NA49 series are basic needle roller bearings with assembled outer ring, cage and needle roller. The inner ring is separable.

Since their friction coefficient is higher than that of ball bearings, they can endure heavy load. Moreover, a cage is present that prevents the needle rollers from making contact with each other. Therefore, high speed rotation is possible for certain load.

That is, even if under heavy load, if the contact surface is large enough, local plastic deformation caused by contact surface stress on trajectory of rolling bodies and needle friction area exceeding elastic limit of the material, in other words indentation, is smaller than ball bearing, Therefore, it can be used on a wide variety of applications including light and medium load.

In addition, needle roller bearings can be used for various applications since the space occupied by the application area is small.

Moreover RNA49, an outer ring assembly without an inner ring, is designed to be assembled directly onto the shaft and is also suitable for light intermittent motions.

A variety of usages includes automobile transmissions, universal joints, printing machines, reducers, crank shafts of small engines, piston pins, air pumps, electromagnetic clutches and hydraulic machines.