NKX25Z Combined Needle Roller Bearing for Radial and Axial Loads

Some machine assemblies need more than radial shaft support.

When a rotating shaft is exposed to both radial force and axial force, using two separate bearings can increase the number of components, consume additional space and make the surrounding design more complicated.

The NKX25Z combined needle roller bearing is designed for this type of mechanical arrangement. It combines a needle roller bearing for radial load support with a thrust bearing arrangement for axial load support in one compact bearing assembly.

The bearing version covered here uses Chrome Steel GCr15 as the bearing material, providing a conventional bearing-steel solution for industrial rotating mechanisms.

For OEM engineers and purchasing teams, the main attraction of NKX25Z is therefore not simply its needle roller construction. It is the ability to address two load directions within one bearing arrangement.

The basic working concept of NKX25Z can be understood by separating the two functions.

Radial section:
The needle rollers support forces acting perpendicular to the shaft.

Thrust section:
The axial bearing components accommodate forces acting along the shaft.

This combination is useful when both types of force are present in the same mechanical assembly.

This does not mean the bearing can accept unlimited loads in either direction. The actual capacity depends on the exact configuration, lubrication, speed, mounting and operating conditions.

*The commonly used NKX25Z designation corresponds to a 25 mm nominal bore. Exact dimensions and performance values should be verified against the drawing for the required manufacturer configuration.

A designer could theoretically support radial and axial loads using separate bearing components.

The problem is that every additional component affects the machine.

Two separate bearings may require:

additional axial space

separate locating features

more housing details

additional assembly operations

closer coordination between components

A combined bearing provides another approach.

For compact transmissions and mechanisms, reducing the number of individual bearing components can be a worthwhile design consideration.

For many bearing purchases, buyers focus almost entirely on radial capacity.

That is not enough when considering NKX25Z.

If the shaft is subjected to axial force, the direction and magnitude of that force should be understood before the bearing is approved.

Examples include:

helical gear forces

screw-driven mechanisms

axial positioning forces

thrust generated by rotating components

spring-loaded mechanisms

The axial load may be continuous, intermittent or generated only during certain stages of the machine cycle.

That distinction matters when selecting the bearing.

A combined needle roller bearing can be useful in mechanical drives where a shaft needs radial guidance while another component produces axial force.

Consider a compact gear assembly.

The shaft may experience:

Radial force from gear engagement

and at the same time:

Axial force caused by the gear geometry

A bearing arrangement that only addresses radial loading may therefore require a separate thrust component.

NKX25Z can provide a compact alternative where its load ratings and operating conditions match the application.

The presence of both radial and thrust rolling elements makes lubrication an important part of the design review.

The lubricant has to reach the working contact areas under the actual operating conditions.

Factors to consider include:

For OEM equipment, it is preferable to define the lubrication method during the design stage instead of treating it as an installation detail.

For buyers who are new to combined needle bearings, the number in the designation can be useful but should not be treated as the complete dimensional specification.

In the commonly used designation, NKX25Z indicates a nominal 25 mm shaft/bore size.

However, the actual outside diameter, width, thrust section dimensions and load ratings still need to be checked from the manufacturer's dimensional table.

This prevents a common purchasing mistake: assuming that matching the bore automatically means the complete bearing will fit the existing assembly.

NKX25Z can also be encountered in maintenance and replacement work.

When replacing an existing combined needle bearing, inspect more than the bearing itself.

Look at:

The shaft
Check for scoring, wear or discoloration.

The housing
Check whether the bearing seat remains within the required condition.

The thrust surfaces
Look for wear caused by axial loading.

The lubrication
Check whether the original lubricant has degraded or become contaminated.

If the previous bearing failed unusually early, replacing it without investigating these areas may simply reproduce the same problem.

For regular industrial supply, incoming inspection does not need to be complicated.

A basic inspection program can focus on the dimensions and functions that affect assembly.

For larger OEM orders, additional inspection requirements can be agreed before production.

A combined bearing is not automatically the best solution for every shaft.

If the axial load is particularly high, if the machine requires a specialized thrust arrangement, or if the radial and axial bearing functions need to be positioned far apart, separate bearings may provide greater design flexibility.

The choice should therefore be based on the machine architecture.

NKX25Z is most attractive when combining the two bearing functions provides a genuine mechanical or packaging benefit.

What is NKX25Z?

NKX25Z is a combined needle roller bearing designed to accommodate both radial and axial loads within a single bearing arrangement.

What does the 25 mean in NKX25Z?

The "25" commonly identifies a 25 mm nominal bore in the NKX25Z designation. The complete bearing dimensions should still be confirmed from the applicable manufacturer's drawing.

What is the Z designation?

The suffix can relate to the configuration of the bearing's thrust section. Exact designation conventions can vary between manufacturers, so the supplier's catalogue should be used for final confirmation.

What material is NKX25Z made from?

The version specified here uses Chrome Steel GCr15 as the bearing material.

Can NKX25Z handle both radial and axial loads?

Yes. Its combined construction is intended to provide radial support through the needle roller section and axial support through the thrust bearing section, within the applicable load ratings.

Is NKX25Z suitable for gearboxes?

It can be suitable for certain gearbox and transmission arrangements where radial and axial loads occur together. The actual gear forces and operating speed should be checked first.

Does NKX25Z need lubrication?

Yes. Suitable lubrication is important for maintaining the rolling and thrust contacts, especially under continuous operation or elevated loads.

Can NKX25Z replace two separate bearings?

In some designs, yes. However, the bearing capacity, available dimensions, shaft location and axial load direction must be checked before replacing a multi-bearing arrangement.

Is GCr15 stainless steel?

No. GCr15 is Chrome Steel bearing steel, not stainless steel. Applications exposed to significant corrosion may require a different material solution.

What should be checked when replacing an NKX25Z?

Check the bore, outside diameter, width, radial and axial load requirements, speed, housing arrangement, lubrication and thrust contact surfaces.

Is NKX25Z available for OEM orders?

Yes. OEM supply can be arranged according to the required material, dimensions, clearance, lubrication, inspection and packaging specifications.

The main reason to consider NKX25Z is its combined function.

Instead of treating radial and axial support as completely separate bearing tasks, the design brings the two functions together in one compact bearing arrangement. The needle roller section handles radial support, while the thrust section addresses axial loading.

With Chrome Steel GCr15 construction, NKX25Z provides a familiar material solution for industrial rolling applications.

For OEM designers and purchasing teams, the key is to evaluate the complete load path. If radial and axial forces occur at the same bearing location, a combined needle roller bearing can offer a cleaner solution than assembling several separate bearing components.

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