At the core of the XI/XSI series is the crossed roller arrangement, where cylindrical rollers are oriented at 90° to one another between the inner and outer rings, with each roller alternately positioned perpendicular to the next. This geometry provides a single raceway that simultaneously accommodates axial, radial, and tilting moment loads – a distinct advantage over conventional ball-bearing or double-row designs. The internal gear teeth are hobbing and induction-hardened on the inner ring’s bore, ensuring consistent mesh stiffness and wear resistance over extended duty cycles.

Both XI and XSI variants share this fundamental layout, but the XSI type is distinguished by a more compact cross-section relative to its pitch diameter, achieved through optimized roller sizing and raceway geometry. This makes the XSI particularly suitable for space-constrained installations where weight reduction is critical without compromising stiffness.