NKIB 5903 INA 17x30x20 mm - Combined Needle Roller

NKIB 5903 INA 17x30x20 mm - Combined Needle Roller and Angular Contact Ball Bearing

NKIB 5903 INA is a combined needle roller and angular contact ball bearing manufactured under the INA brand, part of the Schaeffler Group. It has a bore diameter of 17 mm, an outside diameter of 30 mm and an overall width of 20 mm. The bearing combines a radial needle roller section with a double-direction angular contact ball bearing arrangement. This construction accommodates radial loads and axial loads in both directions, providing axial shaft location in compact bearing assemblies.

Technical Specifications - NKIB 5903 INA

The dimensions and construction correspond to the NKIB 5903 bearing series. Detailed dynamic and static load ratings, limiting speeds, tolerances and operating parameters must be verified against current Schaeffler documentation for the specific bearing version.

What Does NKIB 5903 INA Mean?

NKIB - Bearing Design Series

The NKIB designation identifies a combined bearing consisting of two cooperating sections:

• A radial needle roller bearing.

• A double-direction angular contact ball bearing.

This arrangement allows combined radial and axial loads to be accommodated without requiring two completely separate bearings in the assembly.

5903 - Bearing Size Designation

5903 identifies the specific size within the NKIB series.

Principal dimensions:

• d = 17 mm.

• D = 30 mm.

• B = 20 mm.

INA - Manufacturer Brand

INA is a brand of the Schaeffler Group, known for needle roller bearings, linear motion components and advanced industrial bearing solutions.

NKIB 5903 INA Bearing Construction

Radial Needle Roller Section

The radial section uses needle rollers whose length is considerably greater than their diameter.

This design provides radial load-carrying capability within a relatively small radial cross-section.

In the NKIB 5903, the needle roller elements accommodate loads acting perpendicular to the shaft axis.

Double-Direction Angular Contact Ball Bearing Section

The angular contact ball bearing section accommodates axial loads acting in both directions.

This allows NKIB 5903 to function as a locating bearing, restricting axial shaft displacement in both directions.

However, this does not mean that the bearing can accommodate unlimited axial loads. Permissible loads depend on the catalog ratings and operating conditions.

Split Inner Ring

The NKIB design incorporates a two-piece inner ring.

During installation, its components must be correctly positioned and appropriately retained in the axial direction.

Components from different bearing assemblies should not be mixed.

Open Bearing Construction

NKIB 5903 is not equipped with integrated rubber seals such as 2RS.

Protection against contamination and the lubrication arrangement must be provided by the equipment design.

NKIB 5903 - Radial and Axial Load Accommodation

Radial and axial load ratings are separate technical parameters.

When selecting the bearing, consider:

• Magnitude and type of load.

• Rotational speed.

• Lubrication method.

• Shaft and housing fits.

• Operating temperature.

• Required service life.

• Axial retention of the bearing rings.

NKIB 5903 vs NKIA 5903 - Technical Comparison

NKIB 5903 and NKIA 5903 are not directly interchangeable.

Although they have identical bore and outside diameters, they differ in overall width and axial load-carrying arrangement.

Any substitution requires verification of the complete bearing system.

Applications of NKIB 5903 INA

Combined NKIB bearings are used in assemblies where radial and axial loads occur simultaneously and installation space is limited.

Potential application areas include:

• Compact shaft assemblies.

• Gearbox mechanisms.

• Selected machine tool bearing arrangements.

• Positioning mechanisms.

• Guidance and adjustment assemblies.

• Systems requiring bidirectional axial shaft location.

These are examples based on the NKIB bearing design, not confirmed fitments for specific machine models.

NKIB 5903 INA vs NKIB 5903 from Other Manufacturers

The NKIB 5903 designation is used by various bearing manufacturers.

Although the principal dimensions and general construction may be compatible, individual versions can differ in:

• Dynamic load rating.

• Static load rating.

• Permissible operating speeds.

• Manufacturing tolerances.

• Internal component design.

• Lubrication requirements.

Before substituting one manufacturer's bearing for another, compare the current technical specifications of both products.

Alternative Designations and References

The product may be identified using the following designation formats:

• NKIB 5903 INA

• INA NKIB 5903

• NKIB5903 INA

• NKIB5903-INA

• NKIB 5903

• Combined needle roller and angular contact ball bearing 17x30x20 mm

• INA combined bearing 17x30x20 mm

The designation NKIB5903-XL may also appear in Schaeffler documentation.

The XL suffix identifies a particular version within Schaeffler's designation system. When ordering, confirm whether the offered product corresponds to the required catalog version.

Alternative commercial designation formats should not be treated as verified OEM references.

How to Select NKIB 5903 INA

Before ordering, verify:

1. Complete designation NKIB 5903.

2. INA manufacturer identification.

3. Bore diameter of 17 mm.

4. Outside diameter of 30 mm.

5. Overall width of 20 mm.

6. Bidirectional axial load accommodation.

7. Split inner ring construction.

8. Required radial load rating.

9. Required axial load rating.

10. Rotational speed.

11. Lubrication conditions.

12. Installation and axial retention requirements.

Distinguishing the NKIB series from the NKIA series is particularly important.

Installation and Operation

Before installation, inspect the cleanliness and condition of the shaft, housing and axial locating surfaces.

During installation:

• Verify shaft and housing fits.

• Follow the correct assembly sequence.

• Ensure proper axial retention of the bearing rings.

• Do not transmit mounting forces through the rolling elements.

• Protect the bearing against contamination.

• Do not mix split inner ring components from different bearings.

• Provide lubrication according to the equipment requirements.

An open bearing should not be assumed to be factory-lubricated for its entire service life.

Frequently Asked Questions

What are the dimensions of NKIB 5903 INA?

The bore diameter is 17 mm, the outside diameter is 30 mm and the overall width is 20 mm. The outer ring width is 18 mm.

Can NKIB 5903 INA accommodate axial loads in both directions?

Yes. Its double-direction angular contact ball bearing section accommodates axial loads acting in both directions.

Is NKIB 5903 a needle roller bearing?

Yes. It is a combined bearing incorporating a radial needle roller section and an angular contact ball bearing section for axial loads.

What is the difference between NKIB 5903 and NKIA 5903?

NKIB 5903 has an overall width of 20 mm and accommodates axial loads in both directions. NKIA 5903 has an overall width of 18 mm and accommodates axial loads in one direction.

Does NKIB 5903 INA have integrated seals?

No. It is an open bearing without integrated seals.

Does NKIB 5903 require lubrication?

Yes. Lubrication must be selected according to the loads, rotational speed and equipment design.

Can NKIB 5903 INA be replaced by a bearing from another manufacturer?

A replacement may be considered, but dimensions, construction, load ratings, tolerances and operating conditions must be compared.

Does NKIB 5903 INA have a split inner ring?

Yes. Its two-piece inner ring is a characteristic feature of the NKIB bearing design.

NKIB 5903 INA - Quick Technical Answer

NKIB 5903 INA is a combined needle roller and angular contact ball bearing from INA, part of the Schaeffler Group, with dimensions of 17x30x20 mm. Its radial needle roller section carries radial loads, while the double-direction angular contact ball bearing section accommodates axial loads in both directions. The bearing has an open construction and a split inner ring.

INA Bearings at simmering.pl

simmering.pl supplies INA bearings, including needle roller bearings, combined bearings and other industrial bearing components for manufacturing companies, technical service providers and maintenance departments.

For accurate identification of NKIB 5903 INA, specify the complete bearing designation and dimensions of 17x30x20 mm.

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