A ball spline transmits rotary motion and torque while allowing linear movement along the spline shaft. This guide covers structure (flange SLF / tube SLT / roller BSHR), torque rating, preload classes P0/P1/P2, the torque-life formula, and the 12-model BSHR series table.
Rated torque life (revolutions):
where Ca is the dynamic rating and P the equivalent torque load. Convert to hours: Lh = L × 10^6 / (60 × rpm). For a life target (e.g. 20,000 h) solve for the required Ca.
Allowable torque vs shaft size: larger shaft diameter d and more ball turns raise both dynamic Ca and static Coa. The BSHR table below shows the trade-off across d = 8–25 mm.
Rigidity: axial/rotational rigidity (kgf/µm) rises with preload; a preloaded spline is stiffer but has higher friction torque. Keep within the DN-type limit for the groove lead and speed.
| Type | Code | Characteristic | Typical use |
|---|---|---|---|
| Flange type | SLF | Flange-mounted outer race, easy to bolt to a housing; 40° gothic-arc groove | Robot joints, indexing, automation |
| Tube type | SLT | Thin-wall outer race, light and compact | Semiconductor, medical, compact mechanisms |
| Roller / heavy-load | BSHR | Roller-type recirculation, high torque density, 12 models d = 8–25 mm | Injection, stamping, heavy transfer |
SLF (flange) and SLT (tube) are the two structural families of the MOSIONX ball-spline line; BSHR is the roller-type heavy-load series with full dimension data on this site — see the table below.
Ball splines use a two-point (or multi-point) contact preload expressed as P0 / P1 / P2:
Do not confuse this with ball-screw / linear-guide preload (ZF/Z0/Z1/Z2/Z3). They are separate systems — applying the screw classes to a spline is a common spec error.
Full dimension drawings, torque ratings and CAD are available per model. Click a model for the spec sheet.
| Model | Shaft ∅ d (mm) | Lead I (mm) | Ball turns | Dynamic Ca (kgf) | Static Coa (kgf) | Rigidity (kgf/µm) | Structure |
|---|---|---|---|---|---|---|---|
| BSHR0082.5-2.5 | 8 | 2.5 | 2.5 | 189 | 381 | 11 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01002-3.5 | 10 | 2 | 3.5 | 277 | 664 | 17 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01004-2.5 | 10 | 4 | 2.5 | 400 | 754 | 14 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01204-3.5 | 12 | 4 | 3.5 | 804 | 1649 | 23 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01205-3.5 | 12 | 5 | 3.5 | 801 | 1644 | 24 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01404-3 | 14 | 4 | 3 | 748 | 1609 | 26 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01604-3 | 16 | 4 | 3 | 759 | 1804 | 24 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01605-3 | 16 | 5 | 3 | 1077 | 2289 | 25 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR01610-2 | 16 | 10 | 2 | 779 | 1601 | 14 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR02005-3 | 20 | 5 | 3 | 1211 | 2906 | 30 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR02505-4 | 25 | 5 | 4 | 1724 | 4904 | 37 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
| BSHR02510-4 | 25 | 10 | 4 | 2954 | 7295 | 41 | Flangeless · miniature (d≤12 external / d≥14 internal circulation) |
Data from the original MOSIONX catalog; always use the actual mounting dimensions. Shaft ∅ d in mm, lead I in mm, Ca/Coa in kgf, rigidity in kgf/µm.
Use the selector to filter by shaft diameter, structure and preload, then open the CAD / 3D drawing for the exact model.
Dig deeper into precision grades, preload and the ball-screw / linear-guide families: