THK's Cross Roller Bearing for Inner Ring Rotation Model RAU in the Small Diameter, 5 mm Thin Type SERIES represents a pinnacle of precision engineering designed for applications demanding minimal space without compromising performance. This bearing features a compact cross roller arrangement where cylindrical rollers are alternately positioned at right angles between the inner and outer rings. This configuration allows the bearing to simultaneously withstand radial, axial, and moment loads with high rigidity and rotational accuracy. The inner ring rotation design is optimized for scenarios where the shaft is stationary, and the housing rotates, making it ideal for integrated assembly in compact machinery. With a slim profile of just 5 mm in cross-section, this series excels in environments where space constraints are critical, yet high load capacity and precise motion control are non-negotiable. Key technical features include the use of high-grade steel for rollers and rings, ensuring durability and resistance to deformation under stress. The bearing incorporates a sealed structure to prevent contamination from dust, debris, or moisture, thereby extending service life in harsh industrial settings. Precision grinding of raceways and rollers guarantees smooth, low-friction rotation with minimal vibration and noise, critical for high-speed operations. Additionally, the RAU series is designed for easy installation, with pre-drilled mounting holes in the outer ring that simplify integration into machinery frames or rotating components. Its lightweight construction reduces inertia, enabling rapid acceleration and deceleration in dynamic applications. Performance advantages of this bearing are substantial, starting with its ability to handle complex load combinations in a single unit, eliminating the need for multiple bearing setups and saving valuable space. The cross roller design ensures high rotational accuracy, with minimal runout, making it suitable for precision positioning systems. Its thin type construction allows for a lower center of gravity in assemblies, enhancing stability in automated equipment. The bearing's low torque characteristics contribute to energy efficiency, reducing power consumption in continuous operation. Moreover, its robust sealing mechanism maintains lubrication integrity, minimizing maintenance intervals and downtime in demanding environments like automotive or semiconductor manufacturing. Typical applications span a wide range of industries, including industrial robotics, where the RAU series is used in joint axes, rotary tables, and manipulator arms to provide smooth, precise rotation in confined spaces. In automotive systems, it finds use in electric power steering mechanisms, transmission components, and sensor mounts, where reliability and compactness are crucial for vehicle performance and safety. Precision equipment such as medical devices, optical instruments, and CNC machining centers leverage this bearing for its accuracy in rotary stages, indexing heads, and measuring apparatus. Overall, the THK RAU Small Diameter Series delivers a reliable solution for high-precision, space-sensitive applications, driving efficiency and innovation across advanced machinery sectors.

THK's Cross Roller Bearing for Inner Ring Rotation, specifically the RAU Model and RA Interchangeable Type SERIES, represents a pinnacle of precision engineering designed for applications demanding high rigidity, exceptional accuracy, and smooth rotational motion under significant loads. These bearings feature a unique structure where cylindrical rollers are arranged crosswise between inner and outer rings, with each roller oriented at a right angle to the adjacent one, separated by precision spacers or retainers. This cross-roller configuration enables the bearing to simultaneously withstand radial, axial, and moment loads with a single compact unit, eliminating the need for multiple bearing combinations and simplifying mechanical design. Key technical features include the use of high-carbon chromium bearing steel for rollers and rings, ensuring superior hardness, wear resistance, and longevity. The RAU Model is engineered specifically for inner ring rotation scenarios, where the inner ring is fixed while the outer ring rotates, making it ideal for applications requiring a stationary shaft and rotating housing. The RA Interchangeable Type SERIES offers compatibility with other industry-standard cross roller bearings, facilitating easy replacement and integration into existing machinery without extensive redesign. Both models boast precision-ground raceways and rollers, resulting in minimal rotational torque variation, high running accuracy, and excellent repeatability. Optional sealing configurations are available to protect against contaminants and retain lubrication, enhancing operational reliability in harsh environments. Performance advantages are substantial, starting with their compact design that saves space and reduces overall system weight while maintaining high load capacity. The cross-roller arrangement provides high rigidity, minimizing elastic deformation under load and ensuring stable, precise positioning—critical for applications involving oscillating or indexing motions. Low friction characteristics contribute to smooth, quiet operation and reduced heat generation, extending service life and minimizing maintenance requirements. Additionally, these bearings offer high rotational accuracy, with minimal radial and axial runout, making them suitable for high-speed applications where precision is paramount. Typical applications span across various high-demand sectors. In industrial machinery, THK's Cross Roller Bearings are extensively used in rotary tables for machining centers, indexing units in automated assembly lines, robot arm joints, and precision stages for semiconductor manufacturing equipment. Their ability to handle complex loads in a compact form factor makes them ideal for space-constrained robotic applications, including articulated arms and swivel mechanisms. Within automotive systems, they find use in precision steering mechanisms, advanced driver-assistance system (ADAS) components, and testing equipment where reliable rotational performance is essential. In precision equipment, these bearings are critical for optical instrument rotators, medical device positioning systems, and measuring instrument pivots, where their accuracy and rigidity ensure consistent, repeatable results. The RA Interchangeable Type SERIES further enhances versatility by allowing seamless integration into legacy systems, reducing downtime and upgrade costs for manufacturers transitioning to higher-performance components.