NKIB 5904 INA 20x37x25 mm - Combined Needle Roller and Angular Contact Ball Bearing

Technical Specifications - NKIB 5904 INA

The dimensions of 20x37x25 mm correspond to the NKIB 5904 bearing design.

Detailed load ratings and operating speeds must be verified against the technical documentation for the specific INA version. Specifications from other manufacturers should not automatically be assigned to this product.

What Does NKIB 5904 INA Mean?

NKIB - Bearing Design Series

NKIB identifies a combined needle roller bearing with a double-direction angular contact ball bearing section.

Two bearing functions are integrated into one assembly:

• A radial needle roller bearing section.

• A double-direction angular contact ball bearing section.

This design accommodates combined radial and axial loads while maintaining compact radial dimensions.

5904 - Bearing Size Designation

5904 identifies the specific bearing size within the NKIB series.

The principal dimensions are:

• d = 20 mm.

• D = 37 mm.

• B = 25 mm.

INA - Manufacturer

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

NKIB 5904 Bearing Construction

Radial Needle Roller Section

The radial bearing section contains needle rollers.

Their relatively small diameter compared with their length allows radial loads to be accommodated within a compact bearing arrangement.

In the NKIB 5904, the needle roller section supports loads acting perpendicular to the shaft axis.

Double-Direction Angular Contact Ball Bearing Section

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

This allows the bearing to provide axial shaft location in an appropriately designed assembly.

It is one of the fundamental differences between the NKIB and NKIA bearing series.

Split Inner Ring Construction

The NKIB 5904 features a two-piece inner ring.

During installation, the inner ring components must be correctly positioned and axially retained.

Components from different bearing assemblies should not be mixed.

Open Bearing Design

The bearing does not have integrated rubber seals or metal shields.

Protection against contamination and the supply of lubricant must therefore be provided by the equipment design.

NKIB 5904 INA - Radial and Axial Load Accommodation

Radial and axial load ratings are separate technical parameters.

For combined loading, the relevant catalog ratings, lubrication conditions, rotational speed and axial retention arrangement must be considered.

The bearing should not be selected using dimensions alone.

NKIB 5904 vs NKIA 5904 - Technical Differences

NKIB 5904 and NKIA 5904 are not directly interchangeable.

They differ in overall width and the direction in which axial loads can be accommodated.

Any substitution requires verification of the complete bearing arrangement.

Applications of NKIB 5904 INA

Combined bearings of the NKIB series are designed for applications requiring radial and axial load accommodation within limited installation space.

Typical application categories include:

• Compact shaft assemblies.

• Selected gearbox mechanisms.

• Machine tool bearing arrangements.

• Positioning systems.

• Guidance and adjustment mechanisms.

• Assemblies requiring axial shaft location in both directions.

These are potential applications based on the NKIB bearing design, not a verified list of specific machines fitted with NKIB 5904 INA.

Suitability must be assessed using the actual loads, speeds, lubrication requirements and equipment design.

Alternative Designations and References

The product may be identified using the following designation formats:

• NKIB 5904 INA

• INA NKIB 5904

• NKIB5904 INA

• NKIB5904-INA

• NKIB 5904

• Combined needle roller and angular contact ball bearing 20x37x25 mm

The designation NKIB5904-XL INA may also be encountered in Schaeffler documentation.

The XL suffix identifies a version within Schaeffler's bearing designation system. NKIB 5904 and NKIB5904-XL should not automatically be treated as identical in every technical parameter without comparing the relevant documentation.

Other manufacturers also offer bearings designated NKIB 5904. Matching dimensions do not necessarily mean identical load ratings or operating characteristics.

Bearing Selection and Interchangeability

Before ordering NKIB 5904 INA, verify:

1. Complete designation NKIB 5904.

2. INA manufacturer identification.

3. Bore diameter of 20 mm.

4. Outside diameter of 37 mm.

5. Overall width of 25 mm.

6. Bidirectional axial load accommodation.

7. Split inner ring construction.

8. Required radial load rating.

9. Required axial load rating.

10. Operating speed.

11. Lubrication conditions.

12. Equipment installation requirements.

Identical dimensions alone are not sufficient to establish full interchangeability.

Installation and Operation

Before installation, inspect the shaft, housing bore and axial locating surfaces.

During installation:

• Keep all components clean.

• Verify the required shaft and housing fits.

• Do not transmit mounting forces through the rolling elements.

• Ensure correct axial retention of the bearing rings.

• Maintain the correct position of the split inner ring components.

• Protect the needle roller and ball bearing sections against contamination.

• Provide suitable lubrication.

As an open bearing, NKIB 5904 requires lubrication and sealing arrangements appropriate to the operating conditions of the machine.

Frequently Asked Questions

What are the dimensions of NKIB 5904 INA?

The bearing has a bore diameter of 20 mm, an outside diameter of 37 mm and an overall width of 25 mm. The outer ring width is 23 mm.

Can NKIB 5904 INA accommodate axial loads in both directions?

Yes. Its double-direction angular contact ball bearing section allows axial loads to be accommodated in both directions.

Is NKIB 5904 a needle roller bearing?

Yes, but it is a combined bearing. The radial section uses needle rollers, while the axial section uses an angular contact ball bearing arrangement.

What is the difference between NKIB 5904 and NKIA 5904?

NKIB 5904 has an overall width of 25 mm and accommodates axial loads in both directions. NKIA 5904 has an overall width of 23 mm and accommodates axial loads in one direction.

Does NKIB 5904 INA have integrated seals?

No. It has an open construction without integrated seals.

Does NKIB 5904 require lubrication?

Yes. Lubrication must be appropriate for the equipment design, loads and operating speeds. Depending on the application, oil or suitable grease lubrication may be used.

Can NKIB 5904 INA be replaced by a bearing from another manufacturer?

A bearing of the same type and dimensions may be considered, but load ratings, operating speeds, tolerances and installation requirements must be compared before substitution.

Does NKIB 5904 INA have a split inner ring?

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

NKIB 5904 INA - Quick Technical Answer

NKIB 5904 INA is a combined needle roller and angular contact ball bearing from Schaeffler, with dimensions of 20x37x25 mm. Its radial needle roller section works together with a double-direction angular contact ball bearing section to accommodate radial and bidirectional axial loads. The bearing features a split inner ring and an open construction requiring suitable lubrication.

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 5904 INA, use the complete bearing designation and dimensions of 20x37x25 mm.

Our warehouse is located in Lublin, Poland. We ship orders throughout Poland, the European Union and worldwide.