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Koyo NK Needle Roller Bearing

Metric Series Needle Roller Bearing without inner rings.
NK Metric needle roller bearing has a one-piece, channel-shaped outer ring of bearing -quality steel heat treated to yield maximum load rating. The integral end flanges provide axial location for the needle rollers. The bore of the end flanges serves as piloting surfaces for the cage. A steel cage provides inward retention for the needle rollers, and the design assures roller stability and minimizes friction between the cage and the needle rollers. The cage has maximum strength consistent with the inherent high-load ratings of needle roller bearings. Whenever the shaft can be used as the inner raceway, needle roller bearings without inner rings provide advantages of economy and close control of radial internal clearance in operation. When it is practical to finish the shaft to meet the desired raceway design requirements, an inner ring may be used. Standard needle roller bearings are available with inner rings (such as the NA series) to form a complete bearing. Bearings furnished with inner rings meet the quality requirements in accordance with ISO standards. Needle roller bearings are available in different styles with and without inner rings and seals.