Needle Roller Bearings

Needle roller bearing characteristics and use

Needle roller bearings have reduced radial dimensions, and a very high load capacity, considering their size.

Needle roller bearings can have one or two rows of rollers. They can be used with or without an internal ring, and with or without an external ring, depending on the application.

The internal rings on bearings with seals are 1 mm wider than the external ring, to ensure the efficiency of the seal is maintained even when there is a slight axial displacement of the shaft with respect to the housing.

The external ring has one or more lubrication holes so that, depending on the application, the bearing can relubricate itself, or lubrication can be applied through the external or internal ring.

They are constructed in various sizes and configurations. Most of them have flanges positioned or integrated with the external ring, whereas some are also available with sliding seals.

Technical characteristics

The bearings without an internal ring are an excellent solution when it is possible to harden and grind tracks on the shaft. When there is no internal ring, the diameter of the shaft can be larger and therefore more rigid. Furthermore, the amount of possible axial displacement of the shaft with respect to the housing is limited solely by the width of the track on the shaft itself. By machining the tracks on the shaft with suitable size and shape precision, it is possible to obtain an arrangement with higher drive precision.

Bearings with an internal ring are used in applications where it would not be possible or not cost-effective to harden and grind the shaft.

Bearings with an internal ring only allow axial displacements between the shaft and housing within certain limits.

They are available with sliding seals.

If these displacements are not sufficient, the standard internal rings can be replaced with larger versions.

Needle roller bearings comply with ISO 1206-1982 and ISO 15.1998