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Needle bearing
Needle Roller Bearing(NA, RNA, RNA69, NKI, NKIS, NK) FBX needle bearing can take big radial load. Such a bearing has two kinds, with and without inner ring which is made up of a machined outer ring, a needle and cage assemblies and a separable inner ring.
Main structure frame:
NK- needle bearing without inner ring, light series
NKI- needle bearing, light series
NKS- needle bearing without inner ring, heavy series
NKIS- needle bearing, heavy series
RNA48, RNA49- needle bearing without inner ring, size series 48 49
NA48, NA49- needle bearing, size series 48 49
NA69- needle bearing, size series 69
Applying condition
Needle roller bearing without inner ring uses the shaft which is quenched and grinded as its raceway nest, shaft diameter is bigger than it with inner ring, and it's independent from the inner ring precision, has high rotation precision. Inner diameter for such kind of a bearing is according to tolerance grade F6. Various radial tolerances can be obtained through selecting a suitable shaft diameter. Needle roller bearing with inner ring used in the situation of that the shaft can't be quenched. The inner ring can be axially fastened with contacted parts or stopping loop. Needle roller bearing with double row is used under heavy load or a wide bearing surface is required.
Radial clearance
The radial clearance of needle roller bearing is the same as the cylindrical roller bearing, the needle bearing provided in the catalogue are normally Group 0 clearance in the national standard GB/T4604, group C2, C3 or C4 is also available if required.
Fitting tolerance
When installing the needle bearing, usually the strict fitting is applied, so that its thin-walled outer ring can be supported well. A larger interference will be applied if there is a big load, especially for there is a percussive load. In addition, the temperature difference should notice between bearing outer ring and its connecting parts.
Needle bearing