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Machined Needle Roller Bearings

Machined needle roller bearing is a type of rolling-element bearing designed to handle high radial loads in compact spaces. It uses long, thin cylindrical rollers (“needles”) with a length-to-diameter ratio of about 4:1 to 10:1, enabling them to support heavy loads while minimizing space requirements.

ZMS supply very full series machined needle roller bearings in China for 15 years.Machined needle roller bearings can be full complement without cage, with or without inner ring, and single row or double rows.Needle roller bearings with ribs come in single or double-row designs, with options for open or sealed units.Metric and Inch series also are available.

Main series are following: NK NKI series, NKS and NKIS series, NA48 and RNA48 series, NA49 and RNA49 series, NA59 and RNA59 series, NA69 and RNA69 series, NAV49 series.

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Key Feature

High Load Capacity: Handle heavy radial loads due to the large number of needle rollers in contact with the raceways.
Compact Design: Their thin profile allows them to be used in space-constrained applications.
Low Friction: The design enables smooth operation, which is beneficial for high-speed applications.
Durability: Typically made from high-quality steel, these bearings are engineered for long service life.

Applications

Automotive: They are heavily used in components such as rocker arm pivots, pumps, compressors, and transmissions. For instance, the drive shaft of a rear-wheel drive vehicle typically includes at least eight needle bearings, with four in each U joint, and more for longer vehicles or those on steep slopes.
Industrial Machinery: Found in conveyors, pumps, printing presses, and machine tools, where their high rigidity and precision are critical for operational efficiency.
Aerospace: Utilized in actuators and landing gear systems, where reliability under extreme conditions is paramount.
Robotics and Office Equipment: Employed in joints, rotary axes, and devices like photocopiers and fax machines, benefiting from their compact size and high load capacity.

Customization and Stocking

Stocking: We have very full series modals stocking in the warehouse can be fast delivery and MOQ can be very low.
Customization:When standard modals can’t fit well your requirements, we can custom made by your requirements. You can detail discuss with our technician. Normally there will have certain quantity for production.

Heavy-Duty Performance in a Low Cross-Section

Unlike drawn cup needle bearings that use a thin stamped outer shell, ZMS Machined Needle Roller Bearings feature outer rings machined from solid, high-carbon chromium bearing steel. This robust construction provides exceptional structural rigidity, allowing these bearings to support significantly higher static and dynamic radial loads, tolerate mild shock loads, and operate at much higher speeds—all while maintaining a highly compact radial profile.

RNA & NK Series: Designs Without Inner Rings

To achieve the absolute minimum radial space, the RNA and NK series are supplied without an inner ring.

Engineering Advantage: The needle rollers run directly on the machine’s shaft. This requires the shaft to be hardened (HRC 58-64) and precision-ground. By eliminating the inner ring, engineers can utilize a larger shaft diameter within the same housing space, resulting in a massively stiffer and more rigid shaft assembly.

NA & NKI Series: Designs With Inner Rings

When it is impossible or uneconomical to harden and grind the shaft to bearing tolerances, ZMS offers the NA and NKI series, which come complete with a precision-machined inner ring.

Engineering Advantage: These bearings provide a ready-to-mount solution for standard unhardened shafts. Our inner rings are designed to allow slight axial displacement between the shaft and housing, accommodating thermal expansion during high-speed operations.

Optimized Lubrication and Sealing Options

ZMS machined needle roller bearings (with outer diameters ≥ 20mm) typically feature an annular lubrication groove and one or more lubrication holes in the outer ring. This allows for highly efficient relubrication directly through the housing.
Additionally, for environments prone to dust and moisture, we offer versions with integrated contact lip seals (RS or 2RS suffix) to protect the rolling elements and retain grease.