Rotary Ball Spline SPB

The NB ROTARY BALL SPLINE can be used for both rotational motion and linear motion. The applications include SCARA robots, the vertical shaft of assembly equipment, tool changers, and loaders, etc.

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The NB ROTARY BALL SPLINE SPB type combines a spline nut and a set of angular contact bearings in a compact, high accurate, and high-speed rotation-capable assembly, providing both linear and rotational motion at the same time.

Structure of SPB type

Structure of SPB

Preload and Clearance

The amount of clearance and preload for the spline nut is expressed in terms of the clearance in the rotational direction. Three levels of preload are available: standard, light( T1), and medium( T2).
The preload is properly adjusted by the spacer for the angular contact bearings.

Table 1 Preload and Clearance in Rotational Direction( Linear Motion) – unit/μm

Table 2 Operating Conditions and Preload

The spacer is adjusted to give a proper spacing for the best preload condition. Please do not adjust the spacer.


The NB ROTARY BALL SPLINE is measured for accuracy at the points shown in Figure 2.

Figure 2 Accuracy Measurement Points

Table 3: Tolerance of Spline Shaft Groove Torsion(Max.)

The groove torsion is indicated per 100mm, arbitrarily set as the effective length of the spline shaft section.

Table 4: Tolerance Relative to Spline Support Area(Max.) – unit/μm

Table 5: Radial Runout of Outer Surface of Rotary Spline Nut Relative to Spline Shaft Area(Max.) – unit/μm

Table 6: Radial Runout of Spline Nut Relative to Spline Support Area(Max.) – unit/μm

★SPB16 shaft maximum length : 1,500mm

Part Number Structure