NRA Needle Rollers with Spherical Ends
REDHILL supplies NRA needle rollers with spherical ends for needle roller bearings and cage assemblies. Their long, slender shape supports compact bearing designs. As a result, engineers can provide radial support where space is limited.
Rounded End Geometry
NRA identifies rollers with rounded end faces. By comparison, NRB rollers have flat end faces. However, load distribution depends on the rolling surface profile, raceways and alignment. Therefore, specify the end-face shape and rolling surface profile separately.
Key Technical Specifications
- Material: 100Cr6 (1.3505) bearing steel, commonly cross-referenced to AISI 52100.
- Hardness: Typical reference range of 60–66 HRC after heat treatment. Confirm the final range for the roller size and order.
- Reference Standards: DIN 5402-3 and ISO 3096 for steel needle roller dimensions and tolerances.
- Precision Grades: G2, G3 and G5, subject to size and order requirements.
- Diameter Sorting: Specify both the precision grade and the diameter sorting group.
For example, 0/−10 µm describes a diameter deviation band, while G2 describes a precision grade. Therefore, confirm both requirements when ordering.
Bearing Design and Lubrication
A suitable rolling surface profile helps reduce stress peaks near the ends of the raceway contact. In addition, the surface finish and lubricant affect friction and wear. Therefore, match the roller, raceways and lubrication to the load, speed and operating conditions.
Typical Applications
- Gearboxes and Planetary Gears: Compact radial bearing assemblies.
- Automotive Transmissions: Needle roller and cage assemblies in powertrain mechanisms.
- Industrial Mechanisms: Selected small motors, actuators, pivots and guide systems.
Available Sizes and Custom Requirements
- Diameter (Dw): 1.0–6.0 mm.
- Length (Lw): 5.8–59.8 mm.
- Type: NRA with spherical end faces.
Availability depends on the diameter, length and grade. In addition, we can review custom dimensions and special material requests.
Finally, send us your drawing, material, diameter, length, precision grade, sorting group and quantity. We can then confirm suitable options, availability and lead time.
