RNA and NK types of needle roller bearings without inner rings
Needle roller bearings without inner rings are suitable for components with limited radial dimensions. Due to the absence of inner rings, the surface of the journal that matches them directly serves as the rolling surface. It is required that the surface hardness should not be lower than HRC60, and the surface roughness Ra value should not exceed 0.63 μ m. This type of bearing does not limit the axial displacement of the shaft or casing, and has a higher limit speed.
NA and NKI types with inner ring needle roller bearings
This type of bearing can be installed separately with inner and outer rings, complete sets of needle rollers, and cages due to the lack of retaining edges on the inner ring, without limiting the axial displacement of the shaft or casing
Due to the use of a cage to separate the needle rollers and reduce friction, it can be used in components with higher rotational speeds.