THK’s Ball Screw Lock Nut Model RN SERIES represents a critical advancement in securing ball screw assemblies, designed to prevent backlash and maintain precise positioning under demanding operational conditions. This specialized lock nut features a unique two-piece construction with a precision-ground thread profile that ensures uniform clamping force distribution across the ball screw shaft. Manufactured from high-grade chromium molybdenum steel (SCM435) and subjected to THK’s proprietary heat treatment process, the RN SERIES achieves a core hardness of HRC 32-38 while maintaining surface toughness for exceptional wear resistance. The lock nut incorporates a precision-engineered locking mechanism with a slit structure and clamping screws, allowing for easy adjustment and reliable fixation without damaging the ball screw threads. Standard models are available in metric sizes ranging from 10mm to 100mm shaft diameters, with custom configurations supporting specialized pitch requirements and environmental adaptations.

Technical features that distinguish the RN SERIES include its optimized slit design that minimizes stress concentration during clamping, preventing thread deformation even after repeated installation cycles. The lock nut utilizes class 3J or higher precision ground threads that maintain consistent preload characteristics, critical for eliminating axial play in high-precision applications. A phosphating surface treatment provides corrosion resistance while improving lubricant retention, extending service intervals in contaminated environments. The design incorporates wrench flats for standardized tool engagement and features balanced mass distribution to minimize rotational imbalance at high speeds. For specialized requirements, THK offers optional configurations including different screw hole patterns, vibration-resistant locking compounds, and high-temperature variants capable of sustained operation up to 150°C.

Performance advantages manifest in several key areas: the RN SERIES maintains positional accuracy within 5μm during continuous operation, significantly reducing machine downtime for recalibration. Its thermal stability coefficient of 0.8μm/°C ensures consistent preload maintenance across operating temperature ranges from -30°C to 120°C. The design’s high rigidity (3 times greater than conventional lock nuts) enables direct mounting without additional support elements, simplifying machine design while improving natural frequency response by up to 25%. Installation efficiency sees marked improvement through the standardized wrench flat design, reducing assembly time by approximately 40% compared to traditional locking methods. The optimized clamping force distribution extends ball screw service life by preventing localized wear, with documented cases showing 15,000+ hours of operation without preload degradation in continuous production environments.

Typical applications span multiple precision industries: in industrial machinery, the RN SERIES secures ball screws in CNC machining centers, providing stable positioning for spindle movement and tool changers while withstanding cutting forces up to 15kN. Automotive manufacturing systems employ these lock nuts in robotic welding arms and assembly line positioning stages, where their vibration resistance maintains alignment accuracy despite constant start-stop cycles. Semiconductor manufacturing equipment utilizes the series in wafer handling robots and photolithography stages, where sub-micron positioning stability is mandatory. Medical device manufacturers integrate RN lock nuts into MRI positioning systems and surgical robot arms, benefiting from the non-magnetic variants and cleanroom-compatible designs. Additional applications include precision measuring instruments, optical alignment systems, and aerospace actuation mechanisms where reliability under extreme conditions is paramount. The series’ compatibility with THK’s comprehensive ball screw lineup ensures seamless integration into both new designs and retrofit applications across these diverse sectors.