The THK Ball Screw Rotary Nut Ball Screw Model BNS SERIES represents a specialized configuration where the nut rotates while the screw shaft remains stationary, offering unique mechanical advantages in compact motion control applications. Engineered for high-speed operation and precise positioning, this series features a precision-ground screw shaft with optimized ball groove geometry that ensures smooth motion transmission and minimal vibration. The rotary nut design incorporates a high-rigidity flange for secure mounting and efficient torque transmission, while advanced sealing systems protect internal components from contaminants in harsh industrial environments. Preloaded ball nuts eliminate axial play, delivering exceptional positioning accuracy and repeatability across millions of operating cycles.

Key technical features include the series’ ability to achieve rotational speeds up to 10,000 rpm while maintaining thermal stability through optimized heat dissipation characteristics. The ball recirculation system utilizes THK’s proprietary circuit design that minimizes noise generation and prevents ball crowding during high-velocity operation. Available in nominal diameters from 6mm to 50mm with standardized lead options, the BNS series offers multiple accuracy classes (C3 to C7) to match application requirements. The compact nut design reduces overall system footprint while maintaining high load capacities, with dynamic load ratings reaching 8.9 kN and static load ratings up to 22.5 kN depending on model specifications.

Performance advantages stem from the reversed operational concept where rotating the nut instead of the screw eliminates potential whip in long-stroke applications and simplifies drive system integration. This configuration provides superior rotational balance at high speeds, reducing system vibration and enabling smoother motion profiles. The design achieves positioning accuracy within ±5μm/300mm while maintaining operational efficiency exceeding 90% due to optimized ball contact angles and surface finishing. Maintenance requirements are significantly reduced through the incorporation of long-life grease reservoirs and wear-resistant components that extend service intervals even in continuous operation scenarios.

Typical applications leverage these characteristics across multiple industries. In industrial machinery, BNS series units drive automated tool changers in machining centers, provide precise indexing in rotary tables, and actuate high-speed pick-and-place systems in packaging equipment. Automotive manufacturing systems employ these ball screws for wheel assembly robots, transmission testing apparatus, and precision welding positioners requiring both rotational and linear motion. Within precision equipment, the series enables accurate Z-axis positioning in semiconductor wafer handlers, optical alignment stages in measurement instruments, and sample manipulation systems in medical analyzers where compact dimensions and vibration-free operation are critical. The combination of high-speed capability, positional accuracy, and robust construction makes the BNS series particularly suitable for applications demanding both rotary and linear motion in space-constrained environments.