Needle bearings with guide ribs with inner ring

Needle bearings without inner ring and with inner ring are the roller bearings for high loading with simple spatial construction. Needle rollers guided evenly to the axis in fix cage are made with tolerance diameter of 2 µm. Outer ring with ribs and a cage with needle rollers create the construction unit.

Needle bearings with ribs with inner ring are supplied in following design: NKI, NKIS, NA48, NA49, NA 69.

 

The design with inner ring is used when the raceway cannot be made on the shaft. Outer ring with a cage and inner ring may be assembled independently. The shift values (“s”) specified in the dimension tables cannot be exceeded in view of the manufacturing tolerances and the thermal expansion of connecting elements during operation. If the table values are insufficient, needle bearings may be combined with wider IR and LR rings, as shown in the dimension tables. For lubrication purposes the bearings have a lubrication groove and opening, this does not apply for bearings NKI d ≤ 7 mm.

 

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Boundary dimensions

The boundary dimensions of needle bearings, which are given by the dimensional tables, correspond to the international dimensional plan of ISO 1206.

Designation

Designation of needle roller bearings in the basic design is stated in dimensional tables.

Precision

Needle bearings are produced in normal tolerance class P0 (P0 symbol is not marked). For special placing, demanding high precision, bearings with higher class of tolerance P6 are supplied.

Radial clearance

Normally produced needle bearings have normal radial clearance which is not marked. Bearings with reduced (C2) or increased (C3, C4, C5) radial clearance are supplied for special placing cases. The radial clearance of needle roller bearings with inner rings corresponds to the ISO 5753-1 norm.

Cages

Needle bearings have a steel cage which is not marked. For special cases of placing some bearings are made with a polyamide cage which is marked TV. Supply of the bearings with this cage must be negotiated in advance.

Misalignment

In the case of needle bearings with inner rings, rings can only be tilted slightly. The admissible misalignment is up to 2´. The specific admissible misalignment depends on the internal bearing design, radial clearance during operation, and the force and torque transmitted by the bearing. The quoted value is therefore approximate.

 

Dynamic equivalent radial load

Pr = Fr

Static equivalent radial load

Por = Fr