According to whether the ferrule has flanges or not, cylindrical roller bearings produced by China bearing manufacturers can be divided into NU, NJ, NUP, N, NF and other single-row cylindrical roller bearings, as well as NNU, NN and other double-row cylindrical roller bearings.
Now, let's learn more about the two types of cylindrical roller bearings. Single-row cylindrical roller bearings: The bearings of single-row cylindrical roller bearing are separable for easy installation and disassembly. Both ferrules can adopt tight fit. The modified contact line between the roller and the raceway can reduce stress concentration. Double-row cylindrical roller bearings:The double row cylindrical roller bearing belongs to travelling bearings, and the installation and disassembly are very convenient due to their separability. Both ferrules can adopt tight fit. Almost no inclination is allowed in double-row cylindrical roller bearings.
1. N type and NU type
There is no flange on the outer ring of N type bearing, and there is flange on both sides of the inner ring, which allows the displacement of the shaft relative to the bearing pedestal in both axial directions. There is a flange on each side of the outer ring of NU type bearing, but there is no flange on the inner ring, which also allows the displacement of the shaft relative to the bearing pedestal in both axial directions. Therefore, this kind of structure is suitable to be used as a travelling end bearing.
2. NJ type and NF type
There are flanges on both sides of the outer ring of NJ type bearing and on the one side of the inner ring, which makes the NJ type bearing withstand a certain amount of unidirectional axial load. There are flanges on one side of the outer ring of NF type bearing and on both sides of the inner ring, so that the NF type bearing can also withstand a certain amount of unidirectional axial load. Therefore, this kind of structure is suitable to be used as an unidirectional axial positioning bearing.
3. NUP type
There are flanges on both sides of the outer ring of NUP type bearing and a fixed single flange on one side of the inner ring, while the other side is a separable loose rib, which makes the NUP type bearing withstand a certain amount of bidirectional axial load. One side of the NFP bearing outer ring is provided with a (fixed) single flange, while the other side is a separable loose rib and the inner ring is provided with flanges on both sides, so that it can withstand a certain amount of bidirectional axial load. This kind of bearing structure can limit the displacement of the shaft relative to the bearing pedestal in two axial directions. Therefore, it is suitable to be used as a fixed end bearing.
1. NN type
There are flanges on both sides of the inner ring and in the middle of NN type bearing, but no flange on the outer ring, which allows the displacement of the shaft relative to the bearing pedestal in both axial directions.
2. NNU type
There are flanges on both sides of the outer ring and in the middle of NNU type bearing, but no flange on the inner ring, which allows the displacement of the shaft relative to the bearing pedestal in both axial directions. Therefore, this kind of structure is suitable to be used as a travelling end bearing. The cages of this type of bearing mostly adopt vehicle solid cages.
