrusions, each separated by 120 degrees. Each protrusion is supported by two rows (a total of six rows) of load-bearing balls. The spline shaft bushing is preloaded, ensuring zero clearance in the rotational direction and enhancing rigidity.

　　The preload of ball splines significantly affects their precision, load-carrying capacity, and stiffness; therefore, it is essential to select an appropriate clearance based on the specific application. Currently, the clearance values for various models have been standardized, allowing users to make suitable selections according to operating conditions. In ball splines, the sum of the circumferential clearances is considered the rotational clearance and has been normalized. Preloading involves applying a predetermined load to the balls in order to eliminate clearance in the rotational direction and enhance stiffness. When preloaded, the ball spline can eliminate clearance in the rotational direction and increase its stiffness, depending on the magnitude of the preload.