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STRUCTURE AND ADVANTAGES
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
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 |
| part number | standard | light（T1） | medium（T2） |
| SPB16 | －3～＋1 | －8～－3 | －13～－8 |
| SPB20 | －4～＋2 | －12～－4 | －20～－12 |
| SPB25 |
| Table 2 Operating Conditions and Preload |
| preload | symbol | operating conditions |
| standard | blank | minute vibration is applied. a precise motion is required. a torque is applied in a given direction. |
| light | T1 | slight vibration is applied. slight torsional load is applied. cyclic torque is applied. |
| medium | T2 | shock/vibration is applied. over-hang load is applied. torsional load is applied. |
※HANDLING PRECAUTION
The spacer is adjusted to give a proper spacing for the best preload condition. Please do not adjust the spacer.
ACCURACY
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.） |
accuracy grade |
high |
precision（ P） |
tolerance |
13μm/100mm |
6μm/100mm |
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 |
| part number | ①radial runout of part attachment area | ②perpendicularity of the end of the spline shaft section （when grinding is requested on the drawing） |
③perpendicularity of the flange | |||
| high-grade | precision-grade（P） | high-grade | precision-grade（P） | high-grade | precision-grade（P） | |
| SPB16 | 19 | 12 | 11 | 8 | 18 | 13 |
| SPB20 | ||||||
| SPB25 | 22 | 13 | 13 | 9 | 21 | 16 |
| Table 5 Radial Runout of Outer Surface of Rotary Spline Nut Relative to Spline Shaft Area（Max.） | unit/μm |
| part number | ④lateral runout of flange mounting side | ⑤radial runout of outer ring | ||
| high-grade | precision-grade（P） | high-grade | precision-grade（P） | |
| SPB16 | 8 | 8 | 9 | 9 |
| SPB20 | 10 | 10 | ||
| SPB25 | ||||
| Table 6 ⑥Radial Runout of Spline Nut Relative to Spline Support Area（Max.） | unit/μm |
| spline shaft total length（mm） |
part number | ||||
| SPB16 | SPB20･25 | ||||
| greater than | or less | high-grade | precision-grade（P） | high-grade | precision-grade（P） |
| － | 200 | 34 | 18 | 32 | 18 |
| 200 | 315 | 45 | 25 | 39 | 21 |
| 315 | 400 | 53 | 31 | 44 | 25 |
| 400 | 500 | 62 | 38 | 50 | 29 |
| 500 | 630 | 75 | 46 | 57 | 34 |
| 630 | 800 | 92 | 58 | 68 | 42 |
| 800 | 1,000 | 115 | 75 | 83 | 52 |
| 1,000 | 1,250 | 153 | 97 | 102 | 65 |
| 1,250 | 1,600 | 195★ | 127★ | 130 | 85 |
| 1,600 | 2,000 | － | － | 171 | 116 |
★SPB16 shaft maximum length : 1,500mm
↓It expands by click.
Use and Handling Precaution
NBRotaryBallSplineSPBtypeisaprecisioncomponent.Handlewith Careaccordingtothefollowi ngprecaution
Donotadjustthespacer.Thespacerispre-adjustedforabestpreloadcondition. NeverholdthespacerbyhandandavoidexcessivevibrationorsllOCktoassuretheexpected precision.
Donottakeoffthenutfromtheshaft.Incasetheshafttobereinsertedtothenut,aligntheNB markonthenutandshaft.Makesuretoalignthesha splinegrooveswiththerowsofballsandthe seallipofthenutwheninsertingtheshafttothenut.Forthepreloadedset,exerciseaddedca
Never disasSemble the Nut
Removeburrs,dustandanti-rustoilfromthemountingsurfacebeforeinstallation.
MakethehousingofSPBtypetobeanH7toleranceandtobeenough depthsothattheflangeouter m gandtheouterm gareinsidetllehousing.Otherwise,thespacershallbedislocatedandthenthe spacerwillcomeoutofthenut.
Re-lubricatethesplineportionandangularcontact-bearingportionwithasimilartypeofgrease periodically.
OperatingTemperatureRange:from120oCto80oC.
